15- Renal Phys (Kruse & Pierce) Flashcards
What is the basic unit of structure in the kidney?
Nephron
A ________ is used separate to water, ions and small molecules from the blood, filter out wastes and toxins, and facilitates the concentration of urine.
Nephron
Each nephron contains a tuft of glomerular capillaries called the _________.
Glomerulus
Glomerular capillaries are covered by epithelial cells and are encased in ________ ________. Large amounts of fluid are filtered from the blood here.
Bowman’s Capsule
Fluid filtered from the glomerular capillaries flows into Bowman’s Capsules and then into the ________ ________.
Proximal Tubule
What is actively reabsorbed in the Proximal Tubule (convoluted and straight)?
85% sodium bicarbonate (NaHCO3)
65% sodium chloride (NaCl)
65% potassium (K+)
100% glucose and amino acids
What is passively reabsorbed in the Proximal Tubule (convoluted and straight)?
Water
In the Proximal Tubule (convoluted and straight) uses the _________ to maintain low intracellular Na+ concentrations.
Na+/K+ ATPase
This is an enzyme in the Proximal Tubule that catalyzes the formation/dehydration of carbonic acid.
Carbonic Anhydrase
In the proximal tubule, acid and base secretory systems secrete drugs into the ________ from the blood (i.e., diuretics, NSAIDs, antibiotics).
Lumen
What is the Thin Descending Loop of Henle responsible for?
Water reabsorption
The (THICK/THIN) Ascending Loop of Henle is relatively impermeable to water, and other ions/solutes.
Thin
What are the main functions of the Thick Ascending Limb?
Impermeable to water
25% sodium reabsorption
Na+/K+/2Cl- Cotransporter (NKCC2)
Reabsorption of cations
In the Thick Ascending Limb, this is what establishes the ion concentration gradient in the interstitium.
NKCC2
***Na+/K+/2Cl- Cotransporter
In the Thick Ascending Limb, there is an increase in ______ concentration in the cells that causes back diffusion of ______ into the tubular lumen. This allows a lumen-positive electrical potential to drive reabsorption of cations (Mg2+, Ca2+) via the paracellular pathway.
K+
K+
Tubular fluid is (DILUTE/CONCENTRATED) in the descending limb and (DILUTE/CONCENTRATED) in the ascending limb.
Concentrated
Dilute
What are the main functions of the Distal Convoluted Tubule?
10% NaCl reabsorbed
Relatively impermeable to water
Na+/Cl- Cotransporter (NCC)
Ca2+ passively reabsorbed by Calcium channels
In the Distal Convoluted Tubule, this actively transports NaCl out of the lumen.
NCC
***Na+/Cl- Cotransporter
In the Distal Convoluted Tubule, Ca2+ is passively reabsorbed by Calcium channels. What is this regulated by?
PTH
In the Distal Convoluted Tubule, the result if tubular fluid is (DILUTE/CONCENTRATED).
Dilute
In the Collecting Tubule, this is responsible for 2-5% of Na+ reabsorption. It creates an electrical gradient that facilitates K+ secretion down the concentration gradient.
Epithelial Sodium Channel (ENaC)
This is the most important site of K+ secretion by the kidney.
Collecting Tubule
This is the site at which all diuretic-induced changes in K+ balance occur. More Na+ delivered here will induce more K+ secretion.
Collecting Tubule
In the Collecting Tubule, _______ _______ increase urine acidity.
Proton Pumps
In the Collecting Tubule, this increases the expression of ENaC and basolateral Na+/K+ ATPase. This increases Na+ reabsorption and K+ secretion which leads to water retention and increase in blood volume and BP.
Aldosterone
This controls permeability of the Collecting Tubule to water by regulating the expression levels of aquaporin-2 (AQP2) water channels.
ADH (vasopressin)
What happens in the Collecting Tubule is there is no ADH?
It becomes impermeable to water and the urine is dilute.
ADH levels are controlled by serum osmolality and volume status. ________ decreases ADH release and increases urine production.
Alcohol
In the Collecting Tubule, the tubular fluid is (DILUTE/CONCENTRATED).
Concentrated