REGULATION OF BODY TEMPERATURE NORMAL BODY TEMPERATURE AND

REGULATION OF BODY TEMPERATURE

NORMAL BODY TEMPERATURE AND ITS REGULATION • Human beings are Homoeothermic • Normal body temperature is 37 c(98. 6 F)

BODY TEMPERATURE REGULATION Two types 1. Core temperature 2. Shell temperature

CORE TEMPERATURE • • • Body temperature means core temperature It is the temperature of deep or central organ temperature It should always kept constant -- in homoeothermic

SHELL TEMPERATURE • It is the skin temperature or surface body • temperature It varies with environment temperature

MEASUREMENT OF BODY TEMPERATURE Usually measured at : • oral cavity -- Oral temperature : • Normal value -- 37 c or 98. 6 F • Arm pit – Auxiliary temperature (0. 55 c or 1 F less • than oral temperature) Anus –Rectal temperature -- (0. 55 c or 1 F more than oral temperature)

Why regulation of body temperature is required?

1. Chemical reaction 2. Enzyme system Required optimal level of Temperature

NORMAL TEMPERATURE Heat Production 1. Metabolism 2. Assimilation of food (SDA) 3. Heat gain from environment 4. Shivering 5. Endocrines Heat Loss 1. Radiation(60%) 2. Conduction (3%) Convection(15%) 3. Evaporation of sweat 4. Heat loss in urine & Feces

BODY TEMPARETURE REGULATION MECHANISM They are thermoregulatory reflex mechanism Mechanism activated by exposure to cold : Posterior hypothalamus control(Heat gain center) 1. 2. Increased heat production Decreased heat loss

Increased heat production : 1. Increased heat production by shivering 2. Increased hunger and food intake 3. Increased voluntary activity 4. Increased TSH secretion from anterior pituitary 5. Increased secretion of catecholamine Decreased heat loss : 1. Cutaneous vasoconstriction 2. Curling up 3. Horipilation – goose pimples

Mechanism activated by exposure to heat : Anterior hypothalamus control(Heat loss center) 1. Increased heat loss • Cutaneous vasodilation • Sweating • Increased respiration 2. Decreased heat production • Decreased TSH secretion

DISTURBANCE OF BODY TEMPERATURE 1. 2. 3. Fever Hyperthermia Hypothermia FEVER OR PYREXIA 1. Body temperature 98. 6 F But 104 F 2. Physiologic adaptation : Prevent bacreteal growth Enhances immunity

3. Cause of fever : Due to the action of bacterial toxins on macrophages Secrete cytokines and interleukins (IL 1, IL 6) Stimulate prostaglandins formation Raise the set point of hypothalamic thermostat

HYPERTHERMIA : Body temperature 102 F Heat stroke. Dehydration and electrolyte loss, Failure of temperature regulation, Death of neurons, Circulatory shock Death HYPOTHERMIA: Fall in body temperature between 30 – 25 c. O 2 consumption of body HR, BP are all reduced. Induced hypothermia useful for surgery of heart and brain.