Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Exercise Physiology > chapter 12/23 > Flashcards

chapter 12/23 Flashcards

1
Q

what are homeotherms

A
  • maintain constant body core temperature - rely on unefficiencies to produce heat to maintain body temperature
  • heat loss must match heat gain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the normal core temperature

A

37 degrees C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

at what temperatures is hyperthermia and hypothermia

A

hyperthermia = above 45 degrees C – can damage proteins and enzymes and lead to death (denaturing of protein and enzymes)

hypothermia = below 34 decrees C – can result in decreased metabolism and cardiac arrhythmias and neural function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the thermal gradient

A

difference between deep body core to skin surface temperature
* typical is about 4 degrees – in extreme cold may be 20 degrees C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do you measure deep body (core) temperature

A
  • rectum, ear, or esophagus
  • ingestible temperature sensor telemetry system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is an example of voluntary heat production

A

exercise – b/c not efficient = release more heat
- 70-80% energy expenditure released by heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is an example of involuntary heat production

A
  1. shivering = increases heat production by about 5%
  2. nonshivering thermogenesis = thyroxine (thyroid hormone, catecholamines – in brown adipose tissue produce heat without releasing more E)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the 4 mechanisms of heat loss

A
  1. evaporation: primary mechanism in hot environments
  2. radiation
  3. conduction
  4. convection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

explain what evaporation is

A

body heat causes pirspiration which is lost from the body surface when changed from liquid to vapro

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

explain what radiation is

A

body heat is lost to nearby objects wihtout physically touching them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

explain what conduction is

A

body heat is lost ot nearby objects through direct physical contact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

explain what convection is

A

body heat is lost to surrounding air which becomes warmer, rises and is replaced with cooler air
* similar to a fan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

evaporation rate depends on what 3 things

A
  1. temparature and relative humidity
  2. convective currents around the body – if sweating and have fan = more conduction
  3. amount of skin surface exposed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

a high relative humidity decreases or increases the vapor pressure gradient between the skin and environment why?

A

decreases vapor pressure gradient – decreases rate of evaporation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is heat index? how does it effect evaporative heat loss

A

measure of body’s perception of how hot it feels
* high relative humididty reduces evaporative heat loss –> increased perception of how hot it feels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what temperature increases evaporation

A

high temperatures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what anatomical location is the body’s thermostat

A

preoptic anterior hypothalamus (POAH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what does the preoptic anterior hypothalamus do for body temperature

A
  • responds to increased core temeprature
  • stimulation of sweat glands - evaporative heat loss
  • cutaneous vasodilation (release heat)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

explain the sympathetic cholinergic control of sweat glands and cutaneous vasculature

A

SNS – cutaneous vasculature
* preganglionic neuron releases ACh to nicotinic receptors on postganglionic neuron
* postganglionic neuron releases Norepi onto adrenegic receptors on effector cells

SNS – sweat glands
*preganglionic neuron releases ACh to nicotinic receptors on postganglionic neuron
* postganglionic neuron releases Ach onto muscarininc receptors on cells of sweat gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

in eccrine sweat glands stimulation is caused by what and what does it bind to

A

stimulation occurs via activation by Ach which binds to the glands mAchR == production of sweat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Ach acting on mAchR causes what in the blood vessels in the skin at the periphery

A

causes vasodilation of blood vessels

removal of vasoconstriction tone = increase vasodilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Explain the physiological response to heat load

include thermal receptors, integrators, and effectors

A

heat load –> thermal receptors: core, skin –> integration: preoptic-anterior hypothalamus –> effectors: cutaneous vasodilation, sweating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

As exercise intensity increase describe the thermal events that occur

A
  • heat production increases due to musclular contraction - heat increase b/c metabolism = production of E
  • linear increase in body temperature – core temp increases proportional to active muscle mass
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What happens to muscle temperature vs skin temperature with increasing exercise intensity

A

muscle temperature increases, mean skin temperature decreases (vasodilation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What determines heat production during steady state exercise

A

exercise intensity
* and NOT environmental temperature

at same work rate = same amount of heat and rely on convection and radiation to change temperature

with negative radiation and convection you are gaining heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

in a humid/hot environment during submax exercise what happens to core temperature

A

higher core temperature
* risk of hyperthermia and heat injury – cannot rely on evaporation

(vs. in cool environment you can rely on evaporation, vonduction, radiation for decrease in heat)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

explain the cardiovascular response to exercise in the heat

A

upward drive in VO2 during prolonged exercise in hot and humid environment – cannot reach steady state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

To maintain cardiac output what happens to compensate for the decrease in SV

A

HR that gradually creeps upward to compensate for decrease in SV

  • HR increases with heat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what happens to blood flow in different locations of the body in response to exercise in heat

A

blood flow is shunted away from working muscle and nonessential areas (gut, liver, kidneys –> to skin (more blood to periphery to decrease temp)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What happens to sweat rate during exercise

A

sweat rate inreases

  • increases with body mass and genetic variations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what are the two major endocrine responses to exercise in the heat

A

increased release of vasopressin and aldosterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

explain what vasopressin and aldosterone do for the body with exercise in the heat

A
  • vasopressin acts on kidneys increasing H2O permeability of renal tubules = increased reabsorption of water = minimize body fluid loss
  • aldosterone acts on the kidney to increase Na+ absorbtion –> urine volume decreases b/c water goes back into body maintaining BP/plasma volume
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What three factors contribute to impaired exercise performance in the heat

A
  1. CNS dysfunction
  2. cardiovascular dysfunction
  3. accelerated muscle fatigue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Explain how the CNS dysfunction contributes to impaired exercise performance in the heat

A
  • decreased motivation
  • reduced voluntary activation of motor units
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Explain how the cardiovascular dysfunction contributes to impaired exercise performance in the heat

A
  • reduced SV
  • decreased cardiac output during high-intensity exercise
  • decreased muscle blood flow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Explain how the accelerated muscle fatigue contributes to impaired exercise performance in the heat

A
  • increased radical production
  • decreased muscle pH
  • muscle glycogen depletion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

How does CNS dysfunction, cardiovascular dysfunction, and accelerated muscle fatigue relate to each other

A
  • accelerated muscle fatigue effects motivation b/c if low glycogen = low motivation
  • if have cardiovascular dysfunction with decreased muscle blood flow –> decrease muscle pH with accelerated muscle fatigue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what is acclimation

A

rapid physiological adaptation that occurs within days to a few weeks, or is artifically induced in a climatic chamber in a lab

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what is acclimatization

A

gradual, long-term adaptation that occurs within months to years of exposure to the environmental stress (ie. climate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what is the impact of heat acclimation on HR and core temp

A

the end result of acclimation is lower HR and core temperature during submax exercise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

to get the largest response the body requires what change to the environment

A

requires exercise in hot environment
* elevated core temperature promotes adaptations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what are the 5 major adaptations during heat acclimation

A
  1. increased plasma volume (10-12%)
  2. earlier onset of sweating and higher sweat rate
  3. reduced sodium chloride loss in sweat
  4. reduced skin blood flow
  5. increased cellular heat shock proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Explain why plasma voluma increases during heat acclimation

A

maintains blood volume, SV, and sweating capacity
* replace fluids/hydration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Explain why reduced sodium chloride loss in sweat is an adaptation during heat acclimation

A

reduced risk of electrolyte (loss) disturbance

41
Q

Explain why earlier onset of sweating and higher sweat rate occurs during heat acclimation

A

less heat storage, maintin lower body temperature
* sweating more = storing less heat
* more sweating = heat adaptation better in heat

42
Q

what happens to the sweat rate in someone with microgravity exposure or bed rest threshold

A

dont sweat – sweat threshold increased

43
Q

why is it beneficial to have low sodium chloride loss in sweat

A

becuase sodium chloride is needed along with the release of aldosterone to bring water back into the body to maintain blood volume

44
Q

Explain why reduced skin blood flow is an adaptation during heat acclimation

A

because you are able to maintain core body temperature better

45
Q

Explain why increased cellular heat shock proteins is an adaptation during heat acclimation

A

becuase it prevents cellular damage due to heat and it helps us with heat injuries

46
Q

What is the effect of heat acclimation on heat injury

A

heat acclimation reduces risk of heat injury
* in response to exposure of heat stress

47
Q

What is the effect of heat acclimation on heat shock proteins

A

increased heat exposure increases the synthesis of heat shock proteins
* protect cells from thermal injury
* stabilizing and refolding damaged proteins

48
Q

With the number of days required for heat acclimation what two factors are linked

A

HR decrease and increase in plasma volume

49
Q

explain the sex and age difference in thermoregulation

A
  • small difference in SEX variablity in thermoregulation and heat tolerance
  • aging results in reduced availability to lose heat during exercise – skin blood flow is reduced in older individuals = decrease thermoregulation
50
Q

What happens to acclimation with inactivity
- what happens physiologically

A

acclimation lost within few days of inactivity (no hear exposure)

  • body begins to decrease plasma volume to avoid high BP putting pressure on organ systems
51
Q

Explain what 2 things happen in shivering

A
  • if core temperature drop significantly involuntary shivering begins – create heat
  • somatic motor neurons stimulate skeletal muscle contraction
51
Q

What anatomy responds to a decrease in core temperature

A

reoptic anterior hypothalamus
* shivering (generate heat)
* decreased skin blood flow (vasoconstriction)

52
Q

in shivering explain what the neurons do to produce shivering

A

somatic motor neuron from the spinal chord releases Ach to the skeletal muscle to begin shivering

53
Q

Explain the process of non-shivering thermogenesis (NST)

A

POAH initiates the release of NE and throxine –> increases the rate of cellular metabolism –> nonshivering thermogenesis

  • cuase the mitochondria to be more active and produce more heat to increase core temperature
54
Q

Explain what causes cutaneous vasoconstriction

A

Norepi acts on α1-ADR –> cuase vasoconstriction of blood vessels in the skin

55
Q

Explain the whole process of response to cold stress

*include receptors, integrators, and effectors

A

cold –> receptors: skin, core –> integrator: preoptic-anterior hypothalamus –> effectors: shivering, cutaneous vasoconstriction, catecholamine release (norepi), throxin release

56
Q

Explains what happens when exercise in cold environment and hypothermia

A
  • enhanced cold loss
  • can result in hypothermia – loss of judgment and risk of further cold injury
57
Q

explain the 4 factors that influence hypothermia

A
  1. insulating factors: subcutaneous fat, clothing (wet vs. dry)
  2. environmental factors: temperature, water vs. air, water-vapor pressure, wind
  3. descriptive characteristics: age, gender
  4. heat production
58
Q

What is subcutaneous fat

A
  • very effective in cold water for insulatin
  • fat is primary fuel for shivering (in thermogenesis ) in well fed individuals

** just below skin but closer to skin than visceral fat**

59
Q

what happens to heat loss with increased wind speed

A

with higher wind speed causes temperatures to feel colder

60
Q

what is the effect of water temperature on heat loss

A

w/ water immersion the rate of heat loss in 25x greater than air of same temperature

61
Q

Explain what happens to blood flow in response to exercise in the cold

A

blood flow shunted away from the skin –> to the core

  • cutaneous vasoconstriction
62
Q

explain how muscle function is impaired in a cold environment

(ie. hands)

A
  • hands = numb b/c reduced blood flow and depressed rate of neural transmission
  • reduction in neural transmission and blood flow = loss in dexterity and loss of motor skills
63
Q

what are the endocrine responses to exercise in the cold
* what three things release more

A

increased release of norepi, epi, and thyroxine (thyroid hormone) for metabolic heat production –> non shivering thermogenesis

64
Q

what temperature is associated with hypothermia

A

when decline from 37 to 25 or lower – life threatening cardiac arrhythmias

65
Q

explain the difference in health risks in exercise in cold air vs. water

A
  • exercise in cold air presents less risk of developing hypothermia than cold water
  • in air skin at risk for frostbite if temp blow freezing
  • breathign cold air doesnt pose risk to respiratory tract or lung b/c air rapidly warmed
  • breathing cold air can trigger exercise induced asthma
65
Q

Explain the 3 results of cold acclimation

A
  1. result in lower skin temperature at which shivering begins
  2. maintian higher hand and food temperature
  3. improved ability to sleep in the cold
66
Q

Explain why in cold acclimation it results in lower skin temperature at which shivering begins

A

b/c there is increased non-shivering thermogenesis

67
Q

Explain why in cold acclimation individuals maintian higher hand and food temperature

A

because there is imporved peripheral blood flow

68
Q

Explain why in cold acclimation improved ability to sleep in the cold

A

due to reduced shiver – less wakefulness

69
Q

explain how cold-acclimatized poeple maintain heat production with both types of shivering

A

with involuntary heat production
* decreased shivering – somatic neurons no longer send signal
* nonshivering thermogenesis – maintain heat (rely on this more)

70
Q

How does Hunter’s phenomenon relate to cold acclimation

A

have cold endued vasodilation — to keep dexterity

71
Q

explain the sex difference in response to cold exposure

A
  • women show faster reduction in body temp than men – body mass
  • in water, decrease in body temp similar in men and women
72
Q

explain the age difference in response to cold exposure

A
  • older (>60) less tolerant to cold
  • children experience faster fall in body temp
73
Q

explain Dalton’s law

A

total pressure of a gas mixture is euqual to the sum of the pressure that each gas would exert independently

74
Q

how do you calculate the partial pressure of air? what is the equation?

A

Pair = PO2 + PCO2 + PN2

PO2 = (% in air - fraction = 0.2093)(Barometric pressure)

75
Q

what value always remains constant in atmospheric condidiotns at any elevation

A

% of O2 in the air
always 20.93

  • only the number of molecules change
76
Q

explain the comparison of PO2 at sea level and altitude

A

at sea level:
* greater PO2 entering lungs –> reduced amount actually going through alveoli –> more muscle O2 absorbtion
* diffusion gradient = 100 (arterial) - 40 (venous) = 60 mmHg

at altitude
* much less PO2 entering lungs –> reduced amount actually going through alveoli –> less muscle O2 absorbtion
* diffusion gradient = 42 (arterial) - 27 (venous) = 15 mmHg

77
Q

What are the effects of altitude on oxygen-hemoglobin dissociation curve

A
  • hypoxia == shift left and drop off O2 even more – low PO2
  • normoxia = normal PO2
  • hyperoxia == shift right and dropp off less O2 to tissues – high PO2
78
Q

what are the 4 effects of altitude on oxygen content

A
  1. arterial O2 content
  2. saturation
  3. hemoglobin concentration
  4. partial pressure of oxygen in the arteries (minor)
79
Q

what is the euqaiton for arterial O2 content (CaO2)

A

CaO2 = (SaO2 * [Hb] * 1.37) + (PaO2 * 0.003)

80
Q

Explain how max aerobic power is effected by altitude

A

there is decreased VO2 max at higher altitude – less O2 delivered to the muscles

81
Q

explain the change in percent decline in VO2 max
* in trained? why?

A
  • trained individuals have a larger decline in VO2 max from sea level
  • b/c they have a higher VO2 max b/c of the pulmonary-capillary transit time (less time)
82
Q

explain the decline in VO2 max from sea level to altitude

A
  • at sea level the blood isnt moving too fast and aple to keep up with fast capillary time
  • at altitude the PO2 is Low and there is a small change in capillary transit time which effects O2 uptake –> reducing driving force of O2 into blood
83
Q

explains why there are individual variability in % decline of VO2max from sealevel to altitude

A

climitize over time and variablity with how people respond
* mutations in p50 and Hb-O2 affinity
* intrapulmonary arteriovenous anastamosis (IPAVA) - deal w/ high pressure – not fully oxygenated blood: dont go through capillary bed

84
Q

what is the effect of altitude on the HR response to submax exercise

A

HR increases

  • acute hypoxia (altitude) –> increase epinephrine –> increase HR, SV, and Q
84
Q

What is the effect of altitude on ventilation response to submax exercise

A

ventilation increases
* peripheral chemoreceptors sense lower PaO2
–> ventilatory drive switch @ high altitude to be sensitive to O2

85
Q

explain the influence of short-term anaerobic performance with altitude

A

lower PO2 at altitude = no effect on performance
* O2 transport to muscle does not limit performance (anaerobic)
* lower air resistance may improve performance

be careful for the exam

86
Q

explain the influence of long-term aerobic performance with altitude

A

lower PO2 results in poorer aerobic performance
* dependent on O2 delivery to the muscle

86
Q

What happens to plasma volume upon initital arrival to altitude? why?

A

decreased plasma volume upon initital arrival to altitude –> lower SV
* b/c humidifying air through ventilation and more urine output = increased hematocrit
* fluid shift: decrease in PO2 –> physiological response = fluid shift from bloodstream into intersitital spaces surrounding cells –> incrase concentration of RBC and hemoglobin in blood – increase carrying capacity

87
Q

What happens to plasma volume after a few weeks at altitude

A

diminished plasma volume returns to normal if adequate fluid is ingested

88
Q

What are the two acclimatizations to high altitude and what type of breathing does this cause

A
  1. production of more RBCs
  2. greater O2 saturation
  3. hyperventilation
89
Q

Why is there production of more RBCs with acclimatization to high altitude? What creates RBCs?

A

higher RBC concentration via EPO
* counter the desaturation cuased by lower PO2 == able to maintain high hematocrit

89
Q

Why is there greater O2 saturation with acclimatization to high altitude

A

due to an increase in blood flow to the lungs – everyone has strong vasoconstriction in the lungs

*at high altitude – vasoconstrict vasculature –> increase pulmonary artery pressures –> force more O2 into blood

90
Q

Explain how more RBCs are produced. Explain the pathway

A

decreased blood O2 –> sensor: kidney –> increased erythropoietin (EPO) –> red bone marrow increases RBC production –> increase blood O2 –> increase hematocrit

91
Q

What happens to hemoglobin concentration with altitude

A

at higher altitudes there will be a higher hemoglobin concentration – to increase O2 delivery and absorbance

92
Q

Explain how hyperventilation is an acclimatization to hgih altitude

A

increased sensititvity of carotid chemoreceptor
* respond quickly in change in CO2 then pH at sea level or low altidue with O2
* greater change in partial pressure = greater change in ventilation

92
Q

what are the negative consequences of carotid chemoreceptor sensitization

A
  • hyperventilation: extreme dsypena, increase work to breathe, blood flow disruption, hypertension
  • sleep disruption
  • decrease in plasma volume
  • HAPE and HASE
93
Q

how do tibetan sherpas adapt to high altitude

A

increase O2 saturation of the existing hemoglobin –> larger release of nitric oxide == greater vasodilation

94
Q

with those who live at high altitude what is the adaptation to altitude

A

more nitric oxide released and higher hematocrit

  • if move after childhood = less complete adaptation
95
Q

What are the benefits of living at high altitude

A

decrease PO2 –> increase EPO –> increase plasma volume
* elicit an increase in RBC mass via EPO – increase VO2max
- greater then 22 hr/day at altitude requried
- intermittent hypobaric hypoxia = need greater stimulus for effects

96
Q

explain why you train at low altitude

A

so you can maintain high interval training velocity
* some athletes still experience hemoglobin desaturation

97
Q

What happesn to race time in athletes that lived at altitude and trained at low altitude

A

performance increased 1.1% and VO2 max increased 3.2%

98
Q

Explain the change in VO2 in athletes that trained for competition at atltitude

A

some have higher VO2 max upon reutrn to low altitude and some do not
* could be “detraining” effect – cannot train as intensely at altitude

98
Q

what are the effects in living at high altitude and training at low

A
  • increased RBC mass leads to increased VO2 max in some individuals
  • avoid negative effects of prolonged altitude exposure
  • no real change in VO2 max or hemoglobin

Exercise Physiology (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions