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 temperature continues to drop, control center signals muscles to contract involuntarily. too high too low Normal body temperature 37°C (98.6°F) Control center Hypothalamus detects the deviation from the set point and signals effector organs. Control center Hypothalamus detects the deviation from the set point and signals effector organs. Stimulus Body temperature rises above normal. Effectors Dermal blood vessels dilate and sweat glands secrete. Response Body heat is lost to surroundings, temperature drops toward normal. Effectors Dermal blood vessels constrict and sweat glands remain inactive. Effectors Dermal blood vessels constrict and sweat glands remain inactive. Response Body heat is conserved, temperature rises toward normal. Stimulus Body temperature drops below normal. Receptors Thermoreceptors send signals to the control center. Receptors Thermoreceptors send signals to the control center. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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) Scar tissue Fibroblasts Scar tissue Blood cells Site of injury Scab Blood clot Scab Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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 Adults Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Anterior trunk 18% Posterior trunk 18% Anterior upper extremities 9% Posterior upper extremities 9% Posterior lower extremities 18% Perineum 1% Anterior and posterior upper extremities 18% Anterior and posterior lower extremities 36% 100% Anterior and posterior trunk 36% Anterior and posterior head and neck 9% Anterior head and neck 4 1 / 2 % Posterior head and neck 4 1 / 2 % Anterior lower extremities 18% 9% 41/2%41/2% 41/2%41/2%41/2%41/2% 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