excretion Flashcards
define excretion
the removal of waste products of metabolism out of the body
give 3 organs that are apart of the excretion system in animals
lungs, kidneys, skin
give an example of a feature in plants that is involved in excretion
stomata
what is crenation
when water leaves an animal cell due to osmosis and shrinks
name two methods animals control their temperatures
ectotherms, endotherms
what is an ectotherm
gain/lose heat to or from an external environment e.g fish, frogs, snakes
what is an endotherms
generate their own heat from metabolic reactions. e.g cats
how does the skin help achieve homeostasis
it regulates human body temperature
name the two layers of skin
epidermis, dermis
what is the name of the layer found beneath the epidermis + dermis
subcutaneous tissues which contain adipose tissue (fat-rich cells)
what names are given to the layer of cells that make the epidermis
malphighian layer, granular layer, cornified layer
where is melanin produced
malphighian layer
where is keratin produced
granular layer
what’s the purpose of melanin
gives colour to the skin, hair and iris + protects the skin from UV rays
in what scenario might a lot of melanin be produced
when the skin is subjected to more sunlight exposure
what does the dermis consist of
connective tissues containing collagen
what is the purpose of collagen
gives skin its elasticity
give 4 examples of structures you’d find in the dermis
hair follicle, touch receptor, sweat gland, temperature receptor
what is the function of the epidermis
protects the body from damage and acts as a barrier to prevent water loss and pathogen entry
what is the function of the dermis
protects internal organs
what is sebum + its function
an oil produced by sebaceous glands located along hair follicles… it keeps hair moist and flexible and prevents the skin from drying out
where is vitamin D produced in the body
produced by the skin
are water soluble vitamins stored in the body
no, only fat soluble vitamins are stored
where in the skin acts as a food store
fat in adipose tissue
is skin a sense organ
yes because it has many receptors
what organ of excretion is found in the skin
sweat glands that remove water and salts
explain what happens to the skin in warm conditions
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
explain what happens to the skin in cold conditions
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
