46) While walking down the street, a cat jumps out of an alley into the pathway of an adult. They note that his /her heart is "racing." this response is primarily due to:

The cell body of the first motor neuron that lies in the brain stem

Reflex circuitry produce by the ANS reflex

Parasympathetic effect on the vagus nerve

Secretion of the sympathetic neurotransmitters produce in the adrenal medulla

Answer and Explanation

The Correct Answer is D

A) The cell body of the first motor neuron that lies in the brain stem:
This option refers to the somatic nervous system, which controls voluntary muscle movements. In response to a stressful or fearful situation, like the one described, the sympathetic nervous system is activated, not the somatic motor pathways. This is more related to voluntary motor control rather than the autonomic response to stress.

B) Reflex circuitry produced by the ANS reflex:
The autonomic nervous system (ANS) is involved in regulating involuntary functions like heart rate, blood pressure, and digestion. However, the "racing heart" response described here is primarily triggered by the sympathetic division of the ANS due to a stressor, such as seeing the cat. The reflex itself is part of a larger autonomic reaction, but the direct cause of the increased heart rate is the secretion of neurotransmitters.

C) Parasympathetic effect on the vagus nerve:
The parasympathetic nervous system (PNS) generally works to counteract the "fight or flight" response, promoting a relaxed state and slowing the heart rate. The vagus nerve is the primary parasympathetic pathway involved in decreasing heart rate. However, during stress or a fear response, the parasympathetic system is overridden by the sympathetic system, which increases heart rate, making this option incorrect.

D) Secretion of the sympathetic neurotransmitters produced in the adrenal medulla:
When a person experiences a stressor, like the sudden appearance of a cat, the sympathetic nervous system is activated, triggering the release of neurotransmitters like norepinephrine from sympathetic nerve endings and epinephrine (adrenaline) from the adrenal medulla. These chemicals act on the heart, causing it to race in response to the perceived threat.

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Correct Answer is D

Explanation

A) The blood cells will migrate to the bone marrow:
While the bone marrow is responsible for producing red blood cells, dehydration and hypertonicity of the blood would not cause the red blood cells to migrate to the bone marrow. Migration of blood cells typically refers to white blood cells moving toward sites of infection or inflammation, not a response to dehydration.

B) The red cells will precipitate out of circulation:
Red blood cells do not precipitate out of circulation due to dehydration or hypertonic conditions. Instead, dehydration causes a shift in water balance that leads to changes in the shape and function of the red blood cells. Precipitation of cells is not a physiological response in this context.

C) They will swell and eventually rupture:
In conditions of hypertonicity, where the concentration of solutes (such as sodium) in the blood is higher than normal, red blood cells actually shrink, not swell. When blood is hypertonic, water moves out of the red blood cells into the extracellular space to balance the osmotic pressure, leading to cell shrinkage. Cells only swell in hypotonic conditions, when water moves into the cell.

D) The cells will shrink and shrivel, decreasing their oxygen-carrying ability:
When the body becomes dehydrated, the blood becomes hypertonic (more concentrated), leading to a shift of water out of the red blood cells to try to balance the osmotic gradient. As a result, the red blood cells shrink and shrivel. This shrinkage can impair their ability to carry oxygen effectively, as the cells may become more rigid and less flexible, making it difficult for them to navigate through small blood vessels and perform gas exchange in the lungs and tissues.

A. Norepinephrine B. Dopamine C. Acetylcholine D. Enkephalin

Correct Answer is B

Explanation

A) Norepinephrine: Norepinephrine is a potent vasoconstrictor primarily used in cases of shock to increase blood pressure by constricting blood vessels. However, it does not have a vasodilatory effect on renal blood vessels. Instead, it tends to decrease renal perfusion due to its strong vasoconstrictor properties, which could worsen renal insufficiency.

B) Dopamine: Dopamine is a catecholamine that has a dose-dependent effect on various receptors. At low doses, dopamine specifically acts on dopaminergic receptors in the kidneys, leading to vasodilation of renal blood vessels, which can improve renal perfusion. This makes it particularly useful in treating shock when there is concern about renal insufficiency or reduced kidney function.

C) Acetylcholine: Acetylcholine is a neurotransmitter of the parasympathetic nervous system, not a catecholamine. It is involved in promoting various physiological effects such as slowing the heart rate and stimulating digestive processes, but it does not have a specific role in vasodilation of renal blood vessels or shock management.

D) Enkephalin: Enkephalins are endogenous peptides involved in the regulation of pain and stress responses. They do not have a direct effect on vasodilation of renal blood vessels. Enkephalins are not typically used to treat shock or manage renal insufficiency.

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46) While walking down the street, a cat jumps out of an alley into the pathway of an adult. They note that his /her heart is "racing." this response is primarily due to:

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A patient is severely dehydrated from vomiting and diarrhea causing his or her blood to become hypertonic. What effects does the nurse expect this will have on the red blood cells

Correct Answer is D

Explanation

Which of the following catecholamines may have a vasodilator effect on renal blood vessels and be prescribed for a client in shock who are experiencing renal insufficiency manifestations?

Correct Answer is B

Explanation

Drugs do not metabolize the same way in all people. For what patient would a nurse expect to assess for an alteration in drug metabolism?

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