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thermoregulation 

heat loss or gain from the body

  • conduction - when in contact with a cold environment

  • convection - air movement can add or remove heat to the body

  • radiation - the body will radiate heat if the environment is cooler than the body or gain heat from a hot environment

  • evaporation - change of state from a liquid to a gas requires energy

  • this will have a cooling effect

  • core body temperature is maintained at a constant 37 degrees. The perihelion is often lower

  • body temperature in excess of 43 degrees, hyperthermia is rapidly fatal as brain cells die

  • hyperthermia is a core temperature of 35 - 32 degrees or lower

  • death occurs at about 25 degrees

body temperature changes when wet or in water because water is a very poor conductor of heat

skin

  • it has thermoreceptors in it

  • largest organ

  • major organ involved in thermoregulation

  • largest organ in the body

heat gain or retention mechanisms

  • vasocontraction of blood vessels supply capillaries in the skin.reduction of blood supply to the surface heat loss to the environment

  • concentration of hair erector muscle raises hair on the skin and trapping an insulating layer of air close to the skin.AIR is a poor conductor of heat

shivering

  • short,small contractions of skeletal muscle requires energy from respiration

  • heat is produced as a by product

heat loss mechanisms

  • sweating, exocrine sweat glands secrete sweat which is mainly water but contains sodium ions and small amount of urea

  • sweat is deposited on the skin surface

  • the evaporation of the water in sweat requires energy which is provided by the body’s heat in the cooling of the body

  • vasodilation of vessels supplying capillaries in the skin increasing the blood supply to the surface of the skin.more heat is lost to the environment

  • relaxation of hair erector muscles

  • hairs lie flat reducing the insulating layer of air close to the skin

hormonal control of body temperature

  • adrenaline releases produces a temporary increase in metabolic rate

  • as more respiration takes place more heat is produced as by product

  • increase in levels of thyroxine increases the metabolic rate long term

  • an increase in metabolic rate will increase the rate of heat production

hyperthermia

  • body temperature higher than normal as a result of failure of control mechanisms

  • symptoms include

  • dizziness,itchy skin,cramps,swelling of ankles

  • causing fainting,confusion,irregular heat beat and result of death

hypothermia

  • body temperature falls below norm

  • the usual body warming mechanisms cannot warm the body enough

  • severe hypothermia can cause unconsciousness weak and irregular heart beat,confusion

  • death can result

MT

thermoregulation 

heat loss or gain from the body

  • conduction - when in contact with a cold environment

  • convection - air movement can add or remove heat to the body

  • radiation - the body will radiate heat if the environment is cooler than the body or gain heat from a hot environment

  • evaporation - change of state from a liquid to a gas requires energy

  • this will have a cooling effect

  • core body temperature is maintained at a constant 37 degrees. The perihelion is often lower

  • body temperature in excess of 43 degrees, hyperthermia is rapidly fatal as brain cells die

  • hyperthermia is a core temperature of 35 - 32 degrees or lower

  • death occurs at about 25 degrees

body temperature changes when wet or in water because water is a very poor conductor of heat

skin

  • it has thermoreceptors in it

  • largest organ

  • major organ involved in thermoregulation

  • largest organ in the body

heat gain or retention mechanisms

  • vasocontraction of blood vessels supply capillaries in the skin.reduction of blood supply to the surface heat loss to the environment

  • concentration of hair erector muscle raises hair on the skin and trapping an insulating layer of air close to the skin.AIR is a poor conductor of heat

shivering

  • short,small contractions of skeletal muscle requires energy from respiration

  • heat is produced as a by product

heat loss mechanisms

  • sweating, exocrine sweat glands secrete sweat which is mainly water but contains sodium ions and small amount of urea

  • sweat is deposited on the skin surface

  • the evaporation of the water in sweat requires energy which is provided by the body’s heat in the cooling of the body

  • vasodilation of vessels supplying capillaries in the skin increasing the blood supply to the surface of the skin.more heat is lost to the environment

  • relaxation of hair erector muscles

  • hairs lie flat reducing the insulating layer of air close to the skin

hormonal control of body temperature

  • adrenaline releases produces a temporary increase in metabolic rate

  • as more respiration takes place more heat is produced as by product

  • increase in levels of thyroxine increases the metabolic rate long term

  • an increase in metabolic rate will increase the rate of heat production

hyperthermia

  • body temperature higher than normal as a result of failure of control mechanisms

  • symptoms include

  • dizziness,itchy skin,cramps,swelling of ankles

  • causing fainting,confusion,irregular heat beat and result of death

hypothermia

  • body temperature falls below norm

  • the usual body warming mechanisms cannot warm the body enough

  • severe hypothermia can cause unconsciousness weak and irregular heart beat,confusion

  • death can result