Kidneys Flashcards
Role of kidneys involved with blood flow?
- regulates BP by maintaining homeostasis of body fluid volume
An increase in extracellular fluid results in an increase of what?
blood volume and arterial pressure
–> kidneys excrete excess extracellular fluid to return BP to normal
Excess salt intake causes an increase in what?
MAP
_________ in blood volume –> ________ in blood pressure
increase; increase
Two determinants of long-term arterial pressure?
- location of renal output curve
- level of intake line
equation for arterial pressure?
CO x TPR
Direct effect of an increase in CO on arterial pressure?
increase in arterial pressure
What is the main determinant of extracellular fluid volume?
amount of salt accumulation in body
The effect of increase in sodium is _______ than effect of increase in H2O?
greater
What is it called if MAP > 110mmHg
Chronic hypertension
What is the first mechanism of controlling arterial pressure?
kidney
What is the 2nd mechanism of controlling arterial pressure?
renin-angiotensin
What hormone acts as an enzyme and is released when arterial pressure drops?
renin
Function of renin?
raises arterial pressure
Renin-angiotensin pathway?
decreased arterial pressure –> renin released from kidney –> renin acts on angiotensinogen –> forms angiotensin I –> transforms into angiotensin II –> retention of water/salt and vasoconstriction –> increase arterial pressure
What hormone is a powerful vasoconstrictor?
angiotensin II
2 effects of angiotensin? (effects that increase arterial pressure)
Direct - acts on kidneys to retain salt and water
Indirect - causes adrenal glands to secrete aldosterone which increases salt/water reabsorption by kidneys
salt regulation pathway?
increase in salt intake –> increase in extracellular volume –> increase in arterial pressure –> decrease in renin and angiotensin –> decrease in renal retention of salt and water –> return of extracellular volume to normal –> return of arterial pressure to normal
What is the cause of primary hypertension (silent killer)?
unknown cause
Weight gain and obesity role in hypertension?
- cardiac output increased
- SNS activity increased (SNS promotes renin)
- angiotensin II/aldosterone levels increased
