Question

you decided to take a break after grading all of the final exams for our course and took a much-needed vacation. Unfortunately, he went surfing and was attacked by a shark that ate his arm. you, an expert one-handed swimmer, made his way back to shore. During his swim back,

Group of answer choices

1. you sympathetic nervous system stimulated the smooth muscle around his arterioles to contract to increase his mean arterial pressure

2. you  pondered your history of making poor choices and decided is safer than surfing in shark infested waters

3. your sympathetic nervous system stimulated his heart to increase cardiac output to increase his mean arteriole pressure.

4. your circulating levels of vasopressin increased to promote the insertion of aquaporins into his collecting ducts to reabsorb as much water as possible.

5. three or four of these answers (depending on whether you lost too much blood to his brain to affect his ability to think properly).

Answer 1

ANSWER :

During a serious injury (e.g.- arm are by a shark), the large amount of blood loss would cause to decrease mean arterial blood pressure, which detected via central and peripheral baroreceptors located in the medulla and the aortic and carotid bodies. It further stimulates the sympathetic division of the autonomic nervous system (ANS) to cope with these hypovolemic or hemorrhagic shock the following ways :-

1. The sympathetic nervous system contracts the arteries and arterioles (resistance vessels) to increase the peripheral vascular resistance to stabilize the mean arterial pressure back to its normal range.

2. Overall, the sympathetic nervous system increases the cardiac output of blood via enhancing the peripheral vascular resistance to increase the MAP.

3. It also stimulates the release of large amount of vassopresin hormone from posterior pituitary, because it increases the reabsorption of water in the collecting duct of the kidney nephrons, which lead to increase blood plasma volume and results in elevated mean arterial blood pressure.