Flashcards in BIOL 0800 Reading- Chapter 14 Deck (137)
Where does gluconeogenesis occur?
In the kidneys
What are the three main hormones/enzymes secreted by the kidneys?
Erythropoeitin, 1,25 dihydroxyvitamin D, and renin
What are the two components of the nephron?
Renal corpuscle and the tubule
What is the renal corpuscle?
The initial filtering component of the nephron: Bowman's capsule and the glomerulus
What happens in the Bowman's space?
Where protein-free fluid is filtered from the blood in the capillaries of the glomerulus
What is a podocyte?
The epithelial cells on the visceral layer of the Bowman's capsule
What parts of the nephron are in the renal cortex vs medulla?
In the cortex: the renal corpuscles; in the medulla: varying lengths of the loops of Henle
What are peritubular capillaries?
The capillaries that run alongside the renal tubules
What is the blood flow through a nephron?
From afferent arteriole into glomerular capillaries into the efferent arteriole into the peritubular capillaries into the veins
What are the two types of nephrons?
Juxtamedullary and cortical
What are juxtamedullary nephrons?
Renal corpuscle is close to the cortical-medullary border, and tubule dips deep into the medulla: useful for reabsorption of water; lined by vasa recta
What is the vasa recta?
The long capillaries that line that juxtamedullary nephrons
Do all cortical nephrons have loops of Henle?
No: involved in reabsorption and secretion, but don’t contribute to hypertonic medullary interstitium
What is the juxtaglomerular apparatus?
Where the macular densa and JG cells combine between the afferent and efferent arterioles
What is the macula densa?
The patch of cells in the wall of the distal convoluted tubule
What are JG cells?
On the wall of the afferent arteriole; secrete renin
What is the formula for amount of substance excreted?
Amount filtered (in glomerulus) + amount secreted (in tubules) - amount reabsorbed (in tubules)
Why are proteins not included in the fluid filtered through the nephrons?
Because they're too big, and because the filtration pathways in the corpuscular membranes are negatively charged and oppose plasma protein movements
Why aren't plasma calcium and fatty acids filtered?
Because they're usually bound to proteins in the plasma
What does glomerular capillary hydrostatic pressure favor?
Filtration of fluid out of the capillaries into Bowman's space
What does the Bowman's space hydrostatic pressure favor?
Opposition of filtration of fluid from capillaries into Bowman's space
What does the osmotic force of the GC favor?
Opposition of filtration of fluid form capillaries into Bowman's space; wants the fluid to stay in the GC
What does the osmotic force of Bowman's space favor?
Nothing: there is no osmotic pressure in Bowman's space because there aren't any protein particles
What is the formula for net glomerular filtration pressure?
(P gc) - (P bs) - (pi gc)
What determines GFR?
Net filtration pressure, permeability of corpuscular membranes, and surface area available for filtration
How does afferent arteriole constriction affect GC hydrostatic pressure?
Decreases (P gc), decreases GFR
How does efferent arteriole constriction affect GC hydrostatic pressure?
Increases (P gc), increases GFR
How does mesangial cell activity affect GFR?
Contraction of mesangial cells (surround glomerular capillaries) reduces SA of capillaries; decreases GFR
What is filtered load?
The amount of any nonprotein/bound substance filtered into Bowman's space: = (GFR)(concentration in plasma)