(a) afferent neurons and efferent neurons (b) impulse conduction in a myelinated nerve fibre and unmyelinated nerve fibre (c) aqueous humor and vitreous humor (d) blind spot and yellow spot (e)...
Distinguish between:
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Control and Coordination
The region of the vertebrate eye, where the optic nerve passes out of the retina, is called the
(a) fovea (b) iris (c) blind spot (d) optic chaisma Correct Answer: (c) Blind spot Explanation: The optic nerve exits the brain, the retinal blood vessels enter the brain at a time when the...
Answer the following:
(a) Which part of the ear determines the pitch of a sound? (b) Which part of the human brain is the most developed? (c) Which part of our central neural system acts as a master clock? Answers: (a)...
Differentiate between:
(a) Thalamus and Hypothalamus (b) Cerebrum and Cerebellum (d) Thalamus and Hypothalamus ThalamusHypothalamusContains grey matterContains both white and grey matterThalamus do not secrete...
Differentiate between:
(a) Myelinated and non-myelinated axons (b) Dendrites and axons (c) Rods and cones (a) Myelinated and non-myelinated axons FeaturesMyelinated axonsNon-myelinated axonsMyelin...
Explain the following:
(a) Role of Na+ in the generation of action potential. (b) Mechanism of generation of light-induced impulse in the retina. (c) Mechanism through which a sound produces a nerve impulse in the inner...
Answer briefly:
(a) How do you perceive the colour of an object? (b) Which part of our body helps us in maintaining the body balance? (c) How does the eye regulate the amount of light that falls on the retina?...
Give a brief account of mechanism of hearing
The Mechanism of hearing: The outer ear canal collects sound waves that pass through the outer ear canal to the eardrum. This causes the ear to move. This vibration is transmitted from the eardrum...
Give a brief account of mechanism of vision.
The Mechanism of Vision: The passage of light rays is as follows – the pupil, lens, aqueous humour, vitreous humor and finally retina. This light causes the separation of photo-pigment rhodopsin in...
Give a brief account of mechanism of synaptic transmission.
The synapses are connections where nerve impulses are transmitted from one neuron to another. This is formed by the pre-synaptic membrane and the post-synaptic neuron, which may or may not be...
Write short notes on the following:
(a) Retina (b) Ear ossicles (c) Cochlea (d) Organ of Corti (a) Retina: The retina forms the finest internal, neurosensory layer of the eyeball. The surface of the retina interacts with the choroid...
Write short notes on the following:
(a) Neural coordination (b) Forebrain (c) Midbrain (d) Hindbrain (a) Neural coordination: It is a condition in which two or more organs interact with each other through the body's neural system. The...
Draw labelled diagrams of the following:
(a) Neuron (b) Brain (c) Eye (d) Ear (a) Neuron (b) Brain (c) Eye (d)Ear
Explain the Transmission of a nerve impulse across a chemical synapse.
The pre-synaptic neuron membrane and the post-synaptic neuron form the synapse Synaptic cleft is a synapse that can be separated or not separated by a gap The pre-synaptic neuron and the...
Explain the Conduction of a nerve impulse along a nerve fibre
When nerve pressure is pushed across the fiber, it occurs in a systematic way. During the manipulation of the pressure in the nerve fiber, a portion of it is constantly broken down while the nearby...
Explain the Depolarisation of the membrane of a nerve fibre
The sensory nerve is said to be in a state of depression when stressed. In this case, the action force is derived from the nerve membrane fiber. During the process of depolarization, the following...
Explain the Polarisation of the membrane of a nerve fibre
The nerve fiber is said to be in a state of relaxation when it is in the resting phase. In this isolated state, the membrane of nerve fibers has the ability to relax. Listed below are the steps that...
Compare the following:
(a) Central neural system (CNS) and Peripheral neural system (PNS) (b) Resting potential and action potential (c) Choroid and retina (a) Central neural system (CNS) and Peripheral neural system...
Briefly describe the structure of the following: Eye
The Structure of the Eye: The human eye is encased in a skull bone and is round. The walls of the eyeball have three layers, namely - the neurosensory inner lining, the central vascular coat and the...
Briefly describe the structure of the following: Ear
The Structure of the ear: The human ear has two sensory functions - It enables hearing and maintains body balance. It can be divided into three main categories - inner ear, outer ear, middle ear. 1....
Briefly describe the structure of the following: Brain
The structure of the Brain: The mind is a leading physical information processing center that acts as a control and command system. Protected in the skull. Covered by three membranes known as...
53. Why is the flow of signals in a synapse from axonal end of one neuron to dendritic end of another neuron but not the reverse?
Solution - travelling of the electrical impulses takes place in the neurons . When it is transmitted to another neuron it takes the form of the neurotransmitter . Neurotransmitter are...
51. “Nervous and hormonal systems together perform the function of control and coordination in human beings.” Justify the statement.
Solution : the function of control and coordination is regulated by the hormonal and nervous system . All the organs and organ system in the body are under the control of the brain . Brain controls...
50. What are reflex actions? Give two examples. Explain a reflex arc .
Solution – reflex action is a rapid and involuntary response to a stimulus . Examples of reflex action are – in bright light the pupil of the changes in size . ...
49. Name various plant hormones. Also give their physiological effects on plant growth and development.
Solution – some of the plant hormones are gibberellin – it is responsible for the growth of the stemauxin – it causes the cell to elongateabscisic acid – the growth of the plant is halted and...
48. Mention one function for each of these hormones :
(a) Thyroxin (b) Insulin (c) Adrenaline (d) Growth hormone (e) Testosterone. Solution – (a) Thyroxin : it is important in the role of digestion , heart and muscle function , development of brain and...
47. What constitutes the central and peripheral nervous systems? How are the components of the central nervous system protected?
Solution – Brain and spinal cord makes up the central nervous system . peripheral nervous system comprises of nerves which are present outside the spinal cord . Central nervous system is very well...
46. What are the major parts of the brain? Mention the functions of different parts.
Solution – major parts of the brain along with their functions are – forebrain - it has an important role in information processing , sensory and associative functions and voluntary motor...
45. Draw the structure of a neuron and explain its function.
Solution - neurons transmit information among the different areas of the brain and rest of the nervous system . Structure of the neuron – Cell body have dendrites which are responsible to receives...
43. Answer the following :
(b) Dwarfism results due to deficiency of which hormone? (a) Which hormone is responsible for the changes noticed in females at puberty? (c) Blood sugar level rises due to deficiency of which...
42. What happens at the synapse between two neurons?
Solution – electrical impulse releases chemicals at the end of the axon . These chemicals cross the synapse and in the dendrite similar electrical impulses are created .
41. What will happen if the intake of iodine in our diet is low ?
Solution – our metabolism is controlled by thyroid hormone . Low levels of iodine results in low thyroid function and also causes abnormal enlargement of the thyroid gland ( hypothyroidism ) known...
40. What is a tropic movement? Explain with an example .
Solution – when a plant shows some growth movement in response to a stimulus then it is known at tropic movement . Movement can be either direction that is it can be towards the stimulus or away...
39. Match the terms of Column (A) with those of Column (B)
Column AColumn B(a) Olfactory receptors(i) Tongue(b) Thermo receptors (temperature receptors)(ii) Eye(c) Gustatoreceptors(iii) Nose(d) Photoreceptors(iv) Skin solution Column AColumn B(a) Olfactory...
38. Label the parts of a neuron in Figure 7.5.
Figure Solution – DendriteCell bodyAxonAxon terminal
37. In Figure 7.4 (a), (b) and (c), which appears more accurate and why?
Figure Solution – figure ( a ) is more accurate . It is so because the plant is showing the ideal condition that is the roots are showing positive geotrophism and the shoot system is showing...
36. Label the endocrine glands in Figure 7.3.
figure Solution – Pineal glandPituitary glandThyroid glandThymus
35. Name the plant hormones responsible for the following
(a) elongation of cells (b) growth of stem (c) promotion of cell division (d) falling of senescent leaves. Solution – (a) elongation of cells – Auxin (b) growth of stem – gibberellin (c) promotion...
34. Label the parts (a), (b), (c) and (d) and show the direction of flow of electrical signals in Figure 7.2.
Solution – Sensory neuron Spinal cord Motor neuron Muscle Flow of electrical signals: Receptors in hand ==> Sensory neurons ==. Spinal cord (CNS) ==>Motor neurons ==> Effector - muscles in...
33. In humans, the life processes are controlled and regulated by
(a) reproductive and endocrine systems (b) respiratory and nervous systems (c) endocrine and digestive systems (d) nervous and endocrine systems Correct option – ( d ) Explanation for correct option...
30. The hormone which increases the fertility in males is called
(a) oestrogen (b) testosterone (c) insulin (d) growth hormone Correct option – ( b ) Explanation for correct option – Testosterone is the male sex hormone produces in testes of males which promotes...
29. A doctor advised a person to take an injection of insulin because
(a) his blood pressure was low (b) his heart was beating slowly (c) he was suffering from goitre (d) his sugar level in blood was high Correct option – ( d ) Explanation for correct option –...