1. The given diagram shows axon terminal. Select the option that correctly matches the steps in transmission of impulses (list i – vii) with the labellings (A – D) in diagram.
(i) Chemicals called neurotransmitters are released in the synaptic cleft through ion channels.
(ii) When an impulse arrives at the axon terminal, it stimulates the movement of synaptic vesicles.
(iii) Neurotransmitters are endocytosed into the neurons.
(iv) The ion channels close with the binding of neurotransmitters to their specific receptor vesicles.
(v) Synaptic vesicles move towards the membrane where they fuse with the plasma membrane.
(vi) Neurotransmitters are released in the synaptic cleft.
(vii) The released transmitters bind to their specific receptors on postsynaptic membrane.
2.Read the following five statements (i) to (v) regarding left cerebral hemisphere and select the option that correctly states the true (T) and false (F) statements.
(i) It receives most modalities of sensory information from the right side of the body.
(ii) It is usually larger than the right cerebral hemisphere.
(iii) It is the dominant cerebral hemisphere in most individuals.
(iv) It is connected to the right cerebral hemisphere by the corpus callosum.
(v) It contains the main areas for the understanding and production of speech in most individuals.
3. The given figure shows a section of brain. Identify : the parts labelled as A, B, C and D and match them : with the names (i – vii) given below:
(i) Arachnoid membrane
(ii) Subdural space
(v) White matter
(vi) Grey matter
4.brain. Match the labelled parts with the respective statements given below and select the correct option.
(i) Consists of fibre tracts that interconnect left and right hemispheres
(ii) Secretes a hormone melatonin
(iii) Alcohol interferes with the function of this part
(iv) Contains centres which control respiration, cardiovascular reflexes and gastric secretions.
5.While travelling to higher altitudes, people can feel pain in the ear and dizziness. Which part, among the following is involved?
(a) Cochlea, ear ossicles
(b) Tympanic membrane
(c) Eustachian tube, utricle, saccule and semicircular canals
(d) None of the above
6. If a patient suffers a stroke that destroys the optic tract on the right side of the brain, which of the following visual defects will result ?
(a) There will be no vision in the left eye, but vision will be normal in the right eye.
(b) The patient will not perceive images of objects striking the left half of the retina in the left eye.
(c) The patient will not perceive images of objects striking the right half of the retina in the right eye.
(d) Neither eye will perceive objects in the right side of the patient’s field of view.
7. Two neurons, A and B, synapse onto a third neuron, C. If neurotransmitter from A opens ligand-gated channels permeable to Na+ and K‘ and neurotransmitter from B opens ligand-gated Cl” channels, which of the following statements is true ?
(a) An action potential in neuron A causes a depolarization in neuron B.
(b) An action potential in neuron B causes a depolarization in neuron C.
(c) Simultaneous action potentials in A and B will cause hyperpolarization of neuron C.
(d) Simultaneous action potentials in A and B will cause less depolarization of neuron C than if only neuron A fired an action potential.
8. Which of the following is an example of conditioned reflex?
(a) Hand withdraws when pierced with a needle
(b) Eyes close, when anything enters into them
(c) During digestion, food goes forward in alimentary canal
(d) Trained dog salivates when you ring a bell
9. Read the given statements and select the correct ones.
(i) Autonomic neural system transmits impulses from the CNS to the voluntary organs and striated muscles of the body.
(ii) Unmyelinated nerve fibres do not have Schwann cells which form the myelin sheath.
(iii) Axonal membrane of a neuron, when not conducting any impulse, is comparatively more permeable to potassium ions (K+) than to sodium ions (Na+).
(iv) A synapse is formed by the membranes of a pre- synaptic neuron and a post synaptic neuron.
(a) (i) and (ii) (b) (ii) and (iii)
(c) (iii) and (iv) (d) (i) and (iv)
10. During the transmission of nerve impulse through a nerve fibre, the potential on the inner side of the plasma membrane has which type of electric charge?
(a) First positive, then negative and continue to be negative
(b) First negative, then positive and continue to be positive
(c) First positive, then negative and again back to positive
(d) First negative, then positive and again back to negative
11. The function of vagus nerve innervating the heart is to
(a) initiate the heart beat
(b) reduce the heart beat
(c) accelerate the heart beat
(d) maintain constant heart beat.
12. Refractory period comes in between
(a) resting potential and depolarization
(b) depolarization and repolarization
(c) action potential and depolarization
(d) two cycles of impulse conduction.
13. Column-I lists some disorders associated with brain. Column-ll lists the causes for these disorders. Match the two columns and identify the correct option from those given
14. Under prolonged starvation, brain receives energy from
15. The nerve fibres that emerge from the taste bud pass to the brain stem through the
(a) olfactory and trigeminal nerves
(b) auditory and trigeminal nerves
(c) facial, glossopharyngeal and vagus nerves
(d) olfactory and abducens nerves.
True or False
16. Stapes is the smallest bone in the body and its foot plate covers fenestra ovalis.
17. The scala vestibuli and scala tympani are filled with endolymph and connected with each other through helicotrema.
18. Rhodopsin is composed of a protein called scotopsin and an aldehyde of vitamin A called retinal.
19. Less energy is required for saltatory conduction than for conduction along a nonmyelinated neuron.
20. Reflex action is important for survival of an organism and protects us from harmful situations.
21. Vagus nerve is the longest cranial nerve controlling visceral movements such as peristalsis, sound production, respiratory movements and heart beat.
22. Wernicke’s area is located in both the right and left temporal lobes, and plays an important role in understanding speech and writing words.
23. Hypothalamus is the ‘thermostat’ of the body and keeps the body temperature at roughly 37°C.
24. The post-ganglionic fibers of both sympathetic and parasymphathetic neural system are cholinergic.
25. A sub threshold stimulus is unable to generate a nerve impulse, due to ‘all or none’ principle.
Match The Columns
Match Column-I with Column-ll and select the correct option from codes given below.
Passage Based Questions
28. (A) Complete the given passage with appropriate
words or phrases.
Certain components of the (i) , and (ii) constitute the limbic system. Its main components are (iii). which are present behind the infundibulum; (iv) which are scattered masses of grey matter; (v) which is almond shaped and located in the tip of the temporal lobe; (vi) which roughly resembles the sea horse and is located inside the temporal lobe, and (vii). which are located within the sepal area formed by the regions under corpus callosum and paraterminal gyrus.
(B) Read the passage and correct the errors, wherever present.
Pacinian corpuscles occur in the epidermis and are responsible for touch; while Krause’s corpuscles are located in the papillary layer of dermis, just below epidermis, and respond to touch. Ruffini’s corpuscles are excited by cold, while Meissner’s corpuscles respond to heat.
Assertion & Reason
In each of the following questions, a statement of Assertion is given and a corresponding statement of Reason is given just below it. Of the statements, mark the correct answer as
(a) if both A and R are true and R is the correct explanation of A
(b) if both A and R are true but R is not the correct explanation of A
(c) if A is true but R is false
(d) if both A and R are false.
29. Assertion : In myelinated nerve fibers, Schwann cells form myelin sheath around the axon.
Reason : Myelinated nerve fibers are found in autonomic and somatic neural systems.
30. Assertion: Basal ganglia are the scattered masses of grey matter, submerged in the subcortical substance of cerebral hemispheres.
Reason: Parkinson’s disease occurs due to the damage of the basal ganglia.
31 . Assertion : Purkinje cells are among the most complex of all neurons.
Reason : These flask shaped cells lie in the middle layer of cerebrum.
32. Assertion : Sympathetic neural system constricts arteries and raises blood pressure.
Reason : It also speeds peristalsis and increases activity of the digestive tract.
33. Assertion : There are certain reflex actions in which an individual does not have any knowledge of the reflex actions.
Reason : Peristalsis of alimentary canal and beating of the heart are examples of such reflex actions.
34. Assertion : At an electrical synapse, there is continuity between the presynaptic and postsynaptic neurons.
Reason : The continuity is provided by tight junctions between the two neurons.
35. Assertion : In Alzheimer’s disease (AD) patients, there is loss of neurotransmitter, ACh.
Reason : Drugs that inhibit AChE improve alertness in the patients.
36. Assertion : Nocieceptors respond to potentially damaging stimuli that result in pain.
Reason : Overstimulation of any receptor is painful, and over time, it starts functioning as nocieceptors.
37. Assertion : Cristae are present in the ampullae of semicircular canals.
Reason : Each crista contains calcareous ear stones called otolith.
38. Assertion: In an action potential, the interior of neuron is electropositive and the exterior is electronegative.
Reason : There is an active sodium potassium pump operating.
Figure Based Questions
39. In the given figure, identify the areas marked A to I. 40. Observe the figure again and identify 1, 2 and 3.