Physiology Flashcards
What is the normal core temperature of the body?
37.8 degrees celcius
What is the term used to decribe normal body temperature?
Normothermia
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
In which two ways can the body gain heat?
- Metabolic heat
- Radiation from external environment
How can the body lose heat?
- Convection
- Conduction
- Radiation
- Evaporation
Which hormones can increase heat production and why?
Adrenaline, noradrenaline and thyroxine
These hormones can speed up metabolic rate, so more heat is produced
Besides hormonal/metabolic control, what is one mechanism utilised by the body to increase body temperature?
Shivering
(increases muscular activity)
The level of heat conduction is dependent on which two factors?
- The temperature gradient
- Thermal conductivity
Why does evaporation result in heat loss?
Energy is used to convert water from the lquid to gaseous state
What are the two types of evaporation?
- Passive - this happens continuously, water molecules diffuse from bodility surfaces
- Active - the sympathetic nervous system is employed to increase sweating
Where can thermoreceptors be located?
- Central - hypothalamus, abdominal organs, other locations
- Peripheral locations - skin
Where is the control centre for body temperature located?
Hypothalamus
What are the effectors used by the body to control temperature?
- Skeletal muscle (shivering)
- Skin arterioles (dilatation/constriction)
- Sweat glands
The posterior hypothalamus is activated by ______, whilst the anterior is activated by ______.
Cold
Warmth
When activated, what will the posterior hypothalamus cause?
- Vasoconstriction
- Increased muscle tone
- Shivering
- Behavioural changes - voluntary movement/clothing changes