excretion

Question 1

define excretion

Answer 1

the removal of waste products of metabolism out of the body

Question 2

give 3 organs that are apart of the excretion system in animals

Answer 2

lungs, kidneys, skin

Question 3

give an example of a feature in plants that is involved in excretion

Answer 3

stomata

Question 4

what is crenation

Answer 4

when water leaves an animal cell due to osmosis and shrinks

Question 5

name two methods animals control their temperatures

Answer 5

ectotherms, endotherms

Question 6

what is an ectotherm

Answer 6

gain/lose heat to or from an external environment e.g fish, frogs, snakes

Question 7

what is an endotherms

Answer 7

generate their own heat from metabolic reactions. e.g cats

Question 8

how does the skin help achieve homeostasis

Answer 8

it regulates human body temperature

Question 9

name the two layers of skin

Answer 9

epidermis, dermis

Question 10

what is the name of the layer found beneath the epidermis + dermis

Answer 10

subcutaneous tissues which contain adipose tissue (fat-rich cells)

Question 11

what names are given to the layer of cells that make the epidermis

Answer 11

malphighian layer, granular layer, cornified layer

Question 12

where is melanin produced

Answer 12

malphighian layer

Question 13

where is keratin produced

Answer 13

granular layer

Question 14

what’s the purpose of melanin

Answer 14

gives colour to the skin, hair and iris + protects the skin from UV rays

Question 15

in what scenario might a lot of melanin be produced

Answer 15

when the skin is subjected to more sunlight exposure

Question 16

what does the dermis consist of

Answer 16

connective tissues containing collagen

Question 17

what is the purpose of collagen

Answer 17

gives skin its elasticity

Question 18

give 4 examples of structures you’d find in the dermis

Answer 18

hair follicle, touch receptor, sweat gland, temperature receptor

Question 19

what is the function of the epidermis

Answer 19

protects the body from damage and acts as a barrier to prevent water loss and pathogen entry

Question 20

what is the function of the dermis

Answer 20

protects internal organs

Question 21

what is sebum + its function

Answer 21

an oil produced by sebaceous glands located along hair follicles… it keeps hair moist and flexible and prevents the skin from drying out

Question 22

where is vitamin D produced in the body

Answer 22

produced by the skin

Question 23

are water soluble vitamins stored in the body

Answer 23

no, only fat soluble vitamins are stored

Question 24

where in the skin acts as a food store

Answer 24

fat in adipose tissue

Question 25

is skin a sense organ

Answer 25

yes because it has many receptors

Question 26

what organ of excretion is found in the skin

Answer 26

sweat glands that remove water and salts

Question 27

explain what happens to the skin in warm conditions

Answer 27

sweat is produced and released onto the skin. when water evaporates it lowers body temperature. blood vessels expand and dialate which increase heat loss and reduce body temperature

Question 28

explain what happens to the skin in cold conditions

Answer 28

erector muscles contract to form goosebumps. this causes hair to stand up in a process called pyloerection. a layer of warm air is trapped close to the skin by the hairs and this helps to reduce heat loss from the body. vasoconstriction also occurs which means the blood vessels in the skin contract