Blood Pressure and the Kidney

Question 1

What is the equation for BP?

Answer 1

BP = CO x TPR

Question 2

What is the equation for CO?

Answer 2

CO = HR x SV

Question 3

What is capillary refill time a good measure of?

Answer 3

TPR (=systemic vascular resistance)

An increased capillary refill time makes you cold and clammy.

Question 4

What are some mechanisms for renin release from the kidney?

Answer 4

Direct sympathetic stimulation of JGA

Reduced renal blood flow detected by baroreceptors in JGA

Reduced NaCl to JGA

Question 5

RAAS System

Answer 5

Angiotensinogen from liver is converted to angiotensin I by Renin

Angiotensin I coverted to angiotensin II by ACE.

Angiotensin II causes release of aldosterone from adrenal cortex.

Question 6

What does angiotensin II do?

Answer 6

Vasocontstriction

ADH from hypothalamus and pituitary - H2O reabsorption.

Increase sympathetic activity

Aldosterone secretion causes Na,Cl and H2O retention / reabsorption and K excretion.

Question 7

Where is aldosterone made?

Answer 7

From the adrenal cortex of the adrenal glands. (Zona glomerulosa)

Question 8

What does aldosterone do?

Answer 8

INCREASE SODIUM AND WATER REABSORPTION

Upregulates Na/K pump in basolateral membrane of DCT.

Upregulates Na channels in collecting duct and colon.

Stimulates secretion of K into tubule.

Stimulates Na and H2O un gut and salivary and sweat glands.

Stimulates H+ secretion in collecting duct.

Upregulates Na/Cl cotransporters in DCT

Question 9

How does ADH work?

Answer 9

More water is reabsorbed by the DCT and CD of the kidney because of the increased AQP2

Question 10

What is `ADH also know as?

Answer 10

Vasopressin

ADH also causes vasoconstriction

Question 11

What mechanisms cause vasoconstriction?

Answer 11

Sympathetic nervous system

ADH

Question 12

What happen to leaky capillaries in heart failure?

Answer 12

Decreased BP
Increased NaCL and water retention
Increased BP and ECF
More leaky capillaires.

Question 13

Reasons for high BP?

Answer 13

Liver disease 
Pain
Hyperaldosteronism
Sleep deprivation
White coat effect
Underlying hypertension
Fear
Kidney disease
CVD
Fluid overload

Question 14

What is the pressure natriuresis curve?

Answer 14

Need particular BP to excrete sodium.

Over period of time with consistent high BP, the curve will shift so you need a higher BP to excrete same Na. This is dangerous.