Chapter 7 - Homeostasis Of Body Temperature Flashcards Preview

Human Biology - Unit 3 > Chapter 7 - Homeostasis Of Body Temperature > Flashcards

Flashcards in Chapter 7 - Homeostasis Of Body Temperature Deck (27)
Loading flashcards...
1
Q

What is thermoregulation?

A

Maintaining the balance between heat production and heat loss

2
Q

What is the optimum body temperature?

A

37 degrees Celsius

3
Q

What causes heat input?

A
  • heat from body processes (metabolism), especially respiration of muscle and liver cells
  • heat gained from surroundings by conduction and radiation
4
Q

What causes heat output?

A
  • radiation, convection and conduction to surroundings

- evaporation of water from skin and lungs, warm air breathed out, warm urine and faeces

5
Q

What does a high temperature above normal cause?

A

Enzymes denature, change shape, disrupts cellular activity

6
Q

What is higher, internal or external temperature?

A

Internal due to metabolism

7
Q

Cold conditions: to decrease heat loss

A
  • vasoconstriction
  • reduction in sweating
  • conscious behaviour such as putting on a jumper
  • reduction of surface area by curling into a ball
8
Q

Cold conditions: to increase heat production

A
  • shivering
  • increase in voluntary activity
  • increased metabolic rate
9
Q

Hot conditions: to increase heat loss

A
  • vasodilation
  • increase in sweating
  • conscious behaviour
  • increase surface area by spreading out
10
Q

Hot conditions: to decrease heat production

A
  • decrease in voluntary activity

- decreased metabolic rate

11
Q

Where are peripheral thermoreceptors found?

A

Skin and mucous membranes

12
Q

Where are central thermoreceptors found?

A

Hypothalamus

13
Q

What are the two types of peripheral thermoreceptors?

A
  • cold receptors: stimulated by temperatures lower than normal
  • heat receptors: stimulated by temperatures higher than normal
14
Q

Where are other central thermoreceptors located?

A

Spinal cord and abdominal organs, connected to hypothalamus

15
Q

What is the body’s main temperature regulation centre?

A

Hypothalamus

16
Q

What would peripheral receptors alone not be efficient in temperature regulation?

A

Because it is the core body temperature that needs to be controlled

17
Q

What controls vasoconstriction and vasodilation?

A

Autonomic nerves

18
Q

What is sweating?

A

The active secretion of fluid by the sweat glands and the periodic contraction of cells surrounding the ducts to pump sweat to the skin surface

19
Q

What is sweat made of?

A

Water, sodium chloride, urea, lactic acid and potassium ions

20
Q

How does sweat work to increase heat loss?

A

Evaporation of sweat from the body has a cooling effect: heat is removed from the skin when liquid sweat changes into vapour

21
Q

What stimulates secretion of sweat?

A

Sympathetic nerves

22
Q

What is shivering?

A

Rhythmic muscle tremors that occur at a rate of 10-20 per second

23
Q

At what temperature does death occur?

A

Above 45 degrees

24
Q

What causes heat exhaustion?

A

When extreme sweating and vasodilation occurs to lose heat

25
Q

What happens when the body is heat exhausted?

A
  • the loss of water in sweating reduces the volume of blood plasma and vasodilation reduces resistance to blood flow
  • blood pressure is decreased and the output of blood from the heart is reduced
26
Q

What is hypothermia?

A

When a persons core temperature falls below 33 degrees, the metabolic rate is so low that heat production is unable to replace heat lost and body temperatures continue to fall

27
Q

What is heat stroke?

A

When humidity is high and it is difficult for the body to lose heat by radiation or evaporation