3/18-3/25 Endotherms and Ectotherms Flashcards

1
Q

On average only birds and mammals use homeothermy, why don’t most animals use this method of temperature regulation?

A

It is very expensive.

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2
Q

To be an endotherms should you have a large or small body size?

A

large decent body size

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3
Q

from burning one gram of carbs does endothermic animals gain any more energy/heat than ectothermic animals?

A

No

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4
Q

What role does insulation play into the maintainment of a constant body temperature?

A

Very minimal. Birds have very poor insulation aka feathers. Over time they have decreased their weight and increased their power for flight and the birds that do have a very strong insulation cannot fly aka penguins. Humans also have very poor insulation we have coarse hair and no fur. It does not require good insulation to be an endotherm.

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5
Q

If you are small aka have a small mass to surface area ratio will you gain or lose heat?

A

You will lose heat more readily

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6
Q

Why are endotherms able to keep a stable warm body temperature?

A

Across the membranes, endotherms have anywhere from 5-10 times the number of sodium/potassium molecular pumps and the cycles in between the movement of sodium and potassium are much shorter so 5-10 times more ions are moved overall. Since ATP is hydrolyzed each action of the pump heat is also produced and thus the metabolic rate is 5-10 times greater than ectotherms.

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7
Q

For the membranes of endotherms to work 5-10 times harder what characteristic must the pumps have?

A

They must be extremely leaky. They leak potassium quickly and sodium is even leaked easier across endothermic membranes than ectothermic membranes.

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8
Q

What is the futile cycle?

A

Expenditure of energy with no net work being done no net outcome

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9
Q

What is the main difference between the ecothermic and endothermic animals?

A

Endothermic animals have an increase in the number of molecular pumps and number of ions moved that leads to a higher metabolic rate and thus a relatively constant internal temp.

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10
Q

What is the specific control mechanism in endotherms that has the ability to sense the heat generated and ensures enough to keep a stable body temperature?

A

hypothalamus

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11
Q

WHat happens when lesions are introduced into the hypothalamus of endothermic animals such as dogs?

A

They lose the ability maintain a stable body temperature. They still have a futile cycle going on but they over heat then cool down too much and cannot regulate their own body temperature.

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12
Q

What can be considered the thermostat of the human body?

A

The hypothalamus

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13
Q

What was the experiment done on Beagles to provide evidence that the hypothalamus is the specific control center for body temperature?

A

Into the hypothalamus a thermocouple was inserted. The thermocouple temperature can be increased or decreased. Dogs have a body temp of 37.8 degrees. When researchers reduced the temperature in the hypothalamus, when the temperature reached 36 degrees the dog began to shiver regardless of the temperature outside. When the temp was increased to 39 degrees the dog began to pant. The set point exhibited were precise.

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14
Q

What role does the outside temperature play in the hypothalamus maintenance of the internal body temp?

A

It is a form of physiological anticipation That when combined with a change in the hypothalamus temperature, a faster reaction is seen to regulate body temperature.

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15
Q

True or false the hypothalamus is sensitive to its own temperature?

A

True

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16
Q

The set point is constant in the hypothalamus, however changes in the ambient temperature will cause what?

A

changes in the set points for shivering and panting.

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17
Q

Heat production and heat loss mechanisms are plastic. What does this mean?

A

They are graded responses they can be moved.

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18
Q

What is shivering thermogenesis?

A

Skeletal muscles that spontaneously contract involuntary that produces heat but very little to no physical work is being done.

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19
Q

What type of ectotherm uses shivering thermogenesis?

A

Female indian pythons

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20
Q

Through shivering thermogenesis the female indian python could keep her eggs how many degrees water than the ambient temperature?

A

7-9 degrees centigrade

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21
Q

How do honey bee swarms use thermogenesis?

A

They shiver as a group. A ball of bees that constantly move, they vibrate their wings and the bees in the middle migrate towards the outside and the bees on the outside migrate towards the middle. The inside of the ball of bees is 25-30 degrees warmers than the ambient temperature.

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22
Q

Hoe do large flighted insects such as dragonflies generate heat? And by how much can they increase their body temperature?

A

They shiver they vibrate the wings and it generates heat. They can increase their body temperature up 20 degrees.

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23
Q

What is nonshivering thermogenesis?

A

Method to produce heat through some homeostatic control without shivering. Rats when paralyzed placed in cold weather still maintained warm temperatures.

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24
Q

What is BAT?

A

Brown adipose tissue

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25
Q

What is the significance of BAT?

A

Produces heat for animals. Only found in three specific types of mammals. It is only about 1-3 percent of the total body weight.

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26
Q

What three types of mammals does BAT show up in?

A
  1. newborn mammals
  2. cold acclimatized adults
  3. hibernate and torpid animals
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27
Q

What is the difference between acclimation and acclimatization?

A

Acclimation occurs in the lab and only one factor is changed. Acclimatization occurs in nature

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28
Q

Where is the location of BAT on animals?

A

between the shoulder blades and up onto the neck, also in the axilla, and the under sternum…aka wraps around the heart

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29
Q

How is metabolism of the BAT started?

A

The CNS recognized your cold and one begins to shiver and two if you have BAT it begins the metabolism of that.

30
Q

WHat is the difference between white adipose tissue and BAT (brown adipose tissue)?

A

White adipose tissue is strictly for energy storage. BAT is strictly for heat production.

31
Q

What is the difference in the structure of what and brown adipose tissue?

A

White adipose tissue is stored in huge vesicles, avascular, and contain few mitochondria. BAT is stored in very many very tiny vesicles, highly vacularized, and contains mitochondria.

32
Q

What are the difference in the white fat mitochondria and the brown fat mitochondria? And why is this important?

A

The white fat has sausage shaped and the brown fat has oval/round mitochondria. On the inside the white fat mitochondria has an inner and outer membrane seletively permeable for the E- transport chain to produce ATP. On the inside of the BAT there is a special protein called thermogenin- which makes the inner membrane permeable to protons and chloride ions therefore if there is no proton gradient ATP cannot be generated. No possibility to give off ATP so all the energy is give off as heat.

33
Q

Why do newborns need BAT?

A

Surface area to mass ratio is much lower therefore they need to be able to generate more heat to keep their body temperature stable.

34
Q

What are three mechanisms used to conserve metabolic energy?

A
  1. dual det point regulators
  2. brumation
  3. estivation
35
Q

What are duel set point regulators?

A

Animals who have a regular set point (37-39 degrees) in the summer and then in the winter they set a second set point down around 3-4 degrees and act as an ectotherm bc they allow body temp to fluctuate with environment until it gets too low.

36
Q

What are three types of dual set point regulators?

A
  1. hibernation
  2. diel torpor
  3. carnivorous lethargy
37
Q

WHat is hibernation? And how do animals proceed into it?

A

Do not understand all the aspects but it is under CNS control and not a long sleep. Occurs only in mammals! As the hibernation period approaches the animal will undergo test drops in their body temperature and the drops will become more frequent until the animals enter into the hibernative state.

38
Q

What happens to the animal when it is in its hibernation state?

A

Metabolic processes are shut off. Certain organs are shut off. Processes are put in place to prevent bad things from happening such as muscle atrophy and bone deterioration.

39
Q

Hibernating animals most often are too small to store a lot of body fat to get through winter and are too large to get through with what they do store-they are in between group. true or false

A

true

40
Q

WHat types of animals use diel torpor?

A

Small animals such as hummingbirds and shrews

41
Q

What id diel torpor also known as?

A

noctivation

42
Q

Why do hummingbirds go into diel torpor?

A

They eat continuously because they have such a high metabolic rate and at night they can not afford to stop eating for 6-7 hours or they will starve to death.

43
Q

What happens in diel torpor in the hummingbird?

A

The animals will perched itself in a tree somewhere or something and its metabolic rate shuts down for the night

44
Q

What happens in diel torpor for the shrew?

A

They remain in the active and inactive state throughout the day. For 5-7 minutes throughout the day they run around kill everything they can and eat. Then they into a sleep mode for 2 minutes and when they wake up they’re starved.

45
Q

Do bears hibernate?

A

NO

46
Q

What is carnivorous lethargy and how do bears participate in it?

A

It is most pronounced in polar bears and female polar bears about to give birth to cubs. They gorge themselves on food in the fall and summer and then the females den up and they crash for long periods of time and give birth during that time and remain in the carnivorous lethargy state while young suckle.

47
Q

During carnivorous lethargy do the bears body temperature fluctuate?

A

Yes but sloppy they are not dual set point regulators.

48
Q

Can the bears in carnivorous lethargy be aroused?

A

yes

49
Q

How is carnivorous lethargy different from hibernation?

A

no dual set point regulators and they can be easily aroused

50
Q

What are the two states ectotherms go into when its too cold or too warm?

A

brumation and estivation

51
Q

What type of animal shows seasonal torpor?

A

Bats. They become inactive in the coldest parts of winter.

52
Q

Ectotherms have a ______ array of adaptations they can practice. What are some examples?

A

wider
supercooling
freeze tolerance
freeze resistance

53
Q

What soecies supercool?

A

Willowgaull flies-flies int he artic circle and can cool down to -60 degrees

bats- -1 or -2 degrees

fish -2degrees

54
Q

WHat is freeze tolerance?

A

Let the body freeze not the cells. Secrete the water out of the cells and let it freeze there not in the cells. Restrict freezing to the outside of the cells.

55
Q

What is freeze resistance?

A

Antifreeze compounds typically in fish. They don’t stop freezing but they do prevent the growth of ice crystals. proteins are produced and as the ice crystal forms and the proteins bind to the spaces between the peaks and prevent the ice crystal from growing

56
Q

What is regional heterothermy?

A

based on the ability to shut down bloodflow to various parts of the body for example the extremities and therefore allowing certain parts of the body to cool down to a point where tissue viability is maintained but a great deal of energy isn’t expended to reheat the blood

57
Q

What is a main reason for the four chambered heart?

A

To support endothermy - ability to move large volumes of water at relatively high pressure=precise blood flow to heat entire body

58
Q

what is rete mirabile

A

refers to the mesh like arrangement of capillaries that exchange heat=counter current exchange

59
Q

what is counter current exchange?

A

Heat exchange-warm blood moves in one direction and cold blood moves in the other direction and if those two are brought close togeter heat can be exchanged between the two

60
Q

WHat does countercurrent exchange allow?

A

outer extremities to have a drop in temperature without being detrimental to the core because the blood is heated on its way back into the core of the body through countercurrent exchange

61
Q

how can counter exchange be made very efficient?

A

The resha the net like mesh of the capillaries can be very complex and intertwined to allow max reabsorption of heat

62
Q

How do caribou use counter current exchange?

A

On the bottom of their hoof is living tissue. They allow the temperature of their hoof to drop within one degree of freezing to allow to keep it from freezing but not waste any energy bc the hoofs are always contact with frozen surface. If the temp of the hoof get too low they open a second capillary bed and flood that with warm blood to warm it back up.

63
Q

How do herring gulls use counter current exchange?

A

They have very well developed resha that develop prior to the arrival of each winter. The vasculature of resha has to be rebuilt every year.

64
Q

What is the reverse situation found in fish? How do they get the name “ideal ectotherms”?

A

The gills of fish that easily allow co2 to diffuse out also lose a lot of heat so the fish use reesha to keep certain parts of their body warmer than others. Fish are exactly the same temperature as the water and are called ideal ectotherms

65
Q

WHat is another strategy fish use that allow them to reclaim the heat and not lose it all across the gills?

A

The fish pick up the heat before it gets to the gills and outer surfaces of the body. Put the reesha in between the gills and the heart and the external surfaces and the rest of the internal musculature and in that case you can use that to keep certain parts of your body warmer.

66
Q

What is the term used to describe fishes that use reesha and countercurrent exchange to keep certain parts of their body warmer than others?

A

Warm bodied fishes. They are not homeotherms heterotherms or poikilotherms.

67
Q

What are some types of warm bodied fishes

A

sharks and tuna and mackrel

68
Q

What is ram jet ventilation?

A

water rushes across the gills so they can get oxygen therefore they must swim continuously!

69
Q

How do tuna use reesha and countercurrent exchange?

A

They are predatory fish so they must keep certain parts if their body warmer than other to improve speed and coordination so they use reesha and keep heat for muscles and eyes etc.

70
Q

What parts of the body do the bill fish warm? And why? what muscle is used to heat up the fish?

A

The brain and the eyes. These fish hunt at very deep dark cold areas in the ocean and so vision is highly important. They heat up the brain and eye using the interocular muscle which has lost its ability to contract so it gives all the energy off as heat?

71
Q

WHat is the difference between the bill fish and the tuna?

A

The bill fish uses a set of muscles to heat he brain and eye where the tuna uses capillary reesha nets to keep certain muscles warm.

72
Q

Warm blooded fish such as tuna and bill fish must eat _____ .

A

continuously