Kidneys

Question 1

Route of urine from the kidney

Answer 1

Urine travels from the kidneys, through the ureters, to the bladder where it is stored and then through the urethra out of the body

Question 2

How is urea formed?

Answer 2

Breakdown of amino acids in the liver

Question 3

Kidney process

Answer 3

Ultrafiltration - Blood enters the nephron into the glomerulus and is filtered under pressure in the Bowman’s capsule

Selective reabsorption - The filtrate enters the tubule where glucose is reabsorbed by selective reabsorption. Active transport using energy from respiration occurs through the loop of Henlé where water and ions are exchanged into the tubule

Urine formation - The filtrate enters the collecting duct where excess water is removed. Urine is formed from water and urea

Question 4

ADH (anti diuretic hormone)

Answer 4

Decreased water potential in blood causes osmoreceptor cells in the hypothalamus to loose water. This stimulates ADH to be released from the pituitary gland. ADH travels through the bloodstream to the kidney and makes the loop of Henle and collecting duct more permeable, causing more water to be reabsorbed into the bloodstream, preventing dehydration.

Question 5

Dialysis

Answer 5

1) Blood leaves body into dialysis machine, flowing between a partially permeable membrane
2) Dialysis fluid on the other side of the membrane has the same concentration of glucose and mineral ions but no urea of excess minerals
3) The urea and excess minerals diffuse down their concentration gradient into the dialysis fluid
4) The dialysis fluid must be constantly replaced to maintain the steep concentration gradient