Quiz - 14 - Diving Knowledge Workbook - Diving Physiology

[Pedro Burrito]

From the Diving Physiology Section of the PADI Diving Knowledge Workbook Version 2.02 © PADI 2009:

Objective 2.5 - Explain the physiological mechanism that causes a "carotid-sinus reflex" and how this affects the diver.

Question 1

The carotid-sinus receptors, which are located in the carotid arteries, stimulate the ___, which is located in the ___.

a. thyroid / throat

b. cardioinhibitory center / brain

c. S-A node / heart

d. adrenal glands / kidneys​

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[Ukmc]

I maybe a little rusty on physiology, but carotid sinus sends an impulse to the cardioinhibitory center which is part of the brain stem, which sends a signal through a vagus nerve which effects an SA node which is located in the heart... thus, there appears to be at least two right answers...
It has been quite a few years since I studied this. I better go hit the books.

 

[Pedro Burrito]

Spoiler: Answer

b. cardioinhibitory center / brain

Although the impulse that stimulates the heart originates in the heart (sino-arterial node), the brain has the capability to inhibit this impulse. This is what occurs in a carotid-sinus reflex. The heart rate slows down to a point where it is unable to maintain sufficient blood flow to the brain.


Editors note: The book says, "that simulates the". Is it simulates or stimulates?

.

 

[TMHeimer]

I maybe a little rusty on physiology, but carotid sinus sends an impulse to the cardioinhibitory center which is part of the brain stem, which sends a signal through a vagus nerve which effects an SA node which is located in the heart... thus, there appears to be at least two right answers...
It has been quite a few years since I studied this. I better go hit the books.

I don't know what SA stands for because I don't recall (may be wrong) reading about it in the PADI Workbook-- therefore, it must be wrong....