urinary part 3 Flashcards
filtration=
renal corpuscle
reabsorption=
PCT
loop
DCT
collecting duct
secretion=
DCT
minimal in PCT
what is driving force in glomerular capillaries
BP
fluid and small molecules out of blood->
filtrate
filtration is based on what
size/ charge of molecules
blood cells
most proteins (not go through)
filtration only removes substances that are what?
small enough to fit through filtration membrane
renal fraction
CO % flowing through Kidneys / minute (12-30% - AVERAGES 21%)
renal blood flow rate
CO x Renal Fraction = 5600 ml/min x 0.21 = 1176 ml/min
= Renal Blood Flow Rate x % Plasma portion of Whole Blood = 1176 x 0.55 = 650 ml/min
renal plasma flow rate
filtration fraction=
= % Plasma filtered from Blood = ~19%
= Renal Plasma Flow Rate x Filtration Fraction
650 ml/min x 0.19 = ~125 ml/min FILTRATE = ~180 L of Filtrate Produced DAILY
glomerular filtration rate
99% of filtrate volume is reabsorbed what happens to the other 1%
removed in urine
what does GFR assess
severity of renal disease
what is an intrinsic mechanism
autoregulation (due to renal corpuscles structures)
myogenic mechanism
tubuloglomerular feedback
how is myogenic mechanism done
smooth muscle stretch to change the BP
what does tubuloglomerular feedback do
matches filtrate flow past the macula densa of JGA and GFR
what does increase flow cause in tubuloglomerular feedback
JG cells of afferent arteriole to constrict
what decreases due to less glomerular capillary pressure
decreases
what are extrinsic mechanism
controlled by ANS and hormones
in severe conditions means arterial pressure drops which causes
SNS significantly decreases renal blood flow and GFR to keep BP homeostatically stavle
intense stimulation with shock or vigorous exercise =
decrease rate of filtrate formation to a few ml/ min
if xs shock what happens
vasoconstriction of afferent arterioles, renal damage, TX quick
if low BP what happens
JG cells secrete enzyme renin to keep GFR stable
what moves H2O and filtered molecules back into blood via peritubular capillaries
transport proteins
what of solutes that are useful
retention
what mvoes 2 molecules or ions in the same direction
symporters
there is secondary active transport with what
Na diffusion energy driving movement of 2nd ion/ molecule
tubular reabsorption occurs where
PCT
tubular reabsorption is necessary for what
preventing dehydration
nearly 9% of solutes and H2O are quickly returned to blood in what
renal tubes for quick toxic removal
examples of things reabsorbed
AA
Glc
Frc
Na
K
Ca
where is tubular secretion
mostly in PCT and secreted into DCT and CD
what are examples of tubular secretion
Toxic By-Products of Metabolism & Drugs or Molecules NOT normally made in Body Ammonia is Toxic By-product of Protein metabolism, Also K+, ACh, Epi, Bile pigments, Urea, Uric acid, Drugs, Toxins & Morphine
Antiport = Kidney secretes H+, regulating pH (Too acidic = Kidney secretes
what are 3 urine concentration mechanism
- countercurrent mechanism
- medullary concentration gradient
- hormonal mechanisms
Fluid in separate structures flow in opposite directions, and as pass materials exchanged Imperative to Conserve or Eliminate water in Body
countercurrent mechanism
what is the countecurrent multiplier
nephron loop
what is the countercurrent exchanger
vasa recta
what does the countercurrent multiplier do
responsible for large % of very high concentration of solutes found in IF within the renal medulla
what does the countercurrent exchanger do
maintains high solute concetration in IF, flow rate and BP in vasa recta is slow and slow, blood and IF in equilibrium and solutes not carried away from IF by blood in vasa recta
IF in Medulla has very high solute concentration compared to Cortex requires what mechanism
medullary concentration gradient
in medullary concentration gradient there is a high solute concentration due to action of what
2 countercurrent mechanisms and recycling of protein breakdown
in renal tubule what happens during medullary concentration gradient
Na ions and solutes are actively transported into IF of medulla
what mechanism: Renin – Angiotensin – Aldosterone Hormone: Will review
Renin + Angiotensinogen Angiotensin I + ACE Angiotensin II Vasoconstriction &
Aldosterone secretion from Adrenal Cortex
hormonal
Hypothalamus makes Post Pit. When Osmolality (Solute Concentration) of blood & IF
increases = Stimulation & ADH released = Water conservation.
adh
Secreted by Right Atrial Cells (Heart) when stretched more than normal.
Occurs when increased stretch of Right Atrium, when BV high. Decreases BV , Also
inhibits ADH secretion & Increases Urine volume, Lowering BV & BP. Dilates arteries
to decrease Peripheral Resistance & Lower BP.
anf
