body temperature-mechanism-Medicine

1. BODY TEMPERATURE
AND ITS REGULATION
Dr Nisar Ahmed Arain
Assistant Professor
Anesthesia/Critical care/ER

2. SLOS
-1-Introduction
-2-Normal Temperature
-3-Heat Loss Mechanism
-4-Heat Gain Mechanism
-5-Regulation of body Temperature
-6-Abnormalities of body Temperature
regulation

3. INTRODUCTION
-Homeo-thermic-Maintaining constant
internal body Temperature
-Endotherms -Generate their
own body Heat
Why Temperature should be
maintained
-1-For normal enzyme activity
-2-For normal neuronal activity
-3-Rise in high Temperature.
cause denature of proteins

4. BOY TEMPERATURE
-BODY TEMPERATURE
Core Temperature measured in
-Oral or
-Rectal routes
-VALUES of Normal body Temperature
-1-Oral : 98.6-degree F (97.3 – 98.8-degree F
OR
37 degree C(36.3 – 37.1 degree C)
-2-Rectal :0.5 degree C more then Oral
-3-Axilla :0.5 degree C less than Oral
-4-Skin :Depends upon environment
-5-101 degree to 104-degree F
RECTAL 0.5 degree C > ORAL 0.5 degree C >0.5 degree C > AXILLA

5. BOY TEMPERATURE

6. MAINTAINANCE OF
BODY TEMPERATURE
Heat Loss Heat Gain
=

7. HEAT GAIN MECHANISM
-1-Shivering
-2-Increase in metabolism by Epinephrine
nor-epinephrine and Thyroxin
-3-Cutaneous vasoconstriction

8. HEAT LOSS MECHANISM
-1-Evaporation of sweat
-2-Radiation
-3-Conduction and Convection
-4-Cutaneous vasodilation
-5-Decrease in Metabolism
-6-Through Respiration

9. -Receptors: Warmth and Cold receptors from skin, Deep tissues
spinal cord and Hypothalamus
-Heat loss center – Pre-optic and Anterior Hypothalamic Nuclei
-Heat Gain Center – posterior hypothalamus
-Set point 37 degree C in Hypothalamus
(+-) 0.1 degree C cause Hypothalamus to activate heat loss
or heat gain mechanism
Regulation of body temperature
Role of the Hypothalamus

10. Preoptic & Ant.
Hypothalamic nuclei
Posterior
hypothalamus
Inhibition of Sympathetic
nervous system
-Vasodilation
Sweating
decrease in thermogenesis
(heat production).
-Increase in body
temperature
- Warmth receptors from skin
deep viscera are stimulated
TEMPERATURE-DECREASING MECHANISMS
when the body is too HOT
Normal body
temperature set

11. Posterior
Hypothalamus
Sympathetic
stimulation
-Skin vasoconstriction throughout
the body piloerection
-Increase in Thermogenesis
(Heat Production)
-Normal body
temperature
Set point: 37D C
Decrease in body
Temperature
Cold receptors from
Skin are stimulated
-Pre-optic and Anterior
Hypothalamic Nuclei
Temperature-increasing mechanisms when the body too COLD

12. RESPONSE OF HYPOTHALAMUS

13. ABNORMALITIES OF BODY TEMPERATURE REGULATION
-HYPOTHERMIA :-Decrease in body temperature below normal range
-HYPERTHERMIA:- Increase in boy temperature above normal range
-HYPERTHERMIA - FEVER
-1-Increase n body Temperature above Normal
-2-Due to rise in set point of Hypothalamus
by pyrogen
-3-Pyrogen:-Any substance that raises the
“set point” of Hypothalamus
a-Bacterial endotoxins:-Cell membrane
proteins and their breakdown products
b-IL-1
C-Inflamatory mediators;-Kinin, Brady
-Kinin, Prostaglandin E
-4-Characteristics of febrile condition
a-Crisis
b-Fever
c-Crisis or Flush
-5-Anti-Pyretics:-Aspirin blocks PG-E

14. HEAT-STROKE
-This occurs when body temperature rises beyond the
“critical temperature”. It ranges from 105 to 1080F
SYMPTOMS
-1-Dizziness
-2-Abnormal distress
-3-Vomiting
-4-Delirium
-5-Loss of consciousness
-6-Circulatory shock
-7-Death

15. TEPIDS SPONGING

16. HYPOTHERMIA
-If person is exposed to “Iced water” for 20 to 30 minutes
ordinarily dies because of Heart Fibrillation
-If the body Temperature has fallen below 85°F,the
abilityoftheHypothalamus toregulateTemperature islost
FROST BITE
-When the body is exposed to extremely
low temperatures surface areas can freeze
this freezing is called “Frost-bite”
-This occurs specially in the
a-Lobes of the ears and in the
b-Digits of the Hands and Feet