Question 1

The structural and functional unit of the nervous system is the:

Accepted Answer

Neuron. The neuron (nerve cell) is the basic unit that conducts nerve impulses.

Question 2

The part of a neuron that receives impulses and carries them toward the cell body is the:

Accepted Answer

Dendrite. Dendrites receive signals and carry them toward the cell body; the axon carries impulses away.

Question 3

At rest, the inside of a neuron's membrane is ______ relative to the outside:

Accepted Answer

Negatively charged. The resting membrane potential (~ −70 mV) keeps the axon interior negative relative to the outside.

Question 4

During the generation of an action potential, the membrane suddenly becomes permeable to ______ ions:

Accepted Answer

Sodium (Na⁺). Depolarisation occurs when Na⁺ channels open and Na⁺ rushes in, reversing the membrane polarity.

Question 5

The junction between two neurons across which an impulse passes is the:

Accepted Answer

Synapse. A synapse is the junction between the axon terminal of one neuron and the dendrite of the next.

Question 6

At a chemical synapse, the impulse is transmitted by molecules called:

Accepted Answer

Neurotransmitters. Neurotransmitters (e.g. acetylcholine) diffuse across the synaptic cleft to relay the impulse.

Question 7

The largest and most developed part of the human brain, controlling thought and voluntary actions, is the:

Accepted Answer

Cerebrum. The cerebrum is the seat of intelligence, memory, and voluntary control.

Question 8

The part of the brain that controls balance and coordination of muscular activity is the:

Accepted Answer

Cerebellum. The cerebellum coordinates and maintains posture, balance and precise muscular movement.

Question 9

A rapid, automatic, involuntary response to a stimulus (e.g. knee-jerk) is called a:

Accepted Answer

Reflex action. A reflex action is an involuntary, automatic response mediated by the spinal cord (reflex arc).

Question 10

The light-sensitive layer of the eye that contains the photoreceptor cells is the:

Accepted Answer

Retina. The retina holds the rods and cones (photoreceptors) that detect light.

Question 11

The autonomic nervous system is divided into two antagonistic parts:

Accepted Answer

Sympathetic and parasympathetic. The ANS has the sympathetic ("fight or flight") and parasympathetic ("rest and digest") divisions.

Question 12

Conduction of a nerve impulse is faster in a myelinated fibre because:

Accepted Answer

The impulse jumps from node to node (saltatory conduction). In myelinated axons, the impulse leaps between nodes of Ranvier, making conduction much faster than in unmyelinated fibres.

Question 13

The all-or-none law of nerve impulses states that:

Accepted Answer

A stimulus above threshold produces a full-sized impulse; below threshold produces none. Once threshold is reached, the action potential is of a fixed magnitude regardless of further stimulus strength.

Question 14

At the peak of an action potential, the membrane potential becomes about ______, a state called:

Accepted Answer

+30 mV; depolarised (reversed polarity). At the action potential peak the potential reverses to about +30 mV (inside positive) — depolarisation.

Question 15

Neurotransmitters are released from the pre-synaptic terminal by:

Accepted Answer

Exocytosis of synaptic vesicles into the synaptic cleft. Synaptic vesicles fuse with the pre-synaptic membrane and release neurotransmitter by exocytosis.

Question 16

The key difference between chemical and electrical synapses is that chemical synapses:

Accepted Answer

Use neurotransmitters and have a synaptic delay; electrical use direct ion flow with no delay. Chemical synapses transmit via neurotransmitters (with a brief delay); electrical synapses conduct current directly and rapidly.

Question 17

The three main regions of the human brain are the:

Accepted Answer

Forebrain, midbrain and hindbrain. The brain is organised into forebrain (cerebrum, thalamus, hypothalamus), midbrain, and hindbrain (pons, cerebellum, medulla).

Question 18

The structure that acts as a major coordinating/relay centre for sensory and motor signalling, located in the forebrain, is the:

Accepted Answer

Thalamus. The thalamus is a relay station that channels sensory (and some motor) information to the cerebrum.

Question 19

The correct sequence of the reflex arc is:

Accepted Answer

Receptor → sensory neuron → spinal cord (interneuron) → motor neuron → effector. A reflex arc: receptor → afferent (sensory) neuron → CNS interneuron → efferent (motor) neuron → effector (muscle/gland).

Question 20

The three ear ossicles (malleus, incus, stapes) in the middle ear function to:

Accepted Answer

Amplify and transmit sound vibrations to the inner ear. The ossicles amplify and relay vibrations from the eardrum to the oval window of the cochlea.

Neural Control and Coordination — NEET Biology MCQs with Solutions

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Sample questions with solutions