Sodium Channels and Cellular Transport

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What type of transport is involved in the reabsorption of potassium ions in the ascending loop of Henle and early DCT?

Active transport

Facilitated diffusion

Secondary active transport (correct)

Passive transport

What is the function of the potassium ion channels in the luminal and basolateral membranes?

To allow potassium ions to diffuse back into the filtrate (correct)

To regulate the cell's potassium concentration

To pump chloride ions into the cell

To transport sodium ions out of the cell

What is the component of the luminal membrane involved in reabsorption?

Cotransport molecule (K+/2Cl−) (correct)

Glycoprotein layer

Sodium/glucose cotransporter

Sodium/potassium ATPase

What is similar between the cells in the basolateral membrane and the cells of the PCT?

They both have sodium/potassium ATPase ion pumps and potassium channels Signup and view all the answers

What is the function of the sodium/potassium ATPase ion pumps in the basolateral membrane?

To pump sodium ions out of the cell Signup and view all the answers

What is the characteristic of the microvilli in the ascending loop of Henle and early DCT?

They are short and contain many ion channels and secondary active transport molecules Signup and view all the answers

What happens to the principal cells when stimulated by ADH?

They quickly insert luminal water channels, increasing their water permeability Signup and view all the answers

What is the effect of ADH on the formation of urine?

It enhances the formation of concentrated urine Signup and view all the answers

What is the outcome when the collecting ducts remain impermeable to water?

The urine becomes more dilute Signup and view all the answers

What type of diuretics include high glucose levels and alcohol?

Osmotic diuretics Signup and view all the answers

What is the significance of the medullary osmotic gradient in the formation of urine?

It is essential for the formation of concentrated urine Signup and view all the answers

What is the last step in the formation of urine?

Passage through the medullary collecting duct Signup and view all the answers

Where does the bulk of reabsorption occur in the nephron?

Early tubular segments Signup and view all the answers

What happens to the membrane permeabilities in the early tubular segments?

They are relatively fixed Signup and view all the answers

What is the function of intercalated cells in the late distal convoluted tubule and the collecting ducts?

To help balance the blood pH by secreting hydrogen ions Signup and view all the answers

What is required for the principal cells to be permeable to sodium ions and water?

The presence of aldosterone from the adrenal gland Signup and view all the answers

What is the function of principal cells in the late distal convoluted tubule and the collecting ducts?

To perform hormonally regulated water and sodium reabsorption and potassium secretion Signup and view all the answers

What is the precise regulation of in the late distal convoluted tubule and the collecting ducts?

The final balance of fluid and solutes returned to the blood Signup and view all the answers

What is the function of ureters?

To convey urine from the kidneys to the bladder Signup and view all the answers

What is the composition of the ureter wall?

Transitional epithelial mucosa, smooth muscle muscularis, fibrous connective tissue adventitia Signup and view all the answers

What is a predisposing condition for renal calculi?

Chronic bacterial infection Signup and view all the answers

What happens to the ureters when bladder pressure increases?

They close their distal ends Signup and view all the answers

What is the function of the urinary bladder?

To temporarily store urine Signup and view all the answers

What is a consequence of large kidney stones?

Obstruction of urine drainage and increase in pressure in kidneys, causing pain Signup and view all the answers

What is the direction of sodium ion movement across the luminal membrane?

From high extracellular concentration to low intracellular concentration Signup and view all the answers

What type of transport occurs in the sodium channels of the luminal membrane?

Simple diffusion Signup and view all the answers

What is the role of the sodium/potassium pumps in the basolateral membrane?

To lower the sodium ion concentration in the cytosol Signup and view all the answers

What is the result of the sodium/hydrogen countertransport molecule's activity?

Sodium ions are transported into the cell, and hydrogen ions are secreted into the filtrate Signup and view all the answers

What drives the secondary active transport of the sodium/hydrogen countertransport molecule?

The movement of sodium ions down their concentration gradient Signup and view all the answers

Where are the sodium ions ultimately transported to after moving through the luminal membrane?

The interstitium Signup and view all the answers