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Flashcards in bevan Deck (35):

why do animals lose heat more quickly in water than in air

water has a higher thermal conductivity


what happens when water temperature increases

body temperature increases, oxygen demand increases BUT oxygen content decreases


why does aquatic ventilation use passive through through systems and not tidal

discuss some examples of flow through systems

because too much energy would be required to accelerate and deaccelerate water into an organism (tidal)

polycheate worms have external tenticle fans or external gill tufts

sea stars have tubed feet with gill function


discuss an aquatic animal which performs tidal ventilation

sea cucumber (Holothurian echinoderm) draws water in, oxygen diffuses across respiritory trees before water is pushed back out of the same whole


discuss an aquatic animal that does active oxgen extraction using a through flow system


squids are hard to work with so octopuses are used for experimentation

water in drawn in over gills through a slit before being forced out of a siphon


what is the process by which fish do respiritory exchange

opercular pumping
water is gulped into mouth, which moves into the operculum cavity. when the cavity is compressed the water is forced out through gills.


discuss the structure of fish gills

gills consist of many tube like structures called filaments, which have folds on their surface called lamellae. blood flows through the lamellae in a counter current direction to water


what ventilaiton method is done by fish swimming at high speeds

how is this different to normal ventilation

ram ventilation

operculum cavity doesnt need to be compressed

this process is less metabolically demanding than normal ventilation


which fish have a large SA;weight ratio

those who are very active, such as mackral


how do terrestrial animals ensure their respiritory surfaces are always kept moist

stay in mosit humid areas or fully enclose their respiritory structures


do terrestrial animals perform through flow or tidal ventilation

mostly tidal


discuss different ventilation methods displayed by terrestrial animals

insects have tracheae and spiricles.

lungfish, amphibians and some reptiles use positive pressure systems. compressing a buccel cavity to force air through respiratory surface

crocodiles and mammals contract muscles which increases the volume of the lungs and create negative pressure which draws air in.


what is a possibly explanation for the fact that birds are better at oxygen extraction compared to similar sized mammals

this system evolved perhaps due to the fact that birds fly at higher altitudes than mamals (over mountains etc)


apart from birds, which is one other group of animals which also perform uni directional ventilation

crocodiles have areas of unidirectional flow


what are the 4 types of circulatory system

systemic; to and from body tissues (high pressure)
pulmonary; to and from lungs (low pressure)
open; blood not contianed in blood vessels or only partially contained in blood vessels
closed; the blood is always contained in the heart or pumping systems


what is an auricle

a cone shaped pouch is the atrium of vertebrates that increases blood holding capacity


describe structural differences between the vessels in the arterial and venous sytems

arterial system vessels have a narrow lumen to maintain high pressure, and a thick layer of smooth muscle, elastin and collagen for stregth to withstand the pressure

the vessels in the venous systems have a wide lumen, and thin walls containing little smooth muscle etc because high pressure is not needed
the venous system has valves present to prevent backflow


how is the flow of blood altered

changing pressure or resistance, for example changing the lumen diameter of the vessel by vasoconstriction or vasodialation


how did the heart evolve

a muscular tube elongated and bent back against itself and certains regions evolved spatially


name how vasodialation can be brought about

a tissue that is doing a lot of metabolic work will have high concentrations fo CO2 and therefore decreased pH, which signals for vasodialation and therefore increased blood flow which replensihes oxygen concentration and removes waste products


why are respiritory pigments used

respiritory gasses need to be transported, and transport in solution is not efficient


what is something all respiratory pigments have in common

they are metalloproteins (proteins with a metal element)

have more than one subunit and are allosteric
they bind reversibly to oxygen
there is a positive correlation between pO2 and % saturation


name some of the adaptions animals thts fly have

they ventilate quickly, but this doesnt cause hypocapnia (loss of co2 leafing to vasoconstriction and anoxia)

relatively large hearts comapred to similar sized mammals

small muscle fibres so oxygen diffuses quickly

many capillaries

very good at fat metabolism, which mammals arent


unique features to high flyers

large lungs to increase surface area for diffusion

more effective breathing pattern

haemoglobin has a higher affinity for oxygen

mitochondria have been redistributed and are close to the capillaries so Atp can be used to increase rate of oxygen diffusion


discuss isotonic, hypotonic and hypertonic environments

isotonic; ion concentration insode and outside of RBC's is the same

hypertonic; ion concentration outside RBC's is higher than inside them; water leaves RBC's

hypotonic; ionic concentration outside a RBC is lower than inside the RBC; water moves into RBC's and causes rupture


what are 2 general methods of osmoregulating

changing the permeability of membranes

actively transporting ions


why are rockpools are difficult environment

salinity changes as water evaporates and sea water hits etc


where can soft and hard water be found

soft water; lakes
hard water; rivers


what is the primary osmoregulation organ



why can the waxy monkey frog and the chiromantis frog survive long periods of time in dry environment

they have impeareable skin with a waxy substance on it. it melts when its hot


what part of a reptile is impeareable to water loss



which animal has 90% of its water gain from metabolic water (breakdown of sugars etc)

kangaroo rat


how do animals have to modify air thats being breathed in order to extract oxygen from it

air must be heated up to 38 degrees and water must be added to increase the relative humidity to 100%


air that is breathed out has water in it, how do kangaroo rats minimise this water loss

their nasal structures have swirled bones that increase the surface area for water extraction via the counter current blood system


how do marine vertebrates osmoregulate differently to terrestrial vertebrates

reniculate kidney (many small lobes)