Q.1 Which part of a neuron receives incoming signals from other neurons?
Axon
Dendrites
Myelin sheath
Node of Ranvier
Explanation - Dendrites are the branched extensions of a neuron that receive chemical and electrical signals from other neurons.
Correct answer is: Dendrites
Q.2 The resting membrane potential of a typical neuron is approximately:
+30 mV
0 mV
-70 mV
-120 mV
Explanation - Neurons maintain a resting potential of about -70 mV due to ion gradients across the plasma membrane.
Correct answer is: -70 mV
Q.3 Which ion is primarily responsible for depolarization during an action potential?
Potassium (K+)
Sodium (Na+)
Calcium (Ca2+)
Chloride (Cl−)
Explanation - During depolarization, voltage-gated sodium channels open, allowing Na+ influx and making the cell interior more positive.
Correct answer is: Sodium (Na+)
Q.4 The myelin sheath increases the speed of conduction by:
Continuous conduction
Saltatory conduction
Decreasing ion permeability
Blocking Na+ channels
Explanation - Myelin enables saltatory conduction, where action potentials jump between nodes of Ranvier, greatly increasing conduction speed.
Correct answer is: Saltatory conduction
Q.5 Which neurotransmitter is primarily used at the neuromuscular junction?
Serotonin
Dopamine
Acetylcholine
GABA
Explanation - Acetylcholine is the neurotransmitter released by motor neurons at the neuromuscular junction to stimulate muscle contraction.
Correct answer is: Acetylcholine
Q.6 Which type of glial cell forms the myelin sheath in the central nervous system?
Schwann cells
Oligodendrocytes
Astrocytes
Microglia
Explanation - Oligodendrocytes form myelin in the CNS, while Schwann cells perform this function in the PNS.
Correct answer is: Oligodendrocytes
Q.7 During repolarization of an action potential, which ion moves out of the neuron?
Na+
K+
Ca2+
Cl−
Explanation - Repolarization occurs when potassium ions (K+) exit the cell, restoring the negative resting potential.
Correct answer is: K+
Q.8 Which region of the brain controls balance and coordination?
Cerebrum
Cerebellum
Medulla oblongata
Thalamus
Explanation - The cerebellum is responsible for fine-tuning motor activity, maintaining posture, and coordinating balance.
Correct answer is: Cerebellum
Q.9 The autonomic nervous system is divided into:
Somatic and motor
Parasympathetic and sympathetic
Sensory and motor
Central and peripheral
Explanation - The autonomic nervous system has two major divisions: sympathetic (fight-or-flight) and parasympathetic (rest-and-digest).
Correct answer is: Parasympathetic and sympathetic
Q.10 Which brain structure acts as a relay station for sensory information?
Hypothalamus
Thalamus
Cerebellum
Hippocampus
Explanation - The thalamus processes and relays most sensory information to the cerebral cortex for interpretation.
Correct answer is: Thalamus
Q.11 Nodes of Ranvier are important because they:
Store neurotransmitters
Increase signal speed
Block ion flow
Generate energy
Explanation - Nodes of Ranvier allow action potentials to jump along the axon, speeding up conduction.
Correct answer is: Increase signal speed
Q.12 Which lobe of the brain is primarily responsible for vision?
Frontal lobe
Temporal lobe
Occipital lobe
Parietal lobe
Explanation - The occipital lobe, located at the back of the brain, is the main center for processing visual information.
Correct answer is: Occipital lobe
Q.13 Which neurotransmitter is most associated with mood regulation and depression?
Dopamine
Serotonin
Acetylcholine
GABA
Explanation - Serotonin regulates mood, sleep, and appetite; imbalances are linked to depression and anxiety disorders.
Correct answer is: Serotonin
Q.14 The blood-brain barrier is formed mainly by:
Astrocytes
Oligodendrocytes
Microglia
Schwann cells
Explanation - Astrocytes help form the blood-brain barrier, regulating the movement of substances between blood and brain tissue.
Correct answer is: Astrocytes
Q.15 Which ion influx triggers neurotransmitter release at synapses?
Na+
K+
Ca2+
Cl−
Explanation - The entry of calcium ions (Ca2+) into presynaptic terminals triggers synaptic vesicle fusion and neurotransmitter release.
Correct answer is: Ca2+
Q.16 The sympathetic nervous system primarily uses which neurotransmitter at target organs?
Acetylcholine
Dopamine
Norepinephrine
Serotonin
Explanation - The sympathetic division releases norepinephrine at most target organs to prepare the body for fight-or-flight.
Correct answer is: Norepinephrine
Q.17 Which brain structure regulates body temperature, hunger, and thirst?
Cerebellum
Thalamus
Hypothalamus
Medulla
Explanation - The hypothalamus is a key homeostatic regulator controlling temperature, hunger, thirst, and hormone release.
Correct answer is: Hypothalamus
Q.18 Which part of the neuron carries impulses away from the cell body?
Dendrites
Axon
Soma
Synapse
Explanation - The axon transmits electrical impulses away from the cell body toward other neurons or effectors.
Correct answer is: Axon
Q.19 Which glial cells act as immune defenders in the CNS?
Astrocytes
Oligodendrocytes
Microglia
Ependymal cells
Explanation - Microglia act as macrophages in the CNS, removing pathogens and debris.
Correct answer is: Microglia
Q.20 What is the main excitatory neurotransmitter in the central nervous system?
Glutamate
GABA
Acetylcholine
Serotonin
Explanation - Glutamate is the primary excitatory neurotransmitter in the CNS, crucial for learning and memory.
Correct answer is: Glutamate
Q.21 Which part of the nervous system controls voluntary muscle movements?
Autonomic nervous system
Somatic nervous system
Sympathetic system
Parasympathetic system
Explanation - The somatic nervous system controls voluntary skeletal muscle movements through motor neurons.
Correct answer is: Somatic nervous system
Q.22 The refractory period ensures that:
Signals move backward
Signals move only one way
Neurons never fatigue
Ions stop moving
Explanation - The refractory period prevents action potentials from traveling backward, ensuring one-way signal propagation.
Correct answer is: Signals move only one way
Q.23 Which brain structure connects the two cerebral hemispheres?
Thalamus
Corpus callosum
Medulla
Hippocampus
Explanation - The corpus callosum is a bundle of nerve fibers that allows communication between the left and right hemispheres.
Correct answer is: Corpus callosum
Q.24 Which lobe of the brain is involved in decision-making and personality?
Temporal
Frontal
Occipital
Parietal
Explanation - The frontal lobe controls higher cognitive functions, decision-making, and aspects of personality.
Correct answer is: Frontal
Q.25 Which neurotransmitter is the main inhibitory neurotransmitter in the CNS?
Acetylcholine
GABA
Serotonin
Glutamate
Explanation - Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter, reducing neural excitability.
Correct answer is: GABA