Human Physiology and Nervous System Practice Quiz (11 questions)

1. What is the nephron's primary role in the kidney?

A. To produce red blood cells in the kidney

B. To regulate blood pressure by pumping blood

C. To filter blood and form urine

D. To store urine before it leaves the body

Answer: (C)

Explanation

A nephron is a filtering unit in the kidney's cortex and medulla that filters blood to form urine. The kidneys stimulate red blood cell production by secreting erythropoietin, but the nephron itself is defined by filtration and urine formation.

2. An enzyme's final product slows the enzyme's activity, reducing further production of that product. What type of feedback is occurring?

A. Feedforward stimulation

B. Positive feedback

C. Negative feedback

D. Predictive feedback

Answer: (C)

Explanation

Negative feedback occurs when a reaction's final product slows or stops the activity of the enzyme that initiated the reaction. Positive feedback is the plausible alternative, but it increases rather than reduces the process.

3. Which sequence best describes the processes involved in urine formation?

A. Tubular reabsorption, glomerular filtration, tubular secretion, and water retention in the kidney

B. Tubular secretion, glomerular filtration, water secretion into the urine, and tubular reabsorption

C. Glomerular filtration, tubular reabsorption, tubular secretion, and further water reabsorption into the blood

D. Glomerular filtration, tubular secretion, water reabsorption into the blood, and tubular reabsorption

Answer: (C)

Explanation

Urine formation involves glomerular filtration, tubular reabsorption, tubular secretion, and further water reabsorption into the blood. A plausible alternative places tubular secretion before reabsorption and describes water as being secreted into urine, which does not match the stated process.

4. Before a predictable change occurs, the body takes action to prepare for it. What type of feedback does this illustrate?

A. Reactive feedback

B. Predictive feedback

C. Positive feedback

D. Negative feedback

Answer: (B)

Explanation

Predictive feedback occurs when the body anticipates a change and acts in advance to prepare for it. Negative feedback responds by slowing a process, rather than describing anticipatory preparation.

5. What does water-sodium homeostasis mean?

A. Maintaining balance between the body's water and sodium levels

B. Controlling blood carbon dioxide through changes in respiration

C. Regulating potassium levels by altering their excretion in urine

D. Keeping blood pH stable by eliminating hydrogen ions

Answer: (A)

Explanation

Water-sodium homeostasis is the maintenance of balance between water and sodium in the body. Blood pH regulation also involves the kidneys, but it concerns hydrogen ions rather than the water-sodium balance.

6. Which hormone decrease characterizes andropause?

A. A decline in follicle-stimulating hormone at puberty

B. A decline in estrogen and progesterone with age

C. A decline in inhibin secretion that raises testosterone

D. A decline in testosterone with age

Answer: (D)

Explanation

Andropause refers to an age-related decrease in testosterone. The decrease in estrogen and progesterone describes menopause, not andropause.

7. What is the primary role of Schwann cells in a neuron?

A. They form myelin around the axon, helping nerve impulses travel faster between nodes of Ranvier.

B. They carry messages from the central nervous system to muscles or glands.

C. They receive incoming information from other neurons and pass it to the cell body.

D. They process incoming signals and organize a response within the neuron.

Answer: (A)

Explanation

Schwann cells form the myelin sheath around axons, which speeds impulse transmission between nodes of Ranvier. Dendrites receive information, but they do not form myelin around the axon.

8. How does an electrical synapse differ from a chemical synapse in transmitting a message between cells?

A. An electrical synapse passes ions through intercellular channels, while a chemical synapse uses neurotransmitters.

B. An electrical synapse releases neurotransmitters into a gap, while a chemical synapse passes ions through intercellular channels.

C. An electrical synapse depends on neurotransmitter receptors, while a chemical synapse opens voltage-gated channels between cells.

D. An electrical synapse passes signals from axon to dendrite, while a chemical synapse passes them from dendrite to axon.

Answer: (A)

Explanation

Electrical synapses transmit an action potential directly through intercellular channels that allow ions to flow, whereas chemical synapses convey messages using neurotransmitters. The second choice reverses these defining mechanisms.

9. If a drug prevents neurotransmitter breakdown after it has bound to receptors at a chemical synapse, what is the likely immediate effect?

A. The electrical signal is prevented from reaching the synapse.

B. Calcium entry is blocked before neurotransmitter release begins.

C. The neurotransmitter remains available longer to act on receptors.

D. The neurotransmitter is prevented from binding to its receptors.

Answer: (C)

Explanation

Preventing breakdown prolongs the neurotransmitter's availability at the synapse, allowing it to continue acting on receptors. Blocking calcium entry would instead interfere with neurotransmitter release, which occurs earlier in synaptic signaling.

10. A drug is designed to keep a neurotransmitter available in the synapse for longer without preventing its release. Which mechanism should the drug use?

A. Prevent neurotransmitter secretion from the releasing neuron

B. Block neurotransmitter reuptake into the releasing neuron

C. Block the neurotransmitter's receptor

D. Imitate the neurotransmitter at its receptor

Answer: (B)

Explanation

Blocking reuptake leaves the neurotransmitter in the synapse for longer after release. Preventing secretion would reduce the amount released rather than prolong its presence.

11. Which sequence describes the pathway of a spinal reflex from detecting a stimulus to producing a response?

A. Sensory neuron → receptor → motor neuron → interneuron → muscle

B. Receptor → sensory neuron → interneuron → motor neuron → muscle

C. Receptor → sensory neuron → motor neuron → interneuron → muscle

D. Receptor → motor neuron → interneuron → sensory neuron → muscle

Answer: (B)

Explanation

A reflex pathway carries information from a receptor through a sensory neuron and interneuron, then sends a response through a motor neuron to a muscle. Placing the motor neuron before the interneuron reverses the response pathway.