Homeostasis

Question 1

homeostasis

Answer 1

“steady state” maintenance of internal balance and dynamic; all living things regulate internal conditions in same way

Question 2

feedback regulation

Answer 2

basic homeostatic mechanism acheived via feedback reg.; stimulus triggers response; pos or neg stim.

Question 3

negative feedback

Answer 3

response to stimulus decreases stimulus (ex: excerice, heat inc, body temp inc, inc sweating (evap. cooling), dec body temp

Question 4

positive feedback

Answer 4

positive feedback; response to stimulus increases stimulus (ex: childbirth, inc pressure from baby’s head, inc contractions from mom, inc birth)

Question 5

homeostasis via osmoregulation

Answer 5

goal: regulate internal env by exchanging w external env

Question 6

osmoregulation

Answer 6

regulation of solute and H2O; orgas want int [solute] < or > env so they use osmosis/diffusion

Question 7

osmoreg in protocells

Answer 7

non living but still maintains homeostasis via osmoreg; internal env diff from ext env; osmosis and idffusion of H2O across mem

Question 8

osmoreg in paramecium

Answer 8

unicellar SAR protist that lives in hypotonic acuqatic env.; water moves in via osmosis; osmoreg this via contractile vacuole to pump H2O out and prevent bursting

Question 9

osmoreg in jellyfish

Answer 9

diploblastic cnidarians; no circ sys; all fluid osmoreg via diffusion; “flat” morphology, less tissue=better diffusion; osmoreg via simple diffusion works for simple animals; evey cell close to fluid, easy to diffuse

Question 10

osmoreg in plants

Answer 10

colonized land so adapted for terrestiral life; still require H2O: cuticle keeps H2O in, vascular tissue, seed plants need H2O for germination

Question 11

osmoreg in humans

Answer 11

terrestial but very clear acquatic origins; internal env very H2O based so helps regulate gas exchange, pH, nutr exchange, etc; terrestrial adaptions: amniotic sac during dev, fancy water balance (osmoreg) via skin and excretory sys

Question 12

constraints of “complex” life

Answer 12

strength, movement, diffusion, heat exchange dependent on body size/shape; body size/shape limited by physical laws; ex: swimming animals are limited by water env that is denser/more viscous than air, adaptions: smooth, streamlined, fusiform body shape; many acquatic orgs w fusiform due to covert evo (function=swimming)

Question 13

env exchange

Answer 13

animals are not closed systems; must exchange w env: nutr, gas, wastes; done via internal H2O env; movement across internal cell mem

Question 14

animal homeostasis

Answer 14

constraints of “complex” life; env exchange; heirachical org of animal body plan

Question 15

heirachical org of animal body plan

Answer 15

cell = basic unit of life; tissue; organs; systems

Question 16

4 types of tissues in animals

Answer 16

epithelial, connective, cardiac, muscle

Question 17

homeostatic processes

Answer 17

often internal (blood glucose); often involves exchange btwn internal/external, body/env; adaptions for exchange: branching, folding, internal exchange fluid

Question 18

internal exchange fluid

Answer 18

adaptions for exchange; blood and interstitial fluid (ISF)

Question 19

2 strategies for animal homeostasis

Answer 19

regulators and conformers, on continuum

Question 20

regulator

Answer 20

use internal mechs to control internal env; indep of ext env; maintain variables at/near specific value (“set point”) and keep at “normal range” via neg feedback

Question 21

conformer

Answer 21

allows internal env to vary w ext changes

Question 22

coordination and control

Answer 22

need “guides” to allows complex body components (ex: nervous sys, endocrine sys)

Question 23

endocrine regulation

Answer 23

via hormonal feedbacks (ex: blood glucose regulation)

Question 24

hormones

Answer 24

long distance chem signal/message

Question 25

blood glucose regulation

Answer 25

via 2 antagonisitic (control mech) hormones: insulin vs. glucagon; coordination btwn pancreas (hormone production) and liver (glycogen storage)

Question 26

insulin

Answer 26

store/uptake glucose

Question 27

glucagon

Answer 27

release glucose