Homeostasis Flashcards
homeostasis
the ability of an organism to maintain a constant internal environment
what is the external environment
surrounding environment where an organism is
most organisms bar humans have little to no ability to control their external environment
what is the internal environment
surrounding of cells in a multicelled organism
for example in humans this refers to tissue fluid
examples of homeostasis in humans
body temp 37C
pH of blood and tissue fluid close to 7.4
preventing build-up of toxic chemicals in the body
maintaining sufficient oxygen levels
regulating the level of glucose in blood plasma so it stays close to 0.1%
what disease is associated with regulating the level of glucose in blood?
diabetes- pancreas cannot produce insulin
organs + systems involved in homeostasis
skin
kidneys
liver
defence system
function of skin
controls body tempurature
function of kidneys
controls blood plasma and tissue fluid pH
prevents build up of toxic waste
function of liver
prevent build up of toxic waste
function of defence system
prevents infection
how is diffusion and gas exchange improved in the respiratory system
increased surface area for exchange of gas by diffusion ie alveoli in lungs
how is diffusion and gas exchange improved in the excretory system
takes materials waste materials to the body surface ie waste products excreted from human body
how is diffusion and gas exchange improved in circulatory system
used to transport materials such as gases, nutrients and toxic waste over long distances
transpiration
release of water through stomata
how does temperature regulation work in plants?
if a plant is too hot then it will increase transpiration in an effort to cool down
endotherms
animals who’s internal temperature remains constant despite environmental temperature changes eg mammals and birds
ectotherms
animals who’s internal temperature changes with environmental temperatures
eg lizards insects
how does temperature regulation work in endotherms
have a variety of different ways throughout the body but mainly through the skin ie sweating or goose bumps
how does temperature regulation work in ectotherms
activity levels depend directly on the temp of their environment. if they need to warm up, they will sit in direct sunlight etc
advantage of being endothermic
enzymes stay at optimum temperature, so metabolism is carried out optimally
how to endotherms remail at a constant temperature?
metabolism produces lots of heat energy. our bodies have the ability to control the loss of this heat mainly through the skin
