Lab 9 Flashcards
(60 cards)
What is thermoregulation
Physiological or behavioral responses by which organisms regulate body temp
How do endothermic species warm their tissues
From metabolic heat production
How do ectothermic species warm their tissues
Using their external environment
Changes of what magnitude of core temp can be fatal
Reductions of 10°C or elevations of 5°C
What are 7 common measures of core temp
Rectal, oral, axillary, tympanic, temporal, esophageal, and gastrointestinal temps
How can gastrointestinal temp be measured
Using an ingestible pill sensor
How can esophageal temp be measured
By inserting a thermistor through the nose into the esophagus
What factors might cause small variations in core temp
Circadian variation (both males and females) and mestrual phase (females)
When does stage one hypothermia occur
At or below a core temp of 35°C (95°F)
When is core temp low enough to be a medical emergency and why
Core temp at or below 32°C can cause hallucinations, delirium, and excessive sleepiness
Which low temps can cause respiratory or cardiac arrest
24-26°C can cause this as well as comatose and death
What are physiological responses to increases in core temp
Increases in sweat rate, heart rate, and breathing rate
After initial physiological response to increased temp, what can happen if temps continue to rise
Nausea, dizziness, weakness, and fainting
When can heat exhaustion and heat stroke occur
At temps above 40° (104°F) with death often occuring at 45°C
Describe radiation as a means of heat transfer
Body heat lost to nearby objects without physically touching them
Describe convection as a means of heat transfer
Body heat lost to surrounding air, which becomes warmer, rises, and is replaced with cooler air
Describe evaporation as a means of heat transfer
Body heat causes perspiration, which is lost from the body surface when changed from liquid to vapor
Describe conduction as a means of heat transfer
Body heat is lost to nearby objects through direct physical touch
What is the only mechanism for heat loss at temps higher than body temp
Evaporation
What happens to maximal capacity for evaporative heat loss as humidity and ambient temp increase
It decreases
When does little-to-no evaporative heat loss occur
When humidity is near 100% and ambient temp is 30°C and over
What measurements are part of the Wet Bulb Globe Temperature (WBGT) test
Air temp (Td), temp of a wet bulb (Tw), and temp of a black globe (Tg)
What is the equation for the Wet Bulb Globe Temperature (WBGT) index
WBGT = 0.7 Tw + 0.2 Tg + 0.1 Td
What influences the temp of the wet bulb (Tw) in a WBGT test
Humidity