L66. Kidney 3 Flashcards
How is fluid reabsorption promoted in the kidneys?
In the distal convoluted tubule, ADH and aldosterone promote fluid reabsorption to produce a small volume of concentrated urine.
What does ANP promote?
fluid excretion producing a large volume of dilute urine.
Give the definition of GFR.
The rate at which blood is filtered through the glomerulus and into the bowman’s capsule, regulated by the renin-angiotensin-aldosterone system.
What does the juxtaglomerular apparatus do?
Connects the distal convoluted tubule with the glomerulus to measure the filtrate’s Na+ concentration.
What do the macula densa cells do?
detect sodium concentration
What do the juxtaglomerular cells do?
adjusts afferent arteriole diameter
What do the mesangial cells do?
they are supporting cells.
What can the afferent arteriole be constricted by?
Adenosine
What does the macula densa release in response to low blood pressure/low glomerular filtration rate?
Prostaglandins
Describe the 3 stages of the Angiotensin system.
- Angiotensinogen is released into the circulation by the liver.
- Renin converts angiotensinogen to angiotensin 1
- An enzyme converts angiotensin 1 to angiotensin 2.
What does angiotensin 2 do?
A strong vasoconstrictor with rapidly increases blood pressure.
What counteracts the renin-angiotensin-aldosterone system?
ANP
Describe the pathway from high Na+ to tubuloglomerular feedback.
High Na+ > adenosine release > vasoconstriction > tubuloglomerular feedback
Describe the pathway from low Na+ to activation of renin-angiotensin-aldosterone system.
Low Na+ > release of prostaglandins > renin release > activation of RAAS
What does chronic kidney disease cause?
Inadequate fluid and waste removal, inappropriate activation of RAAS.
