Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
11 Cards in this Set
- Front
- Back
|
Describe how the set point works in the body to help regulate core temperature.
|
IL-1 increases the synthesis of cyclooxygenase, as evidenced by the increased conversion of arachidonic acid into prostaglandins after fibroblasts are pre-incubated with IL-1. Evidence is also presented that fever is caused by interleukin-1-induced prostaglandin E2.
PGE 2 does not appear to be involved in the normal regulation of body temperature since massive doses of aspirin and NSAID’s for arthritis does not alter body temperature (NSAIDS don’t alter set point , but block fever by blocking PGE2 ) |
|
|
Explain the difference between skin temperature (Ts) and core temperature (Tc ) and how they are regulated.
|
Heat gain/loss:
Radiation Conduction Convection Evaporation Changing environment remains a primary mechanism of temperature regulation. |
|
|
Explain how shivering is used as a mechanism to help regulate body temperature.
|
Neural signals are transmitted to the muscle. The tone of the muscle is increased to a point where shivering will start.
Shivering can increase body heat production 4-5X normal. |
|
|
Describe how the set point can be altered to induce fever in the human.
|
Drugs can alter
Set point – nonsteroidals (i.e. aspirin) blocks PGE production Skin blood flow – alpha agonsists constrict, beta agonists dilate Sweating –acetylcholine blockage blocks sweating Shivering-opiates Children: aspirin increases risk of Reye's syndrome |
|
|
Explain the difference between hyperthermia and pyrexia.
|
Hyperthermia is characterized by a normothermic setting of thermoregulatory center in conjunction with uncontrolled increase in body temperature that exceeds the body's ability to lose heat
Fever: Occurs in conjunction with increase in hypothalamic set point. (e.g. a resetting of the bodies thermostat) Heat stroke: 106 degrees/41.1 degrees, occurs in people who cannot modulate environment mostly Exertional heatstroke (EHS) generally occurs in young individuals who engage in strenuous physical activity for a prolonged period of time in a hot environment. Classic nonexertional heatstroke (NEHS) more commonly affects sedentary elderly individuals, persons who are chronically ill, and very young persons. |
|
|
List several pathological and drug induced caused of fever.
|
Pyrogens, such as endotoxin or lipopolysaccharide(LPS), stimulate the release of interleukin-1. IL-1 stimulates the brain to increase the set-point 8-10 mins after injection.
Esterified AA->Free AA->cyclooxygenase (prostaglandins) or lipooxygenase (leukotrienes) |
|
|
Describe how sweating can lower body temperature.
|
Blood flow to skin varies greatly under different situations. It can be as low as near zero or as high as 30% of cardiac output. The mechanisms that control skin blood flow are complex.
|
|
|
Explain the effect of sweating on body fluids.
|
Normal is 100ml/day
Heavy exercise 1-2 L/hour Insensible water loss- Different from sweating Evaporation from skin = 400 ml/d Evaporation from Lungs = 400 ml/day When sweat is secreted it is hypotonic to plasma (thus lose more water than salt) Neural control -Sympathetic nervous system releases acetylcholine to stimulate sweat gland activity in most of our body. Endocrine control -Epinephrine and norepinephrine from the adrenal gland Decreased sodium chloride in sweat Increased sweat production results in a reduced concentration of NaCl in the sweat. This is due to the effect of aldosterone from the adrenal cortex |
|
|
Explain the changes that will occur in sweat production in a hot environment as compared to a cool environment.
|
Larger volume of sweat but a lot less sodium chloride in hot environment (acclimatized)
|
|
|
What is one of the most potent tool we use to control our body’s temperature?
|
Change our environment
|
|
|
We know if we do not drink enough, we can become dehydrated. Can we drink too much?
|
Partial List of potential problems:
Marathon runners Ecstasy users Individuals after heat stress Iatrogenic induced cases |
