Animal Physiology Exam 3 Flashcards
All water compounds contain what?
dissolved salts, gases, and organic compounds
What is physiologically important?
Temperature and water compounds
Body fluids account for how much of body weight?
60%
What are the 3 major body fluid compartments?
(1) intracellular
(2) interstitial
(3) blood plasma
Which body fluid compartments have similar ionic compositions?
blood plasma & interstitial fluids
Which body fluid compartment usually has very different Na, K, etc.. compositions?
intracellular fluids
Osmoregulation
regulation of water & ion balance
Ionic regulation
adjusting particular ionic concentrations
Excretion
elimination of metabolic wastes
body fluids are what?
dilute saline solutions
Excretion & osmoregulation are managed by the same what?
organs
Optimal function requires hydration state & [solute] to be what?
maintained within relatively narrow limits
What the main problem in terms of water and ion balance?
proper internal conditions almost always very different from environmental conditions
What is necessary to maintain water and ion balance?
regulatory mechanisms
Osmolarity
measure of the solute concentration of a solution; depends on # of dissolved particles
Hyperosmotic
[body fluids] > environment
Isosmotic
[solute] of body fluids = environment
Hyposmotic
[body fluids] < environment
Most marine inverts are what?
Osmoconformers; isosmotic with seawater; but they often regulate certain solute concentration to some extent
Freshwater animals are all what?
osmoregulators
Freshwater animals maintain what?
hyperosmotic body fluids
Marine vertebrates are almost always what?
hyposmotic osmoregulators
Terrestrial environments vary greatly in what?
temperature & humidity
U/P ratio
index of action of the kidneys in osmotic regulation
isosmotic urine
U/P = 1; e.g. seabirds
Hyposmotic urine
U/P < 1; e.g. freshwater organisms
Hyperosmotic urine
U/P > 1; e.g. terrestrial mammals, insects, marine mammals
What are the 3 sources of water?
drinking water, dietary water, metabolic water
Dietary water
preformed water in plant & animal tissues
Desert mammals gain water from where?
dietary &/or metabolic
How do kangaroo rats compare to lab rats?
Kangaroo rats retain more water because they lose less water through their wastes (feces & urine)
What does a freshwater animal’s blood plasma composition look like compared to a river?
higher ion concentrations and higher osmotic pressure
Freshwater animals are what compared to ambient water?
hyperosmotic
Freshwater animals gain and lose what from gills?
Gain: water, Na+, Cl-
Lose: salt
Freshwater animals gain what from food?
salt (ions) & water (don’t drink)
Freshwater lose what from feces?
salt & water; large amounts of urine, very hyposmotic to plasma
What structure is on lobsters that dilutes urine?
corpious
Freshwater animals have dilute what?
blood plasma & urine
Bicarbonate ions and protons are actively (require ATP) exchanged for what in the gills of Freshwater fish?
Cl- and Na+
Marine water animals are what to seawater?
isosmotic
Hagfish are what?
Marine, stenohaline, osmoconformers & isosmotic
Hagfish have to influx or efflux of what?
water
Hagfish undergo what kind of regulation like marine invertebrates?
ionic regulation
Marine teleost gain and lose what from gills?
Gain: salt
Lose: water, Cl- (active) & Na+ (passive or active)
Marine teleost lose what from feces & urine?
Salts and water; small amounts of urine; nearly isosmotic to plasma, rich in Mg 2+ & SO4 2-
Marine teleost gain what from food & seawater?
salts & water
Whats the problem for osmoregulating marine air breathing vertebrates?
high salt load; Receive high salt from food and drink
What the solution to marine air breathing vertebrate osmoregulators problem?
Kidney & extrarenal salt glands
Kidney
excretes hyperosmotic urine (relative to body fluids) in birds and mammals
Extrarenal salt glands
produce highly concentrated fluid containing mainly NaCl; intermittent function in response to high salt loads; e.g. birds, sea turtles
What is the advantage of living in a terrestrial environment? disadvantage?
advantage: abundant oxygen
disadvantage: major water loss
What two groups have successfully invaded land?
arthropods & vertebrates
Some groups who live in terrestrial environments have to exploit what?
moist environments
What is the key to reducing water loss on land?
integumentary permeability; high resistance (thick skin)
Rate of water loss equation
J = K x (WVPi - WVPo) / X
What contributes to decreased permeability of the integument?
Thin layers, increasing temperature (transition temperature), lipid composition
Lipids undergo what as temperature increases?
phase changes, which leads to more water loss
Transition temperature
temperature at which water loss increases drastically rather than gradually
Variation in lipid composition exists among what?
population of single species & related species
Organisms that use what is at a major disadvantage in terms of respiratory water loss?
cutaneous respiration
Mammals, birds & reptiles control respiratory water loss via what?
regulating breathing movements
Insects open & close what?
spiracles to tracheal system
How is water conserved by cooling exhalant air done?
countercurrent mechanism in the nasal passage
Total respiratory water loss is dependent on what?
body size and phylogeny
Smaller organisms have what in terms of water loss?
greater evaporative water loss
Osmoregulation of earthworms
- lose water via evaporation through skin
- live in damp soil
- osmoregulate like freshwater animals
Osmoregulation of amphibians
- lose water via evaporation
- in water, osmoregulate like freshwater animals
- must live near or in water/humid air
- skin is main osmoregulatory organ
- actively pump in Na & Cl follows passively
- lots of urine
Osmoregulation of desert frogs
- live underground during drought
- explosively breed after rainfall
- some australian frogs: store 30% water as dilute urine in bladder; [Urea] is high
Stenohaline
survive in only narrow range of salinities
Euryhaline
survive across broad range of salinities
Osmoconformers
permit blood osmotic pressure to match ambient osmotic pressure
Osmoregulators
maintain relatively stable osmotic pressure despite ambient variation
What are the salinity trends in estuaries?
higher salinity closer to sea; brackish water animals typically euryhaline
What are the two types of osmotic regulation?
hyper-isosmotic & Hyper-hyposmotic
hyper-isosmotic
regulate at low water concentration, isosmotic at high water concentration
hyper-hyposmotic
regulate at low and high water concentrations
Frogs and toads have high water loss because of what?
low skin resistance
Some frogs and toads have what? Or secrete what?
impermeable or secrete a waxy substance to increase resistance
Some frogs and toads excrete what?
Uric acid
How does Urea compare to Uric acid?
-urea at high concentrations is toxic & must be highly diluted
- Uric acid is not as toxic & reduces excretory water loss
Lower elevations are typically?
warmer & drier (high VPD)
If salamanders are acclimated to cool conditions & exposed to high VPD then what occurs?
water loss increases
If salamanders are acclimated to cool conditions & exposed to warmer environment then what occurs?
lose less water
heat loss equals what?
heat gain
Body temperature depends on what?
heat exchange with environment
Animals obey the laws of what?
thermodynamics
What is the 2nd law of thermodynamics?
in an isolated system, change is always towards disorder; energy from outside (an open system) is necessary to maintain order
Why must animals consume energy?
because energy is lost when moved through system
Energy enters an animal’s body as what?
chemical energy
Energy leaves an animals body as what?
heat, chemical energy or external work
Absorbed chemical energy is used to perform what three major types of physiological work inside the body?
1) biosynthesis
2) maintenance
3) generation of external work
Metabolic rate
quantity of energy used per unit time
Aerobic
oxidative metabolism of food into ATP
oxidative metabolism
Chemical bonds of glucose (generally) broken to produce energy; requires oxygen; e.g. cellular respiration
Anaerobic
ATP production without oxidative metabolism; e.g. glycolysis
Anaerobic is faster but…
less efficient; makes less ATP
How is metabolic rate calculated?
direct calorimetry or indirect calorimetry
Why is metabolic rate important?
- determines how much food an organism needs
- provides quantitative measure of the total activity of all physiological mechanisms
Direct calorimetry
directly measuring the rate of heat loss from an animals body; Lavoisier’s experiment
Latent heat of fusion
energy necessary to change from solid to liquid