Chapter 40 - Homeostasis and Thermoregulation Flashcards
what kind of exchange happens with the environment with single-celled organisms?
direct exchange with the environment
(ex: amoeba and water, the water goes past membrane pretty easily)
what kind of exchange happens with the environment with multicellular organisms?
most parts of the organism have a direct exchange with the environment but there are layers to it
they have a complex body plan
environment water => 2 layers of cells
homeostasis
maintenance of a stable internal environment (dynamic equilibrium around a target value)
(ex: your target value of homeostasis is different during day and night, it fluctuates)
set point
target value, in regards to homeostasis
anatomy
study of form
physiology
study of form function
parameter
changes we can measure
measurable characteristic of a biological system or process
(ex: cardiovascular function parameters = blood pressure and pulse rate
carbohydrate metabolism parameters= glucose level in blood)
regulator/endotherm
(animal category)
they can control their internal environment regardless of their external surroundings
they avoid changes (by regulating their internal environment)
(ex: mammals and birds)
why are mammals and birds regulators? give an example por favor.
its because they maintain a constant body temperature by adjusting their temperatures through heat production and metabolic processes
(ex: when mammals want to cool down they sweat)
conformer/ectotherm
(animal category)
they depend upon the changes in their external environment
they allow change
(ex: amphibians, reptiles, insects, etc.)
why are amphibians and reptiles conformers? give an example.
they cannot regulate their own internal temperature
(ex: amphibians and reptiles move to warmer or cooler environments whey they are too warm or too cold, lizard to rock to sunbath, frog to water to cool down)
what are the main human parameters?
1.) pH
2.) temp
3.) mean arterial pressure (M.A.P.)
4.) blood glucose level
all of these change/fluctuate and can be numerically measured
how does homeostasis resist change?
it resists change through sensing, integrating, and responding
what are the homeostatic control elements? explain briefly what they do.
receptor/sensor = detects change
integrator = receives input, triggers a response
effector = carry out response
negative feedback (define and explain)
response opposes the original stimulus
the negative feedback loop resists change
it occurs when the output of a system or process is fed back into the input to reduce the changes caused by the output
homeostasis => stimulus (change in internal variable) => sensor/receptor => control center => response/effector => back to homeostasis
thermoregulation
maintenance of internal body temperature
endotherm
internally heated (metabolism)
(ex: walrus, seal, etc.)
ectotherm
externally heated (environment)
(ex: lizard)
what are the 4 physical processes organisms use to exchange heat?
1.) radiation = sun (heat) => organism
(ex: lizard sunbathing)
2.) evaporation = moisture (water) => environment
(ex: sweating)
3.) convection = heat (gain/loss) by moving air/water of a different temperature over an animal
(ex: wind)
4.) conduction = heat (gain/loss) from direct solid contact
(ex: lizard on a rock, rock is heated by the sun and then the heat is transferred to the lizard)
true or false: organisms utilize various methods to regulate heat exchange
true
what are the thermoregulatory mechanisms? explain them.
behavior = (examples) finding shade, lying on a warm rock
insulation = reduces heat flow within the environment
evaporation = liquid to gas, absorbs energy
metabolic adjustment = thermogenesis (heat production)
circulatory adaptations = vasodilation and vasoconstriction (of arteries), countercurrent exchange
thermogenesis
heat production (losing energy)
shivering = increased metabolism
nonshivering = convert more energy to heat
vasodilation
increase flow to the periphery, increase the transfer of heat to the environment
(ex: arteries dilate (become wider/open up more) when there is an increase in body temperature)
vasocontriction
decrease flow to the periphery, decrease the transfer of heat to the environment
(ex: arteries constrict (become narrower/close up more) when there is a decrease in body temperature)
countercurrent exchange
transfer of heat between fluids flowing in opposite directions
(ex: arterial blood heats returning venous blood)
hypothalamus
homeostatic “supercenter”, it maintains your body’s internal balance
set point
target value, in regards to homeostasis
can fluctuate based on changes (ex: fever, day vs night, etc.)
