Excretion in humans

Question 1

excretory products

Answer 1

• carbon dioxide is excreted through the lungs
• the kidneys excrete urea and excess water and ions
• the skin excretes sweat, wish contains waste products e.g: urea

Question 2

structure and function of a nephron and its associated blood vessels

Answer 2

(a) the role of the glomerulus in the filtration from the blood of water, glucose, urea and
ions

(b) the role of the nephron in the reabsorption of all of the glucose, some of the ions and most of the water back into the blood

(c) the formation of urine containing urea, excess water and excess ions

Question 3

role of the liver

Answer 3

assimilation of amino acids by converting them to proteins

urea is formed in the liver from excess amino acids

Question 4

deamination

Answer 4

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

Question 5

importance of excretion

Answer 5

our body constantly excretes metabolic waste products. urea can be toxic if present in high levels. it can cause abdominal pain, irregular heartbeat, nausea and muscle cramps