Biology Thermoregulation

Homeostasis

Maintaining a body Balance

Maintaining a constant internal environment despite changes in the external environment.

Monitor/Sensor

Detects the change

The thermometer detects the temperature of the room

Coordinating/Control Centre

Relays the information

The thermostat determines when the furnace needs to be switched on or off.

Regulator/Effector

Restores the normal balance.

the furnace is turned on when the temperature is set below the point

Negative Feedback loop

Process by which a mechanism is activated to restore conditions to their original state (most common)

Resists change by restoring original conditions

Examples:

Blood Sugar, Blood Pressure

Positive Feedback

Process by which a small effect is amplified

Amplifies state and moves further from steady state

Examples:

Child birth

Thermoreregulation

How the Body Regulates Temperature

Heat is Lost or Gained in Four Ways? What are the four ways?

Conduction: Transfer of heat by contact, direct transfer (gained)

Convection: transfer of heat by movement of air or liquid past the body surface (lost)

Radiation: transfer of heat by electromagnetic energy (gained)

Evaporation: loss of heat from a surface of a liquid turning into a gas (lost)

Thermoregulation Strategies in Animals

There are 2 strategies

Endotherms and ectotherms.

Endotherm

• Maintain's a constant body temperature despite external environment

• High metabolic rate

• Body gains heat through metabolism (cell respiration)

Examples:

Mammals, birds

(warm blooded)

Ectotherm

• Body Temperature Fluctuates depending on the external environment

• Low Metabolic Rate

• Body Heat gained through Environment

• Most Invertebrates, amphilbians, reptiles

(cold blooded).

Thermoregulation - Heating

Coordinating Centre: Hypothalamus turns on cooling system

Regulator: skin blood vessels dilate, increased blood flow to skin, heat excluds from skin

Regulator: sweat glands initate sweating and evaporation leads to cooling

Result: Body temperature decreases

Thermoregulation - Cooling

Coordinating Centre: Hypothalamus turns on warming system

Regulator: skeletal muscles contract (shivering) generating heat

Regulator: Skin blood vessels constrict decreasing blood flow to reduce heat loss from skin

Result: Body temperature increases, hypothaamus turns of warming systems.