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Chapter 4. Excitable Tissue: Nerve

Glia are critical for the development of the nervous system and have important roles in some neurodegenerative disorder. Which of the following statements correctly describe a property of a type of glia?

A. Microglia arise from macrophages outside of the nervous system and are physiologically and embryologically similar to other neural cell types.

B. Fibrous astrocytes are found primarily in the gray matter and induce capillaries to form tight junctions to form the blood-brain barrier.

C. Protoplasmic astrocytes produce substances that are tropic to neurons to maintain the appropriate concentration of ions and neurotransmitters by taking up K+ and the neurotransmitters glutamate and GABA.

D. Oligodendrocytes and Schwann cells are involved in myelin formation around axons in the peripheral nervous system and central nervous system, respectively.

E. Macroglia are scavenger cells that resemble tissue macrophages and remove debris resulting from injury, infection, and disease.

Primary erythromelalgia due to a peripheral nerve sodium channelopathy was diagnosed in a 13-year-old girl who was experiencing frequent episodes of red, painful, warm extremities. Which part of a neuron has the highest concentration of Na+ channels per square micrometer of cell membrane?

A. dendrites

B. cell body near dendrites

C. initial segment

D. axonal membrane under myelin

E. node of Ranvier

A 45-year-old woman who works in an office had been experiencing tingling in her index and middle fingers and thumb of her right hand. Recently, her wrist and hand had become weak. Her physician ordered a nerve conduction test to evaluate her for carpal tunnel syndrome. Which one of the following nerves has the slowest conduction velocity?

A. Aα fibers

B. Aβ fibers

C. Aγ fibers

D. B fibers

E. C fibers

Axoplasmic flow is a cellular process responsible for movement of proteins and polypeptides within a neuron. Which of the following statements correctly describes a property of orthograde or retrograde axonal transport?

A. Synaptic transmission: Antidromic conduction

B. Molecular motors for orthograde and retrograde transport are dynein and kinesin, respectively.

C. The rate of retrograde fast ...

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