Chapter 40 - Homeostasis and Thermoregulation

Question 1

what kind of exchange happens with the environment with single-celled organisms?

Answer 1

direct exchange with the environment

(ex: amoeba and water, the water goes past membrane pretty easily)

Question 2

what kind of exchange happens with the environment with multicellular organisms?

Answer 2

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

Question 3

homeostasis

Answer 3

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)

Question 4

set point

Answer 4

target value, in regards to homeostasis

Question 5

anatomy

Answer 5

study of form

Question 6

physiology

Answer 6

study of form function

Question 7

parameter

Answer 7

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)

Question 8

regulator/endotherm
(animal category)

Answer 8

they can control their internal environment regardless of their external surroundings

they avoid changes (by regulating their internal environment)

(ex: mammals and birds)

Question 9

why are mammals and birds regulators? give an example por favor.

Answer 9

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)

Question 10

conformer/ectotherm
(animal category)

Answer 10

they depend upon the changes in their external environment

they allow change

(ex: amphibians, reptiles, insects, etc.)

Question 11

why are amphibians and reptiles conformers? give an example.

Answer 11

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)

Question 12

what are the main human parameters?

Answer 12

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

Question 13

how does homeostasis resist change?

Answer 13

it resists change through sensing, integrating, and responding

Question 14

what are the homeostatic control elements? explain briefly what they do.

Answer 14

receptor/sensor = detects change

integrator = receives input, triggers a response

effector = carry out response

Question 15

negative feedback (define and explain)

Answer 15

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

Question 16

thermoregulation

Answer 16

maintenance of internal body temperature

Question 17

endotherm

Answer 17

internally heated (metabolism)

(ex: walrus, seal, etc.)

Question 18

ectotherm

Answer 18

externally heated (environment)

(ex: lizard)

Question 19

what are the 4 physical processes organisms use to exchange heat?

Answer 19

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)

Question 20

true or false: organisms utilize various methods to regulate heat exchange

Answer 20

true

Question 21

what are the thermoregulatory mechanisms? explain them.

Answer 21

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

Question 22

thermogenesis

Answer 22

heat production (losing energy)

shivering = increased metabolism
nonshivering = convert more energy to heat

Question 23

vasodilation

Answer 23

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)

Question 24

vasocontriction

Answer 24

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)

Question 25

countercurrent exchange

Answer 25

transfer of heat between fluids flowing in opposite directions

(ex: arterial blood heats returning venous blood)

Question 26

hypothalamus

Answer 26

homeostatic “supercenter”, it maintains your body’s internal balance

Question 27

set point

Answer 27

target value, in regards to homeostasis

can fluctuate based on changes (ex: fever, day vs night, etc.)