Blood Volume Loss

Question 1

Increase in sympathetic activation

Answer 1

-Hypoxia, hypercapnia, reduction of pH

Question 2

Blood loss

Answer 2

-hemorrhage from many different events (ex.trauma, internal bleed)

Question 3

What does blood loss result in?

Answer 3

-Decreased blood volume= decreased preload, CO, MAP
-Decreased MAP=means decrease in perfusion to organs=organ failure and death
-Altered blood gas

Question 4

Initial response of blood loss (detection)

Answer 4

-decrease in blood volume, decrease in CO, decrease in MAP
>detected by baroreceptors, resulting in increase in sympathetic
»increase in HR and contractility at heart, and constriction in blood vessels =BP trying to increase (Note that sympathetic does not really act strongly on heart and brain)
**redistribution of cardiac output=blood flow to heart and brain remains, but blood flow to muscle will decrease

Question 5

Second response to hypoperfusion in the muscles

Answer 5

-constricted arteries, and low MAP (because blood pressure)
-organs are under perfused
-Mismatch between organ metabolism and oxygen delivery resulting in increased reliance on anaerobic metabolism= systemic acidosis

Question 6

Acidosis Detection

Answer 6

-detected by chemoreceptors
-increases sympathetic nervous system even more

Question 7

Third response/humoral compensation (recovery)

Answer 7

-stopped bleed, but reduced blood volume
-increase in sympathetic=results in adrenals increasing catecholamines
-increase in RAAS, and Ang II= vasoconstriction and aldosterone/ADH
>increase in NA and H2O retention
**hopefully will be able to restore blood volume and blood pressure