1 Flashcards
What refers to tissue damage associated with excessive cooling of the skin and the underlying tissue?
And what occurs in more extreme cases of the said term?
- Frostbite
- In the more extreme cases, cellular death takes place due to ice crystal formation or a lack of liquid water
What is a prolonged decrease in body temperature below the normal range and beyond the body’s ability to compensate?
- Hypothermia
What is an increase in body temperature that results from an immune response to infection or inflammation and involves the release of endogenous pyrogens from macrophages?
And, what is its mechanism of action?
- Fever
- These endogenous pyrogens are responsible for changing the set point of the hypothalamus, initiating a “cold response.” Thus, in a fever, the hypothalamus initiates compensatory mechanisms that increase the internal body temperature to match the altered set point.
What is a more dangerous condition that results from a breakdown of the thermoregulatory ability of the hypothalamus, such that body temperature increases in the absence of the normal compensatory mechanisms?
- Heat stroke
What involves a drop in BP and results from overactivity of the body’s heat loss mechanisms, such that body temperature increases despite the normal compensatory mechanisms, such as sweating and vasodilation?
- Heat exhaustion
What is a prolonged increase in body temperature above the normal range and beyond the body’s ability to compensate?
What may it result from physiologically & pathologically?
And, does it include fever?
- Hyperthermia
- May result physiologically from exercise or pathophysiologically from abnormalities associated with the hypothalamus or metabolic rate
- It doesn’t include fever
What occurs to heat production and heat loss mechanisms in response to heat exposure (coordinated by the anterior hypothalamus)?
- Decreased Heat Production: Such as, decreased muscle tone & decreased voluntary exercise
- Increased Heat loss (Heat Conservation): Such as, skin vasodilation, sweating, & cool clothing
What occurs to heat production and heat loss mechanism in response to cold exposure (coordinated by the posterior hypothalamus)?
- Increased heat production: Such as, increased muscle tone, shivering, increased voluntary exercise, & nonshivering thermogenesis
- Decreased heat loss (Heat Conservation) – Such as, skin vasoconstriction, postural changes to reduce exposed surface area (e.g., hunching shoulders etc.), & warm clothing
The coordinated adjustments to both heat production and heat loss occur in response to…
- Occur in response to decreases and increases in internal core temperature
What occurs to the thermal information after it is detected by peripheral & central thermoreceptors?
- This thermal information is integrated & compared to a set point in the hypothalamus
- Which then relays this efferent information to the effectors in response to deviations from the set point
Which two thermoreceptors are thermal information detected by?
And what are their locations?
- By central thermoreceptors located in the hypothalamus, CNS, & abdominal organs
- By peripheral thermoreceptors located in the skin
What does the anterior hypothalamus coordinate the response to?
- To increases in body temperature
What does the posterior hypothalamus coordinate the response to?
- To decreases in body temperature
What is the strucutre called that homeostatically regulates body temperature?
- The hypothalamus
What is the loss of the heat required to transform a liquid into a gas?
And, how does it occur in humans (passively & actively)?
- Evaporation
- It occurs in humans both passively (through respiration & from skin surfaces) and actively (through sweating).
What is the transfer of heat energy by air or water currents?
- Convection
What is the transfer of heat between objects in physical contact with each other?
- Conduction
What is the emission of heat as electromagnetic (heat) waves?
And, how does it relate to humans?
- Radiation, also humans emit & absorb radiant energy.
List the 4 mechanism by which heat exchange occurs
- Radiation, conduction, convection, & evaporation
Which 2 factors can be regulated to maintain body temperature?
And, how is a decrease in internal core temperature counteracted?
- Heat input & output
- Counteracted by increasing the internal heat production & minimizing heat loss
What are the sources of heat output from the body? Or how does heat output occur from the body?
- Occurs through heat loss from exposed body surfaces to the external environment
What are the sources of heat input into the body?
- Can originate from the external environment or from internal heat production
What needs to occur for the internal core temperature to be maintained at a given level?
- Heat input into the body must equal heat output from the body
What does the temperature of the outer shell consist of? And how does it differ from the internal core temperature?
- It consists of the skin & the subcutaneous fat of the body
- It is much more variable than the internal core temperature