Function of Kidney

Question 1

What is glomerulus filtration rate, and what does it indicate

Answer 1

GFR is the rate at which kidney filters blood, measured in ml/min per 100g body mass
Indicates kidney health and filtration efficiency

Question 2

What are the 3 amin factors affecting GFR

Answer 2

Blood pressure
Osmotic pressure
Intra-renal pressure

Question 3

Where do the the following susbstances enter and leave the nephron - urea, glucose, water, protein, sodium

Answer 3

Urea - enter glomerulus, mostly stays in filtrate
Glucose - enters glomerulus, reabsorbed in PCT
Water - enters glomerulus, reabsorbed along nephron
Protein - doesn’t enter
Sodium - enters glomerulus, reabsorbed in multiple segments

Question 4

What adaptations make PCT ideal for reabsorption

Answer 4

Microvilli - increase SA
Basal membrane folds increase exchange with capillaries
Many mitochondria provide ATP for active transport
Tight junctions prevent backflow

Question 5

How is glucose reabsorbed in PCT

Answer 5

Na⁺/K⁺ pumps reduce sodium inside epithelial cells

Sodium and glucose/amino acids cotransported into cells

Glucose moves into blood via facilitated diffusion

Water follows by osmosis due to low water potential

Question 6

What is the function of loop of Henle

Answer 6

Concentrates urine by creating a medullary osmotic gradient

Enables water reabsorption from collecting duct

Question 7

How do ascending and descending limbs of loop of Henle differ

Answer 7

Ascending limb: Impermeable to water, actively pumps Na⁺ out

Descending limb: Permeable to water, no active transport – water exits by osmosis

Question 8

How does the countercurrent system in loop of Henle work

Answer 8

Na⁺ actively transported out of ascending limb

Lowers water potential in medulla

Water moves out of descending limb by osmosis

Increases filtrate concentration, supporting gradient

Longer loop = more concentrated urine

Question 9

What is the main function of DCT

Answer 9

Reabsorbs water and regulates electrolyte balance

Affected by hormones like aldosterone

Question 10

What is the function of collecting duct and how is it hormonally regulated

Answer 10

Reabsorbs water, influenced by ADH

ADH increases aquaporins, enhancing water reabsorption

Concentrates urine before it enters the renal pelvis