This set of Class 11 Biology Chapter 21 Multiple Choice Questions & Answers (MCQs) focuses on “Human Neural System”.
1. Based on which of the following, the neurons are divided into three major types?
a) Based on the size of neurons
b) Based on the length of neurons
c) Based on the number of axons and dendrites
d) Based on the power of their division
View Answer
Explanation: Based on the number of axons and dendrites, the neurons are divided into three major types:
i. Multipolar neurons-with one axon and two or more dendrites
ii. Bipolar-with one axon and one Dendrite
iii. Unipolar-cell body with one axon only.
2. Which of the following cells secrete a myelin sheath?
a) Schwann cells
b) Adipocytes
c) Cartilage cells
d) Bone marrow cells
View Answer
Explanation: The myelinated nerve fibres are enveloped with Schwann cells, which form a myelin sheath around the axon. The gaps between the two adjacent myelin sheaths are called Nodes of Ranvier.
3. Where are the myelinated neurons found?
a) Only in the embryonic condition
b) In Spinal cord and cranial nerves
c) In peripheral nerve
d) In motor neurons
View Answer
Explanation: Myelinated nerve fibres are found in spinal and cranial nerves. Unmyelinated nerve fibres are enclosed by a Schwann cell that does not form a myelin sheath around the axon and is commonly found in autonomous and the somatic neural system.
4. How are impulses transmitted from one neuron to another?
a) Through intercellular junctions
b) Through tight junctions
c) Through gap junctions
d) Through synapses
View Answer
Explanation: A nerve impulse is transmitted from one neuron to another through junctions called synapses. A synapse is formed by the membranes of pre-synaptic and a post-synaptic neuron.
5. There are three types of synapses.
a) True
b) False
View Answer
Explanation: Two types of synapses exist in the human body-electrical and chemical synapses. The transmission of impulse is very fast in electrical synapses as compared to the transmission of impulse in the chemical synapse.
6. Which of the following statements is incorrect regarding electrical synapses?
a) Transmission of signals is faster than chemical synapses
b) Pre and postsynaptic membranes are in very close proximity
c) They are very common in our system
d) Electrical synapse can flow directly from one neuron to another
View Answer
Explanation: Electrical synapses are very rare in our system. At electrical synapses, the membranes of pre and post synaptic neurons are in very close proximity. Impulse transmission across an electrical synapse is always faster than chemical synapse.
7. What is the fluid-filled space known as in chemical synapses?
a) Synaptic cleft
b) Gap junctions
c) Synapse
d) Synaptic vesicles
View Answer
Explanation: At a chemical synapse, the membranes of the pre-and post-synaptic neurons are separated by a fluid-filled space called the synaptic cleft. Chemicals called neurotransmitters are involved in the transmission of impulse at these synapses.
8. Which of the following is not a feature of the chemical synapse?
a) Slow
b) Common
c) Neurotransmitters
d) Multidirectional
View Answer
Explanation: The impulse through chemical synapses passes slowly and only in one direction. Unlike electrical synapses, where no neurotransmitters are involved, in chemical synapses neurotransmitters are involved here.
9. Where are the specific receptors of neurotransmitters present?
a) Synaptic cleft
b) Post-synaptic membrane
c) Pre-synaptic membrane
d) Synaptic vesicle
View Answer
Explanation: The released neurotransmitters bind to their specific receptors which are present on the post-synaptic membrane. The new potential developed may be either excitatory or inhibitory.
10. Which of the following is the central processing organ of our body?
a) Heart
b) Kidney
c) Brain
d) Spinal cord
View Answer
Explanation: The brain is the central information processing organ of our body and acts as the command and control system. It is the site for processing vision, hearing, speech, memory, intelligence, emotions, and thoughts.
11. Which of the following is not the function of the brain?
a) Thermoregulation
b) Circadian rhythm of our body
c) Voluntary movements
d) Generates heartbeat
View Answer
Explanation: Our brain controls the voluntary movements, the balance of the body, functioning of vital involuntary organs, thermoregulation, hunger, thirst, circadian rhythms of our body, activities of several endocrine glands and human behaviour.
12. The brain can be divided into three major parts.
a) True
b) False
View Answer
Explanation: The brain can be divided into three major parts:
i. Forebrain
ii. Midbrain
iii. Hindbrain
The human brain is well protected by the skull. Inside the skull, the brain is covered by cranial meninges.
13. Which of the following is not a part of the cranial meninges?
a) Dura mater
b) Arachnoid
c) Pia mater
d) Corpus callosum
View Answer
Explanation: Cranial meninges consist of an outer layer called dura mater, a very thin middle layer called arachnoid and an inner layer which is not in contact with the brain tissue, pia mater.
14. Which of the following is not a part of the forebrain?
a) Cerebrum
b) Cerebellum
c) Thalamus
d) Hypothalamus
View Answer
Explanation: The forebrain consists of:
i. Cerebrum
ii. Thalamus
iii. Hypothalamus
The layer of cells which covers the cerebral hemispheres is called the cerebral cortex and is thrown into prominent folds.
15. Which of the following forms the major part of the human brain?
a) Cerebrum
b) Medulla oblongata
c) Cerebellum
d) Hypothalamus
View Answer
Explanation: Cerebrum forms a major part of the human brain. A deep cleft divides the cerebrum longitudinally into two halves, which are termed as the left and the right cerebral hemispheres which are connected by the corpus callosum.
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