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Physical Basis of Mental Life: NBSE Class 12 Education
Get summaries, questions, answers, solutions, extra MCQs, PDF for Physical Basis of Mental Life: NBSE Class 12 Education, which is part of the syllabus for students studying under NBSE (Nagaland Board). These solutions, however, should only be treated as references and can be modified/changed.
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Summary
Our minds and bodies are closely linked. What happens to our body can affect our thoughts, and our thoughts can affect our body. This connection is managed by the nervous system, which acts like the body’s main communication network. It has two main divisions. The Central Nervous System, or CNS, is made up of the brain and the spinal cord. It is the body’s main control center. The Peripheral Nervous System, or PNS, consists of all the nerves that branch out from the CNS to the rest of the body, connecting it to the outside world.
The brain is the most complex part of the nervous system. It is protected by the skull and has several important regions. The cerebrum is the largest part and is responsible for thinking, memory, and voluntary actions. The cerebellum, located at the back, controls balance and coordinates our movements. The brain stem connects the brain to the spinal cord and manages vital automatic functions like breathing and heartbeat. The brain works by sending and receiving signals to control everything we do.
The nervous system is made of billions of special cells called neurons. A neuron receives signals through branches called dendrites and sends signals out through a long fiber called an axon. The small gap where a signal passes from one neuron to another is called a synapse. Sometimes the body needs to react very quickly without thinking, like when you touch something hot. This is a reflex. The signal for a reflex travels along a simple path called a reflex arc, from a sense organ to the spinal cord and then directly to a muscle.
We learn about the world through our senses. The process of our sense organs, like our eyes and ears, gathering basic information is called sensation. Sensation is like receiving raw data. For example, your eyes detect light and color, and your ears detect sound waves. After sensation comes perception, which is how our brain organizes and interprets this data to give it meaning. Perception turns the raw data of light and color into the image of a friend’s face.
Our past experiences and expectations can change how we perceive things. Sometimes, our brain can misinterpret information, which is called an illusion. For example, a rope in a dark room might be perceived as a snake. Beyond perception, we form concepts. A concept is a general idea that helps us group things together, like the concept of “dog” which includes all different breeds. Sensation, perception, and conception work together to help us understand and interact with our environment.
Textual
Very Short Answer Questions
1. Expand the terms CNS and PNS.
Answer: CNS stands for the central nervous system and PNS stands for the peripheral nervous system.
2. Name the specific subdivisions of the autonomic nervous system concerned with the following:
(a) Slowing down the heart beat
(b) Increasing salivary secretion
(c) Dilatation of the pupil
(d) Increasing intestinal peristalsis
(e) Muscle contraction of the urinary bladder giving of the feeling the need for urination.
Answer: The specific subdivisions of the autonomic nervous system are:
(a) The parasympathetic nervous system is concerned with slowing down the heart beat.
(b) The parasympathetic nervous system is concerned with increasing salivary secretion.
(c) The sympathetic nervous system is concerned with the dilatation of the pupil.
(d) The parasympathetic nervous system is concerned with increasing intestinal peristalsis.
(e) The parasympathetic nervous system is concerned with the muscle contraction of the urinary bladder, which gives the feeling of the need for urination.
3. Name the two divisions of the nervous system.
Answer: The two major divisions of the nervous system are the central nervous system (CNS) and the peripheral nervous system (PNS).
4. Name the chemical involved in the transmission of nerve impulse across a synapse.
Answer: The chemical involved in the transmission of nerve impulse across a synapse is acetylcholine.
5. State the functions of the following parts of the eye:
(a) Iris
(b) Ciliary muscles
(c) Pupil
(d) Vitreous humour
(e) Retina
Answer: The functions of the parts of the eye are:
(a) The iris is the colored part of the eye, responsible for controlling the size of the pupil and, therefore, regulating the amount of light entering the eye.
(b) These muscles are attached to the lens and change its shape, allowing the eye to focus on objects at different distances. When the ciliary muscles contract, the lens becomes thicker, decreasing its focal length for focusing on near objects. When the muscles relax, the lens becomes thinner, increasing its focal length for viewing distant objects.
(c) The pupil is the black opening in the center of the iris through which light enters the eye. Its size is controlled by the iris muscles to regulate the amount of light reaching the retina.
(d) The vitreous humour is involved in the transmission of light, as reflected light rays from an object enter the eyes through it.
(e) The retina is the innermost sensitive layer where an image is formed. It contains two kinds of sensory cells: the rods, which are sensitive to dim light, and the cones, which are sensitive to bright light and colours.
6. Name the following:
(a) Area of sharp vision in the eye
(b) The kind of lens used for correcting near-sightedness
(c) The condition in which the lens of the eye turns opaque
(d) The capacity of the eye to focus objects at different distances
Answer: The names are as follows:
(a) Area of sharp vision in the eye: The Fovea (also called Fovea Centralis).
(b) The kind of lens used for correcting near-sightedness: Concave lens.
(c) The condition in which the lens of the eye turns opaque: Cataract.
(d) The capacity of the eye to focus objects at different distances: Accommodation (or Power of Accommodation).
7. Name the following:
(a) The part into which the sound waves are directed by the ear pinna.
(b) The kind of balance with which the semi-circular canals are concerned.
(c) Any two sensations felt through free nerve endings in the skin.
Answer: The names are as follows:
(a) The ear pinna directs sound waves into the auditory canal.
(b) The semi-circular canals are concerned with the physical balance of the body.
(c) Two sensations felt through the skin are pain and heat.
Short Answer Questions
1. Give brief details of the nervous system.
Answer: The nervous system has three main functions: sensory input, integration of data, and motor output. Sensory input is when the body gathers information or data through neurons, glia, and synapses. The nervous system is composed of excitable nerve cells called neurons and synapses that connect them to centres throughout the body. It consists of about 100 billion neurons, which are its simplest parts, and the neuron is the structural unit of the nervous system. The nervous system is comprised of two major parts: the central nervous system (CNS) and the peripheral nervous system (PNS).
2. Give a brief classification of the nervous system.
Answer: The nervous system is comprised of two major parts or subdivisions: the central nervous system (CNS) and the peripheral nervous system (PNS).
The Central Nervous System (CNS) includes the brain and the spinal cord.
The Peripheral Nervous System (PNS) consists of all nerves arising from the brain and the spinal cord. It includes nerves and ganglion. The PNS consists of two kinds of pathways: the afferent (receiving) sensory pathways and the efferent (carrying away) motor pathways. The efferent pathway is subdivided into the somatic nervous system and the autonomic nervous system. The autonomic nervous system consists of two parts: the sympathetic nervous system and the parasympathetic nervous system.
3. Name the main parts of the brain.
Answer: The brain consists of three main regions:
- Forebrain consisting of cerebrum and diencephalon,
- Midbrain, a small tubular part between the fore and the hindbrain, and
- Hindbrain consists of cerebellum, pons, and medulla oblongata.
4. What are the two subdivisions of the autonomic nervous system?
Answer: The autonomic nervous system consists of two parts: (a) Sympathetic nervous system and (b) Parasympathetic nervous system.
5. What is gray matter?
Answer: The outer region of the cerebral hemispheres, called the cerebral cortex, contains cell bodies of the nerve cells and because it is grayish in colour it is called gray matter.
6. Mention the one function each of (a) Cerebrum (b) Cerebellum (c) Medulla oblongata (d) Hypothalamus
Answer:
(a) Cerebrum: It carries out mental activities of thinking, reasoning, planning, and memorising.
(b) Cerebellum: It helps to maintain the balance of the body.
(c) Medulla oblongata: It is the centre for breathing, coughing, and swallowing.
(d) Hypothalamus: It controls motivated behaviour such as eating, drinking, and sex.
7. Give two examples of sensory nerves.
Answer: Two examples of sensory nerves are the optic nerve, which is stimulated by photon waves, and the auditory nerve, which carries impulses from the ear to the brain.
8. Name the respective areas of the retina concerned with best vision and no vision.
Answer: The area of the retina concerned with the best vision is the yellow spot. The area concerned with no vision is the blind spot, as there are no sensory cells at this point.
9. State the alternative terms for sensory and motor nerves.
Answer: The alternative term for sensory nerves is afferent, and the alternative term for motor nerves is efferent.
10. What is the role of the eustachian tube in the ear?
Answer: The Eustachian tube connects the tympanic cavity with the pharynx. Its role is to equalise the pressure on both sides of the eardrum or tympanum.
11. List the functions of medulla oblongata.
Answer: The functions of the medulla oblongata are:
- It is the centre for breathing, coughing, swallowing, etc.
- It controls heartbeat, the movement of the alimentary canal, and many other involuntary actions.
Long Answer Questions
1. Name and explain the event that happens immediately when a nerve fibre gets stimulated.
Answer: When a neuron is stimulated, a nervous impulse of an electrical character is produced. This event is the immediate result of stimulation. A nerve impulse is an energy change within the neuron itself.
Stimulation is defined as a “change in the environment of nervous tissue which is sufficient to excite it.” This does not mean that energy is transmitted into the nerve cell from the outside. Instead, the energy change is contained within the neuron and is released by the dendrites. This impulse is then transmitted by way of the axon. The nature of this nervous impulse is partly electrical, partly chemical, and partly thermal. It is also called a nerve current because electrochemical waves are produced during nervous action.
2. Differentiate between sympathetic and parasympathetic nervous systems.
Answer: The sympathetic and parasympathetic nervous systems are the two subdivisions of the autonomic nervous system. The main difference between them is their function in the body. The sympathetic nervous system prepares the body for facing emergency situations. In contrast, the parasympathetic nervous system reestablishes the normal conditions once the emergency is over.
The opposite effects of these two systems on different organs are listed in the table below:
| Organ | Effect of Sympathetic Activity | Effect of Parasympathetic Activity |
| 1. Eye pupil | Dilated | Constricted |
| 2. Heart beat | Speeded up | Slowed down |
| 3. Blood vessels | ||
| a. on skin | Constricted | Dilated |
| b. on muscles | Dilated | No effect |
| 4. Bronchioles | Dilated | Constricted |
| 5. Urinary bladder | Muscles relaxed | Muscles contract (feeling of urination) |
| 6. Sweat secretion | Sphincter contracted | Sphincter relaxed |
| 7. Blood sugar | Increased | No effect |
| 8. Salivary secretion | Stops | Increased |
| 9. Tear glands | Activated | Slowed down |
| 10. Erector muscles of skin hair | Stimulated (hair raised) | Relaxed (hair flattened) |
| 11. Adrenal glands | Increased secretion of adrenalin | No effect |
| 12. Intestine | Peristalsis decreased | Peristalsis increased |
| 13. Stomach glands | Decreased secretion | Increased secretion |
3. Explain the following terms: (a) Synapse (b) Stimulus (c) Impulse
Answer:
(a) Synapse: A synapse is the form of connection between neurons, which is by contact only. It is not a physical object like a neuron but is the point of junction between the axon of one neuron and the dendron of the next neuron in the conduction path of a nerve impulse. The function of a synapse is to resist the nervous impulse as it is conducted from one neuron to another.
(b) Stimulus: A stimulus is a “change in the environment of nervous tissue which is sufficient to excite it.” For example, the eye reacts to light, and the skin to temperature changes.
(c) Impulse: A nervous impulse is an energy change of an electrical character that is produced when a neuron is stimulated. This impulse is contained within the neuron and is released by the dendrites and transmitted by the axon. The nature of the nervous impulse is partly electrical, partly chemical, and partly thermal, and it is also called a nerve current because electrochemical waves are produced in the process of nervous action.
4. Nervous system is the basis for mental life. Justify.
Answer: The nervous system is the basis for mental life because there is a close relation between the mind and the body.
This connection is evident in several ways. For instance, an injury to or disease of a part of the brain can produce a mental disorder or loss of consciousness. The influence of bodily conditions on mental processes is also a matter of common observation; for example, drinking strong coffee causes mental stimulation, and sleeping drugs have a sedative influence.
Conversely, mental processes can influence bodily conditions. Under hypnotic suggestion, a strong pinprick may not hurt at all. The advancement of behaviour in animals is connected with the development of their nervous system, and the evolution of the brain corresponds to the evolution of intelligence. Furthermore, emotional life is closely connected with parts of the nervous system like the thalamus, sympathetic, and parasympathetic systems.
5. Differentiate among perception, sensation and conception in cognitive development.
Answer: Sensation, perception, and conception are distinct but related processes that play an important role in cognitive development.
Sensation is the process by which our senses gather information from the environment and send it to the brain. It is the initial step that allows a child to gather information through seeing, hearing, tasting, and smelling. Sensation is a normal, initial mental process that begins with a stimulus and is based on external conditions.
Perception refers to the interpretation of what we take in through our senses. It is the way we make sense of the raw information provided by sensation. For example, perception allows a child to take in sensory information and convert it into a signal that the brain can understand and act upon. Perception is a complex and refined mental activity that is linked with actual life experience and is influenced by internal mental conditions and past experiences.
Conception involves making meaning out of all the incoming information from sensation and perception. Concepts are mental categories used to group objects, events, and information. Conception organises the interpreted information into these categories for better understanding and comprehension, reducing our experience of the world down to the fundamentals.
6. Draw a neat labelled diagram of neuron and mention its function.
Answer: A neuron is a nerve cell and the structural unit of the nervous system. Its function is to receive and transmit nerve impulses.
A neuron has two types of branches: a single axon and a number of dendrites. The function of the dendron (or dendrite) is to receive the nerve impulse and transmit it to the cell body. The function of the axon is to conduct the nerve impulse away from the cell body to a muscle or gland.
From a functional point of view, neurons can be of two kinds: sensory (or afferent) and motor (or efferent). Sensory neurons carry impulses from a sense organ to the central nervous system, while motor neurons carry impulses from the central nervous system to muscles or glands. There are also connective neurons, which connect the afferent and efferent neurons.
Additional
Extra Questions and Answers
1. What is the theory of psychophysical parallelism?
Answer: The theory of psychophysical parallelism states that mind and body, being two entirely different entities in nature, move in parallel lines. Parallelism in its extreme form asserts a strict point-to-point correspondence between mental processes and a certain group of physical processes, but denies interaction between the two series.
2. Who gave the theory of parallelism?
Answer: The philosopher, Spinoza gave the theory of parallelism.
3. What is the theory of interactionism?
Answer: The theory of interactionism couples the assertion of causal interaction with the denial of parallelism. It is contended by interactionists that either a certain mental occurrence has no bodily correlative or that certain characteristic features in conscious life have no parallel in the bodily process.
4. What does the central nervous system (CNS) include?
Answer: The central nervous system (CNS) includes the brain and the spinal cord.
5. What does the peripheral nervous system (PNS) include?
Answer: The peripheral nervous system (PNS) consists of all nerves arising from the brain and the spinal cord, and also includes the nerves and ganglion.
6. Name the three coverings of the brain.
Answer: The three coverings of the brain, called the meninges, are:
- An outer tough duramater.
- A thin delicate web-like middle arachnoid.
- The innermost highly vascular pia mater.
7. What is cerebrospinal fluid?
Answer: The space between the membranes covering the brain is filled with a fluid called cerebrospinal fluid.
8. Name the three main regions of the brain.
Answer: The brain consists of three main regions:
- Forebrain, consisting of cerebrum and diencephalon.
- Midbrain, a small tubular part between the fore and the hindbrain.
- Hindbrain, which consists of cerebellum, pons, and medulla oblongata.
9. What is the largest part of the brain?
Answer: The cerebrum is the largest part of the brain.
10. What is the function of the corpus callosum?
Answer: The corpus callosum is a sheet of criss-cross nerve fibres that connects the two cerebral hemispheres.
11. What are the two parts of the diencephalon?
Answer: The diencephalon is part of the forebrain and consists of two parts: the thalamus and the hypothalamus.
12. What is the main function of the cerebellum?
Answer: The two main functions of the cerebellum are to maintain the balance of the body and to coordinate muscular activities.
13. What are the main functions of the medulla oblongata?
Answer: The medulla oblongata is the centre for breathing, coughing, and swallowing. It also controls the heartbeat, the movement of the alimentary canal, and many other involuntary actions.
14. What are the three main functions of the spinal cord?
Answer: The functions of the spinal cord are:
- It carries out reflexes below the neck.
- It conducts sensory impulses from the skin and muscles to the brain.
- It conducts motor responses from the brain to the trunk and limbs.
15. What is a neuron?
Answer: A neuron is the structural unit of the nervous system. It is a nerve cell that has two types of branches: one single axon and a number of dendrites.
16. What is the function of a dendrite?
Answer: The function of the dendrite, or dendron, is to receive the nerve impulse and transmit it to the cell.
17. What is the function of an axon?
Answer: The function of the axon is to conduct the nerve impulse to the muscle or gland.
18. Name the two kinds of neurons from a functional viewpoint.
Answer: From the point of view of function, neurons are of two kinds: sensory or afferent, and motor or efferent.
19. What is a stimulus?
Answer: A stimulus is a “change in the environment of nervous tissue which is sufficient to excite it”.
20. What is the law of excitability or irritability of nerves?
Answer: The law of excitability or irritability is a fundamental character of nerves. It states that each neuron is excited by its adequate stimulus. For example, photon waves stimulate the optic nerve.
21. What is the all-or-none law of nervous impulse?
Answer: The all-or-none law states that a neuron is either excited or not. If it is excited, it works with all its energy; if not, it does not respond at all.
22. What is a synapse?
Answer: A synapse is the form of connection by contact only between neurons. It is the point of junction between the axon of one neuron and the dendron of the next neuron in the conduction path of a nerve impulse.
23. What is a reflex action?
Answer: A reflex action is an unlearned, unconscious, immediate, and uniform response to a stimulus exciting the peripheral extremity of a sense organ.
24. Name the five elements in a reflex arc.
Answer: The five elements in a reflex arc are:
- Receptive nerve-endings, which are situated at the periphery of a sense organ.
- The afferent or sensory nerve, which carries the impulse to the nerve centre in the spinal cord or the brain.
- The central nervous system, which consists of the spinal cord and the brain.
- The efferent or motor nerve, which carries the motor nerve impulse to a muscle or a gland.
- The effectors organ, consisting of muscles or glands, which produces movement or secretion.
25. What are the two kinds of pathways in the peripheral nervous system?
Answer: The peripheral nervous system consists of two kinds of pathways: the afferent (receiving) sensory pathways and the efferent (carrying away) motor pathways.
26. What is the function of the somatic nervous system?
Answer: The somatic nervous system controls the voluntary muscles. It includes most cranial nerves and the motor nerve fibres of the spinal nerves, which convey messages from the CNS to the voluntary muscles.
27. What is the function of the autonomic nervous system?
Answer: The autonomic nervous system (ANS) innervates the involuntary muscles and the glands. It is a motor system that regulates the involuntary actions of the internal organs.
28. Name the two parts of the autonomic nervous system.
Answer: The autonomic nervous system consists of two parts: the sympathetic nervous system and the parasympathetic nervous system.
29. Name the three layers of the eyeball wall.
Answer: The wall of the eyeball is made up of three layers: the sclera, choroid, and retina.
30. What are rods and cones?
Answer: Rods and cones are two kinds of sensory cells contained in the retina. Rods are sensitive to dim light, and cones are sensitive to bright light and colours.
31. What is the blind spot in the eye?
Answer: The blind spot is the point where the nerve fibres (axons) from all the sensitive cells of the retina converge to form the optic nerve. There are no sensory cells at the blind spot, and any image formed there is not perceived.
32. What is accommodation in vision?
Answer: Accommodation, or focussing, is the process of focussing an image on the retina. Changing the curvature of the elastic lens brings about accommodation.
33. What are the two sensory functions of the ear?
Answer: The ear serves two sensory functions: hearing and maintaining the balance of the body.
34. Name the two main parts of the internal ear.
Answer: The internal ear contains two main parts: the cochlea and the vestibule.
35. What is the function of the cochlea?
Answer: The cochlea is a long, coiled structure responsible for hearing. Sound vibrations move the fluid inside the cochlea, and the organ of Corti catches this movement and transfers it to the auditory nerve, which carries the impulses to the brain.
36. What is the function of the vestibule?
Answer: The vestibule is concerned with the physical balance of the body.
37. What type of receptors are olfactory cells?
Answer: The olfactory cells are chemoreceptors, which means they have protein receptors that can detect subtle differences in chemicals.
38. Name the four different types of tastes.
Answer: The four different types of tastes are sweet, sour, bitter, and salty.
39. What are proprioceptors?
Answer: Proprioceptors are receptors contained in joints, ligaments, and tendons that detect the position and movement of the limbs.
40. Define sensation.
Answer: Any experience that takes place through sense organs is called sensation. Sensation is also called the gateway of knowledge because all our knowledge is based upon the functioning of sense organs. It is an elementary cognitive experience.
41. Name the five categories of the sensation process.
Answer: The five categories of the sensation process are:
- Visual sensation
- Auditory sensation
- Olfactory sensation
- Tactual sensation
- Taste sensation
42. List the main elements of the sensation process.
Answer: The main elements of the sensation process are:
- Quality
- Intensity
- Extensity
- Duration
- Clarity
43. What is spontaneous conception?
Answer: In psychology, spontaneous conception refers to conceptions about the world that we form without any formal education. These are often connected with physics and may be wrong, such as the idea that “heavier objects fall faster.”
44. Explain the theory of psychophysical parallelism. How does it differ from interactionism?
Answer: The philosopher Spinoza gave the theory of parallelism. According to this theory, mind and body, both being expressions of God, the ultimate reality, would move in parallel lines. Parallelism in its extreme form asserts a strict point-to-point correspondence between mental processes and a certain group of physical processes, but it denies interaction between the two series.
The doctrine of interactionism, on the other hand, couples the assertion of causal interaction with the denial of parallelism. Interactionists contend that either a certain mental occurrence has no bodily correlative or that certain characteristic features in conscious life have no parallel in the bodily process.
45. Why is the final relation between mind and body considered a metaphysical problem?
Answer: The solution of the final relation between mind and body is beyond the scope of psychology and becomes a metaphysical problem. This is because it is difficult to understand how mind and body, being two entirely different entities in nature, could act and interact upon one another.
46. What are the main functions of the nervous system?
Answer: The nervous system has three main functions: sensory input, integration of data, and motor output.
Sensory input is when the body gathers information or data by way of neurons, glia, and synapses.
Integration of data is when the data is processed, which occurs only in the brain.
Motor output occurs after the brain has processed the information, when impulses are conducted from the brain and spinal cord to the muscles and glands.
47. Describe the three coverings, or meninges, that protect the brain.
Answer: The brain is protected by three coverings called the meninges. These are:
- An outer tough duramater.
- A thin delicate web-like middle arachnoid.
- The innermost highly vascular pia mater, which is richly supplied with blood vessels.
48. What is the difference between gray matter and white matter in the cerebrum?
Answer: In the cerebrum, the outer region, or cerebral cortex, contains the cell bodies of the nerve cells. Because it is grayish in colour, it is called gray matter. The inner region is composed of whitish axon fibres and is called the white matter.
49. What are the functions of the thalamus and hypothalamus?
Answer: The thalamus is an egg-shaped mass of gray matter located in the centre below the cerebrum. It is the relay centre for sensory impulses, such as pain and pleasure, going to the cerebrum.
The hypothalamus is a region of the brain located below the thalamus. It controls motivated behaviour such as eating, drinking, and sex. It also controls the secretions of the pituitary gland, and serves as the regulation centre for body temperature and body fluids.
50. Describe the structure of a neuron with its main parts.
Answer: A neuron is a nerve cell that has two types of branches: one single axon and a number of dendrites. The dendrites are short, tree-like branches, while the axon is smooth, slender, and can be over a meter long. The function of the dendron is to receive the nerve impulse and transmit it to the cell, while the axon conducts the nerve impulse to the muscle or gland.
The cell body consists of four parts: the cell wall or tough outer coat; the central liquid part called protoplasm; the nucleus; and smaller particles floating on the nucleus called the nucleoli.
51. Explain the law of forward conduction for a nervous impulse.
Answer: The law of forward conduction states that the course of a nervous impulse is from the axon to the dendron of a neuron, or from a sense organ to a centre of the nervous system, and from that centre to a muscle or gland. The impulse is not conducted in the opposite direction, such as from a muscle or gland to the centre, or from the centre to a sense organ, or from a dendron to an axon.
52. What is a reflex arc? List its five essential elements.
Answer: A reflex action is an unlearned, unconscious, immediate, and uniform response to a stimulus. The total chain of this action constitutes the reflex arc. The nervous path that a reflex travels is called the Reflex Arc.
There are five elements in the reflex arc:
- Receptive nerve-endings, which are situated at the periphery of a sense organ.
- The afferent or sensory nerve which carries the impulse to the nerve centre in the spinal cord or the brain.
- The central nervous system which consists of the spinal cord and the brain.
- The efferent or motor nerve which carries the motor nerve impulse to a muscle or a gland.
- The effectors organ consisting of muscles or glands, which produces movement or secretion.
53. Differentiate between the somatic and autonomic nervous systems.
Answer: The somatic nervous system controls the voluntary muscles, including most cranial nerves and the motor nerve fibres of the spinal nerves. It has voluntary control of skin, bones, joints, and skeletal muscle.
The autonomic nervous system (ANS) innervates the involuntary muscles and glands. It has involuntary control of internal organs, blood vessels, and smooth and cardiac muscles.
54. What is the role of the sympathetic nervous system? What is the role of the parasympathetic nervous system?
Answer: The sympathetic nervous system prepares the body for facing emergency situations. The parasympathetic nervous system reestablishes the normal conditions once the emergency is over.
55. How do we see? Briefly explain the process from light entry to perception.
Answer: The process of seeing involves several steps:
- Transmission of light: Reflected light rays from an object enter the eyes through the vitreous humour.
- Formation of image: The curvature of the cornea and the lens bend the light rays to form an image on the retina. The image formed is inverted and real.
- Production of nerve impulse: The light energy of the image produces chemical changes in the sensory cells (rods and cones) of the retina. These changes produce nerve impulses.
- Transmission: The nerve impulses travel through the optic nerve and reach the brain.
- Perception: The brain interprets the image. For example, it sees the object vertically even though the actual image formed is inverted.
56. Describe the structure of the middle ear and its role in hearing.
Answer: The middle ear consists of an air-filled tympanic cavity, the tympanum or ear drum, and three tiny bones: the malleus (hammer), incus (anvil), and stapes (stirrup). The malleus is connected to the ear drum, and the stapes forms a contact with the oval window of the internal ear. The Eustachian tube connects the tympanic cavity with the pharynx to equalise pressure.
In hearing, sound waves cause the eardrum to vibrate. The vibrations are transferred from the eardrum to the malleus, then to the incus, and finally to the stapes. The stapes transfers these vibrations through the oval window into the cochlea of the internal ear.
57. How do the senses of smell and taste work together?
Answer: The senses of smell and taste work closely together. If you cannot smell something, you cannot taste it, either. Taste buds on the tongue contain chemoreceptors that work in a similar fashion to the chemoreceptors in the nasal cavity.
58. What are the main functions of the skin?
Answer: The functions of the skin are as follows:
- Perspiration (sweating) to cool the body
- Protection from the elements
- The sense of touch is spread through the whole body, with nerve endings sending information to the brain.
- Our skin is the largest organ in our body and contains the most nerve endings.
59. What are the key properties of sensation? Explain with examples.
Answer: Sensations have several key properties, including quality, intensity, and duration.
- Quality: This is the feature that distinguishes sensations from each other. For example, the sensations of sound are of a different quality from those of smell, and the feeling of blue is a different quality from that of red.
- Intensity: This refers to the vividness or strength of a sensation in consciousness. For example, if two sounds are created at once, one may be more intense than the other.
- Duration: This is the length of time a sensation persists. For example, the auditory sensation of an aeroplane sound is more extensive than the sound of a calling bell.
60. How is perception defined? What two processes does it involve?
Answer: The process of interpretation of a stimulus is known as perception. It can be defined as “a process of interpretation of a present stimulus on the basis of past experience.” Perception involves two processes: sensation and interpretation.
61. Differentiate between an illusion and a hallucination.
Answer: An illusion is a false perception where a person mistakes a stimulus and perceives it wrongly. For example, in the dark, a rope might be mistaken for a snake. A stimulus is present but misinterpreted.
A hallucination occurs when an individual perceives a stimulus even when it is not present. For example, a person may see an object or hear a voice when there are no objects or sounds in reality.
62. Explain the role of perceptual learning and mental set in affecting perception.
Answer: Perceptual learning and mental set are factors that affect perception.
- Perceptual learning: Based on past experiences or special training, we learn to attend to some sensory inputs and ignore others. For example, a person trained in artistry can perform better than an untrained person because experience is the best teacher for such perceptual skills.
- Mental set: This refers to a preparedness or readiness to receive a sensory input. This expectancy keeps an individual prepared with good attention and concentration. For example, when we are expecting a train, we listen for its horn even amid a lot of noise.
63. How do motives, needs, and cognitive styles influence our perception?
Answer: Our motives, needs, and cognitive styles influence our perception.
- Motives and Needs: Our motives and needs will definitely influence our perception. For example, a hungry person is motivated to recognise only food items among other articles, and his attention cannot be directed elsewhere until this motive is satisfied.
- Cognitive styles: People differ in the ways they process information, and each individual has their own way of understanding a situation. People who are flexible are said to have good attention and are less affected by interfering influences and internal needs than people at the constricted end.
64. Explain the role of sensation, perception, and conception in cognitive development.
Answer: Sensation, perception, and conception play an important role in cognitive development.
- Sensation is the process by which our senses gather information from the environment through touch, taste, sight, sound, and smell. This allows a child to gather information, which is sent to the brain in raw form.
- Perception is the way we interpret these sensations to make sense of everything around us. The perceptual process allows a child to take in sensory information and convert it into a signal the brain can understand and act upon.
- Conception involves making meaning out of this incoming information by organising it into categories for better understanding and comprehension. It reduces our experience of the world down to the fundamentals.
65. What are concepts? Why are they vital to an individual?
Answer: Concepts are mental categories used to group objects, events, and information. In short, a concept is a generalisation that helps to organise information into categories.
Concepts are vital to an individual because they provide the basis for most of our symbolic behaviour. Our language is a configuration of symbols that we learn to associate with different social concepts. Concepts also allow for economy in reasoning and problem-solving.
66. Describe the development of the number and time concept in children.
Answer: In the development of the number concept, there are three distinct stages. At the first stage, a child can discriminate numbers. At the second stage, the child can match numbers. At the third stage, the child can match groups of different numbers.
For the time concept, it was found that younger children used words indicating the present, while slightly older children used words indicating the future. Children had to be still older to use words denoting the past. The correct time concept was evidenced at the age of twelve; before that, children showed confusion between the present, future, and past.
67. Discuss the different theories regarding the relation between mind and body as mentioned in the introduction.
Answer: There are different theories regarding the relation between mind and body. One is the theory of psychophysical parallelism, and another is the theory of interactionism. The solution of the final relation between mind and body is a metaphysical problem, as it is difficult to understand how mind and body, being two entirely different entities, could act and interact upon one another.
The philosopher Spinoza gave the theory of parallelism, where mind and body, both being expressions of God, move in parallel lines. Parallelism in its extreme form asserts a strict point-to-point correspondence between mental processes and a certain group of physical processes, but it denies interaction between the two. The doctrine of interaction couples the assertion of causal interaction with the denial of parallelism.
However, neither parallelism nor interaction provides a satisfactory account of the relations between physical and psychical facts. While there is a certain parallelism between physical and mental change, the doctrine of strict point-to-point correspondence is not supported by empirical evidence and leaves the connection of body and mind mysterious. On the other hand, the doctrine of interaction has its own difficulties. If interaction occurs, it is of an entirely different kind from the interaction of physical things, and the connection is as mysterious as it is in the alternative theory.
68. Describe the structure of the human brain, including its main regions and their components.
Answer: The brain is a very delicate organ lodged inside the cranium of the skull. It is protected by three coverings called the meninges. These are an outer tough duramater, a thin delicate web-like middle arachnoid, and the innermost highly vascular pia mater, which is richly supplied with blood vessels. The space between these membranes is filled with a fluid called cerebrospinal fluid. There are also cavities inside the brain that are filled with the same fluid.
The brain consists of three main regions:
- Forebrain, which consists of the cerebrum and diencephalon.
- Midbrain, which is a small tubular part between the forebrain and the hindbrain.
- Hindbrain, which consists of the cerebellum, pons, and medulla oblongata.
69. Explain the key functions of the forebrain, including the cerebrum and diencephalon.
Answer: The forebrain consists of the cerebrum and the diencephalon, which have several key functions. The cerebrum is the largest part of the brain, and its outer region, the cerebral cortex, has three main functions:
- It controls and initiates voluntary muscle contractions.
- It receives and processes information from the sense organs, like eyes, ears, and nose.
- It carries out mental activities of thinking, reasoning, planning, and memorising.
The diencephalon is part of the forebrain that lies below the cerebrum and consists of two parts: the thalamus and the hypothalamus.
- The thalamus is an egg-shaped mass of gray matter that acts as the relay centre for sensory impulses, such as pain and pleasure, going to the cerebrum.
- The hypothalamus is a region below the thalamus that controls motivated behaviour like eating, drinking, and sex. It also controls the secretions of the pituitary gland and serves as the regulation centre for body temperature and body fluids.
70. Explain the different laws that govern the transmission of nervous impulses.
Answer: Nervous impulses are governed by a number of laws, which include:
- Excitability or irritability: This is a fundamental character of nerves. Each neuron is excited by its adequate stimulus, for example, photon waves stimulate the optic nerve.
- Law of conductivity: After excitation, the neuron conducts the nerve impulse to the cell-body or to the central nervous system.
- Refractory period: In conducting the nerve impulse, the neuron gets fatigued so that no further stimulus may excite it.
- Law of forward conduction: The course of a nervous impulse is from the axon to the dendron of a neuron, or from a sense organ to a centre of the nervous system, and from that centre to a muscle or gland. It is not conducted in the opposite direction.
- Law of summation: If two or more nerve impulses produce the same reaction simultaneously, they combine to make the reaction stronger.
- Law of inhibition: If two or more nerve impulses move simultaneously towards the opposite direction, one inhibits the other.
- All and none law: A neuron is either excited or not. If it is excited, it works with all its energy; if not, it does not respond at all.
71. Describe the structure and function of a synapse. What is the role of a reflex arc?
Answer: A synapse is the form of connection between neurons, which remain separate cells. It is not a physical object like a neuron but is the point of junction between the axon of one neuron and the dendron of the next neuron in the conduction path of a nerve impulse. The function of a synapse is to resist the nervous impulse as it is conducted from one neuron to another. The degree of this resistance depends on the frequency of the movement of the nerve impulse. All habit and learning are difficult at the beginning because of this synaptic resistance, but repeated practice reduces the resistance.
A reflex action is an unlearned, unconscious, immediate, and uniform response to a stimulus. The total chain of this action constitutes the reflex arc. The nervous path traversed by the reflex is called the Reflex Arc. This neural link includes at least two neurons: the afferent neuron, which conducts the impulse from the receptor, and the efferent neuron, which conducts it outward to the effectors. Reflex arcs are the simplest functional units of the nervous system.
72. Describe the structure and subdivisions of the Peripheral Nervous System.
Answer: The Peripheral Nervous System (PNS) is a vast network of all spinal and cranial nerves that arise from the brain and the spinal cord. It consists of two kinds of pathways: the afferent (receiving) sensory pathways and the efferent (carrying away) motor pathways. The afferent pathways include purely sensory nerves and mixed cranial nerves that send information to the Central Nervous System (CNS).
The efferent (sending) pathway is subdivided into the somatic and autonomic nervous systems.
- The somatic nervous system controls the voluntary muscles, including most cranial nerves and motor nerve fibres of the spinal nerves. It has voluntary control of skin, bones, joints, and skeletal muscle.
- The autonomic nervous system (ANS) innervates the involuntary muscles and glands. It has involuntary control of internal organs, blood vessels, and smooth and cardiac muscles. The ANS consists of two parts: the Sympathetic nervous system and the Parasympathetic nervous system.
73. Describe the structure of the human eye and explain the mechanism of vision.
Answer: The eye is a nearly spherical organ that rotates freely in the bony socket. The wall of the eyeball is made up of three layers: the sclera, choroid, and retina. The sclera is the outermost tough white layer, which continues in the front as the transparent cornea. The choroid is the middle layer, which is dark to prevent reflection. The retina is the innermost sensitive layer containing two kinds of sensory cells: rods, which are sensitive to dim light, and cones, which are sensitive to bright light and colours. Other parts include the iris, pupil, lens, and vitreous humour. The blind spot is where the optic nerve forms, and the yellow spot is the place of best vision.
The mechanism of vision, or how we see, involves several steps:
- Transmission of light: Reflected light rays from an object enter the eyes.
- Formation of image: The cornea and lens bend the light rays to form an inverted and real image on the retina.
- Production of nerve impulse: The light energy of the image produces chemical changes in the rods and cones, which in turn produce nerve impulses. These impulses travel through the optic nerve to the brain.
- Perception: The brain interprets the image, for example, seeing the object vertically even though the image on the retina is inverted.
- Accommodation: The process of focusing the image on the retina by changing the curvature of the elastic lens is called accommodation.
74. Describe the structure of the human ear and explain the mechanism of hearing.
Answer: The ear has three main parts: the external ear, middle ear, and internal ear. The external ear consists of the pinna, which directs sound waves inwards, and the auditory canal. The middle ear consists of an air-filled tympanic cavity, the eardrum (tympanum), and three tiny bones: the malleus (hammer), incus (anvil), and stapes (stirrup). The Eustachian tube connects the middle ear to the pharynx to equalise pressure. The internal ear contains the cochlea for hearing and the vestibule for balance. The cochlea is a long, coiled structure filled with fluid and contains sensory cells called the organ of Corti.
The mechanism of hearing occurs as follows:
- Sound waves enter the auditory canal and cause the eardrum to vibrate.
- The vibrations are transferred from the eardrum to the malleus, then to the incus, and finally to the stapes.
- The stapes transfers the vibrations through the oval window into the cochlea.
- These vibrations move the fluid in the cochlea. The organ of Corti catches this movement and transfers it to the auditory nerve, which carries the impulses to the brain.
75. What are the main factors that affect perception? Explain each one briefly.
Answer: The main factors that affect the perception of people are:
- Perceptual learning: Based on past experiences or special training, we learn to attend to some sensory inputs and ignore others. Experience is the best teacher for such perceptual skills. For example, blind people can identify others by their voice or footsteps.
- Mental set: This refers to a preparedness or readiness to receive some sensory input. This expectancy keeps an individual prepared with good attention and concentration. For instance, when expecting a train, we listen for its horn even amidst a lot of noise.
- Motives and Needs: Our motives and needs influence our perception. A hungry person, for example, is motivated to recognise only food items among other articles, and his attention is not directed elsewhere until this motive is satisfied.
- Cognitive styles: People differ in the ways they characteristically process information. Every individual has his or her own way of understanding a situation. People who are flexible tend to have good attention and are less affected by interfering influences.
76. Differentiate between sensation and perception based on the key points provided in the table.
Answer:
| Sensation | Perception |
| Sensation is a normal, initial mental process. | Perception is a complex and refined mental activity. |
| It begins with stimulus. | It begins with some object/fringe of meaning. |
| It is based on external stimuli, conditions. | It is associated with internal mental conditions. |
| There is passivity in sensation. | There is activity in perception. |
| The basis of sensation is mental analysis. | The processes of perception linked with actual life experience. |
77. Discuss the development of concepts in children, focusing on form and colour.
Answer: Regarding the concept of form, children exhibit definite symbolic behaviour in solving problems. Through cues and verbal behaviour, they can formulate the nature of a problem. An experiment by Crudden found that primary school children could abstract known geometrical figures from an unfamiliar background if it was not too complicated. Girls proved to be superior to boys, which was attributed to their superiority in abstract thinking and earlier growth of verbal concepts.
The concept of colour comes next in the sequence of concept development, developing so close to the concept of form that it is difficult to say which comes first. Colour discrimination comes earlier than naming, which indicates that verbal symbols are learned after the colour concept has developed. A study by Smith showed a steady increase in the discrimination of colour saturation, hue, and lightness with age, continuing until 20 to 30 years of age. After this, there was a decline in discrimination, which can be attributed to a general decline in abilities indicative of age.
78. Explain the development of space, distance, and position concepts in an individual.
Answer: The development of the concepts of space, distance, and position is an important development that an individual goes through. It involves space orientation, understanding the relative position of objects, and the distance of objects. Our adjustment to our surroundings and everyday environment depends on the normal development of the space concept.
Within the space concept is the position concept, where a judgment has to be made about the position of objects. Children gain a functional concept of position before they know the full development of this function. They verbalise the position and reach their conclusions about it based on these verbalisations.
79. Provide a detailed account of the Central Nervous System.
Answer: The central nervous system (CNS) is one of the two major parts of the nervous system and includes the brain and the spinal cord. The brain is the body’s “control centre,” and the CNS has various centres located within it that carry out sensory, motor, and integration of data. These centres can be subdivided into Lower Centres (including the spinal cord and brain stem) and Higher Centres communicating with the brain via the effectors.
The Brain is a very delicate organ lodged inside the cranium of the skull. It is protected by three coverings, the meninges: an outer tough duramater, a thin delicate web-like middle arachnoid, and the innermost highly vascular pia mater. The space between the membranes is filled with a fluid called cerebrospinal fluid, as are the cavities inside the brain. The brain consists of three main regions:
- Forebrain consisting of cerebrum and diencephalon,
- Midbrain, a small tubular part between the fore and the hindbrain, and
- Hindbrain consists of cerebellum, pons, and medulla oblongata.
The individual parts of the brain are:
- Cerebrum: This is the largest part of the brain, divided into two parts called cerebral hemispheres. Their outer surface is highly convoluted with ridges and grooves. The outer region (cerebral cortex) contains cell bodies of the nerve cells and is called gray matter. The inner region is composed of whitish axon fibres and is called the white matter. A sheet of criss-cross nerve fibres called the Corpus callosum connects the two cerebral hemispheres. The left side of the cerebrum controls the right side of the body and vice-versa. The cerebral cortex has three main functions: it controls and initiates voluntary muscle contractions; it receives and processes information from the sense organs; and it carries out mental activities of thinking, reasoning, planning, and memorising.
- Diencephalon: This is the part of the forebrain lying below the cerebrum. It consists of two parts:
- Thalamus: This is an egg-shaped mass of gray matter, located in the centre below the cerebrum. It is the relay centre for sensory impulses like pain and pleasure going to the cerebrum.
- Hypothalamus: This is a region of the brain located below the thalamus. It controls motivated behaviour such as eating, drinking, and sex. It also controls the secretions of the pituitary gland and serves as the regulation centre of body temperature and body fluids.
- Cerebellum: The cerebellum is a smaller region of the brain located at the base and under the cerebrum. It has numerous furrows and a cortex of gray matter. Its two main functions are to maintain the balance of the body and coordinate muscular activities.
- Medulla oblongata: This is the last part of the brain, which is connected to the spinal cord. It is the centre for breathing, coughing, and swallowing. It also controls heartbeat, the movement of the alimentary canal, and many other involuntary actions.
80. “The neuron is the structural unit and the reflex is the functional unit of the nervous system.” Justify this statement with detailed explanations of both.
Answer: The statement is justified as reflexes, or sensorimotor arcs, are the simplest functional units of the nervous system, just as the neuron is the simplest structural unit of the nervous system.
The neuron is the structural unit of the nervous system. The nervous system consists of about 100 billion neurons, which are its simplest parts. A neuron is a nerve cell with two types of branches—one single axon and a number of dendrites. The dendrites are short, tree-like branches, while the axon is smooth and slender and may be over a meter long. The function of the dendron is to receive the nerve impulse and transmit it to the cell, while that of the axon is to conduct the nerve impulse to the muscle or gland. The cell body consists of the cell wall, protoplasm, the nucleus, and smaller particles floating on the nucleus called the nucleoli. From the point of view of function, neurons can be sensory (afferent), motor (efferent), or connective.
A reflex action is an unlearned, unconscious, immediate, and uniform response to a stimulus exciting the peripheral extremity of a sense organ. The total chain of this action constitutes the reflex arc. The neural link in this circuit includes at least two neurons: the afferent neuron, which conducts the impulse from the receptor, and the efferent neuron, which conducts it outward to the effectors. The two are united by a synaptic point of junction. The nervous path so traversed by the reflex is called the Reflex Arc. There are five elements in the reflex arc:
- Receptive nerve-endings, which are situated at the periphery of a sense organ,
- The afferent or sensory nerve which carries the impulse to the nerve centre in the spinal cord or the brain,
- The central nervous system which consists of the spinal cord and the brain,
- The efferent or motor nerve which carries the motor nerve impulse to a muscle or a gland,
- The effectors organ consisting of muscles or glands, which produces movement or secretion.
81. Compare and contrast the effects of the sympathetic and parasympathetic nervous systems on at least five different organs.
Answer: The sympathetic nervous system prepares the body for facing emergency situations, and the parasympathetic nervous system reestablishes the normal conditions once the emergency is over. The opposite effects of these two subdivisions of the autonomic nervous system on different organs are as follows:
| Organ | Effect of Sympathetic Activity | Effect of Parasympathetic Activity |
| 1. Eye pupil | Dilated | Constricted |
| 2. Heart beat | Speeded up | Slowed down |
| 3. Bronchioles | Dilated | Constricted |
| 4. Urinary bladder | Muscles relaxed | Muscles contract (feeling of urination) |
| 5. Salivary secretion | Stops | Increased |
82. Explain the role of chemoreceptors in the human body.
Answer: Chemoreceptors in the human body are responsible for the senses of smell and taste by detecting chemicals in the environment.
The sense of smell works through olfactory cells, which are chemoreceptors. This means the olfactory cells have protein receptors that can detect subtle differences in chemicals. As one breathes, chemicals in the air enter the nasal cavity. One does not “smell” air or dust, but can smell chemicals. These chemicals bind to the cilia on olfactory cells located at the top of the nasal cavity. This generates a nerve impulse that is carried through the olfactory cell, into the olfactory nerve fibre, up to the olfactory bulb, and to the brain, which then determines what is smelled.
The sense of taste works in a similar way, and the senses of smell and taste work closely together. Taste buds on the tongue contain chemoreceptors. There are different types of taste buds, and each detects different types of tastes: sweet, sour, bitter, and salty. When food is put into the mouth, the taste buds detect the chemicals ingested. Each taste bud has a pore with microvilli sticking out and sensory nerve fibers attached to the other end. Chemicals from food bind to the microvilli, generating a nerve impulse that is carried through the sensory nerve fibres and eventually to the brain.
83. Explain the process of sensation, detailing its types, elements, and properties.
Answer: Any experience that takes place through sense organs is called sensation. Sensation is also called the gateway of knowledge because all our knowledge is based upon the functioning of sense organs. It is simple, elementary, and purely sensory knowledge, which does not have any relationship with any knowledge or awareness.
Types of Sensation: The sensation process can be divided into five categories based on the sense organs. The types of sensation, their corresponding sense organs, and the amount of knowledge gained through them are:
| S.No. | Type of Sensation | Sense Organ | Sense | Knowledge gaining |
| 1. | Visual sensation | Eye | Sight | 83% |
| 2. | Auditory sensation | Ear | Hear | 11% |
| 3. | Olfactory sensation | Nose | Smell | 3.5% |
| 4. | Tactual sensation | Skin | Touch | 1.5% |
| 5. | Taste sensation | Tongue | Taste | 1.0% |
The main elements and properties of the sensation process are:
- Quality: The nature of each sensation is different from another. This quality helps us to distinguish one from the other, for example, the green sensation of the eye and the cold sensation of the skin. The sensations of sound are of a generically different quality from those of smell.
- Intensity: Sensation differs in respect of its intensity, or its vividness and strength in consciousness. If two sounds are created at once, one will be more intense than the other. The degree of intensity depends partly on the force of the objective stimulus and partly on the vigour of attention.
- Duration: Every sensation has its duration or lasts for a certain time. The auditory sensation of an aeroplane sound is more extensive than the sound of a calling bell. The duration of a sensation is the length of time during which it persists in existence, determined mainly by the continuance of the stimulus.
- Extensity: This refers to the extension in space. Each sensation has its own extensity. The vaster the stimulus, the more extensive the sensation. This is not true for all types of sensation but is restricted to certain ones.
- Clarity: Every sensation has got clarity. The sensation which lasts for a longer period becomes clearer than the sensation that lasts for a shorter period.
84. Discuss the various errors that can occur in perception.
Answer: Perception is the process of analysing and understanding a stimulus as it is, but it may not always be possible to perceive stimuli as they are. Knowingly or unknowingly, we can mistake the stimulus and perceive it wrongly. This may be due to a defect in our sense organs, defective functioning of the brain, or factors like individual prejudices. There are two main kinds of errors in perception, along with other abnormalities.
- Illusion: An illusion is a false perception. In this case, the person will mistake a stimulus and perceive it wrongly. For example, in the dark, a rope is mistaken as a snake or vice versa. The voice of an unknown person may be mistaken as a friend’s voice. Most of our illusions are visual and auditory, but illusions pertaining to other senses are also possible.
- Hallucination: A hallucination occurs when an individual perceives some stimulus even when it is not present. The person may see an object or person, or may listen to some voice, though there are no objects and sounds in reality. Visual and auditory hallucinations are more common. Usually, persons with an unsound mind, who are emotionally disturbed, alcoholics, or in confused states may experience hallucinations.
- Other Abnormalities: In addition to these errors, there are some abnormalities in our sense perceptions. These include:
- Anesthesia: no sensation.
- Hyperesthesia: excessive sensitivity.
- Paraesthesia: distorted or wrongly localised sensation.
- In these cases, the tactile (skin) sensation is wrongly perceived.
85. Discuss the development of concepts in children, focusing on size, magnitude, number, and time.
Answer: The development of concepts in children occurs in stages and varies with age.
Size and Magnitude Concept: Children at the age of six months show evidence that they can estimate the size of an object independently of its distance from the observer. Children between four and five months, however, reveal a certain amount of confusion in this estimate. The concept of magnitude has been studied by presenting children with objects of different sizes and asking them to discriminate the largest from the smallest and the middle-sized. Studies show that the concept of magnitude is fairly well developed by the age of three years. Before that, frequent errors are committed while arranging objects according to magnitude.
Number and Time Concept: In the development of the number concept, there are three distinct stages. At the first stage, the subject can discriminate the numbers. At the second stage, he can match numbers, and at the third stage, he can match groups of different numbers.
The study of the time concept shows that younger children use words indicating the present, while slightly older children use words indicating the future. Children have to be still older in age for the words denoting the past to become obvious. Primary school children have more accurate responses regarding things that took place a short while ago than those that took place a long time ago. The correct time concept is evidenced at the age of twelve; before that, answers show all kinds of confusion between the present, future, and past.
86. “The nervous system is the physical basis of mental life.” Discuss this statement with a detailed explanation of the nervous system’s complete structure (CNS and PNS) and its various functions.
Answer: It is an accepted fact that there is a close relation between mind and body, which establishes the nervous system as the physical basis of mental life. Injury to or disease of a part of the brain produces mental disorder or loss of consciousness. The advancement of behaviour in animals is connected with the development of their nervous system, and the evolution of the brain corresponds to that of intelligence. Emotional life is closely connected with the thalamus, sympathetic, and parasympathetic systems. The nervous system has three main functions: sensory input, integration of data, and motor output.
The nervous system is comprised of two major parts or subdivisions—the central nervous system (CNS) and the peripheral nervous system (PNS).
The Central Nervous System (CNS) includes the brain and the spinal cord. The brain is the body’s “control centre” and has various centres that carry out sensory, motor, and integration of data.
- The Brain: The brain is a delicate organ lodged inside the cranium of the skull and is protected by three coverings called the meninges. The space between these membranes is filled with cerebrospinal fluid. The brain consists of three main regions: the forebrain (cerebrum and diencephalon), the midbrain, and the hindbrain (cerebellum, pons, and medulla oblongata).
- Cerebrum: This is the largest part of the brain, divided into two cerebral hemispheres connected by the corpus callosum. The outer region, or cerebral cortex, is gray matter and is the seat of intelligence. Its functions include controlling voluntary muscle contractions, receiving and processing information from sense organs, and carrying out mental activities like thinking, reasoning, and memorising.
- Diencephalon: This part of the forebrain consists of the thalamus, which is a relay centre for sensory impulses, and the hypothalamus, which controls motivated behaviour like eating and drinking, and regulates body temperature.
- Cerebellum: Located at the base of the brain, its two main functions are to maintain the balance of the body and coordinate muscular activities.
- Medulla Oblongata: This is the last part of the brain, connected to the spinal cord. It is the centre for breathing, coughing, and swallowing, and it controls the heartbeat and other involuntary actions.
- The Spinal Cord: The spinal cord extends from the medulla downward along the backbone. Its functions are to carry out reflexes below the neck, conduct sensory impulses from the skin and muscles to the brain, and conduct motor responses from the brain to the trunk and limbs.
The Peripheral Nervous System (PNS) consists of all nerves arising from the brain and the spinal cord, including the nerves and ganglion. It has two kinds of pathways: afferent (receiving) sensory pathways and efferent (sending) motor pathways.
- Afferent Pathways: These include purely sensory nerves and mixed cranial nerves that bring sensations to the CNS.
- Efferent Pathways: This sending pathway is subdivided into the somatic and autonomic nervous systems.
- Somatic Nervous System: This system controls the voluntary muscles and includes most cranial and spinal nerves that convey messages from the CNS to these muscles.
- Autonomic Nervous System (ANS): This system innervates the involuntary muscles and glands, regulating the involuntary actions of internal organs. It consists of two parts: the sympathetic nervous system, which prepares the body for emergency situations, and the parasympathetic nervous system, which reestablishes normal conditions after the emergency.
87. Explain the journey from a physical stimulus to a cognitive concept.
Answer: The journey from a physical stimulus to a cognitive concept is a process that involves several distinct yet interconnected stages, which are central to cognitive development. This journey begins with a stimulus, which is a “change in the environment of nervous tissue which is sufficient to excite it.”
The first step involves the sense organs. Sense organs are the organs through which we sense or detect changes in the external environment. Each sense organ has special sensory cells which receive the stimuli and transmit the impulses produced through the concerned nerve to the brain or the spinal cord.
This leads to the second stage, sensation. Sensation is the process by which our senses gather information and send it to the brain. It is the gateway of knowledge, as any experience that takes place through sense organs is called sensation. This is purely sensory knowledge, sent to our brains in raw form, and does not have any relationship with any knowledge or awareness.
The third stage is perception. Perception refers to the interpretation of what we take in through our senses. The brain interprets the raw sensations to make sense of everything around us. This process of ‘interpretation of stimulus is known as perception’ and involves both sensation and interpretation. Importantly, interpretation of any stimulus requires past experience. Therefore, perception can be defined as “a process of interpretation of a present stimulus on the basis of past experience.”
The final stage is conception. Concepts are mental categories used to group objects, events, and information. Conception involves making meaning out of all this incoming information by reducing our experience of the world down to the fundamentals. It organises the interpreted information from perception into categories for better understanding and comprehension.
Together, sensation, perception, and conception play an important role in cognitive development. Sensation allows a child to gather information. The perceptual process allows the child to take in this sensory information and convert it into a signal that the brain can understand and act upon. Conception then provides the basis for our symbolic behaviour, such as language, by organising this information into meaningful categories.
88. Provide a comprehensive overview of the human sensory system.
Answer: Sense organs are the organs through which we sense or detect changes in the external environment. Each sense organ has special sensory cells that receive stimuli and transmit the impulses produced through a nerve to the brain or spinal cord. The brain then sorts out the impulses, interprets them, and transmits messages for the required response. In humans, there are typically five sense receptors.
The Eye (Sense of Vision)
- Structure: The eye is a nearly spherical hollow ball. Its wall is made of three layers: the outer tough white sclera, the middle choroid with blood vessels, and the innermost sensitive retina. The retina contains two kinds of sensory cells: rods (for dim light) and cones (for bright light and colours). Light enters through the transparent cornea, passes through the pupil (an opening in the iris), and is focused by the lens onto the retina.
- Function: Reflected light rays from an object enter the eye. The cornea and lens bend the rays to form an inverted, real image on the retina. The light energy of the image produces chemical changes in the rods and cones. These changes produce nerve impulses, which travel through the optic nerve and reach the brain, where the image is interpreted.
The Ear (Sense of Hearing and Balance)
- Structure: The ear has three parts: external, middle, and internal. The external ear consists of the pinna, which directs sound waves into the auditory canal to the eardrum. The middle ear contains three tiny bones (malleus, incus, stapes) that connect the eardrum to the internal ear. The internal ear contains the cochlea for hearing and the vestibule for balance. The cochlea is a coiled tube filled with fluid and contains sensory cells called the organ of corti.
- Function: Sound waves cause the eardrum to vibrate. These vibrations are transferred through the three bones to the fluid in the cochlea. The organ of corti catches the movement of the fluid and transfers it to the auditory nerve, which carries the impulses to the brain. The vestibule is concerned with the physical balance of the body.
The Nose (Sense of Smell)
- Structure: At the top of the nasal cavity are olfactory cells, which are chemoreceptors. These cells have cilia (hair-like attachments) that project into the nasal cavity. On the other end, olfactory nerve fibres pass through the ethmoid bone into the olfactory bulb, which is attached to the brain.
- Function: When we breathe, chemicals in the air enter the nasal cavity. These chemicals bind to the cilia of the olfactory cells, which generates a nerve impulse. This impulse is carried through the olfactory cell and nerve fibre to the olfactory bulb and then to the brain, which determines what we smell.
The Tongue (Sense of Taste)
- Structure: The tongue contains taste buds with chemoreceptors that detect tastes like sweet, sour, bitter, and salty. The bumps on the tongue are called papillae, and taste buds lie in the grooves between them. Each taste bud has a pore with microvilli sticking out and sensory nerve fibres attached to the other end.
- Function: Chemicals from food bind to the microvilli, generating a nerve impulse. This impulse is carried through the sensory nerve fibres to the brain. The tongue also picks up the texture and temperature of food.
The Skin (Sense of Touch)
- Structure: The skin contains general receptors interspersed throughout it that can detect touch, pain, pressure, and temperature. Nerve endings in the skin send information to the brain, with a greater concentration in areas like the fingertips.
- Function: When these skin receptors are activated by a stimulus like pressure or heat, they generate an impulse. This impulse is carried to the spinal cord and then to the brain for processing.
89. Discuss the mind-body problem. Elaborate on the theories of psychophysical parallelism and interactionism.
Answer: The final relation between mind and body is a metaphysical problem because it is difficult to understand how mind and body, being two entirely different entities in nature, could act and interact upon one another. The solution to this problem is beyond the scope of psychology. There are different theories regarding this relation, primarily psychophysical parallelism and interactionism.
Psychophysical parallelism was proposed by the philosopher Spinoza. This theory suggests that mind and body, both being expressions of God, the ultimate reality, move in parallel lines. In its extreme form, parallelism asserts a strict point-to-point correspondence between mental processes and a certain group of physical processes but denies any interaction between the two series.
- Difficulties with Parallelism: While there is a certain parallelism between physical and mental change, the doctrine of strict point-to-point correspondence is not borne out by empirical evidence. Furthermore, it leaves the connection of body and mind wholly mysterious.
Interactionism is the alternative theory. The doctrine of interaction couples the assertion of causal interaction with the denial of parallelism. Interactionists contend that either certain mental occurrences have no bodily correlative or that certain characteristic features in conscious life have no parallel in the bodily process.
- Difficulties with Interactionism: The doctrine of interaction is not without its difficulties. If interaction occurs, it is of an entirely different kind from the interaction of physical things. Ultimately, the connection is as mysterious as it is on the alternative theory of parallelism.
Neither parallelism nor interactionism, in the forms in which they have generally been expressed, provides a satisfactory account of the relations between physical and psychical facts. The problem is largely extra-psychological, and its solution depends in part on metaphysical questions regarding the nature of causation and the ultimate nature of matter and mind.
Extra MCQs: Knowledge-Based
1. What is the largest part of the human brain, responsible for intelligence?
A. Cerebellum
B. Medulla oblongata
C. Cerebrum
D. Diencephalon
Answer: C. Cerebrum
2. Which part of the nervous system is composed of the brain and the spinal cord?
A. Peripheral Nervous System (PNS)
B. Central Nervous System (CNS)
C. Autonomic Nervous System (ANS)
D. Somatic Nervous System
Answer: B. Central Nervous System (CNS)
3. What is the name of the junction between two neurons where impulses are transmitted?
A. Axon
B. Dendrite
C. Synapse
D. Ganglion
Answer: C. Synapse
4. Which part of the brain is primarily responsible for maintaining the balance of the body?
A. Cerebrum
B. Thalamus
C. Medulla oblongata
D. Cerebellum
Answer: D. Cerebellum
5. The photoreceptor cells in the retina that are sensitive to dim light are called:
A. Cones
B. Rods
C. Bipolar cells
D. Ganglion cells
Answer: B. Rods
6. Which subdivision of the autonomic nervous system prepares the body for “fight or flight” responses in emergency situations?
A. Somatic nervous system
B. Parasympathetic nervous system
C. Central nervous system
D. Sympathetic nervous system
Answer: D. Sympathetic nervous system
7. What is the name for the tough, outer protective layer of the brain?
A. Pia mater
B. Arachnoid
C. Dura mater
D. Corpus callosum
Answer: C. Dura mater
8. The process of interpreting sensory information based on past experience is known as:
A. Sensation
B. Conception
C. Perception
D. Reflex
Answer: C. Perception
9. Which part of the eye contains the highest concentration of cones and is the place of best vision?
A. Blind spot
B. Optic nerve
C. Yellow spot
D. Cornea
Answer: C. Yellow spot
10. What is the primary function of the medulla oblongata?
A. Controlling voluntary movements
B. Processing sensory information like pain
C. Regulating heartbeat and breathing
D. Coordinating muscular activities
Answer: C. Regulating heartbeat and breathing
11. According to the provided data, which sense accounts for the highest percentage of knowledge gained?
A. Hearing
B. Touch
C. Sight
D. Smell
Answer: C. Sight
12. What is the term for a false perception, such as mistaking a rope for a snake in the dark?
A. Hallucination
B. Sensation
C. Conception
D. Illusion
Answer: D. Illusion
13. The three tiny bones in the middle ear are the malleus, incus, and:
A. Cochlea
B. Stapes
C. Pinna
D. Eustachian tube
Answer: B. Stapes
14. The “all and none” law describes a characteristic of which of the following?
A. Synaptic transmission
B. A nervous impulse in a neuron
C. Perceptual organization
D. The reflex arc
Answer: B. A nervous impulse in a neuron
15. What is the structural and functional unit of the nervous system?
A. Nephron
B. Neuron
C. Alveolus
D. Sarcomere
Answer: B. Neuron
16. Which of the following is NOT a main part of the human brain?
A. Forebrain
B. Midbrain
C. Hindbrain
D. Spinal Cord
Answer: D. Spinal Cord
17. Which of the following is NOT a layer of the meninges that protect the brain?
A. Dura mater
B. Cerebrospinal fluid
C. Arachnoid
D. Pia mater
Answer: B. Cerebrospinal fluid
18. All of the following are functions of the skin EXCEPT:
A. Protection from the elements
B. Perspiration to cool the body
C. Production of digestive enzymes
D. Sensing touch, heat, and pain
Answer: C. Production of digestive enzymes
19. Which of the following is NOT a primary taste detected by taste buds?
A. Sweet
B. Spicy
C. Sour
D. Salty
Answer: B. Spicy
20. The cerebral cortex is involved in all of the following functions EXCEPT:
A. Initiating voluntary muscle contractions
B. Controlling heartbeat and swallowing
C. Processing information from sense organs
D. Carrying out mental activities like reasoning
Answer: B. Controlling heartbeat and swallowing
21. Which of the following is NOT an element of the five-part reflex arc?
A. Receptive nerve-endings
B. Afferent nerve
C. Effector organ
D. Cerebrum
Answer: D. Cerebrum
22. Which of these is NOT a property or element of sensation?
A. Quality
B. Intensity
C. Duration
D. Interpretation
Answer: D. Interpretation
23. Which of the following is NOT a part of the internal ear?
A. Cochlea
B. Vestibule
C. Tympanum
D. Semicircular canals
Answer: C. Tympanum
24. The __________ nervous system reestablishes normal bodily conditions after an emergency has passed.
A. sympathetic
B. somatic
C. parasympathetic
D. central
Answer: C. parasympathetic
25. The sheet of nerve fibers connecting the two cerebral hemispheres is called the __________.
A. corpus callosum
B. diencephalon
C. thalamus
D. cerebellum
Answer: A. corpus callosum
26. A __________ is an unlearned, unconscious, and immediate response to a stimulus.
A. perception
B. reflex
C. sensation
D. conception
Answer: B. reflex
27. The outer region of the cerebrum, which is grayish in color, is known as the __________.
A. white matter
B. gray matter
C. pia mater
D. dura mater
Answer: B. gray matter
28. A __________ is a mental category used to group objects, events, or information.
A. sensation
B. perception
C. concept
D. stimulus
Answer: C. concept
29. The part of the forebrain that acts as a relay center for sensory impulses like pain and pleasure is the __________.
A. hypothalamus
B. cerebellum
C. thalamus
D. pons
Answer: C. thalamus
30. A perception of a stimulus that is not actually present is known as a __________.
A. reflex
B. illusion
C. hallucination
D. sensation
Answer: C. hallucination
31. The __________ is the part of the eye where the optic nerve connects, and it has no sensory cells.
A. yellow spot
B. retina
C. pupil
D. blind spot
Answer: D. blind spot
Extra MCQs: Competency-Based
32. Cerebrum: Intelligence :: Cerebellum: __________
A. Emotion
B. Balance
C. Breathing
D. Memory
Answer: B. Balance
33. CNS: Brain :: PNS: __________
A. Spinal Cord
B. Skull
C. Nerves
D. Cerebrum
Answer: C. Nerves
34. Rods: Dim Light :: Cones: __________
A. Black and White
B. Movement
C. Peripheral Vision
D. Color Vision
Answer: D. Color Vision
35. Sympathetic: Speed up heartbeat :: Parasympathetic: __________
A. Dilate pupil
B. Increase breathing
C. Slow down heartbeat
D. Stop digestion
Answer: C. Slow down heartbeat
36. Sensation: Raw data :: Perception: __________
A. Stimulus
B. Interpretation
C. Reflex
D. Receptor
Answer: B. Interpretation
37. Illusion: Misinterpretation of stimulus :: Hallucination: __________
A. Correct interpretation of stimulus
B. Absence of interpretation
C. Perception without stimulus
D. Overreaction to stimulus
Answer: C. Perception without stimulus
38. Assertion (A): The left cerebral hemisphere controls the right side of the body.
Reason (R): The corpus callosum consists of criss-cross nerve fibers that connect the two cerebral hemispheres.
A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is not the correct explanation of A.
C. A is true, but R is false.
D. A is false, but R is true.
Answer: A. Both A and R are true and R is the correct explanation of A.
39. Assertion (A): A person with damage to the cerebellum might struggle with coordinated movements like walking.
Reason (R): The cerebellum is the primary center for intelligence and reasoning.
A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is not the correct explanation of A.
C. A is true, but R is false.
D. A is false, but R is true.
Answer: C. A is true, but R is false.
40. Assertion (A): The sympathetic nervous system is activated during an emergency, causing the pupils to dilate.
Reason (R): The sympathetic nervous system prepares the body for “fight or flight” by increasing alertness and sensory input.
A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is not the correct explanation of A.
C. A is true, but R is false.
D. A is false, but R is true.
Answer: A. Both A and R are true and R is the correct explanation of A.
41. Assertion (A): An image formed on the blind spot of the eye cannot be seen.
Reason (R): The blind spot is the area of the retina with the highest concentration of cone cells.
A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is not the correct explanation of A.
C. A is true, but R is false.
D. A is false, but R is true.
Answer: C. A is true, but R is false.
42. Assertion (A): Perception is a simple, elementary process of receiving sensory information.
Reason (R): Perception involves the complex process of interpreting sensory stimuli based on past experiences.
A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is not the correct explanation of A.
C. A is true, but R is false.
D. A is false, but R is true.
Answer: D. A is false, but R is true.
43. (I) Repeated practice of a task, like tying shoelaces, makes it easier and faster.
(II) Repeated use of a neural pathway reduces synaptic resistance.
A. I is the cause for II.
B. II is the cause for I.
C. I and II are unrelated.
D. I is a contradiction of II.
Answer: B. II is the cause for I.
44. (I) A person in a dark room mistakes a coat hanging on a door for a person standing there.
(II) This is an example of an illusion.
A. I is the cause of II.
B. I is an example of the phenomenon described in II.
C. II is a contradiction of I.
D. I and II are independent statements.
Answer: B. I is an example of the phenomenon described in II.
45. (I) The parasympathetic nervous system slows the heartbeat and stimulates digestion.
(II) The sympathetic nervous system speeds up the heartbeat and inhibits digestion.
A. I is the cause for II.
B. I is an example of II.
C. I and II describe opposing functions.
D. I and II describe the same function.
Answer: C. I and II describe opposing functions.
46. (I) The medulla oblongata controls involuntary actions.
(II) Breathing and heartbeat are regulated without conscious thought.
A. I is a contradiction of II.
B. I and II are unrelated.
C. II is an example of the principle stated in I.
D. I is the result of II.
Answer: C. II is an example of the principle stated in I.
