Nervous System Practice Questions
20 free Nervous System practice questions for the General Science. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which part of the neuron is responsible for receiving incoming signals from other neurons?
- A Axon
- B Dendrite
- C Myelin sheath
- D Node of Ranvier
Correct answer: Dendrite
Dendrites are the branched extensions of a neuron that act as the primary receptors for chemical messages (neurotransmitters) from other cells. They conduct these electrical impulses toward the cell body.
The 'resting potential' of a typical neuron is approximately -70 mV. Which ion's leakage out of the cell is primarily responsible for maintaining this negative internal charge?
- A Sodium (Na+)
- B Calcium (Ca2+)
- C Potassium (K+)
- D Chloride (Cl-)
Correct answer: Potassium (K+)
Potassium ions leak out of the cell through non-gated channels more easily than sodium ions leak in. This loss of positive charge, combined with large internal anions, creates the negative resting membrane potential.
Which division of the nervous system is responsible for the 'fight or flight' response during stressful situations?
- A Parasympathetic nervous system
- B Sympathetic nervous system
- C Somatic nervous system
- D Central nervous system
Correct answer: Sympathetic nervous system
The sympathetic nervous system accelerates heart rate, dilates pupils, and redirects blood flow to muscles to prepare the body for physical exertion. It operates as part of the autonomic nervous system.
What is the primary function of the myelin sheath in the peripheral nervous system?
- A To produce neurotransmitters
- B To protect the neuron from viral infection
- C To increase the speed of nerve impulse conduction
- D To act as a physical bridge connecting two separate neurons
Correct answer: To increase the speed of nerve impulse conduction
Myelin acts as an electrical insulator, allowing for saltatory conduction where the action potential 'jumps' between Nodes of Ranvier. This significantly increases the speed at which signals travel down the axon.
Which lobe of the cerebral cortex is primarily associated with visual processing?
- A Frontal lobe
- B Parietal lobe
- C Temporal lobe
- D Occipital lobe
Correct answer: Occipital lobe
The occipital lobe, located at the back of the brain, contains the primary visual cortex. It processes information such as color, light, and movement received from the retinas.
Which structure in the brain acts as the 'relay station,' filtering and directing sensory information to the appropriate areas of the cerebral cortex?
- A Hypothalamus
- B Thalamus
- C Cerebellum
- D Medulla oblongata
Correct answer: Thalamus
The thalamus processes all sensory input (except smell) before sending it to higher brain centers. It plays a key role in regulating consciousness, sleep, and alertness.
The gap between the axon terminal of one neuron and the dendrite of another is called the:
- A Synapse
- B Axon hillock
- C Ganglion
- D Ventricle
Correct answer: Synapse
The synapse is the functional junction where chemical neurotransmitters are released to transmit a signal to the next cell. This allows for complex communication and modulation within the nervous system.
Damage to the cerebellum would most likely result in which of the following symptoms?
- A Loss of memory
- B Inability to understand or process language
- C Loss of balance and coordination
- D Inability to feel pain
Correct answer: Loss of balance and coordination
The cerebellum is responsible for fine-tuning motor movements, posture, and balance. While it does not initiate movement, it ensures that movements are smooth and precisely timed.
Which neuroglial cells are responsible for forming the blood-brain barrier (BBB)?
- A Microglia
- B Oligodendrocytes
- C Astrocytes
- D Ependymal cells
Correct answer: Astrocytes
Astrocytes have 'end-feet' that wrap around capillaries in the brain, inducing the formation of tight junctions. This creates a highly selective barrier that protects the brain from harmful substances in the blood.
During an action potential, the rapid 'depolarization' phase is caused by the inward movement of which ion?
- A Potassium (K+)
- B Sodium (Na+)
- C Chloride (Cl-)
- D Magnesium (Mg2+)
Correct answer: Sodium (Na+)
When the threshold is reached, voltage-gated sodium channels open, allowing Na+ to rush into the cell down its electrochemical gradient. This makes the inside of the neuron briefly positive.
Which part of the brainstem is essential for regulating involuntary functions like heart rate, breathing, and blood pressure?
- A The midbrain
- B Pons Varolii
- C Medulla oblongata
- D Corpus callosum
Correct answer: Medulla oblongata
The medulla oblongata contains vital centers for cardiovascular and respiratory regulation. Damage to this area is often fatal because it controls the basic life-support systems of the body.
In a simple reflex arc, such as the knee-jerk reflex, where is the integration center typically located?
- A The brain
- B The spinal cord
- C The sensory receptor
- D The skeletal muscle
Correct answer: The spinal cord
Reflex arcs allow for rapid responses by bypassing the brain for initial processing. The sensory neuron carries the signal to the spinal cord, where it is immediately passed to a motor neuron.
What is the primary role of the neurotransmitter Acetylcholine at the neuromuscular junction?
- A To inhibit contraction of the muscle
- B To trigger calcium release in the muscle
- C To promote the growth of new neurons
- D To reduce the sensitivity of pain receptors
Correct answer: To trigger calcium release in the muscle
Acetylcholine binds to receptors on the muscle fiber's motor end plate, leading to depolarization. This electrical signal then triggers the release of calcium ions, which are necessary for the muscle to contract.
Which structure connects the left and right hemispheres of the brain, allowing them to communicate?
- A The hippocampus
- B Corpus callosum
- C The basal ganglia
- D The amygdala
Correct answer: Corpus callosum
The corpus callosum is a large bundle of white matter (myelinated axons) that bridges the two hemispheres. It ensures that both sides of the brain can share information and coordinate complex tasks.
The meninges are three protective membranes surrounding the brain and spinal cord. Which layer is the tough, outermost layer?
- A Pia mater
- B Arachnoid mater
- C Dura mater
- D Choroid plexus
Correct answer: Dura mater
The dura mater is the most superficial and thickest of the meningeal layers. It provides a durable protective covering and contains large blood vessels that drain from the brain.
Which cranial nerve is primarily responsible for the sense of smell?
- A Optic nerve (II)
- B Facial nerve (VII)
- C Olfactory nerve (I)
- D Vagus nerve (X)
Correct answer: Olfactory nerve (I)
Cranial nerve I, the olfactory nerve, carries sensory information from the nasal mucosa to the olfactory bulbs. It is the only sensory pathway that reaches the cerebral cortex without first passing through the thalamus.
What happens during the 'hyperpolarization' phase of an action potential?
- A The membrane potential becomes more negative than resting.
- B The membrane potential becomes positive.
- C Voltage-gated sodium channels open widely.
- D Neurotransmitters are reabsorbed into the axon terminal.
Correct answer: The membrane potential becomes more negative than resting.
Hyperpolarization occurs because potassium channels are slow to close, allowing too much K+ to leave the cell. This temporarily makes the neuron less likely to fire another action potential (refractory period).
Which part of the brain is the primary regulator of homeostasis, controlling thirst, hunger, and body temperature?
- A Pituitary gland
- B Pineal gland
- C Hypothalamus
- D Thalamus
Correct answer: Hypothalamus
The hypothalamus links the nervous system to the endocrine system via the pituitary gland. It monitors blood composition and coordinates the body's internal environment to maintain stability.
In the spinal cord, 'white matter' is mainly composed of:
- A Cell bodies of neurons
- B Myelinated axons
- C Dendrites and synapses
- D Cerebrospinal fluid
Correct answer: Myelinated axons
White matter consists of bundles of myelinated axons (tracts) that transmit signals up and down the spinal cord. The 'gray matter' contains the cell bodies and unmyelinated components.
The 'All-or-None' principle of nerve impulse conduction means that:
- A All neurons in a nerve fire at the same time.
- B A neuron either fires a full action potential or none at all.
- C Energy is only used when the neuron is at rest.
- D The brain uses all its neurons for every thought.
Correct answer: A neuron either fires a full action potential or none at all.
If a stimulus is strong enough to reach the threshold potential, an action potential of constant magnitude is generated. Increasing the stimulus strength does not increase the size of the signal, only its frequency.