40 Questions
What is the primary function of the proximal tubule in the nephron?
Reabsorption of NaCl
Which part of the nephron is specialized to develop urine with variable osmolality and solute composition?
Thin descending limb
Why are the epithelial cells of the thin descending limb very thin and lack significant amounts of mitochondria?
To facilitate water permeability through aquaporins
Which aquaporin isoform is abundant in the collecting duct and is regulated by vasopressin?
AQP2
Why is the ascending limb of Henle's loop referred to as the diluting segment?
As fluid entering it is more concentrated than the interstitium
What is the primary function of the Na/K/2Cl cotransporter in the thick ascending limb?
Electrogenic reabsorption of Na, Cl, and K+
Where is the Na/K/2Cl cotransporter isoform 2 specific to?
Thick ascending limb
What happens to the urine in the distal tubule?
It becomes diluted further compared to plasma
Which hormone can modify calcium reabsorption in the distal tubule?
Parathyroid hormone (PTH)
What is the role of the collecting tubule in the nephron?
To fine-tune electrolyte balance through reabsorption and secretion
What is the primary function of the Nephron?
Filtration
In the nephron, which segment is responsible for the reabsorption of almost all organic substrates?
Proximal tubule
What is the role of NaK ATPase in the nephron?
Creates Electrochemical potential gradient
Which process leads to a drop in the pH of ultrafiltrate in the nephron?
Active H secretion
What is the net effect of the late proximal tubule processes in the nephron?
Reabsorption of NaCl and H2O
What is the primary mechanism for water reabsorption from kidney cells back into the blood?
Hydrostatic pressure gradient
What part of the kidney is responsible for excreting uric acid?
Proximal tubule
What dictates the movement of ionic flow in the nephron?
Properties of epithelial cells
What is the primary function of Carbonic anhydrase in the nephron?
Breaking down carbon dioxide
What is the consequence of accumulation of intracellular HCO3 in kidney cells?
Favoring export via cotransporter
What is the general rule dictating ionic flow across the nephron epithelium?
Na dictates ionic flow
How is active transport of organic substrates across the nephron epithelium typically coupled?
Coupled to Na reabsorption
What is the role of the NHE (Na/H exchanger) in the nephron?
Reabsorbing H from lumen to interstitium
Which transport mechanism is responsible for reabsorption of NaCl in the late proximal tubule?
Cl base exchanger
What happens to uric acid in the proximal tubule of the nephron?
It gets reabsorbed and secreted by specialized transporters
Which process leads to an acidic pH in the ultrafiltrate within the nephron?
Active HCO3 reabsorption
What is the primary consequence of accumulation of intracellular HCO3 in kidney cells?
Increased HCO3 export
What causes water to be reabsorbed into peritubular capillaries from kidney cells?
High colloid osmotic pressure of blood in capillaries
What is a characteristic feature of aquaporin isoform abundantly present in the collecting duct?
Regulated by ADH
What effect does accumulation of organic substrates have on transporters in kidney cells?
Increases transporter capacity
What is the primary function of the thin descending limb in Henle's loop?
Reabsorbs water due to aquaporins
What is the primary function of the thick ascending limb in Henle's loop?
Reabsorption of NaCl and K
What is a key characteristic of epithelial cells in the thin descending limb?
Very permeable to water
Which of the following ions is NOT reabsorbed in the thick ascending limb?
Mg
What drives the movement of Na, Cl, and K into cells of the thick ascending limb?
Electroneutral Na/K/2Cl cotransporter
Which segment of Henle's loop has an extremely hypertonic interstitial fluid?
Thick ascending limb
Which aquaporin isoform is abundant in the proximal tubule and thin descending limb?
AQP1
What happens to tubular fluid as it moves through Henle's loop?
Dilutes due to osmotic pressure gradient
What is a characteristic of the Na/K/2Cl cotransporter isoform specific to Henle’s loop?
Electroneutral transport of Na:K:Cl
What is a feature of the collecting tubule in the nephron?
Plays a role in diluting urine further
Learn about the functions and structure of nephrons, the functional units of the kidney. Explore the segments and epithelium of nephrons, including the filtration, reabsorption, and secretion processes.
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