L4: GFR cont/ Tubular function Flashcards
What are the 3 cells of the Juxtaglomerular apparatus?
MD -Macula densa
EGM - extraglomerular mesangium
GC - granular cells
Info transmitted from ___ cells to the ____ of glomerulus to decrease the GFR by ____
MD, afferent arteriole, increase [Ca]
4 summary steps of the TGF
- Increase in GFR
- Increase in [NaCl] in tubule fluid in the Loop of Henle
- MD cells generate a singal
- Increased resistance of aa (constrict)
Draw the TGF figure
What is Renal clearance based upon?
Conservation of mass (Fick’s principle)
What is renal clearance?
Urinary excretion compared to plasma concentration
Clearance of a substance is in referenece to the ____ and can be __,__,__
GFR
> <
Renal Clearance Equation
C(s) = [U]s x V /[P]
What is the numerator if the renal clearance calculation?
excretion rate of the substance
Why is creatinine only estimated GFR?
bc it is secreted 10%
When does GFR change? (5)
- Loss of SA, Kf will decrease
- Changes in PBS (kidney stones)
- Altered renal perfusion pressure (PGC)
- Drugs that dilate/constrict aterioles (can alter Kf)
- Loss of protein in urine or increased protein synthesis (PiGC)
When is FF altered?
Normally remains constant bc of GFR and RBF (autoreg)
Acute/dramatic changes in arterial BP may alter the FF
Decrease BP - diuretics
Increase - Renal artery stenosis
Proteinuria
High levels of protein in urine
Glomerulus does what
filters plasma
Tubule does what
reabsorbs and secretes
What is the corpuscle made up of?
Corpuscle = capsule + glomerulus
What cells make up the tubule?
Epithelial cell (single layer)
The tubule contains different ____ in different segments that are responsible for ____
cell types, diff functions
What does the lumen of the tubule contains?
fluid from plasma filtrate
Reabsorption is the direction of movement ___
out of the lumen
Secretion is the direction of movement____
into the lumen
Proximal convoluted tubule (PCT) - is responsible for? The apical surface facing the lumen contains? (for what purpose?) There are numerous transporters for electrolytes on the ________
reabsorption
microvilli - Inc SA
apical cell border
Proximal convoluted tubule (PCT)
Reaborsption of ____ of filtered H2O, Na, K, Ca and ___ of HCO3
65%, 80%
Proximal convoluted tubule (PCT) reaborbs what to 100%
filtered amino acids - peptides/proteins and glucose
Proximal convoluted tubule (PCT) is primarly responsible for?
reabsorption
Proximal Nephron is primarily responsible for?
secretion
Proximal Straight Tubule (PST)
secretes (3)
- Foreign substances
- Substance not metabolized or partially/slow
- Drug delivery to tubule
What is the main purpose of the loop?
to concentrate the urine
Loop of Henle
tDLH and tALH
What type of cells?
Cubodial epithelial cells - no active transport
Loop of Henle
tDLH and tALH
Allows for osmotic gradient b/w ___ and _____
Passive H2O movement via ____
Passive ____ and ____ movement (channels)
cortex and medulla
aquaporins
Na and urea
What is necessary for concentrating capacity of kidney?
Loop of Henle
What part of the Loop of Henle is responsible for reabsorption?
TAL - thick ascending limb
reabsorbtion of 25% of filtered Na, K and Ca occurs where?
TAL of the Loop of Henle
TAL is the site of action of
loop diuretics
Loop becomes more _____ going up as more electrolytes are removed and no ___ follows
diluted, water
Absence of water movement (No AQPs)
The Distal Nephron is responsible for
reabsorption and secretion
What occurs in the DCT and CD? (5)
Na reabsorption
K secretion
Water reabsorption
A/B homeostasis
Final adjustment of lumenal fluid volume and composition
