maintaining internal environment Flashcards
homeostasis
maintenance of constant internal environment
AUTOMATIC - uses nerves/ hormones don’t think
what is kept at constant levels
temp water level blood sugar level CO2 level blood pressure
why inputs balance outputs
why we have a constant internal environment
enzymes control all reactions in cells
homeostasis maintains ideal conditions for enzymes
ideal body temp
37 °C - core temp
optimum for enzymes
how to measure temp
thermometer
temp sensitive strips
digital probes
thermal imaging
homeothermic
animal that can keep its temp constant
hypothermia
if temp is below 32°
reaction in cells slows
pulse rate slows
can die
above 40° body temp
heat stroke/dehydration
enzymes denature (active site changes shape ESCs can’t form)
can die
gain heat
- respiration (exothermic)
- shivering + exercise - muscle contraction - increases respiration
- vasoconstriction
- wearing clothes - insulates
- hairs stand in end - trap heat
vasoconstriction
when body is cold
- arteriolar in skin get narrower
- less blood flows to skin surface
- less heat loss (by radiation)
- look paler
loose heat
- vasodilation
- sweating - evaporates water (uses skin heat)
- wear fewer clothes
- hairs lie flat - heat can escape
vasodilation
when body is hot
- arteriolar in skin get wider
- more blood flows to skin surface
- more heat lost (radiation)
negative feedback - body temp control - too hot
hypothalamus detects change
- brain sends impulse to skin to cool
- skin sweats or vasodilation
cool down
negative feedback - body temp control - too cold
hypothalamus detects change
- brain sends impulse to skin to warm
- skin shivers or vasoconstriction
warm up
endotherm
an organism that is internally warmed by heat- generating metabolic process
