Nervous System and the Senses — HS Anatomy & Physiology practice questions

Which part of the brainstem controls breathing rate and heart rate?

1. Medulla oblongata
2. Cerebellum
3. Frontal lobe
4. Thalamus

Answer: A — Medulla oblongata

A) Correct — It contains the respiratory and cardiovascular centers. B) Coordinates movement. C) Handles planning and voluntary movement. D) Relays sensory information to the cortex.

In a neuron, dendrites ___ and the axon ___.

1. send signals; receive signals
2. make myelin; stores neurotransmitters
3. hold the nucleus; receives signals
4. receive signals; sends signals

Answer: D — receive signals; sends signals

D) Correct — Signals travel from dendrites to the cell body, then along the axon. A) Reverses the direction. B) Glial cells make myelin. C) The cell body holds the nucleus.

During the rising phase of an action potential, which ion rushes into the neuron?

1. Potassium (K⁺)
2. Chloride (Cl⁻)
3. Calcium (Ca²⁺)
4. Sodium (Na⁺)

Answer: D — Sodium (Na⁺)

D) Correct — Na⁺ entry depolarizes the membrane. A) K⁺ leaves the cell during repolarization. B) Cl⁻ entry usually makes the neuron less likely to fire. C) Ca²⁺ entry triggers neurotransmitter release at the terminal.

In the retina, cones ___, while rods ___.

1. work in dim light; detect color
2. focus light; detect color
3. detect color; work in dim light
4. detect sound; detect light

Answer: C — detect color; work in dim light

C) Correct — Cones need bright light; rods are very sensitive. A) Reverses the two. B) The lens focuses light. D) Rods and cones respond only to light.

In a spinal reflex arc, the signal travels in which order?

1. Receptor → sensory neuron → interneuron → motor neuron → effector
2. Receptor → motor neuron → interneuron → sensory neuron → effector
3. Receptor → sensory neuron → brain → motor neuron → effector
4. Effector → motor neuron → interneuron → sensory neuron → receptor

Answer: A — Receptor → sensory neuron → interneuron → motor neuron → effector

A) Correct — The spinal cord handles the reflex, skipping the brain for speed. B) Reverses the neuron order. C) Routing through the brain would slow the reflex. D) Runs the whole arc backward.

At a chemical synapse, a signal crosses the synaptic cleft when:

1. neurotransmitters bind receptors on the next cell
2. the action potential jumps directly across the gap
3. the two neurons fuse together
4. hormones carry it through the blood

Answer: A — neurotransmitters bind receptors on the next cell

A) Correct — Ca²⁺ entry triggers their release from the axon terminal. B) At chemical synapses the signal is carried by chemicals. C) A cleft separates the cells. D) Describes endocrine signaling.

Myelin speeds up nerve signals because:

1. it creates new action potentials on its own
2. it stores extra neurotransmitter
3. the signal jumps between gaps in it
4. it makes the axon shorter

Answer: C — the signal jumps between gaps in it

C) Correct — This jumping (saltatory conduction) is faster than continuous conduction. A) Myelin is an insulator; the axon makes the signals. B) Neurotransmitters are stored in axon terminals. D) Axon length does not change.

Reflex arc?

Rapid involuntary response. Sensory neuron → spinal cord → motor neuron. Bypasses brain.

Action potential?

Electrical signal traveling axon. Sodium influx → depolarization → potassium efflux → repolarization.

Cerebrum lobes?

Frontal (thought, motor), parietal (touch), temporal (hearing, memory), occipital (vision).

Synapse?

Junction between two neurons. Chemical (most) or electrical.