1

Regulation of Body Temperature

• Regulation of body temperature is vitally important because even slight shifts can disrupt metabolic reactions.

2

Regulation of Body Temperature

If body temperaturecontinues to drop,control center signalsmuscles to contractinvoluntarily.

too high

too low

Normal bodytemperature37°C (98.6°F)

Control centerHypothalamusdetects the deviationfrom the set point andsignals effector organs.

Control centerHypothalamusdetects the deviationfrom the set point andsignals effector organs.

StimulusBody temperature risesabove normal.

EffectorsDermal blood vesselsdilate and sweat glandssecrete.

ResponseBody heat islost to surroundings,temperature drops towardnormal.

EffectorsDermal bloodvessels constrictand sweat glandsremain inactive.

EffectorsDermal bloodvessels constrictand sweat glandsremain inactive.

ResponseBody heat is conserved,temperature rises toward normal.

StimulusBody temperaturedrops below normal.

ReceptorsThermoreceptorssend signals to thecontrol center.

ReceptorsThermoreceptorssend signals to thecontrol center.

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3

Heat Production and Loss

• Heat is a product of cellular metabolism• The most active body cells are the heat

producers and include: • Skeletal muscle• Cardiac muscle• Cells of certain glands such as the liver

• The primary means of heat loss is radiation• Also there is conduction, convection and

evaporation

4

Problems in Temperature Regulation

• Hyperthermia – abnormally high body •temperature

• Hypothermia – abnormally low body •temperature

5

Healing of Wounds and Burns

• Inflammation is a normal response to injury or stress.• Blood vessels in affected tissues dilate and become more permeable, allowing fluids to leak into the damaged tissues.• Inflammed skin may become:• Reddened• Swollen• Warm• Painful

6

Healing of Cuts

(a) (b)

(f) (g)

(c) (d) (e)

Scartissue

Fibroblasts

Scartissue

Blood cells

Site of injury

Scab

Bloodclot

Scab

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7

Types of Burns

• First degree burn – superficial, partial-thickness• Second degree burn – deep, partial-thickness• Third degree burn – full-thickness• Autograft• Homograft• Various skin substitutes

8

Rule of Nines for AdultsCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Anteriortrunk18%

Posteriortrunk18%

Anterior upperextremities 9%

Posterior upperextremities 9%

Posterior lowerextremities 18%

Perineum 1%

Anterior andposterior upper

extremities18%

Anterior andposterior lower

extremities36%

100%

Anterior andposterior trunk

36%

Anterior and posterior head and neck9%

Anterior headand neck 41/2%

Posterior headand neck 41/2%

Anterior lowerextremities 18%

9% 9% 9% 9%

41/2%

41/2% 41/2% 41/2% 41/2%

41/2%

9

Lifespan Changes

• Skin becomes scaly• Age spots appear• Epidermis thins• Dermis becomes reduced• Loss of fat• Wrinkling• Sagging• Sebaceous glands secrete less oil

• Melanin production slows• Hair thins• Number of hair follicles decreases• Hair loss - alopecia•Nail growth becomes impaired• Sensory receptors decline• Body temperature unable to be controlled because blood vessels diminish and ability to shiver declines as well as loss of fat. • Diminished ability to activate Vitamin D –which can impact skeletal system too.

If someone is homebound or bed ridden they have a greater chance of developing pressure sores (decubitus ulcers).

10

Interconnections between systems

See page 189