Excretory System

Question 1

What is the function of the excretory system?

Answer 1

removes waste products and toxins from the cells in the body

Question 2

What makes up the excretory system?

Answer 2

kidneys
ureters
bladder
urethra

Question 3

How is oxygenated blood delivered to the kidneys?

Answer 3

through the renal artery

Question 4

What are the two main functions of the kidneys?

Answer 4

ultrafiltration
reabsorption

Question 5

What do the kidneys do?

Answer 5

filter blood by separating it out into different substances
allow some substances to be reabsorbed back into the blood

Question 6

What makes up urine?

Answer 6

water
salts
urea

Question 7

Is urea toxic?

Answer 7

no

Question 8

Is urea easy to remove from the body?

Answer 8

yes

Question 9

How is urea formed?

Answer 9

after processing ammonia

Question 10

What is ammonia?

Answer 10

toxic waste product

Question 11

How is ammonia formed?

Answer 11

from the processing of amino acids

Question 12

What organ converts ammonia to urea?

Answer 12

liver

Question 13

What is an example of homeostasis in the kidneys?

Answer 13

kidneys remove water, salt and urea from blood

too much water and salt won’t be reabsorbed by the kidneys and will be turned into urine

too little water and salt will be reabsorb by the kidneys creating small amounts of urine

Question 14

What happens to urine after the kidneys?

Answer 14

kidneys pass urine through the ureter and collects in the bladder

Question 15

What happens to the oxygenated blood after filtration?

Answer 15

passes back into the bloodstream through the renal vein

Question 16

How does the bladder excrete urine?

Answer 16

passes urine out of the body through the urethra

Question 17

What is ultrafiltration?

Answer 17

process of removing substances from blood

Question 18

How are the kidneys able to filter blood?

Answer 18

blood forced through membranes in kidneys at high pressure

membranes don’t allow red and white blood cells or platelets to pass through

membranes do allow water, salt, urea and glucose molecules to pass through

Question 19

How does an animal know when they need to urinate?

Answer 19

bladder walls begin to stretch as it gets full which causes signals to be sent to the brain that it needs to be emptied

Question 19

What is an example of a species that cannot control their bladder?

Answer 19

rats or mice

Question 20

What adaptations do birds have?

Answer 20

kidneys process ammonia into uric acid

converting ammonia into uric acid conserves more water but requires more energy

do not have a bladder instead they have only one chamber that stores both liquid and solid waste

faeces and uric acid excreted out of cloaca as one semisolid paste

Question 20

Why do infant animals not have control over when they urinate?

Answer 20

they have involuntary control over the bladder

they don’t have control over part of the brain that controls the bladder

Question 21

What adaptations do desert animals have that help them survive on small amounts of water and to also drink salt water?

Answer 21

reduce the rate of ultrafiltration

reabsorb more water

an anatomical feature of kidneys called Loop of Henle is much longer which produces much more concentrated urine meaning less water is lost

produce own water by oxidising energy from their food

Question 22

What adaptations do aquatic animals have to remove ammonia from their bodies?

Answer 22

remove ammonia directly

ammonia dissolves in water, aquatic animals are surrounded by water

fish remove ammonia through their gills

Question 23

What adaptations do aquatic animals have to regulate their salt concentration?

Answer 23

many fish have permeable skin meaning water passes through their skin in a process called osmosis

permeable barrier separates water with a low concentration of salts and a high concentration of salts

permeable barrier prevents salts from passing through it

freshwater fish kidneys remove lots of water from the body with large amounts of very dilute urine

saltwater fish kidneys remove lots of salts from the body with small amounts of urine

Question 24

How do sharks regulate their salt concentration?

Answer 24

produce and store some urea which increases the concentration of salts in their body to match the surrounding water