communication and homeostasis Flashcards
stimulus
change in environment
gland
Drüse
homeostasis
maintenance of constant internal environment
how is the enzyme activity influenced if temperature is too high?
enzymes denature
how is the enzyme activity influences if temperature is too low?
rate of metabolic reactions slowed down
what are the main factors that have to be controlled by homeostasis ?
glucose level in the blood & temperature
is positive feedback involved in homeostasis?
no, only negative feedback, cause positive feedback amplifies change
example where positive feedback needed
building of blood clot
- -> platelets activate other platelets until blood clot done
- -> than negative feedback
cell signaling
communication between cells
communication between adjacent cells
nervous system
communication between distant cells
hormonal system
wechselwarme Tiere
ectotherms
gleichwarme Tiere
endotherms
mechanisms to increase body temperature
insulation air layer between hairs
shivering
adrenaline and thyroxine released
vasoconstriction
glycogenesis
forming of glycogen from glucose
genesis
making
lysis
splitting
hepatocytes
liver cells
glycogenolysis
process of breaking down glycogen
neoglucogenesis
forming glucose from non-carbohydrates
how does insulin influence the blood glucose level?
- binds to receptors on liver & muscle cells
- increases permeability to glucose of cell membrane
- activates enzymes –> convert glucose into glycogen
- increases respiration in muscle cells
how does glucagon influence the blood glucose level?
- binds to receptors on liver cells
- activates enzymes –> breakdown of glycogen
- promotes neoglucogenesis
- decreases rate of respiration
osmoregulation
control of water levels and mineral ions (salt) in the blood
anti-diuretic hormone
causes kidney tubules to become more permeable
how does a condition that makes the homeostatic system less responsive affect a homeostatic response?
threshold to respond to a change in the environment is higher –> it has to be more wrong in order that something responds
time of the actual response is not affected though
