Excretion

Question 1

Define excretion

Answer 1

Excretion is the removal of toxic waste substances made by cells. Toxic, waste and Cells are key words!

Question 2

What is the difference between excretion and egestion?

Answer 2

Excretion is removal of waste products from cells Whereas Egestion is passing out of waste material passed through alimentary canal

Question 3

Respiration occurs in all living organisms both plants and animals. What is the waste products of respiration ?

Answer 3

Carbon dioxide

Question 4

Plants both respire and photosynthesise. Does this mean that oxygen and carbon dioxide go into the leaves, or out of the leaves or both in and out?

Answer 4

Both oxygen and CO2 go in and out of leaves. Oxygen taken in and CO2 out for respiration CO2 in and oxygen out for photosythesis

Question 5

Humans cannot store excess amino acids like they can store carbs and lipids. (As fat tissue). So excess amino acids need to be broken down. What is the process of breaking down amino acids called?

Answer 5

Deamination

Question 6

What are the two waste products that need to be excreted?

Answer 6

Carbon dioxide Urea

Question 7

What process produces carbon dioxide as a waste product?

Answer 7

Respiration

Question 8

What removes carbon dioxide?

Answer 8

The lungs via blood plasma

Question 9

What process produces urea as the waste product?

Answer 9

Breakdown of amino acids ( deamination)

Question 10

In what organ are excess amino acids broken down and what waste product is produced?

Answer 10

In the liver producing waste product of urea

Question 11

What organs remove urea?

Answer 11

Kidneys and skin

Question 12

How does the liver break down excess amino acids?

Answer 12

Amino acids filtered into the liver through the hepatic artery Excess amino acids are broken down into carbohydrates and ammonia Ammonia is very toxic so broken down into urea which is less toxic Useful amino acids and the urea released back into blood via hepatic vein

Question 13

The kidneys filter the blood, remove any excess materials and passes them to the bladder. Where in your body are your kidneys and what shape are they?

Answer 13

Central of body cavity shaped like kidney beans!

Question 14

What are the 3 main sections of the kidney?

Answer 14

Cortex - at the top and lighter colour Medulla- triangular shaped Pelvis - yellowy section

Question 15

The kidney contains millions of tiny structures called…

Answer 15

Nephrons

Question 16

List in order the 6 parts of a nephron.

Answer 16

Glomerulus, Bowman capsule, Proximal convoluted tubule, Loop of Henle, Distal convoluted tubule, Collecting duct

Question 17

The artery exiting the glomerulus is smaller diameter than the entrance. This builds up pressure. What does this pressure force into the bowmans capsule?

Answer 17

Small molecules such as urea, glucose, amino acids and salts cross into the bowmans capsule to form the glomerular filtrate

Question 18

Which large molecules do not pass into the bowmans capsule but stay in the blood?

Answer 18

Proteins and red blood cells

Question 19

From the bowmans capsule, the filtrate travels to the proximal convoluted tubule. Here specialist cells use active transport to pump useful materials back into the blood. What 2 key materials are pumped back into the blood?

Answer 19

All the Glucose 80% of the water

Question 20

Your kidneys filter 180L of water a day but how much urine is produced per day?

Answer 20

1.5L

Question 21

What 2 parts of the kidney are used to reabsorb water?

Answer 21

Loop of Henle Collecting duct

Question 22

If you are dehydrated, your body will try to reabsord as much water from the filtrate as it can. What does this do to the urine?

Answer 22

Lower volume of water in urine makes it darker browner colour

Question 23

Your body controls how much water the body reabaorbs. What hormone controls this and where is this hormone produced?

Answer 23

Anti diuretic hormone ADH produced in the pituitary gland which is controlled by the hypothalamus in your brain.

Question 24

Anti diuretic hormone ADH is carried in the blood. The collecting duct is surrounded by capillaries, how does the ADH control how much water is reabsorbed back into the blood?

Answer 24

The ADH released by the pituitary gland diffuses out of the blood and binds with receptors on surface of collecting duct cells. This triggers the collecting duct wall to become more permeable to water so more is reabsorbed.

Question 25

What does urine contain?

Answer 25

Water Urea Ions

Question 26

What are the 3 organs of excretion?

Answer 26

Lungs Kidneys Skin

Question 27

Label the urinary system?

Answer 27

Question 28

The kidneys have 2 roles. What are they?

Answer 28

Excretion Osmoregulation

Question 29

Ultrafiltration in the bowman’s capsule produces a glomerular filtrate. What molecules are contained in the glomerular filtrate?

Answer 29

Urea Glucose Amino acids Salts