30 Questions
What type of transport is involved in the reabsorption of potassium ions in the ascending loop of Henle and early DCT?
Secondary active 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
What is the component of the luminal membrane involved in reabsorption?
Cotransport molecule (K+/2Cl−)
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
What is the function of the sodium/potassium ATPase ion pumps in the basolateral membrane?
To pump sodium ions out of the cell
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
What happens to the principal cells when stimulated by ADH?
They quickly insert luminal water channels, increasing their water permeability
What is the effect of ADH on the formation of urine?
It enhances the formation of concentrated urine
What is the outcome when the collecting ducts remain impermeable to water?
The urine becomes more dilute
What type of diuretics include high glucose levels and alcohol?
Osmotic diuretics
What is the significance of the medullary osmotic gradient in the formation of urine?
It is essential for the formation of concentrated urine
What is the last step in the formation of urine?
Passage through the medullary collecting duct
Where does the bulk of reabsorption occur in the nephron?
Early tubular segments
What happens to the membrane permeabilities in the early tubular segments?
They are relatively fixed
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
What is required for the principal cells to be permeable to sodium ions and water?
The presence of aldosterone from the adrenal gland
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
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
What is the function of ureters?
To convey urine from the kidneys to the bladder
What is the composition of the ureter wall?
Transitional epithelial mucosa, smooth muscle muscularis, fibrous connective tissue adventitia
What is a predisposing condition for renal calculi?
Chronic bacterial infection
What happens to the ureters when bladder pressure increases?
They close their distal ends
What is the function of the urinary bladder?
To temporarily store urine
What is a consequence of large kidney stones?
Obstruction of urine drainage and increase in pressure in kidneys, causing pain
What is the direction of sodium ion movement across the luminal membrane?
From high extracellular concentration to low intracellular concentration
What type of transport occurs in the sodium channels of the luminal membrane?
Simple diffusion
What is the role of the sodium/potassium pumps in the basolateral membrane?
To lower the sodium ion concentration in the cytosol
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
What drives the secondary active transport of the sodium/hydrogen countertransport molecule?
The movement of sodium ions down their concentration gradient
Where are the sodium ions ultimately transported to after moving through the luminal membrane?
The interstitium
Learn about the role of sodium channels in cellular transport, including the movement of sodium ions through the luminal and basolateral membranes. Understand how sodium/potassium pumps and simple diffusion contribute to this process.
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