Temperature Contol Flashcards

1
Q

Give some features of ectotherms

A
  • depend on environment
  • metabolism is 10x lower than endotherms
  • low energy intake
  • narrow-wide enzyme functional temp
  • sun basking and muscle activity (shivering)
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2
Q

Give some features of endotherms

A
  • Independent of environment
  • Metabolism is 10x higher then ectotherms
  • high energy intake
  • narrow enzyme functional temp
  • hibernate
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3
Q

what features do Endothermic Homeotherms (Humans and other mammals) have

A
  • Body surface often slightly lower temp than internal
  • body core temp highly regulated
  • size adjustments of body to change temp
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4
Q

Give the degrees for hypo/hyper-thermia

A

hypo = 35, hyper = 39, 37 degrees is perfect

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5
Q

What is the equations for metabolic heat production and what do the variables mean?

A

H = C (Tb - Ts)

H= metabolic heat production
C = Heat loss
Tb = Body core temperature
Ts = Body surface
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6
Q

What steps happen when there is a temperature rise in the external environment?

A
  • Temperature rise is detected by thermostat
  • Thermostat activates cooling mechanism
  • Sweat glands start to secrete sweat
  • Sweat evaporates on skin and cools body
  • blood vessels dilate increasing SA
  • Increased SA allows more heat to escape
  • Body cools, thermostat shuts off
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7
Q

What steps happen when there is a temperature dip in the external environment?

A
  • Temperature dip is detected by thermostat
  • Thermostat activates warming mechanism
  • Muscles start to contract
  • contraction causes shivering and generate heat
  • blood vessels constrict decreasing SA
  • decreased SA stops heat escaping
  • Body warms, thermostat shuts off
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8
Q

How do organisms regulate temperature within the thermal neutral zone?

A
  • Postural changes (cuddle up)
  • Insulation (hair vs blubber)
  • Vasomotor responses (blood flow regulation)
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9
Q

Give features of blubber

A
  • No grooming required
  • Metabollically available
  • buoyancy doesn’t change with depth
  • incompressible
  • heavy
  • skin near ambient temperature
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10
Q

Give features of Fur

A
  • lightweight
  • skin near body temperature
  • compressed at depth
  • requires air and grooming
  • buoyancy changes with depth
  • metabolically inert and unavailable
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11
Q

How do organisms regulate temperature below the lower cutaneous temp (LCT)?

A

Thermogenesis; Shivering, non-shivering (BAT), and countercurrent heat exchange.

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12
Q

What do white adipocytes do?

A

They convert Tri-glycerides into free fatty acids (FFAs)

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13
Q

What are white adipocytes?

A

Energy storing fat cells

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14
Q

How are FFAs converted to ATP?

A

FFAs are released into the blood and transported to mitochondria where they are oxidised into ATP by respiration.

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15
Q

What are brown adipocytes?

A

brown adipocytes are fat cells that express mitochondrial UCP (uncoupling proteins).

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16
Q

What do Uncoupling proteins do?

A

UCPs generate heat instead of ATP

17
Q

Why are the fat cells brown?

A

They have large amounts of mitochondria and are highly vascularised

18
Q

Where are brown adipocytes found?

A

Cold-acclimatised mammals/ hibernators/newborns

19
Q

What does BAT stand for?

A

Brown adipose tissue

20
Q

Describe the prices BAT goes though when it gets too cold

A
  • Sympathetic stimulation from hypothalamus
  • hydrolysis of triglyceride to FFAs.
  • FFAs move into mitochondria and combine with ADP to produce ATP
  • AKA FFAs are oxidised to ATP through beta-oxidation
  • uses UPC 1 to leak protons from intermediate space of mitochondria back to the matrix - this produces heat
21
Q

In counter current heat exchange which way does the heat flow?

A

From the artery to the vein

22
Q

Where does the most counter-current heat exchange occur in birds

A

Their feet (are highly vascularised)

23
Q

How is countercurrent heat exchange different in mammals?

A

Blubber insulates the body of the dolphin but it does not extend to the flippers so heat is transferred from the artery to the veins

24
Q

How do organisms regulate temperature below the upper cutaneous temp (UCT)?

A
  • Evaporative cooling

- sweating in some mammals and panting in birds and mammals

25
How much energy does it require to evaporate 1g of H20
585 calories - loss of heat energy corresponding to calories
26
Chemical reactions including metabolic rate (MR) depend on...?
Temperature
27
Metabolic heat is ....... in fish?
Rapidly lost
28
What is the equation for Q10 and what do the components mean?
Q10 = (MR2/MR1)^10/(t2/t1) t = temperature MR (1+n) = MR at T(1+n)
29
Rate of chemical reactions increase with a factor of ..... per ...... degree increase in temperature
factor of 2-3 per 10 degrees