urine formation Flashcards
What is the formula for filtration in the kidneys?
A) GFR ÷ Plasma concentration
B) GFR + Plasma concentration
C) GFR × Plasma concentration
D) GFR − Plasma concentration
Answer: C
Which of the following best describes glomerular filtration?
A) Selective for glucose and amino acids
B) Non-selective except for proteins and blood cells
C) Actively controlled process
D) Occurs only in the distal tubule
Answer: B
Which of these substances is almost completely reabsorbed in the nephron?
A) Creatinine
B) Urea
C) Glucose
D) Sodium
Answer: C
Which waste product is poorly reabsorbed by the tubules?
A) Glucose
B) Amino acids
C) Creatinine
D) Sodium
Answer: C
Tubular reabsorption occurs through which two main mechanisms?
A) Osmosis and evaporation
B) Pinocytosis and filtration
C) Passive and active transport
D) Diffusion and ultrafiltration
Answer: C
What must occur first for a substance to be reabsorbed?
A) It must be excreted into the lumen
B) It must be transported across the tubular epithelial membrane
C) It must pass through the collecting duct
D) It must bind to albumin
Answer: B
Through which two routes can water and solutes be reabsorbed?
A) Osmotic and hydrostatic
B) Renal and hepatic
C) Transcellular and paracellular
D) Arterial and venous
Answer: C
Which of the following is a form of primary active transport?
A) Na-glucose co-transport
B) Cl- diffusion
C) Na-K-ATPase
D) Passive osmosis
Answer: C
What type of transport involves Na-glucose co-transport?
A) Primary active transport
B) Passive transport
C) Osmotic transport
D) Secondary active transport
Answer: D
Which process involves engulfing proteins at the brush border?
A) Osmosis
B) Pinocytosis
C) Active secretion
D) Glomerular filtration
Answer: B
After proteins are absorbed via pinocytosis, what happens next?
A) They are excreted
B) They pass through aquaporins
C) They are digested into amino acids
D) They are filtered again
Answer: C
What is required for pinocytosis to occur?
A) Osmotic gradient
B) Plasma proteins
C) Energy
D) Glomerular pressure
Answer: C
Aquaporins are responsible for:
A) Active sodium transport
B) Passive water reabsorption by osmosis
C) Protein digestion
D) Creatinine excretion
Answer: B
Water reabsorption is primarily linked to the reabsorption of which ion?
A) Chloride
B) Calcium
C) Sodium
D) Potassium
Answer: C
Urea is reabsorbed:
A) Actively
B) Completely
C) Minimally and passively
D) By co-transport
Answer: C
Which of the following is almost not reabsorbed at all?
A) Sodium
B) Chloride
C) Urea
D) Creatinine
Answer: D
What percentage of Na and water is reabsorbed in the proximal tubule?
A) 25%
B) 45%
C) 65%
D) 85%
Answer: C
Which feature of proximal tubule cells supports high levels of active transport?
A) Few mitochondria
B) Low metabolic activity
C) Brush border enzymes
D) High number of mitochondria
Answer: D
What is the normal plasma glucose concentration range?
A) 60–90 mg/dL
B) 80–120 mg/dL
C) 100–150 mg/dL
D) 120–180 mg/dL
Answer: B
What type of transport is used to reabsorb glucose on the apical side?
A) Facilitated diffusion
B) Primary active transport
C) Secondary active transport
D) Osmosis
Answer: C
Where does glucose reabsorption occur in the nephron?
A) Loop of Henle
B) Distal tubule
C) Collecting duct
D) Proximal tubule
Answer: D
What happens when glucose concentration exceeds the tubular transport maximum?
A) It is converted to glycogen
B) It remains in the blood
C) It appears in the urine
D) It is stored in the kidneys
Answer: C
What is the average transport maximum for glucose in adults?
A) 150 mg/min
B) 250 mg/min
C) 375 mg/min
D) 500 mg/min
Answer: C
The basolateral side of the proximal tubule reabsorbs glucose through:
A) Simple diffusion
B) Facilitated diffusion
C) Active transport
D) Pinocytosis
Answer: B
