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Exercise Physiology > Exam 2 > Flashcards

Exam 2 Flashcards

1
Q

what percent of the total body weight is composed of muscles

A

40-50%

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2
Q

3 functions of skeletal muscle

A
  1. force production for locomotion and breathing
  2. force production for postural support
  3. heat production during cold stress
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3
Q

order of muscle covering

A
  1. Epimysium
    - surrounds entire muscle
  2. perimysium
    - surrounds fascicles
  3. endomysium
    - surrounds individual muscle fibers
  4. basement membrane
    - just below endomysium
  5. sarcolemma
    - muscle cell membrane
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4
Q

what are the 4 parts of the microstructure of muscle fibers

A
  1. myofibrils
  2. sarcomere
  3. sarcoplasmic reticulum
  4. transverse tubules
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5
Q

what is in the myofibrils

A

Contractile proteins

  • actin
  • myosin
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6
Q

what makes up a sarcomere

A
  1. z line
  2. m line
  3. H zone
  4. A band
    5 I band
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7
Q

where is the storage site for calcium

A

sarcoplasmic reticulum

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8
Q

where is the terminal cisternae

A

in the sarcoplasmic reticulum

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9
Q

where does the transverse tubules extend to and from

A

extend from the sarcolemma to the sarcoplasmic reticulum

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10
Q

what is the neuromuscular junction

A

junction between motor neuron and muscle fiber

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11
Q

what is a motor unit

A

motor neuron and all fibers it innervates

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12
Q

what is the motor end plate

A

pocket formed around motor neuron by sarcolemma

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13
Q

what is the neuromuscular cleft

A

short gap between neuron and muscle fiber

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14
Q

where is acetylcholine released from and what does it cause

A
  1. released from the motor neuron
  2. causes an end plate potential (EPP)
    - causes depolarization of the muscle fiber
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15
Q

what is the sliding filament model

A

muscle shortening occurs due to the movement of the actin filament over the myosin filament
-this causes the formation of cross bridges between actin and myosin filaments POWER STROKE

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16
Q

Energy is needed for Muscle Contraction, how does the muscle utilize the ATP

A
  1. myosin ATPase breaks down ATP as the fiber contracts

- ATP—>ADP +Pi

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17
Q

what are the sources of ATP used for muscle contraction

A
  1. PC
  2. glycolysis
  3. oxidative phoshorylation
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18
Q

what nutrient enforces muscle contraction

A

calcium

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19
Q

what are fast twitch fibers

A

anaerobic muscle
used for strength and power
high sarcoplasmic reticulum development

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20
Q

what are slow twitch fibers

A

endurance muscle, aerobic

everyday muscle

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21
Q

what are free radicals

A

a compound that loses electrons and is unstable which in turn disrupts cell activity

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22
Q

what is excitation-contraction coupling

A

Depolarization of the motor end plates (excitation) is coupled to muscular contraction

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23
Q

how does excitation contraction coupling work

A
  1. the action potential travels down transverse tubules and causes the release of Calcium ions from the sarcoplasmic reticulum
  2. Calcium binds to troponin and causes position change in tropomyosin which eposes active sites on actin
  3. strong binding state formed between actin and myosin

Contraction

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24
Q

what are the 2 main parts of excitation

A
  1. action potential in motor neuron causes release of acetylcholine into synaptic cleft
  2. acetylcholine binds to receptors on motor end plate, leads to depolarization that is conducted down transverse tubules, which causes release of calcium from SR
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25
Q

what are the 5 steps in contraction

A
  1. at rest myosin cross bridges are in a weak binding state
  2. calcium binds to troponin causing a shift in the tropomyosin to uncover active sites, and cross bridge forms strong binding state
  3. Pi released from myosin, cross-bridge movement occurs
  4. ADP released from myosin
  5. ATP attaches to myosin, breaking the cross bridge and forming weak binding state.. ATP then binds to myosin, broken down to ADP-Pi which energizes myosin.
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26
Q

what is muscle fatigue

A

decline in muscle power output

  • decrease in force generation
  • decrease in shortening velocity
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27
Q

how long does muscle fatigue take in high intensity exercise

A

roughly 60 seconds

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28
Q

what accumulates during high intensity exercise

A 
lactate
ADP
Pi
free radicals
-all of these diminishes cross bridges bound to actin
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29
Q

how long do muscles take to fatigue during long duration exercise

A

2-4 hours

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30
Q

what are 3 muscle factors that need to be taken into consideration during long duration exercise

A

accumulation of free radicals
electrolyte imbalance
glycogen depletion

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31
Q

what are muscle cramps

A

spasmodic involuntary muscle contractions

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32
Q

what is the electrolyte depletion and dehydration theory

A

water and sodium loss via sweating causes spontaneous muscle contractions

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33
Q

what is the altered neuromuscular control theory

A

muscle fatigue causes abnormal activity in muscle spindle and golgi tendon organ
-leads to increased firing of motor neurons

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34
Q

characteristics of the slow twitch fibers

A 
Slow Twitch:
1. small motorneuron
2. low recruitment threshold
3. slow conduction velocity
4. small muscle fiber
5.less SR development
6 high mitochondrial density
7. high capillary density
8. high myoglobin content
9. low PC stores
10. low glycogen stores
11. high triglyceride stores
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35
Q

characteristics of fast twitch fibers

A

Fast Twitch

  1. Large motorneuron size
  2. high recruitment threshold
  3. fast conduction velocity
  4. large muscle fibers
  5. more SR development
  6. high mitochondrial density
  7. medium capillary density
  8. medium myoglobin content.
  9. high PC stores
  10. high glycogen stores
  11. medium triglyceride stores
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36
Q

what percentage of slow and fast twitch fibers do non athletes have

A

roughly 50/50 split

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37
Q

predominant fiber type in endurance and power athletes

A
  1. power: fast twitch

2. endurance: slow twitch

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38
Q

2 types of muscle action

A
  1. isometric

2. isotonic

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39
Q

what is isometric muscle action

A
  1. muscle exerts force without changing length
  2. pulling against immovable object
  3. postural muscles
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40
Q

what is isotonic muscle action

A

two types
1. concentric: muscle shortens during force production
2 eccentric
-muscle produces force but length increases.
*** this type is associated with muscle soreness

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41
Q

define muscle twitch

A

contraction as the result of a single stimulus

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42
Q

3 parts of a muscle twitch

A
  1. latent period (5ms)
  2. contraction (tension is developed 40ms)
  3. relaxation (50ms)
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43
Q

3 types of frequency stimulation

A
  1. simple twitch
  2. summation
  3. tetanus (max tension)
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44
Q

what is sarcopenia

A

it is the gradual loss of muscle due to aging

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45
Q

what percent of muscle mass is lost between the age of 25-50 years

A

10%

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46
Q

what percent of muscle mass is lost between 50-80

A

40%

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47
Q

what type of training can delay age related muscle loss

A

resistance training

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48
Q

what is the force velocity relationship

A

at any absolute force the speed of movement is greater in muscle with higher percent of fast twitch fibers

**the max velocity of shortening is greatest at the lowest force

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49
Q

4 processes by which O2 and CO2 are transported and expelled

A
  1. Pulmonary Ventilation (external)
  2. Pulmonary Diffusion (external respiration)
  3. Transport of gases via blood
  4. capillary diffusion (internal respiration
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50
Q

what is pulmonary ventilation

A

process of moving air into and out of the lungs

  1. transport zone
  2. exchange zone
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51
Q

what is the pathway of pulmonary ventilation

A
  1. nose/mouth
  2. nasal conchae
  3. pharynx
  4. larnyx
  5. trachea
  6. bronchial tree
  7. alveoli
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52
Q

Pulmonary Ventilation- Inspiration

A
  1. active process
  2. involved muscles
    - diaphragm flattens
    - external intercostals move rib cage and sternum up and out
  3. expands thoracic cavity in three dimensions
  4. expands volume inside thoracic cavity
  5. expands volume inside lungs
  6. lung volume increases while intrapulmonary pressure decreases
  7. air passively rushes in due to pressure difference
  8. air passively rushes in due to pressure difference
  9. forced breathing uses additional muscles
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53
Q

what additional muscles are used in forced inspiration

A

scalenes
sternocleidomastoid
pectorals

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54
Q

Pulmonary Ventilation- Expiration

A

1 usually a passive process

  • inspiratory muscles relax
  • lung volume decreases while intrapulmonary pressure increases
  • air forced out of lungs
    2. active process (forced breathing during exercise)
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55
Q

what muscles are involved in the active process of expiration

A
  1. internal intercostals pull ribs down
  2. latissimus dorsi
  3. quadratus lumborum
  4. abdominal muscles force diaphragm back up
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56
Q

what is the normal atmospheric pressure

A

760 mmHg

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57
Q

what is the intrapleural pressure

A

756mmHg

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58
Q

how are pulmonary volumes measured

A

spirometry

  • lung volume capacities, flow rates
  • tidal volume
  • vital capacity
  • residual volume
  • total lung capacity
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59
Q

what is the total lung capacity the sum of

A

Vital capacity and Residual Volume

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60
Q

define vital capacity

A

greatest amount of air that can be expired after a maximal inspiration

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61
Q

define tidal volume

A

amount of air entering and leaving the lungs with each normal breath

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62
Q

define functional residual capacity

A

volume of air remaining in the lungs after normal expiration

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63
Q

define residual volume

A

amount of air remaining in the lungs after MAXIMAL expiration

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64
Q

define pulmonary diffusion

A

gas exchange between alveoli and capillaries

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65
Q

what is the inspired air path for pulmonary diffusion

A

bronchial tree and it arrives at alveoli

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66
Q

what is the blood path for pulmonary diffusion

A

right ventricle to the pulmonary trunk to the pulmonary arteries to the pulmonary capillaries

(capillaries surround alveoli)

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67
Q

2 major functions of pulmonary diffusion

A
  1. replenishes blood oxygen supply

2. removes carbon dioxide

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68
Q

at rest how much blood do the lungs receive every minute

A

4-6L

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69
Q

what 2 things are equal at rest with regards to pulmonary diffusion

A

Lung blood flow=systemic blood flow

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70
Q

what is the respiratory membrane within pulmonary diffusion

A

(alveolar-capillary membrane) the surface across which gases are exchanged

(300 million alveoli)

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71
Q

what are the partial pressures of:

  1. Nitrogen
  2. oxygen
  3. carbon dioxide
A
  1. Nitrogen 79.04%
  2. Oxygen 20.93%
  3. Carbon Dioxide 0.03%
72
Q

what is daltons law

A

total air pressure =PN2+PO2+PCO2

73
Q

what is Henry’s Law and what does it depend on

A
  1. gases dissolve in liquids in proportion to partial pressure
  2. depends on specific fluid medium and temperature
74
Q

what is Fick’s law

A

rate of diffusion proportional to surface area and partial pressure gas gradient

PO2 gradient is 65mmHg
PCO2 gradient is 6mmHg

75
Q

At rest, why is oxygen diffusion capacity limited

A

it is due to incomplete lung perfusion

  1. only bottom third of lung perfused with blood
  2. top two thirds of lung surface area has poor gas exchange
76
Q

during exercise why does oxygen diffusion capacity increase

A

increase is due to more even lung perfusion

1. systemic blood pressure increases causing the top 2/3s of the lungs to perfuse

77
Q

how many mL of oxygen can be carried in 100mL of blood

A

20mL

1L O2/5L blood

78
Q

what percent of oxygen is bound to hemoglobin

A

98%

other 2% dissolved in plasma

79
Q

what does the hemoglobin saturation depend on

A

depends on PO2 and affinity between oxygen and hemoglobin

80
Q

Hemoglobin Saturation:

what happens when there is high PO2 in the lungs

A
  1. loading portion of oxygen-hemoglobin dissociation curve

2. SMALL change in Hb saturation per mmHg change in PO2

81
Q

Hemoglobin Saturation:

what happens when there is low PO2 in body tissues

A
  1. unloading portion of oxygen-hemoglobin dissociation curve

2. large change in Hb saturation per mmHg change in PO2

82
Q

2 factors affecting hemoglobin saturation

A
  1. blood pH

2. blood temperature

83
Q

Factors affecting hemoglobin saturation:

Blood pH

A

more acidic causes the O2-Hb curve to shift to the right

  • bohr effect
  • more O2 unloaded at acidic exercising muscle
84
Q

Factors affecting hemoglobin saturation:

blood temperature

A

warmer temperatures causes O2-Hb curve to shift right

promotes tissue O2 unloading during exercise

85
Q

what percent of hemoglobin is saturated at rest

86
Q

does hemoglobin have higher or lower saturation during exercise

87
Q

3 ways that carbon dioxide is carried in the blood

A
  1. as bicarbonate ions
  2. dissolved in plasma
  3. bound to hemoglobin (carbaminohemoglobin)
88
Q

60-70% of CO2 in blood is carried to the blood by what

A

bicarbonate ions

89
Q

what two compounds form carbonic acid (H2CO3)

A

CO2 and water

90
Q

what is carbonic acid catalyzed by

A

carbonic anhydrase

91
Q

what does carbonic acid dissociates into

A

bicarbonate

Hydrogen ions then bind to Hb and triggers bohr effect

bicarbonate ion diffuses from RBC into plasma

92
Q

what percent of CO2 is dissolved in plasma

93
Q

what percent of CO2 is transported bound to Hb

94
Q

what part of hemoglobin does CO2 bind to

A

the globin portion

95
Q

what affects the CO2-Hb binding

A

the partial pressure of CO2

  1. increased PCO2 makes it easier for binding
  2. decreased PCO2 makes it easier for dissociation
96
Q

what transports oxygen within the muscle

A

myoglobin

-higher affinity for oxygen

97
Q

what are 3 factors influencing oxygen delivery and uptake

A
  1. . O2 content of blood
  2. blood flow
  3. local conditions (pH, temperature)
98
Q

what is the O2 content of blood represented by and what does it create

A
  1. represented by PO2, Hb percent saturation

2. creates arterial PO2 gradient for tissue exchange

99
Q

how does blood flow affect the oxygen delivery and uptake

A
  1. as blood flow decreases, the opportunity to delivery oxygen to tissue also decreases
  2. exercise increases blood flow to muscle
100
Q

how do pH and temperature influence oxygen uptake and delivery

A

shift O2-Hb dissociation curve

decrease pH, and increased temp promote unloading in tissue

101
Q

how does CO2 exit the cell

A

simple diffusion

  1. driven by PCO2 gradient
    - tissue PCO2 high
    - blood PCO2 low
102
Q

what are the 2 central mechanisms of regulation

A
  1. respiratory centers

2. central chemoreceptors

103
Q

what are the respiratory centers

  • where are they located
  • function
A
  1. inspiratory and expiratory centers
  2. located in brain stem (medulla oblongata, pons)
  3. establish rate, depth of breathing via signal to respiratory muscles
  4. cortex overrides signals if necessary
104
Q 
function of central chemoreceptors
-stimulated by what
A
  1. increases rate and depth of breathing to remove excess CO2 from body
  2. stimulated by increased CO@ in cerebrospinal fluid
105
Q

list the 2 peripheral mechanisms of regulation

A
  1. peripheral chemoreceptors

2. mechanoreceptors (stretch)

106
Q

where are the peripheral chemoreceptors located and what are they sensitive to?

A
  1. in aortic bodies and carotid bodies

2. sensitive to blood PO2, PCO2, H+

107
Q

where are the mechanoreceptors located and what happens if there is excessive stretch

A
  1. in pleurae, bronchioles, alveoli

2. excessive stretch results in reduced depth of breathing

108
Q

why does the heart generate pressure

A

to drive blood through vessels

109
Q

what must blood flow meet

A

metabolic demands

110
Q

4 main aspects of the heart

A
  1. four chambers
  2. pericardium
  3. pericardial cavity
  4. pericardial fluid
111
Q

relationship between blood viscosity and blood plasma

A

as blood viscosity increases, blood plasma decreases

112
Q

what is the muscle within the heart called

A

myocardium

113
Q

which ventricle has the most myocardium and why

A

Left ventricle

  1. must pump blood to entire body and must do so against the force of gravity
  2. thickest walls,
114
Q

how many muscle fiber types are in the heart

A

1

  • has high capillary density
  • high number of mitochondria
  • striated
115
Q

purpose of desmosomes in cardiac muscle fibers

A

hold cells together

116
Q

purpose of gap junctions in cardiac muscle fibers

A

rapidly conduct action potentials

117
Q

what does the right coronary artery supply and what does it divide into

A
  1. supplies right side of heart

2. divides into marginal, posterior inter-ventricular

118
Q

what does the left main coronary artery supply and what does it divide into

A
  1. supplies left side of heart

2. divides into circumflex, anterior descending

119
Q

what is the name of coronary artery disease

A

atherosclerosis

120
Q

what is spontaneous rhythmicity

A

special heart cells generate and spread electrical signal

121
Q

what are the 4 special heart cells that generate and spread the electrical signal

A
  1. sinoatrial node (SA)
  2. atrioventricular node (AV)
  3. Av bundle (bundle of His)
  4. purkinje fibers
122
Q

what is the intrinsic heart rate

A

100beats/min

123
Q

what initiates the contraction signal and what else does it do

A
  1. SA node
  2. pacemaker cells in upper posterior RA wall
  3. signal spreads from SA node via RA/LA to AV node
  4. stimulates RA, LA contraction
124
Q

what does the AV node do

A
  1. delays and relays signal to ventricles
  2. in RA wall near center of heart
  3. delay allows RA, LA to contract before RV, LV
  4. relays signal to AV bundle after delay
125
Q

what does the AV bundle do

A
  1. relays signal to RV, LV
  2. travels along interventricular septum
  3. divides into right and left bundle branches
  4. sends signal toward apex of heart
126
Q

what do the purkinje fibers do

A
  1. send signal into RV, LV
  2. terminal branches of right and left bundle branches
  3. spread throughout entire ventricle wall
  4. stimulate RV, LV contraction
127
Q

how does the parasympathetic nervous system reach the heart

A

via the vagus nerve

1. carries impulses to Sa, AV nodes

128
Q

when the vagus nerve relays impulse to the heart, what happens

A
  1. releases acetylcholine, which hyperpolarizes cells
  2. decreases HR, force of contraction
  3. decreases HR below intrinsic HR
129
Q

what is the range of normal resting HR

A

60-100 bpm

130
Q

what happens when the sympathetic nervous system reaches the heart

A
  1. releases norepinephrine which facilitates depolarization
  2. increases HR, force of contraction
  3. endocrine system can have similar effect
131
Q

what is the maximum possible HR

132
Q

what does ECG stand for

A

electrocardiogram

133
Q

what does the ECG do

A

record the hearts electrical activity

134
Q

how many leads and electrodes does the ECG use and why

A

10 electrodes
12 leads
this is so we can monitor and see the different electrical views from all angles

135
Q

what are the 3 basic phases that he ECG picks up

A
  1. P wave: atrial depolarization
  2. QRS complex: ventricular depolarization
  3. T wave: ventricular repolarization
136
Q

when does ventricular systole occur on an ECG

A

QRS complex to T wave

1/3 of cardiac cycle

137
Q

when the heart contraction begins, what occurs

A
  1. ventricular pressure rises
  2. atrioventricular valves close
  3. semilunar valves open
  4. blood ejected
  5. at end, blood in ventricle= end-systolic volume
138
Q

when does the ventricular diastole occur in an ECG

A

t wave to the next QRS complex

139
Q

when relaxation (diastole) occurs in the heart, what happens

A
  1. ventricular pressure drops
  2. semilunar valves close
  3. atrioventricular valves open
  4. Fill 70% passively and 30% by atrial contraction
  5. at end blood in ventricle= end diastolic volume
140
Q

what is stroke volume

A

volume of blood pumped in one heartbeat

141
Q

what is the equation for stroke volume

A

EDV-ESV=SV

142
Q

what is the ejection fraction

A

percent of EDV pumped

143
Q

what is the equation for the ejection fraction

144
Q

what is cardiac output

A

total volume of blood pumped per minute

Q=Hr*SV

145
Q

what is the average resting heart rate

A

70 beats per minute

146
Q

function of arterioles

A

control blood flow, and feed capillaries

147
Q

function of capillaries

A

site of nutrient and waste exchange

148
Q

venules function

A

collect blood from capillaries

149
Q

what are the 3 pressures associated with the heart

A
  1. systolic
  2. diastolic
  3. mean arterial pressure
150
Q

what is the equation for blood flow

151
Q

what is intrinsic blood flow

A
  1. ability of local tissues to constrict or dilate arterioles that serve them
  2. alters regional flow depending on need
152
Q

3 types of intrinsic control

A
  1. metabolic
  2. endothelial
  3. myogenic
153
Q

what are the metabolic mechanisms (VD) in intrinsic control

A
  1. buildup of local metabolic by-products
  2. decreased oxygen
  3. increased CO2, K, H, and lactic acid
154
Q

what are the endothelial mechanisms (mostly VD) in intrinsic conrol

A
  1. substances secreted by vascular endothelium

2. nitric oxide, prostaglandins, EDHF

155
Q

what are the myogenic mechanisms (VC, VD) in intrinsic control

A
  1. local pressure changes can cause vasoconstriction or dilation

if pressure increases, VC increases

if pressure decreases, vasodilation

156
Q

what occurs during extrinsic neural control of blood flow

A
  1. redistribution of flow at organ

2. sympathetic nervous system innervates smooth muscle in arteries and arterioles

157
Q

relationship between sympathetic activity and VC and VD

A
  1. as sympathetic activity increases, vasoconstriction increases
  2. as sympathetic activity decreases, vasoconstriction decreases
158
Q

at rest, how much of the blood volume do the veins contain

A

2/3 blood volume

159
Q

why can the veins contain 2/3 of blood volume at rest

A
  1. high capacity to hold blood volume
  2. elastic, balloonlike vessel walls
  3. serve as blood reservoir
160
Q

how can the venous reservoir be liberated and sent back to the heart

A
  1. sympathetic stimulation

2. venoconstriction

161
Q

what is integrative control of blood pressure

A
  1. blood pressure maintained by autonomic reflexes

2. baroreceptors

162
Q

function of baroreceptors

A
  1. baroreceptors are sensitive to changes in arterial pressure
  2. afferent signals are sent from the baroreceptors to the brain
  3. efferent signals are sent from the brain to heart
  4. this adjusts arterial pressure back to normal
163
Q

3 mechanisms that assist venous return to the heart

A
  1. one way venous valves
  2. muscle pump
  3. respiratory pump
164
Q

3 major functions of blood

A
  1. transportation of nutrients
  2. temperature regulation
  3. acid base balance
165
Q

what percent of blood volume is made up from plasma

166
Q

what percent of blood is made up from formed elements

167
Q

what is your hematocrit level

A

total percent of volume composes of formed elements

168
Q

life span of RBC

A

roughly 4 months

169
Q

what is the condition know as Varicose Veins

A

a condition in which the valves within a vein fail to maintain their one way blood flow and blood gathers in them so they become excessively distended and painful

170
Q

where do varicose veins usually occur

A

in the surface veins of the lower extremities

171
Q

what activities should people with varicose veins avoid

A

avoid static, straining type exercises that accompany resistance training

172
Q

when you participate in straining exercise it mechanically compresses the peripheral arterial vessels that supply active muscles. What does the arterial vascular compression dramatically increase?

A

increases total peripheral resistance and reduces muscle perfusion

173
Q

3 layers of the veins

A
  1. tunica adventitia
  2. tunica media
  3. tunica intima
174
Q

what organ kills old red blood cell

175
Q

List the intrinsic control of the heart/heart rate

A
  1. spontaneous rhythmicity
    - SA node
    - AV node
    - Bundle of His
    - purkinje fibers
176
Q

what is the extrinsic control of the heart

A
  1. sympathetic
    - causes the release of norepinephrine from the SA node to facilitate depolarization
  2. Parasympathetic

Exercise Physiology (8 decks)

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