Negative and positive feedback loop

set point

the state of balance, health and comfort, typically a range

stimulus

an action that disrupts changes the situation and evokes a response

receptor

sensory organ that recieves the stimulus

control center

recieves input from receptors (afferent pathway) and gives command to the effectors (efferent pathway)

effector

an organ that does the response

response

the effect, caused by the stimulus

homeostasis of body temp

96-99 F

homeostasis of kidney hydration

68-78%

blood sugar

70-99 mg/dL

homeostasis

maintaining stable internal conditions within a normal range (dynamic equilibrium)

negative feedback failure examples where positive feedback takes over

heart failure, cancer, dementia, diabetes, paralysis and kidney disease

positive feedback

amplifies stimulus to produce a bigger response away from hemeostasis.

positive feedback examples

childbirth (helpful positive feedback), blood clotting (helpful), cancer, menstrual cycle

Catalysts

substances that speed up the reactions without being permanently altered

enzymes

proteins that act as a catalyst in most biological reactions

first step of enzymes

bind to a specific substrate

second step of enzymes

the product is different than the initial substrate

third step of enzymes

enzyme returns to the original shape - doesn’t get used up

denature in enzymes

happens by moving away from narrow set points, makes change in shape of the protein