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Flashcards in Physiology Deck (23)
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1

What is the normal core temperature of the body?

37.8 degrees celcius

 

2

What is the term used to decribe normal body temperature?

Normothermia

3

What can cause variations in body temperature?

  • Natural differences between individuals
  • Time of day (lower in mornings)
  • Physical activity or emotions
  • Exposure to extremes of temperature
  • Menstrual cycle

4

In which two ways can the body gain heat?

  1. Metabolic heat
  2. Radiation from external environment

5

How can the body lose heat?

  • Convection
  • Conduction
  • Radiation
  • Evaporation

6

Which hormones can increase heat production and why?

Adrenaline, noradrenaline and thyroxine

These hormones can speed up metabolic rate, so more heat is produced

7

Besides hormonal/metabolic control, what is one mechanism utilised by the body to increase body temperature?

Shivering

(increases muscular activity)

8

The level of heat conduction is dependent on which two factors?

  1. The temperature gradient
  2. Thermal conductivity

9

Why does evaporation result in heat loss?

Energy is used to convert water from the lquid to gaseous state

10

What are the two types of evaporation?

  1. Passive - this happens continuously, water molecules diffuse from bodility surfaces
  2. Active - the sympathetic nervous system is employed to increase sweating

11

Where can thermoreceptors be located?

  1. Central - hypothalamus, abdominal organs, other locations
  2. Peripheral locations - skin

12

Where is the control centre for body temperature located?

Hypothalamus

13

What are the effectors used by the body to control temperature?

  • Skeletal muscle (shivering)
  • Skin arterioles (dilatation/constriction)
  • Sweat glands

14

The posterior hypothalamus is activated by ______, whilst the anterior is activated by ______.

Cold

Warmth

15

When activated, what will the posterior hypothalamus cause?

  • Vasoconstriction
  • Increased muscle tone
  • Shivering
  • Behavioural changes - voluntary movement/clothing changes

16

When activated, what bodily changes does the anterior hypothalamus confer?

  • Vasodilatation
  • Sweating
  • Decreased muscle tone
  • Behavioural changes - decreased movement, removal of excess clothing

17

How is fever brought about?

Macrophages release pro-inflammatory mediators which act as endogenous pyrogens

They stimulate prostaglandin release which causes the hypothalamus to raise the baseline body temperature that is maintained

Shivering and vasoconstriction will be initiated to raise body temperature

18

Why is it called when the body temperature exceeds 40 degrees?

Hyperthermia

19

What is hypothermia?

When the core body temperature decreases below 35 degrees

20

What is homeostasis?

The process of maintaining an internal environment within the body that is optimal for function

21

What are the two types of bodily control systems?

  1. Intrinsic - within an organ (local controls)
  2. Extrinsic - regulatory mechansims inititaed outside the organ and accomplished by nervous and endocrine systems

22

With respect to homeostatic responses, what does the term "feedward" mean?

The change made by control systems in anticipation of another change

23