Ch 14. Final Part 1 (Book) Flashcards
how was the ability to survive various osmotic environments achieved by more advanced animals
evolution of a stable internal enviornment
what are the 2 environmental factors that restrict animals
temperature
osmotic pressure
a major requirement for cell survival is the retention of appropriate concentrations of _______ and _________
water, solutes
in intracellular and extracellular compartments
what is the extreme percentage of dehydration a cell can survive, and what negative impact can it have
70%
impairs metabolism
composition of extracellular fluids of vertebrates
1/3 ionic concentration of seawater
less magnesium sulfide
some Cl- exchanged for bicarbonate
marine teleost fishes extracellular fluids
more dilute than seawater
maintain ionic and osmotic difference btw body fluids and seawater
the intracellular environment of most animals is low in ___ but high in __, _________, and ________
low in Na+
high in K+, phosphate, and proteins
does the plasma membrane maintain ionic or osmotic differences btw intra and extracellular fluids?
ionic
what maintains both ionic and osmotic differences btw intra and extracellular fluids
epithelium
ex. gills of fish, salt gland of elasmobranchs, kidney of mammals
cell membranes that are permeable to oxygen are also permeable to _______… and consequences
water
must expend energy to maintain ionic/osmotic balance b/c the animal can’t just stop breathing
how do small marine animals deal with excretion of toxic metabolic by-products
they leave by diffusion into the water
how complex animals with circulatory systems deal with excretion of toxic metabolic by-products
blood passes through excretory organs – kidneys
kidneys play an important role in removing organic waste, and are termed the primary organs of _______________
osmoregulation
osmoregulatory
an animal that maintains an internal osmolarity that is different than its environment
osmoconformer
an animal that conforms to the osmolarity of the environment its in
doesn’t actively control the osmotic condition of its body fluids
are more vertebrates osmoregulators or osmoconformers
osmoregulators
slightly hypo-osmotic to seawater
very hyperosmotic to freshwater
osmolytes
substances that increase intracellular osmolatiry
used instead of inorganic ions b/c that could cause problems (imbalances)
2 examples of osmolytes
urea
trimethylamine oxide (TMAO)
2 classes of osmotic exchanges btw an animal and the environment
obligatory osmotic exchange
regulated osmotic exchange
obligatory osmotic exchange
a response to physical factors the animal has no control over
ex. a marine fish with lower [NaCl] in seawater has NaCl diffusing into it
regulated osmotic exchange
physiologically controlled
done to maintain internal homeostasis and to compensate for obligatory exchange
3 barriers to obligatory exchange
integument
respiratory surface
epithelia in contact with the environment
obligatory loss depends on
surface area of the animal
size of the gradient
permeability of the animal’s surface
surface area to volume ratio in relation to animal size
large animals have lower surface are to volume ratios and dehydrate slower
larger animals have a smaller O2 requirement per unit volume and have less respiratory surface per unit volume than smaller animals
transcellular movement occurs…
through cells
paracellular movement occurs…
between cells
inhibited by tight junctions
aquaporins
water channels
amphibian skin
moist and permeable for O2/Co2 exchange
ions and water move via passive diffusion
must use active transport of salts in
how do animals with semipermeable skin (ex. sweating) avoid dessication
behavioral changes
ex. staying in cool damp envir when it is hot and dry outside
desert toads skin
covered in wax
have low evaporative water loss
frogs and toads lymphatic system and bladder
large lymph system
oversized urinary bladder that stores water and transfers ions
pelvic patch
specialized skin on the abd and thighs that takes in water at a rate 3x the body weight per day
vasotocin
amphibian hormone like ADH that enhances water permeability
major route of water loss in terrestrial insects
tracheal system
water and solutes are taken in during __________
feeding
osmotic problems are caused by what types of metabolic end products
nitrogenous end products
ammonia, urea
in terrestrial animals the regulation of ionic concentrations and excretion of nitrogenous wastes are accompanied by ______ loss
water
the ______ is the chief organ of osmoregulation and nitrogen excretion in most terrestrial vertebrates
kidney
the kidneys of birds and mammals utilize ____________ multiplication to produce hyperosmotic urine…
countercurrent multiplication – in loop of henle
this hyperosmotic urine is more concentrated than blood plasma
how does sweating cool you
evaporation of water on the skin means highest energy molecules evaporate and leave behind cooler water
does ventilation of respiratory epithelium by unsaturated water cause water loss?
yes – it causes evap of the moisture wetting the epithelium
kangaroo rat temporal countercurrent system
air entering the nose is warmed and humidified, which cools the nose
outgoing air is cooled and loses water, which wets the nose
euryhaline aquatic animals can tolerate…
many salinities
stenohaline aquatic animals can tolerate…
a narrow range of salinities
the body fluids of freshwater animals is typically __________ to the water… and 2 challenges this causes
hyperosmotic
swelling from water gain
continual loss of body salts to the water
freshwater adaptations
don’t drink water
make dilute urine
impermeable skin so all exchange happens over respiratory epithelium
reabsorb salt from urine
elasmobranch plasma is _________ to seawater and maintain what relative levels of ions
iso-osmotic
low electrolytes but high osmolytes (urea, TMAO)
elasmobranch rectal gland
excretes excess inorganic electrolytes like NaCl
body fluids of marine teleosts in seawater.. challenges
hypo-osmotic
lose water across gills
how do marine teleosts make up for lost water
drink seawater and dilute 50%
excrete excess ions
gills of marine teleosts
have specialized chloride cells that mediate transport of NaCl from blood to water
marine reptiles and birds that drink seawater…challenges and solution
challenge: can’t produce hyperosmotic urine
solution: salt glands to secrete excess salt in the orbit of the eye or nose/eyes of lizards
how much salt can the human kidney remoce
6g/L of urine
2 major problems of desert mammals like the kangaroo rat
high heat
almost no fresh water
widespread desert life adaptation
nocturnal lifestyle
reduces heat
reduces respiratory water loss
rectal adaptation of kangaroo rat and kidneys
high water absorption produces dry pellets of feces
kidneys produce highly concentrated urine
the kangaroo rat survives on ________ water
metabolic
camel adaptations (too large to burrow)
don’t sweat, instead allow body temp to rise instead of losing water by evap cooling in the day
temp drops in the night and rises slowly
instead of peeing, stores urea
land arthropods/insects mechanisms to uptake water
make highly concentrated ion solution that sucks up water in mouth or rectum
