Chapter 18/19 (Pt. 5) Flashcards
why is it that only ~20% of plasma volume gets filtered out of the glomerulus into Bowman’s capsules?
we need to retain some volume to move remaining cells through blood
what is the function of secretion from peritubular capillaries?
provides a second chance for filtration
WHY does the countercurrent multiplier that creates the medullary gradient facilitate reabsorbing water not captured by the proximal tubule?
basically, what’s happening here: we are combatting the rising interstitial osmotic pressure with and increase in vasa recta osmotic pressure
HOW does the countercurrent multiplier that creates the medullary gradient facilitate reabsorbing water not captured by the proximal tubule?
ascending: ions are actively transported into interstitium
so, descending: H2O leaves for interstitium through aquaporins
plasma leaves vessels and is combated by urea
next, urea leaves the collecting duct, goes into the interstitium, and then into the vasa recta
what are some of the differences between epithelial cells of the proximal and distal tubules, and what is the function of each? (3)
- proximal has more surface area. lots of reabsorption.
- proximal has more mitochondria. need ATP for active transport.
- proximal is leaky. loose-tight junctions to allow movement through the cells.
what are three differences between the epithelial cells of the proximal and distal tubules?
- proximal has more surface area
- proximal has more mitochondria
- proximal is more leaky
what is the function of proximal epithelial cells having more surface area?
lots of reabsorption
what is the function of proximal epithelial cells having more mitochondria?
need ATP for active transport
what is the function of proximal epithelial cells being more leaky than distal epithelial cells?
allow for more to pass through
how does calcitrol increase Ca+2 levels? (3)
- increases calcium absorption from the intestines
- increases reabsorption of calcium by the kidneys
- increases the release of calcium from bone
what is calcitrol?
the commercial name for vitamin D3
UV exposure…
converts 7-dehydrocholesterol in the skin to previtamin D3
what is RAAS? aka what does it stand for?
renin-angiotensin-aldosterone system
what is the functino of the reninangiotensinaldosterone system?
secrete aldosterone to increase sodium reabsorption
what triggers the release of renin?
low BP or low Na+
how is renin made?
made by granular cells (aka juxtaglomerular cells) in the kidney
what starts the renin-angiotensin-aldosterone system?
renin
where is angiotensinogen produced?
liver
what does the ending “-ogen” indicate?
inactive form of a protein
where is renin produced?
kidney
what triggers the production of renin?
low BP or low Na+
what is the function of renin?
clip 10 AAs off of angiotensinogen
what is the source of angiotensin II ?
renin clips 10 AAs off of angiotensinogen -> angiotensin I
ACE clips 2 AAs off of angiotensin I -> angiotensin II
what effect does angiotensin II have on the body?
act on adrenal gland to release aldosterone
