Production of body heat 1 most body heat is a result

Production of Body Heat
1. Most body heat is a result of oxidation of the food we eat.
- The rate at which this heat is produced is known as the metabolic
rate.
2. Metabolic rate is affected by exercise , the nervous system ,
hormones , body temperature , ingestion of food , age , sex (lower in
females except during pregnancy and lactation) , climate , sleep , and
malnutrition .
Basal Metabolic Rate (BMR)
1. Measurement of the metabolic rate under basal conditions is called
the Basal Metabolic rate (BMR).
2. BMR is expressed in kilocalories per square meters of body area per
hour (kcal/M2/hr).
Loss of body Heat
1. Radiation is the transfer of heat as infrared heat rays from one object
to another without physical contact.
2. Conduction is the transfer of body heat to a substance or object in
contact with the body.
3. Convection is the transfer of body heat by the movement of air that
has been warmed by the body.

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4. Evaporation is the conversion of a liquid to a vapor.
HOMEOSTASIS OF BODY TEMPERATURE REGULATION
1. A normal body temperature is maintained by a delicate balance
between heat-producing and heat-losing mechanisms.
2. The hypothalamus thermostat is the preoptic area.
3. Mechanisms that produce or retain heat are vasoconstriction,
sympathetic stimulation, skeletal muscle contraction, and thyroxine
production.
4. Mechanisms of heat loss include vasodilation, decreased metabolic
rate, decreased skeletal muscle contraction, and perspiration.
BODY TEMPERATURE ABNORMALITIES
1. Fever is an abnormally high body temperature most commonly
caused by protaglandius, with interleukin-1 and mediators.
2. Heat cramps are painful skeletal muscle contractions due to loss of
salt and water.
3. Heat exhaustion results in a normal or below normal body
temperature, profuse perspiration, nausea, cramps, and dizziness.
Rest and salt tablets are indicated.
4. Heatstroke results in decreased blood flow to skin reduced
perspiration, and high body temperature: fluid therapy and body
cooling are indicated.
5. Hypothermia refers to a lowering of body temperature.

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DISORDERS: HOMEOSTATIC IMBALANCES
1. Obesity is defined as a body weight 10 to 20% above desirable
standard as the result of excessive accumulation of fat.
a. Hypertrophic (adult-onset) obesity - there is an increase in the
amount of fat in adipocytes but no increase in the number of fat
cells.
b. Hyperplastic (lifelong) obesity - in which there is an increase in
the number of adipocytes, as well as an increase in the amount
of fat within them.
3. Malnutrition refers to a state of bad or poor nutrition.
4. Phenylketonuria (PKU) - is a genetic error of metabolism
characterized by an elevation of phenylalanine in the blood.
5. Cystic fibrosis (CF) is a metabolic disease of the exocrine glands in
which absorption of vitamins A, D, and K and Calcium is inadequate.
6. Celiac disease is a condition in which the ingestion of gluten causes
morphological changes in the small intestinal mucosa resulting in
malabsorption.