Kidney

Question 1

Excretion

Answer 1

The removal from the body of potentially toxic waste products of metabolism

Question 2

Osmoregulation

Answer 2

The maintenance of internal solute concentration in teh body fluids of a living organism

Question 3

What does the kidney consist of

Answer 3

Kidney consists of cortex, medulla, pelvis

Question 4

Function of kidney

Answer 4

Osmoregulation
Excretion

Question 5

Basic unit of kidney

Answer 5

Nephron and is found in the medulla and cortex

Question 6

Bowman’s capsule

Answer 6

Cup-shaped structure with porous inner wall which collects the filtrate produced by ultrafiltration of blood in the glomerulus

Question 7

Proximal convoluted tubule

Answer 7

Highly twisted section which carries out selective reabsorption of useful substances from the filtrate back into the blood- have microvilli and mitochondria

Question 8

Loop of Henle

Answer 8

Establishes high solute concentration in teh medulla so hypertonic urine can be produced

Question 9

Distal convoluted tubule

Answer 9

Adjusts solute concentrations and blood pH

Question 10

Collecting duct

Answer 10

Carries out osmoregulation by varying the amount of water reabsorbed

Question 11

Ultrastructure of glomerulus

Answer 11

Pressure is very high and the capillary wall has fenestrations making it permeable. This allows for ions, urea, and glucose to be filtered out but not cells and most proteins

Question 12

Three parts of the ultrafiltration system

Answer 12

1. Fenestrations: cells in the wall of the capillaries that allow fluid, but not blood cells to escape
2. Basement membrane: covers teh outside of capillaries and supports their wall. Made of negatively-charged glycoproteins which form a mesh with small gaps and prevent plasma proteins from passing
3. Filtration slits: narrow gaps between the foot processes of podocytes-specialised epithelial cells that form the inner wall of the Bowman’s capsule, have extensions that wrap around the capillaries adn many short side branches called foot processes. Narrow gaps between foot processes prevent small molecules from being filtered out of the blood.

Question 13

Proximal convoluted tubule function

Answer 13

Carries out selective absorption by AT from the filtrate. Have mitochondria, pumps and microvilli increasing the SA. AT makes the total solute concentration higher so water moves by osmosis. It reabsorbs all glucose and amino acids and 80% water, sodium and other mineral ions.

Question 14

Loop of Henle function

Answer 14

Maintains hypertonic conditions in teh medulla. Descending limbs are permeable to water but impermeable to sodium ions. Ascending limbs are permeable to sodium ions but impermeable to water. Ascending limbs pump sodium ions out of the filtrate to the medulla by AT creating a high solute concentration in the medulla. The wall of the ascending limb is impermeable to water, so water is retained in the filtrate, even though the fluid in the medulla is now hypertonic relative to the filtrate. As the filtrate flows down the descending limb into this region of high solute conc. some water is drawn out by osmosis until the same solute concentration as the fluid in the medulla is reached. This dilutes the fluid in the medulla slightly. The filtrate that leaves the loop of Henle is more dilute than the fluid entering it showing that the loop of Henle increases the solute concentration of the medulla.