Thermoregulation SI worksheet
1. Normothermia is the balance between heat loss and regulation to maintain an outer core
temperature of about 37 degrees Celsius.
o The __hypothalamus____ is considered to be the thermostat of the body
o The body fluctuates about 1.5 degrees Celsius before compensatory
mechanisms are utilized:
2. The four types of compensatory mechanisms include:
o ___sweating_____
Evaporation of water off the skins surface
o Shivering
Involuntary contraction of muscles
o Non-shivering
Utilization of brown fat. Only found in _infants____
o Vasoconstriction of blood vessels
Causes the body to __conserve___ heat through the skin
o __vasodilation____________ of blood vessels
Causes the body to __lose___ heat. Associated with
norepinephrine
These cells: ___thermoreceptors____ are responsible for determining if
the body temperature is high or low. There are more _warm___ receptors
than ___cold__ receptors.
3. Hyperthermia is the significant rise in body temperature (more than 37.6)
o Excessive compensatory sweating can lead to dehydration and sodium
deficiency
o Over time, excessive sweating can lead to
Hypotension
Tachycardia
Decreased perfusion leading to cardiovascular collapse
4. Fever is caused by an increase in core temperature with immunologic benefits
o Supportive fluids, calories, and oxygen can be given
o Cooling is counterproductive
Pyrogens are the substance that causes the hypothalamus to raise
the thermostat set point (often times endogenous cytokines released by the
inflammatory response)
5. Heat Transfer
o Conductive heat loss
Warmer skin to colder surface
o Conductive heat gain
o
o
o
o
o
Warmer surface to colder skin
Convective heat loss
Removal of body heat due to air currents
Convective heat gain
Gain of body heat due to air currents
Radiant heat loss
Electromagnetic energy loss
Radiant heat gain
Sunlight to skin/light to skin
Evaporative heat loss
Loss of heat due to body water evaporating from the skin
6. Heat Production and Loss
o Body heat is mainly produced by body metabolism occurring in liver and
muscle cells
o Body heat is mainly conserved through vasoconstriction of peripheral
blood vessels
o The main ways in which body heat is lost are
Respiration
Perspiration
EXEMPLARS
1) Hypothermia
o Body temperature below 36.2
o Compensatory mechanisms such as vasoconstriction can lead to peripheral
ischemia
o A body temperature below 28 degrees can cause ice crystals to form in the cell
2) Heat stroke
o Due to an overstressed thermoregulatory center
Temperatures above 41.2
Caused by: overexertion, over exposure to environmental heat or loss of
compensatory mechanisms
Signs and symptoms:
High core temperature, absence of sweating, rapid pulse,
confusion, coma
3.) Newborn thermoregulation
o Main heat production occurs through nonshivering utilization of brown fat
Ways to manage newborn heat loss include:
Drying the infant quickly
Utilizing skin to skin
Radiant warmer
Signs and symptoms: crying/restlessness, cool to the touch, acrocyanosis