Review Of Renal Physiology Flashcards
Kidney role
- filter large quantities of plasma
- maintain acid/base balance
- maintain blood volume
3 processes of blood filtering
Glomerular filtration (ultrafiltration) Tubular secretion Tubular reabsorption (selective re-absorption)
How does blood enter the kidney
Through renal artery
The diameter of the afferent arteriole is _______ than the diameter of the efferent arteriole, which _____ the pressure of blood inside the glomerulus
Greater
Increases
The increased blood pressure in the glomerulus helps force what out of the glomerular capillaries (4)
Water
Salts
Glucose
Other molecules <68,000 MW
How does filtered substances enter the bowman capsule?
Fenestrated membrane
What is glomerular filtration driven by?
Cardiac pumping (blood flow)
What is the closest to an ideal endogenous substance for measuring GFR?
Creatinine
T/f creatinine is freely filtered at the glomerulus and not reabsorbed
True
Plasma creatinine is almost exclusively a product of the metabolism of what?
Creatine and phosphocreatine in skeletal muscles
Meat contributes slightly
CrCl equations
Urine creatinine x volume / serum creatinine
What is the basic urine forming unit of the kidneys?
Nephrons
What process is where filtered solutes and water ad reabsorbed via nephrons
Tubular reabsorption
T/f reabsorption is only active transport
False
Active and passive
How can Na diffuse across the luminal membrane?
- electrochemical gradient
- exchanges
- symporters
In the basolateral membrane, what hydrolyzes ATP and transport of Na and other solutes? What does this create?
NaKATPase
Osmotic pressure differential across epithelial cell
How does water move into the intercellular space?
Osmotic pressure differential
As water and solutes accumulate in the intercellular space, ________ increases, providing a driving force for ______
Hydrostatic pressure
Bulk water flow
_______ carries solute out of intercellular space and into the interstitial space, into peritubular capillaries
Bulk water flow
Reabsorption of Cl generally follows reabsorption of _____
Na
How does Cl move in the proximal tubule and thick ascending limb?
Para and transcellular
Where is most of filtered Ca reabsorbed? And how much?
Proximal tubules
70%
Where is most of inorganic phosphate (Pi) reabsorbed and how much?
Proximal tubules
80%
Where is the bulk of Mg reabsorbed and through what transportation?
Thick ascending limb
Paracellular pathway driven by lumen positive voltage
Proximal tubule is a _____ epithelium
Leaky
How much water is reabsorbed in the proximal tubule?
60%
How much sodium bicarb is reabsorbed in the proximal tubule?
85%
How much NaCl is reabsorbed in the proximal tubule?
40%
When bulk water flows across a membrane, solute molecules are usually transferred across the membrane by convection. This is called what?
Solvent drag
Thin descending limb of henle and water permeability
Retains high water permeability
Thick loop of henle is nearly impermeable to ____
Water
Salt reabsorption in the thick loop of henle ______ the tubular fluid
Dilutes
Where does intercellular Ca and Mg reabsorption occur?
Thick ascending loop of henle
The thick ascending loop makes contact with afferent arteriole by means of _____
Macula densa
The macula densa senses ____ leaving loop
NaCl
If NaCl concentration is too high, the macula sends a chemical signal to afferent arteriole causing it to _____. This is known as _____
Constrict
Tubuloglomerular feedback
Tubuloglomerular feedbacks protects the organism from
Salt and volume wasting
The distal convoluting tubule is almost impermeable to _____
Water
Where is a major site for K secretion?
Distal convoluting tubule
