L1 intro Flashcards
factors to keep constant in body
temperature
ph
waterpotential
conc of o2 and co2
conc of glucose and salts
what is external environment and some factors
air water and soil around organism
temp change
light intensity
wind
humidity
wind
how do organisms respond to external environment and why
to reduce stress
behaviour eg penguin huddle
physiological eg change fur colour to match environment or camel store fat and metabolise to water
what is internal environment and some factors
conditions inside body
blood
tissue fluid
water potential (reg by kidney)
co2 from respiration as acidic gas cause change to ph therefore impacting enzymes (diffuses out to lower ph in cell
bloods role in internal environment
removes waste and toxin so dont accumulate in tissue fluid therfore can be excreted
why do multicellular orgs need communication system
to coordinate a response between different parts of the body
features of a good communication system
covers whole organism
specific
intercellular communication
neuronal =
neurones which signal across a synapse
RAPID SHORT TERM
hormonal =
blood transport signals via hormones to target cell
SLOWER LONG TERM
pathway
stimulus
receptor
coordination center
effector
response
receptor role
monitor inside conditions
effector role
respond to reverse change
what does communication allow
organs to function
homeostasis =
maintenance of internal environment in a steady state despite changes in external environment
homestasis 4 processes
reference point eg temp=37
detector
coordination centre
effector
