Excretion in humans

Question 1

Role of the lungs

3

Answer 1

• release of CO2 from the blood
• excretion of water and heat
• in take of oxygen

Question 2

Role of the kidney

2

Answer 2

• excrete all nitrogenous waste (urea)

- excrete non-nitrogenous waste (CO2, water, ions, hormones, poisons, drugs)

Question 3

Role of liver

9

Answer 3

• forms nitrogenous waste
• urea
• uric acid
• creatinine
• forms non-nitrogenous waste
• toxins and drugs
• alcohol
• bile pigments
• cholesterol

Question 4

Role of bladder

2

Answer 4

• stores urine from the kidneys

- apart of the urinary system

Question 5

Role of skin

3

Answer 5

• water, salts and some urea is released
• helps maintain homeostasis
• both excretion and secretion

Question 6

Origin of substances (8)

Answer 6

• CO2 (cellular respiration in cells)
• Urea (excess amino acids, broken down into ammonia and then into urea through deamination)
• Uric Acid (breakdown of nucleic acids)
• Creatinine (formed from creatine phosphate in skeletal muscles)
• Toxins and Drugs (painkillers etc.)
• Alcohol (can cause permanent damage if in excess of an extended time)
• Bile Pigments (breakdown of red blood cells)
• Cholesterol ( breakdown of bile salts)