Which of the following functions does the myelin sheath perform for a nerve cell?
Insulation
Regeneration
Sensory perception
Nutrition
The Correct Answer is A
The myelin sheath is a protective membrane that wraps around parts of certain nerve cells.
Its fatty-protein coating provides protective insulation for your nerve cell like the plastic insulation covering that encases the wires of an electrical cord ².
This allows the electrical impulses to travel quickly and efficiently between one nerve cell and the next ². The other options are not correct because they do not describe the functions of the myelin sheath.
Regeneration, sensory perception, and nutrition are not functions performed by the myelin sheath for a nerve cell.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Most of the carbon dioxide from the blood moves into the alveoli by diffusion down a concentration gradient ¹. Carbon dioxide is always carried in the blood and is released into alveolar air during expiration ¹. Respiratory gases move from higher concentration to lower concentration ¹. In alveolar air, when carbon dioxide is less than in blood, carbon dioxide is released ¹.
The other options are not correct because they do not accurately describe the process by which most of the carbon dioxide from the blood moves into the alveoli. Passive transport using carrier proteins, active transport using energy, and conversion to carbon monoxide are not the processes responsible for moving most of the carbon dioxide from the blood into the alveoli.
Correct Answer is C
Explanation
The parotid gland is an exocrine gland that secretes saliva into the mouth. Exocrine glands secrete their products into ducts that carry the secretions to the body's surface or into body cavities.
The other options are endocrine glands, which secrete hormones directly into the bloodstream. The pineal gland secretes melatonin, the parathyroid glands secrete parathyroid hormone, and the pituitary gland secretes several hormones that regulate various bodily functions.
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