Patho- thermoregulation

thermoregulation

The balance between heat that is produced and lost from the body in an effort to maintain an average core body temperature of 37 C or 98.6 F

what controls thermoregulation in the brain

hypothalamus

what is places throughout the body to help with thermoregulation

thermoreceptors

how does thermoregulation work

with negative feedback system

how is heat produced

through metabolic activity by chemical reactions occurring in cells

where is the greatest amount of metabolic activity

muscles and liver

what decreases with age

basal metabolic rate

shivering

way to produce heat through muscle contraction

conservation

peripheral vasoconstriction

warmer surfaces lose heat to

cooler surfaces

vasodilation

increased heat loss through conduction

heat loss examples

vasodilation and perspiration

what is brown fat in infants

it is due to no shivering in infants

what are infants depended on for thermoregulation

environmental temperature to keep warm

why are infants at greater risk of heat loss

due to greater body surface area to weight ratio

blood vessels closer to skin

thin layer of subcutaneous fat

thermoregulation changes for older adults

Decreased blood circulation, Structural and functional skin changes, Presence of disease, Decreased shivering response, Slowed metabolic rate, Decreased thirst mechanism

hypothermia

below 35 C or 95 F

reasons for hypothermia

• Excessive heat loss

• Insufficient production of heat

• Dysfunction of hypothalamus

how does thermoregulation happen

accidental (environmental exposure)

induced (Targeted Temperature Management (TTM)

Targeted Temperature Management (TTM)

intentionally set to reduce metabolism and preserve tissue by preventing ischemia, particularly after a cardiac arrest and traumatic brain injury. Stabilizes calcium and glutamate release reducing cell death of neurological cells.

hyperthermia

Excessive heat production, inadequate ability to cool, or hypothalamic regulator dysfunction

hyperthermia symptoms

excessive sweating

why excessive sweating is bad

sodium loss and dehydration leads to hypotension, tachycardia, reduced perfusion

heat exhaustion

• Milder, can go on to heat stroke

• Malaise, headache, nausea

• Sweating, vasodilation, weakness, dizziness

heat stroke

• Potentially lethal condition

• Alteration in mental status, hot and dry skin, nausea, bradycardia, weakness – leads to destruction of cell mitochondria

fever

temporary elevation in temperature

Exogenous pyrogens

bacterial endotoxins, viruses, trigger endogenous pyrogens

endogenous pyrogens

produced by our WBC, immunes systems response to pyrogens (fever producing agents)

what does the fveer do in hypothalamus

Triggers the hypothalamus in the brain in increase the set point

fevers can be

beneficial