The Need for Internal
Homeostasis
Homeostasis
The body’s internal environment has to be maintained at a constant level for it to
remain healthy
This includes, fluids, oxygen, carbon dioxide and electrolytes which all need to be
maintained within specific limits
Homeostasis is the ability of the body to regulate itself internally regardless of the
changes taking place externally
Vital signs are used to monitor the body’s ability to maintain homeostasis (body
temperature, pulse, respiration and blood pressure)
Body temperature
Temperature is the balance between heat produced and heat lost through body processes
A relatively constant body temperature is needed for the functioning of all cells
Cell damage (and eventually cell death) can occur in extreme temperatures
The hypothalamus us the main centre for body temperature regulation
The body maintains a temperature in the range of 36°C and 37.2°C
Mechanisms of heat production
1) metabolism of food
During metabolism food is broken down so energy can be released
Energy is stored as ATP in the cells and is also released as heat
2) Muscular activity and movement
Energy is used during movement and some energy is released as heat
Muscular movement causes friction within the tissues which generates heat
3) Blood flow
Friction occurs in blood vessels between the blood and the vessel walls and releases energy
4) Hormones
Thyroid hormones and catecholamines (epinephrine and non-epinephrine) play an
important role in heat production
Mechanisms of heat loss
Heat production must be lost to avoid a dangerous build-up of heat
1) Radiation
Heat is radiated from the body as electromagnetic waves
Heat is lost if the body’s heat is less than that of the environment
Heat is absorbed if the body temperature is less than the environment
2) Evaporation
Moisture evaporates from the skin, mucous membranes and mouth
Humidity of the air, respiratory rate and size of the body surface all influence evaporation
3) Conduction
The transfer of heat from one molecule to another my direct contact
Heat may be lost through contact with a cooler object i.e. water
4) Convection
Movement of gas/liquid from a region of higher temperature to a region of lower temp
Heat is lost due to the layer of air immediately adjacent to the skin by convection currents.
The warm air rises and is replaced by cooler air that in turn is warmed by conduction
,
Homeostasis
Homeostasis
The body’s internal environment has to be maintained at a constant level for it to
remain healthy
This includes, fluids, oxygen, carbon dioxide and electrolytes which all need to be
maintained within specific limits
Homeostasis is the ability of the body to regulate itself internally regardless of the
changes taking place externally
Vital signs are used to monitor the body’s ability to maintain homeostasis (body
temperature, pulse, respiration and blood pressure)
Body temperature
Temperature is the balance between heat produced and heat lost through body processes
A relatively constant body temperature is needed for the functioning of all cells
Cell damage (and eventually cell death) can occur in extreme temperatures
The hypothalamus us the main centre for body temperature regulation
The body maintains a temperature in the range of 36°C and 37.2°C
Mechanisms of heat production
1) metabolism of food
During metabolism food is broken down so energy can be released
Energy is stored as ATP in the cells and is also released as heat
2) Muscular activity and movement
Energy is used during movement and some energy is released as heat
Muscular movement causes friction within the tissues which generates heat
3) Blood flow
Friction occurs in blood vessels between the blood and the vessel walls and releases energy
4) Hormones
Thyroid hormones and catecholamines (epinephrine and non-epinephrine) play an
important role in heat production
Mechanisms of heat loss
Heat production must be lost to avoid a dangerous build-up of heat
1) Radiation
Heat is radiated from the body as electromagnetic waves
Heat is lost if the body’s heat is less than that of the environment
Heat is absorbed if the body temperature is less than the environment
2) Evaporation
Moisture evaporates from the skin, mucous membranes and mouth
Humidity of the air, respiratory rate and size of the body surface all influence evaporation
3) Conduction
The transfer of heat from one molecule to another my direct contact
Heat may be lost through contact with a cooler object i.e. water
4) Convection
Movement of gas/liquid from a region of higher temperature to a region of lower temp
Heat is lost due to the layer of air immediately adjacent to the skin by convection currents.
The warm air rises and is replaced by cooler air that in turn is warmed by conduction
,
