7: Feedback control of body temperature Flashcards

(44 cards)

1
Q

Temperature is an example of a variable which must be maintained within narrow limits in the human body. This process is called _______.

A

Homeostasis

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2
Q

What is the definition of core body temperature?

A

The temperature of structures deep within the body

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3
Q

What is the average core temperature of a human (to 3 significant figures)?

A

37.8 degrees Celsius

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4
Q

Why isn’t the skin a good site for monitoring body temperature?

A

The temperature of the skin varies widely

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5
Q

The core body temperature is kept ____ despite changes in the environment.

A

constant

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6
Q

What is nomrothermia?

A

The normal core body temperature

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7
Q

What is ear drum temperature also known as?

A

Tympanic temperature

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8
Q

Name three areas where body temperature can be taken.

A

Ear drum, rectum, orally

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9
Q

What is diurnal variation in body temperature?

A

Changes in body temperature during the day

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10
Q

To maintain a constant core body temperature, heat ___ and heat ___ must be in balance.

A

gain , loss

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11
Q

What is a source of heat gain within the body?

A

Metabolic heat

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12
Q

What is Basal Metabolic Rate (BMR)?

A

Minimum amount of energy required to sustain vital body functions

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13
Q

Which hormones increase the Basal Metabolic Rate (BMR)?

A

Adrenaline, noradrenaline, thyroxine

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14
Q

Shivering increases ___ production by increasing ___ ___.

A

heat , muscle activity

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15
Q

What is radiation?

A

Emission of heat energy from a surface as electromagnetic waves

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16
Q

The human body both ___ and ___ radiant heat.

A

emits , absorbs

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17
Q

How much of the body’s heat loss occurs through radiation?

A

Around 50%

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18
Q

What is conduction?

A

Transfer of heat between objects in contact

19
Q

In conduction, heat moves from the ___ to ___ object.

A

warmer , cooler

20
Q

What is convection?

A

Transfer of heat energy away from the body by air or water currents

21
Q

Warm air ___, cool air ___.

22
Q

Convection and ____ often work together to dissipate heat from the body.

23
Q

What is evaporation?

A

Conversion of water into vapour using energy

24
Q

Where does evaporation occur in the body?

A

The skin surface, lining of the respiratory tract

25
Sweating is an ___ form of evaporative heat loss.
active
26
Sweating is controlled by the _____ nervous system.
sympathetic
27
What kind of feedback control system regulates core body temperature?
Negative feedback
28
What is the temperature control centre called?
The hypothalamus
29
The posterior hypothalamic centre is activated by \_\_\_.
cold
30
The anterior hypothalamic centre is activated by \_\_\_.
warmth
31
What do skin arterioles do in response to cold?
Vasoconstrict
32
What does vasoconstriction result in?
Decreased heat loss / heat conservation
33
What do skeletal muscles do in response to cold?
Increase their muscle tone Shiver
34
What do skin arterioles do in response to warmth?
Vasodilate
35
How does vasodilation increase heat loss?
Increases blood flow to the skin, increased radiation/convection/conduction
36
Macrophages release chemicals in response to infection or inflammation. What do these chemicals act as?
Endogenous pyrogens
37
Endogenous pyrogens stimulate the release of which chemical in the hypothalamus?
Prostaglandins
38
What do prostaglandins to the body's internal thermostat?
Reset it at a higher temperature
39
Is the resetting of the body's internal thermostat reversible? How?
Yes When pyrogen / prostaglandin release stops
40
Fever is a core body temperature between...
38 - 40 degrees Celsius
41
What is hyperthermia (definition, not values)?
Extreme uncontrolled increase in body temperature
42
What body temperature constitutes hyperthermia?
Any body temperature above 40 degrees Celsius
43
What is hypothermia (definition, not values)?
Drop in body temperature below that required for metabolism and function
44
What body temperature constitutes hypothermia?
Any body temperature below 35 degrees Celsius