Osmoregulation and Bioenergetics Flashcards
What is homeostasis
the maintenance of a relatively stable internal environment despite changing external conditions
what is the internal environment of vertebrates
interstitial fluid
are internal or external fluctuations greater
external
what value do homeostatic mechanisms maintain internal conditions at/within
within a small range of values —> not at a constant value
how are internal conditions maintained
via complex coordination of processes via chemical and electrical signalling
what are two extremes in how animals cope with environmental fluctuations
regulator and conformer
what is a regulator
uses homeostasis to moderate internal change in the face of external fluctuations
what is an example of a regulator
endotherms: thermoregulate
what is a conformer
allows some conditions within its body to vary with certain external changes
what is an example of a conformer
spider crabs: osmoconform
what is osmoregulation
the management of the body’s water content and solute composition
is the surface of the earth covered in mainly fresh or seawater
seawater
what is osmosis
diffusion of water across a selectively permeable membrane
what is osmolarity
osmoles of solute/L
what is osmolality
osmoles of solute/kg
what is a hyperosmotic solution
high solute concentration, low free water concentration
what is a hypoosmotic side
low solute, high free water concentration
what is isoosmotic in the body and why
body fluids: same osmotic pressure as medium
what are hyperosmotic organisms and why
freshwater organisms: have higher osmotic concentration than medium
what are hypoosmotic organisms and why
marine fish: osmotic concentration lower than medium
what is an osmoconformer
animal that does not actively adjust its internal osmolarity because it is isoosmotic with its environment
what is an osmoregulator
animal whose body has a different osmolarity than that of the environment: lives in hypo or hyperosmotic environments
how do animals that live in a hyperosmotic environment osmoregulate
take in water
how do animals that live in a hypoosmotic environment osmoregulate
must discharge excess water
how do osmoregulators control their internal osmolarity
by expending energy
are freshwater animals osmoregulators or conformers
regulators
how do freshwater animals gain water
via osmosis and food
how do freshwater animals lose and gain salts
lose: diffusion and in urine
gain: food and active uptake from surroundings
urination in freshwater animals
excrete large amounts of dilute urine
are marine invertebrates osmoregulators or conformers
conformers
what is osmolarity in marine invertebrates equal to
seawater
is individual solute concentration in marine invertebrates equal to seawater, why?
no, conformers conform to osmolarity of ocean but regulate internal ionic composition
are marine vertebrates osmoregulators or osmoconformers
regulators
how do marine vertebrates lose and gain water
lose: osmosis
gain: in food and by drinking seawater
how do marine vertebrates dispose of salt
active transport out of gills and in urine
urination in marine vertebrates
produce small quantities of urine
what are stenohalines
organisms that cannot tolerate substantial changes in external osmolarity
what are euryhalines
organisms that can tolerate substantial changes in external osmolarity
how does an organism water balance and dispose of waste
by regulating the solute content of body fluid that bathes their cells
what do water balance and waste disposal depend on
transport epithelia
what is transport epithelium
layers of specialized cells that regulate solute movements
what is the most important feature of transport epithelium
the ability to move specific solutes in controlled amounts in particular junctions
how are transport epithelium joined and arranged
joined by tight junctions
arranged into tubular networks with extensive surgace areas
what is the function of nasal glands of marine birds
remove excess sodium chloride from blood via countercurrent exchange
what is anhydrobiosis
the ability to survive in a dormant state when an organisms habitat dries up
what is the largest problem to osmotic balance on land
desiccation (extreme dryness)
how is water loss reduced (4)
body coverings, nocturnal habitat, drinking and eating moist foods, using metabolic water
how does a kangaroo rat reduce water loss (5)
fur for insulation, remains in cool burrow during the daytime, derives water from seeds, concentrates urine and dehydrates feces, condenses respiratory moisture in nasal passages
What do heterotrophs do
harvest chemical energy from the food they eat
what is ingested energy put towards
work, stored, excreted, released as heat
what is heat produced by metabolism useless and useful for
useless for doing work
useful for maintaining body temperature
what is metabolic rate
amount of energy an animal uses in a unit of time; sum of all biochemical reactions occurring over a given time interval
how is metabolic rate measured (3)
rate of heat loss, oxygen consumption, carbon dioxide production
what is basal metabolic rate
stable rate of energy metabolism measured in mammals and birds under conditions of minimum environmental and physiological stress
what is standard metabolic rate
similar to BMR but used for an animal with varying body temp that is maintained at a selected body temperature: resting and fasting metabolism at a given body temperature
what influences metabolic rate
size, internal work, external work, tissue growth/repair, time of day, season, age, sex, stress, type of food
How do birds and animals adjust to changes in external conditions
varying insulation, and capacity for metabolic heat production
how do ectotherms adjust to changing external conditions
adjustments at the cellular level —> production of cryoprotectants
what is torpor
physiological state in which activity is low and metabolism decreases
what is torpor used for
conserving energy during environmental changes
what are three examples of torpor
hibernation (long-term torpor)
estivation (summer torpor)
daily torpor (hummingbird)
how do you hold your breath a long time (3)
lots of blood: store in spleen
lots of muscle myoglobin
low amount of work
how do weddel lseals hold their breath
can store large amounts of oxygen in blood and muscle, have huge spleens, have high myoglobin
what adaptations conserve oxygen in weddell seals
changing buoyancy to glide passively
decreasing blood supply to muscles
deriving ATP in muscles from fermentation once oxygen is depleted
