Tiêu đề Neural Control and Coordination- Ex-3 Solution fie.docx.pdf ✅

24 NEURAL CONTROL AND COORDINATION EXERCISE – 3 : Achiever’s Section Human Neural System 1. The flowchart given here shows functional organization of the human neural system. Identify A to E and select the correct option. A B C D E (a) PNS CNS ANS Sympathetic Neural system Parasym-pat hetic neural system (b) ANS CNS PNS Parasympath etic neural system Sympathetic neural system (c) CNS PNS ANS Sympathetic neural system Parasym-pat hetic neural system (d) ANS PNS CNS Parasympath etic neural system Sympathetic neural system Ans. (c) Sol. The option that correctly identifies the words that fill in the blanks are – A – CNS B – PNS C – ANS D - Sympathetic nervous system E - Parasympathetic nervous system 2. Read the following statements and find out the incorrect statement. a. The CNS is the site of information processing and control. b. The somatic neural system relays impulses from the CNS to the involuntary organs and smooth muscles of the body. c. The autonomic neural system transmits impulses from the CNS to skeletal muscles. d. The autonomic neural system is further classified into sympathetic and parasympathetic neural system. (a) a and b (b) b and c (c) c and d (d) a and d Ans. (b) Sol. The statement (b) is incorrect as the somatic neural system relays impulses from the CNS to the skeletal or voluntary muscles and not to the involuntary organs. Statement (c) is incorrect as the autonomic neural system transmits impulse from the CNS to the involuntary organs and smooth muscles of the body. 3. Given below is a table comparing the effects of sympathetic and parasympathetic nervous systems for four features (a-d). Which one feature is correctly matched? Feature Sympathetic nervous system Parasympathetic nervous system (a) Salivary glands Stimulates secretion Inhibits secretion
25 NEURAL CONTROL AND COORDINATION (b) Pupil of the eye Dilates Constricts (c) Heart rate Decreases Increases (d) Intestinal peristalsis Stimulates Inhibits Ans. (b) Sol. Sympathetic nervous system is responsible for emergency responses. It will inhibit the salivary secretion, dilate the pupil to allow more light into the eye. It increases the heartbeat and inhibits the intestinal peristalsis. The parasympathetic system stimulates the secretion from glands, constricts the pupil, decreases the heartbeat, and stimulate intestinal peristalsis. 4. A person entering in empty room suddenly finds a snake right in front on opening the door. Which one of the following is likely to happen in his neurohormonal control system? (a) Neurotransmitters diffuse rapidly across the cleft and transmit a nerve impulse. (b) Sympathetic nervous system is activated Releasing epinephrine and norepinephrine from Adrenal medulla. (c) Hypothalamus activates the parasympathetic division of brain. (d) Sympathetic nervous system is activated releasing epinephrine and norepinephrine from adrenal cortex. Ans. (b) Sol. Sympathetic nervous system is responsible for the fight, flight, or fright response of the body. It is the emergency response system of the body. Epinephrine and norepinephrine from the adrenal medulla act as transmitters in the sympathetic nervous system. 5. You are watching a horror movie and you notice your heart is beating fast and mouth is dry. It is because of: (a) fight and flight response (b) somatic nervous system (c) sympathetic nervous system (d) both (a) and (c) Ans. (d) Sol. Watching a horror movie incites fear in the person. The sympathetic nervous system is responsible for the fight, flight or fright response of the body. Activation of the sympathetic nervous system increases the heartbeat, decrease the saliva in the mouth, so the mouth feels dry. 6. Which of the following is purely a motor nerve? (a) vagus (b) olfactory (c) abducens (d) trigeminal Ans. (c) Sol. Abducens nerve is a purely motor cranial nerve. It arises from its nucleus in the pons and has the longest intracranial course of all the cranial nerves. It supplies the lateral rectus muscle which is an extraocular muscle in the orbit. Its paralysis causes double vision (diplopia) and deviation of the eyeball towards the center (medial) side, due to the unopposed action of the medial rectus muscle. 7. Cauda equina is (a) end of spinal cord (b) end of meninges (c) end of spinal nerves (d) end of white matter Ans. (c) Sol. The group of spinal nerves at the terminal end ( ) of the spinal cord form a tail like structure called as the Cauda equina which resembles the tail of a horse. Injury to these nerve segments can cause a syndrome known as the ‘Cauda Equina syndrome’ which includes symptoms such as weakness, numbness or paralysis in the lower extremities and bowel, bladder and sexual dysfunctions. 8. The number of sensory, motor and mixed cranial nerves are (a) 5, 4, 3 (b) 3, 4, 5 (c) 3, 5, 4 (d) 4, 5, 3 Ans. (c) Sol. There are total 12 pairs of cranial nerves, that originate from the brain and the brain stem. There are 3 sensory cranial nerves. These include optic, olfactory and auditory. There are 5 motor nerves. These include trochlear, abducens, oculomotor, spinal accessory nerve and hypoglossal nerve. 4 cranial nerves are mixed. These include facial, trigeminal, vagus and glossopharyngeal. 9. The set of mixed cranial nerves is (a) optic - auditory - olfactory
26 NEURAL CONTROL AND COORDINATION (b) auditory - trigeminal - hypoglossal (c) oculomotor - trochlear - abducens (d) vagus - facial - trigeminal Ans. (d) Sol. The Vagus (10 th), Facial (7 th) and Trigeminal (5 th) cranial nerves are examples of mixed cranial nerves. They have both sensory and motor function. Examples of the mixed functions of these nerves are- The Vagus nerve provides sensory innervation to the skin behind the ear, the throat etc., and it provides motor supply to the involuntary muscles of the digestive tract. The Facial nerve provides sensory innervation to the anterior 2/3 rd of the tongue and motor supply to the facial muscles. The Trigeminal nerve provides sensory innervation to the skin over the face and the mouth and motor supply to the jaw muscles. Neuron: Structural and Functional Unit of Neural System 10. Recognise the figure and find out the correct matching. (a) a-axons, b-cell body, c-myelin sheath, d-dendrites, e-node of Ranvier, f-Schwann cell (b) a-dendrites, b-axon, c-Schwann cell, d-cell body, e-myelin sheath, f-node of Ranvier (c) a-dendrites, b-cell body, c-Schwann cell, d-axon, e-myelin sheath, f-Node of Ranvier (d) a-synaptic knobs, b-cell body, c-myelin sheath, d-axon, e-Schwann cell, f-Node of Ranvier Ans. (c) Sol. The correct labelling for the given diagram should be- a-dendrites, b-cell body, c-Schwann cell, d-axon e-myelin sheath, f-Node of Ranvier. 11. Which of the following options correctly describes the sequence of structures present between a receptor and an effector when D refers dendrite, A refers axon, S refers synapse and CB refers to cell body? (a) D - CB - A - S - D - CB - A (b) A - D - CB - S - A - D - CB (c) D - CB - A - S - A - CB - D (d) D - A - S - CB - D - A - CB Ans. (a) Sol. A neuron is a microscopic structure composed of three major parts namely dendrites, cell body and axon. Short fibers which branch repeatedly and project out of the cell body are called dendrites. These fibers transmit impulses towards the cell body. The cell body then transmits the signal to the axon. Axon end has a bulb-like structure called synaptic knob which possesses synaptic vesicles containing chemicals called neurotransmitters. The axon transmits nerve impulses away from the cell body to a synapse or to a neuromuscular junction. Therefore, the order of nerve impulse transmission is D - CB - A - S - D - CB – A
27 NEURAL CONTROL AND COORDINATION 12. Match the columns I and II, and choose the correct combination from the options given. Column I Column II a. Unipolar neuron 1. Cerebral cortex b. Bipolar neuron 2. Embryonic stage c. Multipolar neuron 3. Retina of eye (a) a-1, b-2, c-3 (b) a-3, b-1, c-2 (c) a-2, b-3, c-1 (d) a-2, b-1, c-3 Ans. (c) Sol. Correct match should be – Unipolar neuron is present in the embryonic stage. Bipolar neurons in the retina of eyes while multipolar neurons in the cerebral cortex. 13. Consider the following statements: I. The resting axonal membrane is nearly impermeable to sodium ions. II. Depolarization of the axonal membrane is due to influx of sodium ions. III.The size of the action potential, if produced, does not depend on the strength of the stimulus. Which of the above statements are true? (a) I and II only (b) I and III only (c) II and III only (d) I, II, III Ans. (d) Sol. -The resting axonal membrane is nearly impermeable to sodium ions. -Depolarization of the axonal membrane is due to influx of sodium ions. -The size of the action potential, if produced, does not depend on the strength of the stimulus. -All these statements are true. 14. During propagation of nerve impulse, the action potential results from the movement of: (a) K + ions from extracellular fluid to intracellular fluid. (b) K + ions from intracellular fluid to extracellular fluid. (c) Na + ions from intracellular fluid to extracellular fluid. (d) Na + ions from extracellular fluid to intracellular fluid. Ans. (d) Sol. During propagation of nerve impulse, the action potential results from the movement of sodium ions from the extracellular fluid to the intracellular fluid. This leads to electro positivity inside the cell and depolarization. 15. In the given figure, site A and site B represents (a) Site A-polarized state, site B-depolarized state (b) Site A-depolarized state, site B-polarized state (c) Site A-polarized state, site B-repolarized state (d) Site A-repolarized state site, B-depolarized state Ans. (b) Sol. Site A depicts depolarized state as there is a positive intracellular potential. Site B depicts polarized state as the intracellular potential is still negative. 16. During recovery, a nerve fibre becomes (a) +vely charged on outside and -vely charged on inside (b) +vely charged on both outside and inside (c) -vely charged on outside and +vely charged on inside (d) -vely charged on both outside and inside Ans. (a) Sol. During recovery, a nerve fibre is positively charged on outside and negatively charged on the inside. This process involves the action of the sodium-potassium ATPase pump which utilizes ATP to throw 3 sodium ions outside the cell in exchange for 2 potassium ion which is brought into the cell thereby making the inside of the cell negative. 17. Read the following statements and find out the incorrect statement.