-
adjustment
The ability of humans to survive in stressful environments by non-genetic means.
-
behavioral adjustment
Survival in a stressful environment made possible by cultural means, primarily technology.
-
acclimatory adjustment
Reversible physiological adjustments to stressful environments.
-
hypothermia
Lowered body temperature induced by cold stress.
-
hypothalamus looses its ability to regulate body temp when body temperature falls below...
29.4 degrees C, (85 F)
-
the ability of the hypothalamus to control body temperature is impaired at...
34.4 degrees C (94 F)
-
critical temperature
- The temperature at which the body must begin to resist a lowering of body temperature;
- occurs in the nude human body at approximately 31 degrees C (87.8 F).
-
vasoconstriction (peripheral)
Constriction of the capillaries of the skin in response to cold temperatures that prevents much of the warm blood from reaching the surface of the body where heat could be lost.
-
basal metabolic rate (BMR)
- The measure of the total energy utilized by the body to maintain those body processes necessary for life
- the minimum level of heat produced by the body at rest.
-
BMR can increase as much as...in adults
25%
-
BMR can increase as much as...in infants
170%
-
Four ways the human body looses heat:
- conduction
- convection
- radiation
- evaportion
-
conduction
The movement of heat from one object to another by direct contact.
-
convection
- Movement of heat from an object to the surrounding fluid, either gas of liquid; heat causes the gases and fluid to move away from the object.
- The warm air rises up and cooler air flows down to replace it. Thus, currents carry heat away
-
radiation
- Electromagnetic energy that is given off by an object.
- heat waves
-
evaporation
- liquid is transformed into a gas utilizing energy
- phase change requires energy
-
sweating
- The production of a fluid, sweat, by the sweat glands of the skin; the evaporation of the sweat from the skin leads to a cooling of the body.
- in temperatures above 35 degrees C (95 F)
- humans have a greater capacity to sweat than any other animal.
- acclimatory adjustment
-
vasodilation
- Opening up of the capillaries of the skin in response to warm temperatures, increasing the flow of blood to the surface of the body and thereby increasing the loss of body heat.
- acclimatory adjustment
-
does the color of clothing make a difference in human ability to shed heat?
- No.
- Black gains 2.5X more heat, but greater convection currents between the black robe and the skin make the temperature of the skin the same as that under white robes.
-
high-altuide (mountain) sickness
- Includes shortness of breath, physical and mental fatigue, rapid pulse rate, headaches
- occurs in persons not acclimated to high altitude
-
What percent of world's human population lives at hight altitude (above 4500 meters {14,765 feet})?
Less that 1%
-
High altitude environments impose what stresses?
- low oxygen levels
- high levels of solar radiation
- cold
- high winds
- lack of moisture
- rough terrain
- limited plant and animal life
-
high-altitude hypoxia
Low oxygen pressure due to being at high altitude
-
average atmospheric pressure per square cm at sea level?
In mm of mercury?
-
partial pressure
The pressure exerted by a particular gas in the atmosphere.
-
Average partial pressure of oxygen at sea level?
In the alveoli?
In the circulatory system?
In the tissues?
-
What percentage of air is oxygen?
21%
-
At 4500m, how much is the partial pressure of oxygen decreased?
as much as 40%
-
Small air sacs, located in the lungs that are richly endowed this blood capillaries. Oxygen is absorbed by the blood in the...
alveoli
-
Approximately how many alveoli are in the lungs?
300 million
|
|
