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THERMOREGULATION Maintenance of an internal temperature
Life processes are temperature sensitive
Stable internal temperature despite external fluctuations
Endotherms use their metabolism Some reptiles, fish, and
insects too Ectotherms gain heat
from external sources Not mutually exclusive
HEAT EXCHANGE Conduction: molecules
between 2 objects in direct contact Higher to lower
temperature movement Convection:
movement of air or liquid past an object
Radiation: electromagnetic waves between 2 objects not in direct contact
Evaporation: surface of a liquid losing molecules as a gas
ADAPTATIONS FOR THERMOREGULATION Metabolic heat
Hormonal boost or moving around to contract skeletal muscles, i.e shivering
Insulation Hair, fur and feathers rise to trap insulating layer of air, goose
bumps are vestigial remnant Blubber in aquatic birds and mammals
Circulatory adaptations Change blood flow by constricting blood vessels to surfaces to
conserve heat, dilation to dissipate Countercurrent heat exchange: adjacent vessels flow
opposite directions Standing on ice, cold water across gills, and muscles
Evaporative cooling Sweating and panting expose moisture to be removed with
heat Behavioral response
Migration, basking in sun when cold and damp areas when hot, bathing, and layered clothing
OSMOREGULATION Balancing uptake and loss of water and solutes
Animal cells: net uptake = ? Net loss = ? Water follows solutes by osmosis
Osmoconformers: no net gain or loss of water Marine invertebrates have body fluids of similar [solute]
as seawater Osmoregulators: necessary to regulate to prevent
changes Freshwater fish have higher [solute] than environment
H2O gained and salt lost = doesn’t drink H20, ions from food, and lots of dilute urine
Saltwater fish have lower [solute] than environment H2O lost and salt gained = drinks salt H2O with salt out gills
and little concentrated urine Land animals obtain H2O from food and drink while losing
water through evaporation and excretion Exoskeleton, dead skin layers, egg shells, and amnitotic sac to
prevent dehydration
DISPOSAL OF WASTES
Metabolism produces toxic nitrogenous wastes that are removed by excretion
Form of waste depends on habitat and evolution
Ammonia too toxic to store, but diffuses in water
Urea less toxic so can be stored, but costs energy and H2O loss to remove
Uric acid insoluble in H2O so is semisolid Costs more energy, but
conserves H2O
URINARY SYSTEM Forms and excretes
urine while regulating water and ion concentrations in body fluids Kidneys filter blood to
extract filtrate which contains H2O, urea, glucose, AA’s, ions, and vitamins
Filtrate is processed so valuable solutes not lost in urine
Blood enters kidney through the renal arteries to be filtered and leaves via the renal veins What is the urine
pathway from kidneys to outside?
THE KIDNEYS Consist of renal cortex
(outer) and renal medulla (inner)
Nephrons are the functional units Start and end in cortex,
part in medulla Bowman’s capsule
encloses the glomerulus which filters the blood Nephron tubule has 3
parts Drains to collecting duct to
join filtrate from other nephrons
Capillary system in Bowman’s capsule and around tubule system
URINARY SYSTEM PROCESSING Filtration
H2O and small molecules through capillary tube from glomerulus to nephron tubule
Reabsorption Filtrate returns valuable solutes to blood (tubule capillaries)
Secretion Excess ions, drugs, and toxic substances from blood
transported into filtrate (tubule capillaries) Excretion
Urine from kidneys to outside
BLO
OD
FILT
RA
TE T
O U
RIN
E
NaCl enters interstitial fluid, bringing H2O withExcess H+ secreted and HCO3
- reabsorbed to maintain blood pHToxins from liver into tubule systemLoop of Henle facilitates H2O reclaimationADH sets amount of H2O reabsorbtion
Lots of H2O dilutes solutes so ADH down = less H2O retainedAlcohol inhibits ADH release = excess H2O loss