Temperature Regulation

Homeothermic

Body temperature is carefully regulated as humans are “__”, meaning warm-blooded

Metabolic, muscle, skin

Body heat produced by: __processes and __ (organ tissue) activity

Body heat is mostly dissipated by the: __

Shivering

Rhythmic muscle contractions for heat production

Na/K, O2, heat

Thyroid hormones stimulate metabolism via (1) __ pump, (2) __ consumption → __ byproduct

Hypothyroidism

__ (thyroid disorder) → Cold sensitivity

Brown adipose, sympathetic

__ __ tissue burns fuel to produce heat and is stimulated by the __ (sympathetic vs parasympathetic) nervous system

Conduction

Direct transfer of heat by contact (i.e. to other touching object or skin contact with cold air)

Radiation

Emission of electromagnetic radiation between 2 objects not in direct contact (i.e. sun, cold cement wall)

Evaporation, humidity

__ is the loss of heat by water entering gaseous state (i.e. sweat, respiration)

• Environmental __ reduces rate of water vaporization

Convection

Moving air removes radiated heat (i.e. cool air, fans)

(Cutaneous) vasodilation

Process where warm blood from the core travels to surface

• Available for heat exchange with environment

(Cutaneous) vasoconstriction

Process where blood diverted away from skin toward core

• Avoiding heat exchange with environment

Buffered, warmer

Heat transfer from skin to air is __ by hair and clothing

__ (colder/warmer) air is then trapped in layer of hair/clothing

Core, CNS, skin, sensory, hypothalamus, sympathetic, alpha, thyroid, skeletal, brown, constriction, shivering

• Homeostatic regulation of core temperature: cold exposure AND fevers

  • Regulated variable = __ temperature

  • Sensor = thermosensors in the __ and __

  • Input signal = __ neurons

  • Control center = __

  • Output signal = __ nerve activity, __-motor neurons, __ hormone cascade

  • Effectors = vasculature, __ muscle, __ adipose tissue

  • Controlled variables = skin vaso__, __ (muscle action), metabolic heat

Core, CNS, skin, sensory, hypothalamus, sympathetic, sweat, respiratory, dilation, perspiration (sweating), respiratory

• Homeostatic regulation of core temperature: heat exposure

  • Regulated variable = __ temperature

  • Sensor = thermosensors in the __ and __

  • Input signal = __ neurons

  • Control center = __

  • Output signal =__ nerve activity only

  • Effectors = vasculature, __ glands, __ (breath) muscles

  • Controlled variables = skin vaso__, __ (skin action), increased __ rate (vaporization)

Fevers, cytokine

__ are a stimulus (i.e. endotoxin, inflammation) promote __ release from immune cells

Cytokines, prostaglandin, set

__ (immune component) act as endogenous pyrogens (fever-causers)

• Stimulate __ (hormone) production in hypothalamus

  • This hormone then raises the temperature __ point

Hypothalamus, low, production, dissipation

In fevers

The ___ (endocrine) then responds to prostaglandin release and now “sees” normal core temp as too __ (high/low)

• initiates heat __ (production/dissipation) and limits heat __ (production/dissipation)

  • Febrile state

High, faster, neurological

Adaptive Effects of fevers - Many microorganisms don’t grow well at __ temps, and antibody production is __ in fevers

Harmful Effects of fevers - Excessive core temps are harmful over prolonged period (__ s/s, heat stroke, death, enzyme malfunction)

NE, Alpha-1, tonically, constrict

Sympathetic vasoconstrictor nerves release __ (neuroT), bind to __-_ (Rs), and are __ active

• Lead to a mild increase in heat, withdraw some __tor tone

ACh, not, increases

Sympathetic vasodilator nerves release __ (neuroT) and __ (are/not) tonically active

• Activates when core body temp __ (increases/decreases) (i.e. extreme exercise)

Heat exhaustion, lesser, equal

__ __ is a loss of too much volume from sweating

When core temp is __ or __ to 40 C or 104 F

Heat exhaustion s/s

S/S of hypotension, nausea, headache, fatigue

Heat stroke, greater

__ __ is the lost ability to sweat, core temp elevated to point of tissue damage

When core temp is __ than 40 C or 104 F

Heat stroke s/s

S/S neurological issues, +ALOC, no sweat

Hypothermia

Inability to maintain cellular metabolism, extreme cold

(Disorder)

Hypothermia s/s

S/S CNS dysfunction, eventually cardiorespiratory failure