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Nervous System (GATE - XL)

Description: Nervous System
Number of Questions: 15
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Tags: Nervous System Neurons Brain Reflex GATE - Life Science The Nervous System
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Nissl bodies are large granular bodies found in neurons. They are essential for the process of

  1. nerve respiration

  2. electrical conduction

  3. protein synthesis

  4. neurotransmitter release


Correct Option: C
Explanation:

Nissl bodies synthesise protein for intracellular use. They consist of rough endoplasmic reticulum and associated ribosomal RNA.

Bezold-Jarisch reflex involves

  1. increase in respiratory rate

  2. cardiovascular and neurological processes

  3. prevention of over-inflation of lungs

  4. elevation of the scrotum and testis


Correct Option: B
Explanation:

Bezold-Jarisch reflex involves a variety of cardiovascular and neurological processes which cause hypopnea and bradycardia.

Parkinson's disease is a degenerative disorder of the central nervous system that often impairs the sufferer's motor skills and speech. Which of the following pigments is linked to this disease?

  1. Adrenochrome

  2. Lipofuscin

  3. Catecholamine

  4. Neuromelanin


Correct Option: D
Explanation:

Pigment neuromelanin is linked to Parkinson's disease. Neuromelanin-containing neurons in the substantia nigra undergo neurodegeneration during Parkinson's disease. This makes the cell deficient of neuromelanin.

Golgi type II neuron is a neuron having either no axon or a short axon that does not send branches out of the gray matter. Which of the following is a Golgi type II neuron?

  1. Granule cell

  2. Pyramidal cell

  3. Purkinje cell

  4. Anterior horn cell


Correct Option: A
Explanation:

Granule cell is a Golgi type II neuron. Granule cell is the only excitatory neuron present in the cerebellar cortex of brain.

Clostridium tetani produces a potent toxin which causes constant constriction of muscles. Which of the following cells of the nervous system are targeted by this toxin?

  1. Pyramidal cells

  2. Renshaw cells

  3. Purkinje cells

  4. Basket cells


Correct Option: B
Explanation:

Renshaw cells are targetted by the toxin of Clostridium tetani. When wounds are contaminated with Clostridium tetani, the toxin travels to the spinal cord where it inhibits the release of glycine, an inhibitory neurotransmitter, from Renshaw cells. As a result, alpha motor neurons become hyperactive and muscles constantly contract.

Niemann-Pick disease is a group of inherited severe metabolic disorders in which sphingomyelin accumulates in lysosomes in cells. Which of the following nerve cells are progressively lost in this condition?

  1. Betz cells

  2. Basket cells

  3. Purkinje cells

  4. Lugaro cells


Correct Option: C
Explanation:

Niemann-Pick disease type C involves the progressive loss of Purkinje cells. In this disease, sphingomyelin accumulates in lysosomes in the cells.

Which of the following neurons are interneurons in neurostriatum on the basis of electrophysiological characteristics?

  1. Fast spiking

  2. Phasic or bursting

  3. Tonic or regular spiking

  4. Slow spiking


Correct Option: C
Explanation:

Interneurons in neurostriatum are tonic or regular spiking neurons. They are constantly active.

Myelin sheath provides insulation to the axon that allows electrical signals to propagate more efficiently. Which of the following cells produce myelin sheath in neurons of CNS?

  1. Astrocytes

  2. Oligodendrocytes

  3. Schwann cells

  4. Enteric glial cells


Correct Option: B
Explanation:

Oligodendrocytes are the glial cells that coat axons in the central nervous system (CNS) with their cell membrane, forming a specialised membrane differentiation called myelin, to produce the so-called myelin sheath. Myelin sheath provides insulation to neuron and allows electrical signals to propagate more efficiently.

The ratio of glial cells to neural cells differs in different parts of brain. What is the glial/neuron ratio in cerebral cortex?

  1. 3.72

  2. 0.23

  3. 1.48

  4. 3.76


Correct Option: A
Explanation:

The glial/neuron ratio in the cerebral cortex is 3.72 (60.84 billion glia : 16.34 billion neurons).

Which of the following molecules present at nodes of Ranvier in the CNS enhances the surface expression of Na+ channels?

  1. Versican

  2. Contactin

  3. Ankyrin

  4. Tenascin-R


Correct Option: B
Explanation:

Contactin present at nodes of Ranvier in the CNS enhances the surface expression of Na+ channels.

Thalamus is a part situated between cerebral cortex and the mid-brain. Which of the following arteries supply blood to the thalamus?

a. Polar artery b. Inferolateral artery c. Anterior cerebral artery d. Superior hypophyseal artery

  1. Only c and d

  2. Only a and b

  3. Only a and c

  4. Only b and d


Correct Option: B
Explanation:

Polar artery and inferolateral artery supply blood to the thalamus.

Tentorium cerebelli is a fold of the dura mater. It is found between

  1. thalamus and hypothalamus

  2. medulla and pons

  3. cerebellum and medulla

  4. cerebrum and cerebellum


Correct Option: D
Explanation:

Tentorium cerebelli is a fold of the dura mater separating cerebrum from cerebellum.

Which of the following conditions occurs in holoprosencephaly?

  1. Embryonic forebrain fails to divide the brain into two lobes.

  2. Cerebral hemispheres are absent.

  3. Complete absence of cerebral cortex.

  4. Abnormal accumulation of cerebrospinal fluid.


Correct Option: A
Explanation:

In holoprosencephaly, embryonic forebrain fails to divide into two lobes. In most cases of holoprosencephaly, the malformations are so severe that babies die before birth.

Which of the following areas in subthalamus possesses glutamate that has excitatory effect over neurons of globus pallidus and substantia nigra?

  1. Subthalamic fasciculus

  2. Zona incerta

  3. Subthalamic nucleus

  4. Fields of Forel


Correct Option: C
Explanation:

The neurons of the subthalamic nucleus contain glutamate that has excitatory effects over neurons of globus pallidus and substantia nigra.

Which of the following is a choreiform disorder that is caused by a degenerative process in the striatum?

  1. Parkinson's disease

  2. Non-spastic cerebral palsy

  3. Huntington’s disease

  4. Alzheimer's disease


Correct Option: C
Explanation:

Huntington's disease is a choreiform disorder and is caused by a degenerative process in the striatum. It affects muscle coordination and leads to mental decline and behavioral symptoms.

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