38 Questions
What percentage of the original 125 milliliters per minute of filtrate remains to enter the medullary collecting duct?
5%
What hormone regulates the final amount of water reabsorbed in the collecting duct?
Antidiuretic hormone
What is the primary function of the countercurrent multiplier mechanism?
To concentrate the urine by drawing water from the filtrate
What is the role of urea in the medullary interstitial osmolarity?
It is responsible for up to 40% of the osmolarity
What happens to the filtrate as it travels through the medullary collecting duct?
It decreases in volume and becomes more concentrated
What is the effect of antidiuretic hormone on the collecting duct?
It increases the water permeability of the duct
What is the definition of renal clearance?
The volume of plasma that is cleared of a particular substance in a given time
What is the purpose of the loop of Henle in the nephron?
To allow urea to passively re-enter the filtrate
What drives the reabsorption of substances through the luminal membrane in the kidney?
Sodium ion concentration gradient
Which ion follows sodium ions out of the cell through its own channel in the kidney?
Chloride
Which of the following ions contributes to the increasing osmolarity of the interstitial fluid in the ascending loop of Henle?
Potassium
How much of an osmotic difference do the cells of the ascending limb of the loop of Henle maintain between the filtrate and interstitial fluid?
200 milliosmoles
What substance's reabsorption is regulated by ADH in the DCT and collecting duct?
Water
Which hormone decreases blood volume and blood pressure by affecting Na+ reabsorption?
ANP
What is the concentration of milliosmoles approximately at the bottom of the loop of Henle due to the countercurrent multiplier effect?
1200 milliosmoles
What is the essential purpose of the osmolarity gradient formed by the ascending and descending limbs of the Loop of Henle?
Concentration of urine
What type of mucosa is found in both the ureters and the urinary bladder?
Transitional epithelial mucosa
Which of the following conditions is NOT a predisposing factor for renal calculi?
Low blood levels of calcium
What is the function of the trigone region in the urinary bladder?
Infections tend to persist in this region
Which condition might cause kidney stones to form?
Increased uric acid salts
In which anatomical position is the urinary bladder found in males?
Posterior to the prostate gland
What mechanism is responsible for propelling urine to the bladder through the ureters?
Smooth muscle contraction in response to stretch
What percentage of water in the glomerular filtrate is reabsorbed during processing in the tubules?
99%
Which reabsorption route involves substances moving through the cell membranes themselves?
Transcellular route
Which substances are entirely reabsorbed during the reabsorption process?
Glucose and amino acids
In the proximal convoluted tubule (PCT), which ions utilize both the transcellular and paracellular pathways for reabsorption?
Calcium, magnesium, potassium, and some sodium
What drives water to move from the tubule through the tight junctions into the interstitial space?
Concentration gradient
Which part of the nephron is primarily responsible for fine-tuning the blood's composition by secreting selected solutes into the filtrate?
Distal convoluted tubule
Through which cellular structures do solutes diffuse or actively transport in the transcellular pathway?
Luminal and basolateral membranes
Which route is limited to water movement and the reabsorption of specific ions such as Ca2+ and Mg2+?
Paracellular route
What facilitates the continuous absorption of water in cells permeable to water?
Obligatory water reabsorption
What is the primary effect of raising osmolality in the interstitium by transporting sodium?
Diffusion of water from the tubule into the interstitium
Which of the following is a result of transporting sodium ions?
Water diffusion from tubular lumen to interstitium
Where does major reabsorption of valued substances occur in the renal tubules?
Proximal convoluted tubule
How does the lowered intracellular concentration of sodium ions affect sodium's reabsorption?
Causes additional sodium ions to be reabsorbed through the luminal membrane
How does the active transport of sodium ions aid reabsorption processes in the nephron?
Enables the reabsorption of most substances in the nephron
Which structure is primarily responsible for creating water channels across cell membranes?
Aquaporins
Which statement correctly describes the role of the proximal convoluted tubule (PCT) in reabsorption?
The PCT depends on the active reabsorption of sodium ions for reabsorbing many substances
This quiz covers the Urinary System II chapter in Human Physiology, focusing on the reabsorption of solutes and water in the nephron and the urinary system's functions.
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