Please enable JavaScript.
Coggle requires JavaScript to display documents.
12.1 Controlling body temperature - Coggle Diagram
12.1 Controlling body temperature
What is homeostasis?
Homeostasis is the regulation of internal conditions to maintain stable conditions for cells and enzymes to function properly.
Keeps internal conditions stable despite changes inside or outside the body
Examples include body temperature, blood glucose and water levels
Core body temperature is kept around 37°C
Basic Temperature Control
Controlled by the thermoregulatory centre
Located in the hypothalamus of the brain
Contains receptors that detect the temperature of the blood
Temperature receptors in the skin detect changes in external temperature
Skin receptors send nerve impulses to the thermoregulatory centre
The body responds if temperature becomes too high or too low
What happens if the body is too hot or cold
If the body is too hot
Vasodilation occurs
Blood vessels supplying skin capillaries widen
Body temperature falls back towards 37°C
More blood flows near the skin surface
More energy is transferred to the surroundings
Sweating increases
Sweat evaporates from the skin
Transfers energy from the body to the environment
Cools the body
If the body is too cold
Vasoconstriction occurs
Blood vessels supplying skin capillaries narrow
Body temperature rises back towards 37°C
Less blood flows near the skin surface
Less energy is transferred to the surroundings
Sweating decreases or stops
Shivering occurs
Skeletal muscles contract rapidly
Muscle contractions require respiration
Respiration is exothermic, transferring energy as heat
Water balance and ADH
ADH stands for antidiuretic hormone
Controls the water concentration of the blood
Released by the pituitary gland
Too little water in blood → more ADH
Kidneys reabsorb more water
Small amount of concentrated urine produced
Too much water in blood → less ADH
Kidneys reabsorb less water
Large amount of dilute urine produced
Blood glucose control
Controlled by the pancreas
High blood glucose → insulin released
Glucose moves from the blood into cells
Excess glucose is converted into glycogen for storage
Low blood glucose → glucagon released
Glycogen is converted back into glucose
Glucose is released into the blood