EXAM Notes Flashcards
A neutral buoyancy means the fish would ________ while a positive buoyancy would mean the fish would ______
float , rise
A negative buoyancy would mean the fish would ______
sink
establishing and maintaining neutral buoyancy is _____ specific
species
What are the four strategies to achieve buoyancy in fishes?
retention of low density compounds, generation of lift during forward movement , minimize high density substances (tissues) , use of gas bladder (swim bladders)
The Bohr effect affects Hb-O2 affinity how?
decreases
Hyper osmotic regulators are _______ fishes
freshwater
Is-osmotic regulators and hyposmotic regulators are _______fishes
saltwater
Hagfish are __________
osmoconformers
How is absorptive surface area optimized ? (2)
pyloric cecae, spiral intestine
Buoancy saves ______ energy
energy
gas bladder increases _____ ______ levels
blood gas levels
Explain how niche expansion is an advantage for ectothermic fish?
competetive advantage, being warm means better chemical reaction rates
Hyposmotic regulators gain _____ and loose ______
ion gain and water loss
hyperosmotic regulators gain ____ and loose _______
water gain, ion loss
Is euryhaline salmonids and reciprocal regulation of ion transport common?
no, few fish use this
A vast majority of fish are carnivores over herbivores, name two benefits of this diet
high quality and energy diet
Pyloric cecae, spiral intestine provide what 3 benefits for digestion?
increase intestinal length, increase volume and increase time for digestion
what are the two mechanisms for excreting nitrogenous waste products? differentiate the two
Ammoniotelism (ammonia is toxic) and Ureotelism (urea is less toxic, but energetically expensive to make)
what are 5 ways fish have evolved ways in which they can perceive their environment?
- Bioelectric field
- Vision, eyes
- Olfaction (smell) and taste
- acousticolateralis system
- ear and lateral line system
what is archimedes principle?
an object completely or partially immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced
weightlessness is the same as ______ buoyancy
neutral
positive buoyancy
density of object less than density of water
negative buoyancy
density of object is greater than density of water
what are two low density compounds that help buoyancy ?
fats and oils
what are some strategies to improve buoyancy in agnatha ? (jaweless fishes, lampreys etc)
- retention of fat, fatty livers
- cartilagenous skeleton
- ** do not have swim bladder
what are some strategies to improve buoyancy in sharks?
large livers, stored lipids, squalene (compound in sharks, oil substance), heterocercal caudal fin and streamlining to help generate lift, cartilagenous skelton
** lacks swim bladder
sharks have a close to ______ buoyancy
neutral
when limiting low density compounds for buoyancy there are some limitations, what are these?
- restricted activity
- inhability to rapidly alter density and therefore depth in response to changing pressure, temperature and salinity
do fish swim with swim bladder?
no
where did swim bladder/gas bladder originate?
arose from ancestral lung in early jawed vertebrates
the Coelocanth has a special swimbladder because it is a deep water bottom fish, what is this specialty?
lung/swimbladder is filled with fat that provides buoyancy
what is the difference between the physostomous and physoclistous gas bladder?
physostomous (stoma = mouth, is located in soft ray finned teleosts, digestive tract is attaced to swim bladder)
Physoclistous ( spiny ray finned teleosts, closed gas bladder, digestive tract closed off from swim bladder, separate)
boyles law:
P1V1=P2V2
how does inflation of physostomos bladder occur?
gulping and swallowing air at water surface, air diverted through pneumatic duct by increasing pressure in buccal cavity
why is gulping air less effective in deep water?
high pressure, therefore you would need large amounts of gas in deep water to achieve neutral buoyancy
how does deflation of physostomous bladder by reflux occur?
relax puckreflex, relax pneumatic sphincter, contraction of smooth muscle and elastic recoil of gas bladder wall and contraction of body wall, gas released into pneumatic duct, esophagus and negative buoyancy occurs
pneumatic duct has tissue which ________ ______ vented from gas bladder
reabsorbs gas (O2)
how do spiny ray finned fishes with a physoclistous (closed) gas bladder undergoe volume control?
well vascularized, rete mirable (capillary bed, vascularized),
rete mirable is in both physoclistous and physostomous gas bladder fishes (T/F)
true
Physoclistous gas bladders are missing the pneumatic duct and have a gas gland for ____________ and oval patch for ______________
gas gland for seceretion of gas, and oval patch for reapsortion of gas
counter current multiplier _________ O2 uptake by maintaining relatively stable PO2 gradient.
maximizes
Afferent capilalries have lactate and H+ which does what?
lactate (salting out of CO2, N2, O2)
**H+(root off effect, bhor shift, combine with HCO3 to generate CO2)
efferent capillaries have a slow root on effect meaning
ten seconds to restore HbO affinity, delay ensures PO2 sufficiently high to maintain efferent to afferent capillary PO2 gradient
the counter current multiplier effect can achieve gas exchange partial pressure up to _____atm
300 atm
Diffusion of gases from venous ________ to arterial _________ capillaries ensures very high gas partial pressures at swim bladder
- (efferent)
2. (afferent)
the longer the capillaries the more _______ unloaded
gas
multiplication is ______ to the length of retial capilalries
proportional
what are the 3 concepts in thermoregulation
- properties of water vs air
- high body surface area in contact with water
- low metabolic rates (most fishes)
- high rates of connective heat loss in water
name and describe the 4 strategies of thermoregulation
- Poikilothermy
( Body Temperature varies with environment) - Homeothermy
(maintenance of constant body temperature) - Ectothermy
(Body Temperature determined 1º by environment ) - Endothermy
( Internal generation of Heat, Regional endothermy)
what strategy do majority of fishes use for thermoregulation?
poikilothermy, body temp varies with environment
what is behavioural thermoregulation and why is this beneficial?
select the optimal temperature range, conserves energy, greater metabolic efficiency, temperature selection often transient (quick)
there are high rates of connective heat loss in _______ with thermoregulation
water
which fish species use regional endothermy?
continuous swimmiing species including mackeral and tuna, swordfish, billfish, large body sizes, large cutaneous arteries, those with heat exchange organs
what is the advantage (s) of heterothermy in macheral, sharks etc?
temperature of swimming muscle is greater than water temp, niche expansion, greater power output, higher axtivity for oxidative enzymes, red muscle rich in myoglobin, thicker blood vessels in rete mirable minimizes O2 loss to venous capillaries
regional endothermy in swordfishes and billfishes occurs where? why is it important
they have constant cranial temperature, and a heater organ at base of brain, CNS activity, unaltered by changing temps, vision maintained at all depths
lamnid sharks and tunas have a ____ ______ heat exchanger only
cranial heat
what are the 5 types of water environments?
- freshwater FW = 0.1 to 0.2 ppt
- saltwater SW = 34-37 ppt
- hypersaline water HSW = >40 ppt
- Brackish water BW = 0.5 to 30 ppt
- Inland Saline Lakes 6 up to 200 ppt
(e. g. Great Salt Lake, Dead Sea)
compare osmolarity with fresh and saltwater
fresh 0.5-10 mosM
salt 1050 mosM
osmoregulation
maintenance of osmolarity within body’s normal operating limits
Ionregulation
control of internal ion concentrations in body fluids
ions are ______ which makes osmoregulation and ionregulation closely linked
osmolytes
Osmoconformer
body fluid osmotic pressure changes with medium
Osmoregulator
regulate internal osmotic concentrations
Ion Regulation
Control body fluid solute concentrations
ison regulation is used by _________ and ________
osmoconformers and osmoregulators
Euryhaline
tolerant to wide range of external salts
stenohaline
narrow tolerance range to external salts
***Osmoregulator vs conformer
slide 7
Hyperosmoregulation
diffusion salt across body surface, salt and water in feces
what are the 4 strategies of ion osmoregulatio in freshwater fishes?
- Do not drink
- Highly imperable tegument, deep tight junctions make gill less ion permeable
- produce copius dilute urine
- Active ion uptake via gills, freshwater ionocytes and respiratory cells
Bilge pump is used by ______ and ______ fishes
lampreys and bony fishes
the bilge pump and glomular kidney has a high ______ filtration rate and _______ flow rate
glomular (GFR) and urinary flow rate (UFR)