week 9.1 thermoregulation two

what are two forms of insulation?

fur and blubber

increased volume of insulation can prevent...

loss of heat through conductance

fur

makes a thick insulation so we don't have as much transference from the blood to the environment. it becomes even more effective when it stands up and traps air between the hairs, because air is a rl good insulator as it doesn't have a lot of molecules/less dense, so it makes free energy/heat harder to pass, reducing overall loss of it to the environment. not as beneficial in aquatic organisms, hair will interfere w/ locomotion

blubber

thick outer layer of fat mostly seen in aquatic mammals. creates a secondary pathway where blood will also flow through shunt vessel to keep blood from getting closer to the outside

arctic organisms will contain more...

insulation than tropical organisms; therefore, arctic organisms have a lower conductance/lower exchange of free energy to the environment

describe the circulatory control of cutaneous heat exchange in response to cold temperature

hot blood enters through artery, and in return, vasoconstriction occurs, so superficial vessels are narrowed down/diameters become rlrl small, which increases their resistance, meaning their blood will flow through a different pathway (pathway of less resistance!!!). so basically, hot blood will avoid surface vessels by going to a different blood pathway to return to the core of the body and still be warm!!

describe the circulatory control of cutaneous heat exchange in response to hight temperature

hot blood coming from artery is sent as superficially as possible, and vasodilation occurs, so the diameter of superficial vessels increase, and as they open up, that blood gets closer to the environment w/ a shorter distance of transfer, meaning more heat conductance by dumping heat into environment, so when that blood returns back into the body, its cooled

in what environment would countercurrent heat exchangers be important in?

cold environments, bc these organisms are constantly losing energy/heat to the environment

explain countercurrent heat exchanging

instead of exchanging a molecular gas (like w/ capillaries), we are exchanging energy/heat. arteries are surrounded by venous channels, and blood flows in opposite directions of both channels. as blood is being passed and pulled back out, its gon be tempered w/: cool blood comes back from the environment, but as its running by that warm blood, it gets tempered so that as it enters the heart, its not shocking any systems, instead it will be at a moderate temp by the time it reaches the core

venous blood is...

v cool

arterial blood is...

v warm

heat from ______ is returned to ______ in countercurrent heat exchange

arteries; veins

are arteries cooler or hotter when they get to endpoints?

cooler (bc heat travels to where it is cooler, and all that heat traveled to veins instead), so less body heat is lost to external environments

regional heterothermy

its just when endotherms r lazy asf and give up on maintaining temp on certain parts of their bodies. allows for an endotherm to tolerate colder skin temperatures, and for the conservation of core body temperatures by limiting conduction and convection loss

in what areas of the body does regional heterothermy typically occur at?

areas away from the core of the body, so distal parts of feet, noses, or edges of ears

are fish predominantly endothermic or ectothermic?

ectothermic; but some components of their body do generate heat, which we see in rl demanding fish that are rlrl active, and heavy/fast swimmers

where does lots of heat loss occur in fish?

through the gills, fish also perform countercurrent exchange as well to help temper this loss of energy/heat

heterothermic fish

organisms that have certain portions of their body that are going to be rlrl warm, and some that are gon be rlrl cold. these fish contain vascular retia in muscles to help w/ countercurrent system. the warm blood from muscles are used to keep the core of the fish warm.

vascular retia

located in fish muscles, generates heat and maintains body temperature

why is the opah weird!!!!!!

although fish are ectothermic, the opah displayed ectothermic behavior as they keep internal body temp stable regardless of depth and water temp

what organ has the highest priority in the body?

brain

explain a protective countercurrent exchanger found in animals in tropical locals

brain needs to be kept at a reasonable temp., so we see countercurrent exchange systems to maintain brain temp. panting will cool blood in the pharynx, which will pass through heat exchanger to cool arterial blood, and that cool arterial blood will eventually go to the brain

temperature of the brain will...

stay relatively stable (which doesn't occur in the rectal), showing prioritizations in maintaining a stable temp in the brain.

what happens to the water loss in an organism that prioritizes the cooling of their brain?

water loss increases due to panting (which is needed to cool the brain). it will dump this water and energy to environment in order to go through evaporative cooling in its throat/pharynx, and the blood will run up to the brain

gular fluttering

similar to how organisms cool their brains w/ their pharynx (instead it uses its gular skin)! some birds will move air into its gular skin to do evaporative cooling to cool the blood that will eventually go to the brain

what has thermal inertia and is used to maintain temperature?

water! it helps maintain/manage systems of wide swing temperatures that can occur

how does water conservation help maintain body temp?

water conservation will lead to lack of sweat, and thick urine, so not dumping as much moisture in that urine

environmental dehydration causes _______ in water retention

increase

whats so special ab dromedary camals?

they undergo exhaustive water retention techniques as they through dehydrating periods. if they are dehydrated, their rectal temp reaches high temps, and if they are given water daily, their rectal temp doesn't reach as high temps

what does huddling do?

keeps organisms warm and shows social status. social status will determine rotation rates to inside of huddle, so more popular = more in the middle of the huddle = more warm

what are futile metabolic cycles?

cycles that are not productive. they don't make what they usually make, as for instance, glycolysis contains multiple "side" futile processes that end up producing waste/heat instead of typical products (ATP) and burn ATP

why is brown adipose important?

it is vital component in coming out of hibernation, since it contains a lot of mitochondria!

how is energy released as heat (aka non-shivering thermogenesis which means an increase in metabolic heat production)?

fat oxidation is uncoupled from energy production! in the ETC, instead of protons entering back into the inner mitochondrial membrane through the use of ATP synthase complex, these protons go through a futile process, by passing through an uncoupled protein (that doesn't make ATP). this still gives a buildup of protons for the concentration gradient in ETC, but instead generates waste heat

explain white-nose syndrome

a fungus gets into the nasal passages of the bat and is an irritant. the actual fungus itself isn't hurting the bat, however, it ends up waking the bat multiple times over the course of their hibernation/torpor. in order to come out of torpor, bats need to constantly use energy, and burn so much of their brown adipose, to the point that when their hibernation/torpor is done, there is not enough brown fat to heat them back up

what kind of organisms use non-shivering thermogenesis?

smaller animals (like bats!)

what is non-shivering thermogenesis?

metabolism of brown fat to produce heat; it uses a significant amount of metabolism to maintain body temperature.

why is the metabolic rate per gram going to be aggressively higher in smaller animals?

the volume to surface area ratio is higher in smaller animals, than in larger animals. so smaller animals, therefore, contain more opportunities to exchange w/ the environment, which makes it harder to maintain a body temp = metabolism needs to work harder

larger animals tend to rely on...

insulation!

explain the heater tissues in fish

thsi is another manipulation of a futile system! calcium channels in the sarcoplasmic reticulum are kept open, which leads to the generation of heat as they remove ions across a membrane without the generation of ATP. then, Ca-ATPase in the sarcoplasmic reticulum membrane uses ATP to pump back in. this process is localized, meaning it only occurs within the muscle tissue of fish (bc sarco = muscles remember!!!)

being a small organism is mainly an issue for...

endotherms! remember?? ectotherms base it off environment regardless of size; if an endotherm is small, it has a higher metabolic rate/usage when compared to a larger endotherm

do ectotherm or endotherms have a higher metabolism efficiency?

ectotherms have a higher metabolism efficiency, meaning that they are more efficient in how they manage energy coming in the body (bc they don't have to focus in keeping a stable body temp at the same time)

what are the advantages of being an ectotherm?

lower energy demands, low cost of energy conversion, no cost to maintain constant body temp (bc they dont need to lmao), and smaller minimum body size

why can't endotherms get rlrlrl small?

bc then it becomes too costly! they would have too high of a metabolism use to survive/considered to be successful

what are the disadvantages of being an ectotherm?

more latitudinal and altitudinal restrictions on distribution (meaning that ectotherms cannot survive as well as endotherms do in colder climates; you dont see snakes in antartica lol), more daily/seasonal restrictions on activity (typically not as active at night bc ambient temp gets cooler and no sun can be used for heat/energy), and lower aerobic capacity (so they have a higher cost of locomotion and get more tired easier)

what are the advantages of being an endotherm?

fewer latitudinal and altitudinal restrictions on distribution (can literally be anywhere), fewer daily/seasonal restrictions on activity, and higher aerobic capacity (so they have a lower cost of locomotion and get less tired easier)

what are the disadvantages of being an endotherm?

higher energy demands, high cost of energy conversion, and over 90% of energy acquired is lost as heat