13. excretion

Question 1

describe excretion

Answer 1

removal of toxic materials and the waste products of metabolism from organisms

Question 2

describe the term ‘carbon dioxide’

Answer 2

waste product of respiration, which is excreted through the lungs

Question 3

describe the term ‘urea’

Answer 3

toxic waste product produced in the liver from the breakdown of excess amino acids is

Question 4

identify, on diagrams, the kidneys, ureters, bladder and urethra and state the function of each

Question 5

state the function of the kidneys

Answer 5

removing urea and excess salts and water from the
blood as urine

Question 6

state the function of the ureters

Answer 6

filter blood and create urine as a waste product

Question 7

state the function of the bladder

Answer 7

store urine

Question 8

state the function of the urethra

Answer 8

allow urine to pass outside the body

Question 9

explain the need for excretion

Answer 9

ammonia is from protein foods that we eat and if it builds up, it can be dangerous to our health, so it is converted to urea in the liver which is less toxic but it can still be as toxic if it builds up therefore it is excreted by out body in the form of urine

Question 10

Outline the structure of a nephron and its associated blood vessels, limited to: Bowman’s capsule,
glomerulus, tubules, loop of Henle and collecting duct

Question 10

list the functions of the nephron

Answer 10

• filters water and small solutes out of the bloodstream by glomerulus
• reabsorb all of the glucose, some of the ions and most of the water back into the blood
• form urine containing urea, excess water and excess ions

Question 11

describe the role of the liver

Answer 11

assimilate amino acids and converting them to proteins

Question 12

describe deamination in the liver

Answer 12

removal of the nitrogen-containing part of amino acids and forming urea