ch. 12 Flashcards
_____: the transfer of heat from one solid material to another through direct molecular contact
Conduction
______: moving heat from one place to another by the motion of gas or liquid across a heated surface
Convection
_______________: heat is given off in the form of infrared rays. Primary method of heat dissipation at rest.
Radiation
_______________: heat is lost when fluid evaporates. Primary method of heat dissipation during exercise
Evaporation
• Evaporation accounts for ___% of heat lost during exercise vs. _______% at rest
80
10-20
• As body core temp increases, _________ production increases, the ________________ provides cooling.
sweat
evaporation
• ________ _________ pressure of the air plays a major role in evaporative heat loss
water vapor
• ________ humidity (regardless of temp) limits _____________of ________
high
evaporation
sweat
______ humidity is ideal for sweat ______________
low
evaporation
Internal body temperature: • _____ to ______°F
97
100
Internal body temp Can exceed _____ °F during exercise
104
Internal body temp May be _______°F in active muscles
107.6
• Small increases from resting temp. make muscles’ _________ systems more efficient (warm-up important)
energy
• Body temp. above ______ °F affects the ___________ system, reducing the ability to unload excess heat
104
nervous
• The ________ _____________ houses the thermoregulatory center, acting as a thermostat, monitoring temp
anterior hypothalamus
• ____________________ in the skin and brain transmit information about the body’s internal temp
thermoreceptors
• __________ thermoreceptors (brain) are far more sensitive to changes than _____________ (skin)
central
peripheral
- ________ arterioles: smooth muscle causes these vessels to _______to direct blood to the skin for ______ transfer or to __________ to retain _______ deep in the body
skin dilate heat constrict ' heat
- __________ ___________: _________ activity ____________temp. by increasing ____________heat production
skeletal muscle
muscle
increases
metabolic
.____________ Glands: Heat production is also _____________by actions of _____________such as _______________and _______________
Endocrine increased hormones thyroxine epi/ nor epi
_________ ________ Glands: Increased ________ gland activity ____________temp by increasing _____________heat loss
Eccrine sweat
sweat
decreases
evaporative
ater in sweat comes from the _______________ fluid in our bodies.
interstitial
• During prolonged sweating, water moves out of our _________ __________ into the ____________ spaces to be absorbed and released by the sweat glands.
blood plasma
interstitial
Effects of Exercising in Hot Environment
- Increases _____
- Decreases ______
- __________of ________to the skin
HR
BP
Shunting blood
_________ _______________theory: the ________will send signals to stop exercise when ___________ temp is reached, between _____ and _____ °F
critical temperative
brain
critical core
104 105
• Variables: Air temp, __________, Air_________, Amount of thermal ________
humidity
velocity
radiation
Heat-Related Disorders
- Heat _________
- Heat _________
- Heat__________
cramps
exhaustion
stroke
Heat cramps:
Symptoms: Severe and painful _____________ of the large __________ groups, excessive ________
cramping
muscle
thirst
Heat cramps:
Causes: __________ losses and _____________
sodium
dehydration
Heat Cramps:
Prevention: Proper ____________and liberally ______ food
hydration
salt
Heat cramps:
Treatment: Move to ___________ location and administer ________ or ________ solution
cooler
fluids
saline
Heat exhaustion:
Symptoms: Extreme___________ , dizziness, nausea, vomiting, fainting, ________ pulse, __________, headache
fatigue
rapid
chills
Heat exhaustion:
Causes: Cardiovascular system’s ___________ to meet the body’s ________ as it becomes______________, blood volume decreases, _______
inability
needs
severely dehydrated
Na+
Heat exhaustion:
Treatment: Move to cooler environment, _________feet; give oral saline if conscious or intravenous saline if unconscious
elevate
Symptoms: Core body temp >________ °F, ____________of sweating, ________pulse and respiration, confusion, disorientation, or _____________________
104
cessation
rapid
unconsciousness
Heat stroke:
Cause: Failure of the body’s ________________________
thermoregulatory
Treatment: ___________ ______ body in ______ water or ____ bath or with ____ towels; seek medical attention (911)
rapidly coll
cold
ice
wet
You can achieve heat acclimation by exercising in the heat for ___ _______ or more each day for ___ to ___ days.
1 hour
9
14
- Core temp ___ less during exercise than before _____________
increases
acclimation
- Improved capacity for more _________
work
- ____________ begins __________ during exercise
sweating
earlier
- Sweat becomes more __________
dilute
- ____ Sweating ______during exercise
increase
rate
Peripheral _______________________ reduces _______ flow to skin
vasoconstriction
blood
__________________ thermogenesis is stimulation of metabolism by the _____________ nervous system
nonshivering
sympathetic
_____________ involves rapid ______________ cycle of _____________and relaxation of ____________ to increase _________ production
shivering involuntary contraction muscles heat
Factors That Affect Body Heat Loss
- Body _______ and ______________
- ______ temperature
- _______________
- ____________ immersion
size composition
air
windchill
water
• Water: much __________ thermal conductivity than air
greater
• Heat loss is ___ times ________in water compared to air
4 faster
• Heat loss is _______________if the water is __________ around the
accelerated
moving
Muscle Response to Exercise in the Cold
- It is _______ able to produce _______
- __________can occur more rapidly
- Causes ___ muscle shortening _________
- ___ muscle ________
less force
fatigue
decrease velocity
decrease power
Prolonged Exercise in the Cold
- Become more susceptible to ________________
- __________ supplies diminish
- ____ Metabolic ________ production
hypothermia
energy
decrease heat
Hypothermia: the Ability of the ___________________to regulate body temp. is lost if body core temp. drops below _______ °F
hypothalamus
94.1
• Hypothermia causes HR to ____, from impaired ____________ conduction through the ____ _______.
decrease
cardiac
SA node
• ____ respiratory rate and _________
decrease
volume
frostbite: Consequence of the body’s attempts to prevent heat loss, can lead to tissue __________
necrosis
• ___________ skin can _________ quickly
exposed
freeze
• Can lead to _____________and loss of tissue
gangrene
