B5 - Waste disposal

Question 1

What is excretion?

Answer 1

The process of getting rid of waste from the body.

Question 2

Which body organs excrete waste?

Answer 2

The kidneys, skin, lungs and liver all excrete waste.

Question 3

What does urine contain?

Answer 3

Urine contains water, salt and urea.

Question 4

What is urea?

Answer 4

Urea is a nitrogen containing substance which is cleared from the blood by kidneys and is excreted in urine.

Question 5

What is egestion?

Answer 5

Egestion is the removal of solid waste.

Question 6

What is the difference between egestion and excretion?

Answer 6

Excretion is the removal of waste made by the body, egestion is the removal of waste that is not made by the body.

Question 7

What is the ureter?

Answer 7

The ureter is the tube that connects the bladder and the kidney.

Question 8

What does the renal artery do?

Answer 8

The renal artery brings blood containing waste substances to the kidney.

Question 9

What is urea made from?

Answer 9

Urea is made in the liver from unwanted amino acids.

Question 10

What does the renal vein do?

Answer 10

The renal vein takes filtered blood away from the kidneys.

Question 11

Why is it important that the blood in the kidneys is filtered under high pressure?

Answer 11

So that most of the liquid is forced out of the glomerulus into the Bowman’s capsule which surrounds it. This does not work properly in people who have very low blood pressure.

Question 12

What is a nephron?

Answer 12

A nephron is a kidney tubule which filters blood.

Question 13

What does the glomerulus do?

Answer 13

It removes useful and waste materials from the blood.

Question 14

What are Proximal Convoluted Tubules?

Answer 14

Proximal Convoluted Tubules are coiled up tubes next to the Bowmans Capsule.

Question 15

What do PCT’s do?

Answer 15

This is the place where all that useful glucose is re-absorbed from the ultra-filtrate and put back into the blood.

Question 16

What happens at the Loop of Henlé?

Answer 16

This part of the nephron is where water is reabsorbed.

Question 17

What happens at the Distal Convoluted Tubules?

Answer 17

This is where most of the salts in the ultra-filtrate are re-absorbed.

Question 18

What are Collecting Ducts?

Answer 18

Collecting ducts run through the medulla and are surrounded by loops of Henlé.

Question 19

What do Collecting Ducts do?

Answer 19

It collects the liquid produced by lots of nephrons.

Question 20

What is uric acid?

Answer 20

Uric acid contains nitrogen and is poisonous at high concentrations.

Question 21

What factors affect the amount of urine produced?

Answer 21

• the amount of water you drink
• the surrounding temperature
• the type of exercise you do

Question 22

When will you produce a small amount of concentrated urine?

Answer 22

• when you drink a small amount of water
• when you sweat a lot
• during vigorous exercise

Question 23

What does the skin excrete?

Answer 23

The skin excretes sweat.

Question 24

What does sweat contain?

Answer 24

Sweat contains water and salt.

Question 25

What are the two layers of the skin called?

Answer 25

The outer epidermis and the dermis underneath.

Question 26

Where does hair grow?

Answer 26

Hair grows in follicles.

Question 27

Why is sweating important?

Answer 27

Sweating regulates body temperature.

Question 28

What is reabsorption controlled by?

Answer 28

Reabsorption is controlled by ADH (anti-diuretic hormone)

Question 29

Where is ADH made?

Answer 29

ADH is made in the pituitary gland in the brain.

Question 30

What does ADH do?

Answer 30

ADH increases permeability of the nephrons so that more water is reabsorbed.

Question 31

What mechanism ensures the correct water balance in the blood?

Answer 31

Negative feedback.