Question 1

Which of the following statements best explains why myelinated axons conduct impulses faster than unmyelinated axons?

Accepted Answer

The myelin sheath electrically insulates the axon, enabling saltatory conduction where action potentials jump between nodes of Ranvier.

Question 2

A patient is diagnosed with Multiple Sclerosis (MS). Which of the following best describes the primary cellular target of this disease?

Accepted Answer

Oligodendrocytes in the central nervous system

Question 3

Which equation correctly represents the relationship between conduction velocity ($$v$$), fiber diameter ($$d$$), and myelination in axons?

Accepted Answer

$$v = k \cdot d$$ for unmyelinated fibers, $$v = k' \cdot d$$ for myelinated fibers, where $$k' \u003e k$$

Question 4

Which glial cell type is responsible for forming the myelin sheath in the peripheral nervous system (PNS)?

Accepted Answer

Schwann cells

Question 5

A nerve fiber is classified as a 'B fiber.' Which of the following best describes its properties?

Accepted Answer

Weak myelination, conduction velocity of 10–20 m/s

Question 6

Which of the following best describes the function of astrocytes in the central nervous system?

Accepted Answer

Maintaining homeostasis of the interstitial environment and contributing to the blood-brain barrier

Question 7

During saltatory conduction, where are action potentials generated along a myelinated axon?

Accepted Answer

At the nodes of Ranvier

Question 8

Which of the following best explains why the central nervous system (CNS) has poor axon regeneration compared to the peripheral nervous system (PNS)?

Accepted Answer

Oligodendrocytes in the CNS inhibit axon regrowth, while Schwann cells in the PNS promote it.

Question 9

Which of the following is a correct sequence of events during nerve regeneration in the PNS after axonal injury?

Accepted Answer

Macrophages clear debris, Schwann cells align, axon sprouts grow, new myelin forms

Question 10

A patient presents with rapid-onset muscle weakness following a viral infection. Which disorder affecting the PNS myelin is most likely?

Accepted Answer

Guillain-Barré syndrome

Question 11

Which of the following best describes the main difference between chemical and electrical synapses?

Accepted Answer

Chemical synapses use neurotransmitters for unidirectional signaling, while electrical synapses use gap junctions for bidirectional signaling.

Question 12

Which of the following neurotransmitters is classified as a monoamine and is involved in mood regulation?

Accepted Answer

Serotonin

Question 13

Which of the following best describes the role of microglial cells in the central nervous system?

Accepted Answer

Acting as defense cells and removing debris

Question 14

Which of the following best explains why axons do not contain Nissl bodies?

Accepted Answer

Axons lack rough endoplasmic reticulum, so protein synthesis is decreased and proteins must be transported from the cell body.

Question 15

Which of the following best describes the function of ependymal cells in the CNS?

Accepted Answer

Ensuring circulation of cerebrospinal fluid by lining fluid-filled cavities

Question 16

Which of the following best describes the structure of the oral mucosa in the oral cavity proper?

Accepted Answer

Stratified squamous epithelium, mainly nonkeratinized, with a lamina propria of connective tissue

Question 17

Which of the following best explains why the hard palate and gingiva are exceptions in the oral mucosa?

Accepted Answer

They are covered by keratinized stratified squamous epithelium to withstand mechanical stress during mastication.

Question 18

Which of the following best describes the organization of the digestive tract from the oral cavity to the anus?

Accepted Answer

Oral cavity → pharynx → esophagus → stomach → small intestine → large intestine → anus

Question 19

Which of the following best describes the function of dietary fibers in the human diet?

Accepted Answer

They promote healthy bowel movements and support gut health.

Question 20

A cross-section of a peripheral nerve shows several layers. Which of the following correctly matches the structure to its function?

Accepted Answer

Epineurium: surrounds the entire nerve, providing protection and support

Human Biology & Histology: Nervous Tissue and Digestive Tract Structure

Study Guide - Practice Questions