Renal tubular physiology Flashcards
Site of GLOMERULOTUBULAR BALANCE
Proximal Convoluted Tubule
The result of solute reabsorption in the proximal convoluted tubule is a net (positive/negative) charge in the lumen.
Negative
is defined as the ability of each successive segment of the proximal tubule to reabsorb a constant fraction of glomerular filtrate and solutes delivered to it.
Glomerulotubular Balance
In contrast to the early proximal convoluted tubule, the late proximal tubule mostly reabsorbs .
NaCl
The tubule in the nephron reabsorbs around 67% of the filtered sodium and water.
Proximal Convoluted Tubule
Glucose, amino acids, phosphate, lactate, and citrate are reabsorbed in the proximal convoluted tubule with (ion) as the cotransport ion.
Sodium
With or without the presence of aldosterone, the area of the nephron that always reabsorbs the (most/least) amount of sodium is the proximal convoluted tubule.
MOST
The one countertransport mechanism in the early proximal tubule is the antiporter in the luminal membrane.
Na H antiporter
The major Starling force driving reabsorption in the proximal convoluted tubule is the high of peritubular capillary blood.
Oncotic pressure
The most essential solutes including glucose and amino acids are reabsorbed along with sodium in the (early/late) proximal convoluted tubule.
EARLY PCT
The proximal convoluted tubule causes net reabsorption of (H+/HCO3-) .
HCO3
Glucose is transported into the peritubular capillary blood from the cell via (mechanism) through the GLUT1 and GLUT2 transporters.
Facilitated Diffusion
Typically, % of filtered bicarbonate is reabsorbed in the proximal convoluted tubule.
85%
The ion concentration is high in the fluid entering the late proximal convoluted tubule because of preferential reabsorption of HCO3- in the early proximal tubule.
Chloride
% of a normal filtered glucose load is reabsorbed in the proximal convoluted tubule.
100%
Diuretics that act in EARLY PCT by inhibiting reabsorption of filtered HCO3
Carbonic Anhydrase Inhibitors (Acetazolamide)
The primary transporter for sodium reabsorption in the thick ascending limb of the loop of Henle is the .
Na+-K+-2Cl- cotransporter.
The THIN DESCENDING limb of the loop of Henle (is/is not) permeable to water.
Permeable
The Na+-K+-2Cl- cotransporter in the thick ascending limb of the loop of Henle is inhibited by (drug class) .
Loop Diuretics
The thin ASCENDING limb of the
loop of Henle (is/is not) is to water.
Not permeable
In the loop of Henle, the limb is permeable to water.
thin ASCENDING limb
The fluid that leaves a normally functioning thick ascending limb of the loop of Henle has a (higher/lower) osmolarity than blood.
LOWER
Reabsorption of sodium in the thick ascending limb of the loop of Henle is (transporter/load) dependent.
LOAD
The thick ascending limb of the loop of Henle (is/is not) permeable to water.
NO PERMEABLE
The cells of the collecting duct are involved in potassium reabsorption and hydrogen ion secretion.
alpha intercalated cells
The early distal convoluted tubule is (impermeable/permeable) to water and its permeability is not impacted by antidiuretic hormone.
IMPERMEABLE
Called the CORTICAL DILUTING SEGMENT
Early Distal Tubule
The early distal tubule reabsorbs sodium via co-transporters in the luminal membrane.
Na-Cl
When antidiuretic hormone levels are high, channels are inserted into the luminal membrane of the principal cells in the collecting duct.
Aquaporin 2
Reabsorption in the distal convoluted tubule and collecting ducts are load (independent/dependent) , especially in regard to extra sodium delivered from more proximal segments.
DEPENDENT
Water permeability of the collecting duct depends on the presence of hormone.
ADH
The sodium channels found in the principal cells of the nephron collecting duct are termed sodium channels.
Epithelial Sodium Channels (ENaC)
The two major cell types in the late distal convoluted tubule and collecting ducts of the nephron
Principal cells
Intercalated cells
The cells of the collecting duct are involved in sodium reabsorption, potassium secretion, and water reabsorption.
Principal cells
Antidiuretic hormone activation of vasopressin 1 receptor (increases/decreases) vasoconstriction of arterioles and total peripheral resistance.
INCREASES
