Renal 6 Flashcards
Where does water reabsorbtion occur
In the collecting duct
AVP secretion happens due to
Increased osmolarity
Decreased blood volume
Decreased Blood pressure
What creates the hyperosmotic onterestinium in medulla
Countercurrent exhange system
Urea
Countercurrent Exchnage system
to reduce heat loss
two parts of renal countercurrent exchange system
Countercurrent multiplier
Countercurrent exchanger
Loop of henle
Countercurrent multplier
Peritubular capillaries (Vasa recta)
Countercurrent exchanger
Countercurrent multiplier
the descending limb has a lot of aquaporin channels allowing water to follow its concentration gradient into the hyperosmotic interstitinum
The ascending henle limb of the loop actively trasports Na Cl and K into the interstitinum
What are responsible for the high osmolarity deep in meduula
Nephron and vasa recta of juxtamedullary nephrons
There is a ton of active transport
In the ascending limb
How does urea contribute to the osmolarity of the medullary interstitium
Creates a recycling loop
About half the solute in the meduula interstinium is urea
Increases Osmolarity (NaCl)
Vasopresson secreted and Thirst
Blood pressure goes up, ECF volume goes up
Where is more sodium excereted
Urine
Hormone for Sodium Balance
Renin Angiotensin aldosterone system
Where does this hormone target
Last third of the distal tubule and the portion of the collecting duct
If potassium is high
Blood pressure is low and more aldosterone is secreted
Addiotional modifiers of aldosterone release
Increased osmolarity during dehydration
Abnormally large drops in plasma Na+
Renin Angiotensin System (RAS)
A multistep pathway for maintaining blood pressure
Three stimuli of renin secretion
Low blood pressure in renal arterioles causes granular cells to secrete renin
Sympathetic neurons by CVCC when blood pressure decreases terminate on granular cells and stimulate renin secretion
Paracrine feedback from macula densa cells signal to the granular cells to secrete renin
What is role of renin
Converts an angiotensinogen into angiotensin 1 and then it converts to angiotensin 2 that travels to adrenal cortex and stimulates production of aldosterone
Atrial Natriuretic peptide (ANP)
Causes loss of Na+ and Water
When blood volume and pressure is high
Opposite effects of angiotensin 2
Where is Pottasium Reabsorbed
Proximal Tubule ans ascending limb of loop of henle
Potassium balance is altered by
Secretion
Where is pottasium secreted
Distal tubule and cortical collecting duct
What controls pottasium secretion
Aldosterone
Low pottasium means
Low aldosterone and less pottasium secretion
Hypokalemia
Casues muscle weakness
Hyperkalemia
Hyperexcitability
ANG 2 does
Increased CO
Increased Na+ Reabsorbtion
Peripheral Vasoconstriction
Thirst
Thirst is controlled by
Hypothalamus
Barorecptors
Decrease in blood pressure
Avoidance Behaviours
Helps prevent Dehydration
