13. Excretion in humans

Question 1

Through where is carbon dioxide excreted?

Answer 1

lungs

Question 2

Name 3 excretory products.

Answer 2

CO2
urea
sweat (salts)

Question 3

Name 3 processes of excretion.

Answer 3

gas exchange
urination
thermoregulation

Question 4

Define ‘excretion’.

Answer 4

removal of toxic waste products produced by the metabolism

Question 5

What substances are excreted by the kidneys?

Answer 5

urea + excess water and ions

Question 6

What is the nephron?

Answer 6

unit of filtration in the kidney

Question 7

What is the role of the glomerulus?

Answer 7

filtration

Question 8

Which substances are able to pass through the glomerulus?

Answer 8

amino acids
glucose
urea
salts
ions
water

Question 9

Which substances are NOT able to pass through the glomerulus?

Answer 9

blood cells
platelets
proteins

Question 10

What is the role of the nephron?

Answer 10

reabsorption of:
all the glucose,
some of the ions,
and most of the water back into the blood.

Question 11

What are the components of urine?

Answer 11

urea, excess water and excess ions

Question 12

What is the role of the liver?

Answer 12

assimilation of amino acids by converting them to proteins

Question 13

Where is urea formed?

Answer 13

liver

Question 14

What is urea formed from?

Answer 14

excess amino acids

Question 15

What is deamination?

Answer 15

the removal of the nitrogen-containing part of amino acids to form urea

Question 16

Why is it important to excrete urea?

Answer 16

urea is toxic