Quiz: Neural Tissue Organization and Function — 9 domande

1. What is a neuron in neural tissue?

A. A connective tissue cell that forms the structural framework of the nervous system

B. A type of glial cell that maintains the blood-brain barrier

C. An electrically excitable cell that transfers and processes information within the nervous system

D. A supporting cell that insulates axons in the central nervous system

Answer: (C)

Spiegazione

A neuron is an electrically excitable cell that transfers and processes information within the nervous system, characterized by its soma, dendrites, and axon, and is responsible for transmitting electrical signals.

2. Which of the following cell types is primarily responsible for forming the myelin sheath in the central nervous system?

A. Oligodendrocytes

B. Schwann cells

C. Astrocytes

D. Microglia

Answer: (A)

Spiegazione

Oligodendrocytes are responsible for myelinating axons in the CNS, whereas Schwann cells perform this in the PNS. Astrocytes and microglia have different supportive and immune functions.

3. What is the primary function of the axon in a neuron?

A. Generate cerebrospinal fluid

B. Support and nourish the neuron

C. Transmit electrical impulses away from the soma

D. Receive signals from other neurons

Answer: (C)

Spiegazione

The axon is responsible for transmitting electrical impulses away from the neuron's cell body (soma) to other neurons or effectors, making it the primary pathway for outgoing signals in a neuron.

4. What is the primary difference between gray matter and white matter in the nervous system?

A. Gray matter contains myelinated fibers; white matter contains neuron cell bodies

B. Gray matter contains neuron cell bodies and unmyelinated fibers; white matter contains myelinated axons

C. Gray matter is found only in the brain; white matter is only in the spinal cord

D. Gray matter is made up of efferent neurons; white matter is made up of afferent neurons

Answer: (B)

Spiegazione

Gray matter contains neuron cell bodies, dendrites, and unmyelinated fibers. White matter is mainly composed of myelinated axons, facilitating rapid communication.

5. How do bipolar and pseudounipolar neurons differ in their structural organization?

A. Bipolar neurons have one dendrite and one axon, while pseudounipolar neurons have a single process that splits into two branches.

B. Bipolar neurons are found only in the CNS, while pseudounipolar neurons are exclusively in the PNS.

C. Bipolar neurons have a single process that splits into two branches, while pseudounipolar neurons have one dendrite and one axon.

D. Bipolar neurons have multiple dendrites and a single axon, whereas pseudounipolar neurons lack dendrites entirely.

Answer: (A)

Spiegazione

Bipolar neurons have one dendrite and one axon, making their structure distinct, whereas pseudounipolar neurons have a single process that bifurcates into two branches, functioning as both dendrite and axon. This structural difference is fundamental in neuron classification and relates to their roles in sensory pathways.

6. Which classification of neurons is most commonly found in the motor neurons of the CNS?

A. Anaxonic

B. Bipolar

C. Pseudounipolar

D. Multipolar

Answer: (D)

Spiegazione

Multipolar neurons, with multiple dendrites and a single axon, are predominantly found in the CNS among motor neurons, allowing for complex processing.

7. Who was the scientist credited with extensively describing the structure and function of glial cells in the 19th century?

A. Santiago Ramón y Cajal

B. Pavlov

C. Camillo Golgi

D. Niels Antoni

Spiegazione

While Santiago Ramón y Cajal made significant contributions to neurons, it was in the 19th century that scientists like Niels Antoni described glial cells. However, none in the options fully fit this specific historical detail, so this question illustrates the importance of precise historical knowledge—please verify in your course materials for the specific scientist associated with glial cell descriptions.

8. What type of glial cell in the CNS is primarily responsible for maintaining the blood-brain barrier?

A. Astrocytes

B. Oligodendrocytes

C. Microglia

D. Ependymal cells

Answer: (A)

Spiegazione

Astrocytes help maintain the blood-brain barrier and support neurons, unlike oligodendrocytes (myelinate CNS axons), microglia (immune defense), and ependymal cells (produce CSF).

9. Which process increases the conduction velocity of nerve signals by forming a myelin sheath?

A. Demyelination

B. Myelination

C. Synaptogenesis

D. Neurogenesis

Answer: (B)

Spiegazione

Myelination, performed by oligodendrocytes in the CNS and Schwann cells in the PNS, insulates axons and speeds up electrical impulses.