Excretion Chp31

Question 1

What is the role of leaves as excretory organs in plants

Answer 1

plants lose oxygen and water vapour through the stomata

Question 2

What is the role of the excretory system in homeostasis

Answer 2

regulate body temperature, control osmosis, control concentration of body fluids, remove waste products from metabolism

Question 3

What are ectotherms

Answer 3

gain or lose heat from or to their external environment

Question 4

What are endotherms

Answer 4

generate their own heat from metabolic reactions

Question 5

Learn diagram of the skin

Answer 5

Page 349

Question 6

What are the 3 layer in the epidermis

Answer 6

cornified layer, granular layer and Malpighian layer

Question 7

What are the 3 layers of the skin called

Answer 7

epidermis, dermis and adipose tissue

Question 8

What of the skin

Answer 8

protection, vitamin production, food store, sense organ, excretion, temperature regulation

Question 9

How does the skin regulate temperature (cold)

Answer 9

erector muscles contract causing hairs to stand up trapping air which helps to reduce heat loss from the body and blood vessels contract reducing heat loss

Question 10

How does the skin regulate temperature (hot)

Answer 10

sweat is produced and blood vessels expand increasing heat loss

Question 11

What are the main excretory organs

Answer 11

lungs, skin and kidney

Question 12

What are the functions of the kidneys

Answer 12

excretion, osmoregulation, pH control,

Question 13

What organs/parts are in the urinary system

Answer 13

2 kidneys, 2 ureters, the bladder and the urethra

Question 14

What are the main processes in the kidney

Answer 14

filtration, reabsorption and secretion

Question 15

Learn the diagram of the nephron

Answer 15

Page 354

Question 16

What is filtration

Answer 16

water and small molecules pass from the blood into the nephron under high pressure

Question 17

What is reabsorption

Answer 17

molecules pass from the nephron back into the blood

Question 18

What is active transport

Answer 18

energy is used to move molecules often against a concentration gradient

Question 19

What is secretion

Answer 19

some substances pass from the blood into the nephron

Question 20

Describe the process of filtration

Answer 20

blood enters the nephron and small molecules like glucose amino acids, urea, salts and water are forced into the bowman’s capsule as they are under high pressure from the glomerulus

Question 21

Describe the process of reabsorption

Answer 21

water useful molecules and salts are reabsorbed in the proximal convoluted tubule, the loop of Henle and the distal convoluted tubule

Question 22

What does the proximal convoluted tubule reabsorb

Answer 22

most salts, glucose, amino acids and vitamins

Question 23

What does the loop of Henle (descending limb) reabsorb

Answer 23

some minerals

Question 24

What does the loop of Henle (ascending limb) reabsorb

Answer 24

some salts

Question 25

What does the distal convoluted tubule reabsorb

Answer 25

some salts

Question 26

What hormone controls the volume of urine

Answer 26

ADH (anti-diuretic hormone)

Question 27

What happens when we are dehydrated

Answer 27

pituitary gland releases ADH, travels to the kidneys causing the walls of the distal convoluted tubule and collecting ducts to become more permeable to water so we reabsorb more water

Question 28

What happens when we are hydrated

Answer 28

ADH is not released meaning the walls of the distal convoluted tubule and collecting ducts are not permeable to water so little water is reabsorbed