Quiz: Reflex Behaviors and Nervous System — 7 questions

1. What is the primary role of the nervous system in the body?

A. It produces protective membranes around the central nervous system

B. It rapidly communicates between organs through nerve fibers

C. It slowly regulates organs through circulating chemical signals

D. It transports oxygen between organs through branching vessels

Answer: (B)

Explanation

The nervous system provides rapid communication between organs by maintaining connections through nerve fibers. The endocrine system is associated with chemical signaling rather than the fiber-based communication described here.

2. What is the primary function of the nervous system?

A. A system responsible for hormone production and regulation

B. A structure that stores genetic information in cells

C. A rapid communication system connecting all organs through nerve fibers

D. A network that controls only voluntary muscle movements

Answer: (C)

Explanation

The nervous system's main role is to facilitate rapid communication between organs via nerve fibers. It is not primarily responsible for hormone production, voluntary control alone, or genetic storage.

3. Which structures together constitute the nerve centers of the nervous system?

A. The meninges and the nerve fibers

B. The sensory receptors and the motor fibers

C. The cranial nerves and the spinal nerves

D. The encephalon and the spinal cord

Answer: (D)

Explanation

The nerve centers consist of the encephalon—containing the brain, brainstem, and cerebellum—and the spinal cord. The cranial and spinal nerves are peripheral structures, while the meninges protect the centers.

4. Which of the following structures is NOT contained within the encephalon?

A. The brain

B. The brainstem

C. The spinal cord

D. The cerebellum

Answer: (C)

Explanation

The encephalon includes the brain, brainstem, and cerebellum, but the spinal cord is part of the central nervous system outside the encephalon.

5. Which description best defines a neuron?

A. A supporting cell that surrounds and nourishes neurons

B. A connective fiber that links organs without signaling

C. An excitable cell that conducts information

D. A protective membrane that covers nerve centers

Answer: (C)

Explanation

A neuron is an excitable and stimulable cell specialized for conducting information. Glial cells primarily surround, protect, and nourish neurons rather than serving as the main information-conducting cells.

6. What is the main role of glial cells in the nervous system?

A. To transmit electrical signals between neurons

B. To generate nerve impulses

C. To carry oxygen to nerve cells

D. To protect and nourish neurons

Answer: (D)

Explanation

Glial cells primarily serve to protect and nourish neurons, supporting their function. Unlike neurons, they do not transmit electrical signals or generate impulses.

7. A signal must travel from a sensory receptor toward another neuron or an effector cell; which neuronal pathway best describes this process?

A. Terminal arborization integrates the signal, then Schwann cells conduct it through the neuron

B. Dendrites receive and integrate the signal, then a myelinated axon carries it onward

C. The cell body receives the signal, then the myelin sheath releases it to the gland

D. A myelinated axon receives the signal, then dendrites carry it toward the receptor

Answer: (B)

Explanation

Dendrites receive and integrate information, while the myelinated axon sends the message toward another neuron, muscle cell, or glandular cell. The other choices assign receiving or conducting functions to structures that support or terminate neuronal signaling.