Excretion

Question 1

Renal vein

Answer 1

Transports deoxygenated blood away from the kidney to the vena cava.

Question 2

Renal Artery

Answer 2

Carries oxygenated blood to the kidneys from the aorta.

Question 3

Ureters

Answer 3

Carries urine from the kidneys to the bladder through 2 tubes.

Question 4

Bladder

Answer 4

A muscular bag in which urine is stored.

Question 5

Urethra

Answer 5

A tube leading out of the body from the bladder.

Question 6

Sphincter muscles

Answer 6

2 ring shaped muscles on the urethra, which contract to close the urethra and hold back the urine.

Question 7

Glomerular filtrate

Answer 7

Fluid that enters the Bowman’s capsule.

Question 8

Ultrafiltration

Answer 8

The process where the filter separates different sized molecules under pressure.

Question 9

Glomerus

Answer 9

Ball of blood capillaries where blood is filtered.

Question 10

Bowman’s Capsule

Answer 10

Hollow cup of cells, surrounding the Glomerulus.

Question 11

The loop of Henle

Answer 11

Involved with concentrating the fluid in the tubule by causing more water to be reabsorbed into the blood.

Question 12

Structure of Bowman’s capsule

Answer 12

Divided arteries supply the capillaries of the glomerulus. High blood pressure forces fluid from the blood through the walls of the capillary into the Bowman’s capsule, called Glomerular filtrate. The Glomerulus and the capsule are separated by 2 layers of cells, the capillary wall and the cell wall of the capsule. Between them is the basement membrane which isn’t made of cells. The layers act as a filter, allowing water, ions and small molecules (glucose and urea) to pass through.

Question 13

Selective Reabsorbtion

Answer 13

Kidneys selectively reabsorb small molecules back into the blood stream after they have been filtered out. They reabsorb all the glucose molecules, as much water needed to maintain a constant water level in the blood plasma and as many ions needed to maintain a constant balance of mineral ions in the blood plasma.

Question 14

Kidney

Answer 14

It regulates water content and filters blood.
Blood is carried to the kidney through the renal artery an is filtered at high pressure. The kidney selectively reabsorbs glucose, water and mineral ions back into the blood. The blood then leaves through the renal vein.
The kidneys produce urine which helps maintain water balance. The urine leaves through the ureter.

Question 15

Hypothalamus

Answer 15

Detects changes in the blood plasma.

Question 16

Pituitary gland

Answer 16

Regulates the release of the antidiuretic hormone, ADH.

Question 17

ADH, Antidiuretic hormone

Answer 17

Released by the pituitary gland when the blood is too concentrated and it causes the kidney tubules to become more permeable which allows more water to be reabsorbed back into the blood during selective reabsorption.

Question 18

Control of the body’s water content

Answer 18

Too much water in blood -> hypothalamus detects water level -> pituitary gland releases less ADH -> less water reabsorbed by kidneys -> more urine -> blood water level returns to normal.