Exam 2 Flashcards
1
Q
what percent of the total body weight is composed of muscles
A
40-50%
2
Q
3 functions of skeletal muscle
A
- force production for locomotion and breathing
- force production for postural support
- heat production during cold stress
3
Q
order of muscle covering
A
- Epimysium
- surrounds entire muscle - perimysium
- surrounds fascicles - endomysium
- surrounds individual muscle fibers - basement membrane
- just below endomysium - sarcolemma
- muscle cell membrane
4
Q
what are the 4 parts of the microstructure of muscle fibers
A
- myofibrils
- sarcomere
- sarcoplasmic reticulum
- transverse tubules
5
Q
what is in the myofibrils
A
Contractile proteins
- actin
- myosin
6
Q
what makes up a sarcomere
A
- z line
- m line
- H zone
- A band
5 I band
7
Q
where is the storage site for calcium
A
sarcoplasmic reticulum
8
Q
where is the terminal cisternae
A
in the sarcoplasmic reticulum
9
Q
where does the transverse tubules extend to and from
A
extend from the sarcolemma to the sarcoplasmic reticulum
10
Q
what is the neuromuscular junction
A
junction between motor neuron and muscle fiber
11
Q
what is a motor unit
A
motor neuron and all fibers it innervates
12
Q
what is the motor end plate
A
pocket formed around motor neuron by sarcolemma
13
Q
what is the neuromuscular cleft
A
short gap between neuron and muscle fiber
14
Q
where is acetylcholine released from and what does it cause
A
- released from the motor neuron
- causes an end plate potential (EPP)
- causes depolarization of the muscle fiber
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
16
Q
Energy is needed for Muscle Contraction, how does the muscle utilize the ATP
A
- myosin ATPase breaks down ATP as the fiber contracts
- ATP—>ADP +Pi
17
Q
what are the sources of ATP used for muscle contraction
A
- PC
- glycolysis
- oxidative phoshorylation
18
Q
what nutrient enforces muscle contraction
A
calcium
19
Q
what are fast twitch fibers
A
anaerobic muscle
used for strength and power
high sarcoplasmic reticulum development
20
Q
what are slow twitch fibers
A
endurance muscle, aerobic
everyday muscle
21
Q
what are free radicals
A
a compound that loses electrons and is unstable which in turn disrupts cell activity
22
Q
what is excitation-contraction coupling
A
Depolarization of the motor end plates (excitation) is coupled to muscular contraction
23
Q
how does excitation contraction coupling work
A
- the action potential travels down transverse tubules and causes the release of Calcium ions from the sarcoplasmic reticulum
- Calcium binds to troponin and causes position change in tropomyosin which eposes active sites on actin
- strong binding state formed between actin and myosin
Contraction
24
Q
what are the 2 main parts of excitation
A
- action potential in motor neuron causes release of acetylcholine into synaptic cleft
- acetylcholine binds to receptors on motor end plate, leads to depolarization that is conducted down transverse tubules, which causes release of calcium from SR
25
what are the 5 steps in contraction
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.
26
what is muscle fatigue
decline in muscle power output
- decrease in force generation
- decrease in shortening velocity
27
how long does muscle fatigue take in high intensity exercise
roughly 60 seconds
28
what accumulates during high intensity exercise
```
lactate
ADP
Pi
free radicals
-all of these diminishes cross bridges bound to actin
```
29
how long do muscles take to fatigue during long duration exercise
2-4 hours
30
what are 3 muscle factors that need to be taken into consideration during long duration exercise
accumulation of free radicals
electrolyte imbalance
glycogen depletion
31
what are muscle cramps
spasmodic involuntary muscle contractions
32
what is the electrolyte depletion and dehydration theory
water and sodium loss via sweating causes spontaneous muscle contractions
33
what is the altered neuromuscular control theory
muscle fatigue causes abnormal activity in muscle spindle and golgi tendon organ
-leads to increased firing of motor neurons
34
characteristics of the slow twitch fibers
```
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
```
35
characteristics of fast twitch fibers
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
36
what percentage of slow and fast twitch fibers do non athletes have
roughly 50/50 split
37
predominant fiber type in endurance and power athletes
1. power: fast twitch
| 2. endurance: slow twitch
38
2 types of muscle action
1. isometric
| 2. isotonic
39
what is isometric muscle action
1. muscle exerts force without changing length
2. pulling against immovable object
3. postural muscles
40
what is isotonic muscle action
two types
1. concentric: muscle shortens during force production
2 eccentric
-muscle produces force but length increases.
*** this type is associated with muscle soreness
41
define muscle twitch
contraction as the result of a single stimulus
42
3 parts of a muscle twitch
1. latent period (5ms)
2. contraction (tension is developed 40ms)
3. relaxation (50ms)
43
3 types of frequency stimulation
1. simple twitch
2. summation
3. tetanus (max tension)
44
what is sarcopenia
it is the gradual loss of muscle due to aging
45
what percent of muscle mass is lost between the age of 25-50 years
10%
46
what percent of muscle mass is lost between 50-80
40%
47
what type of training can delay age related muscle loss
resistance training
48
what is the force velocity relationship
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
49
4 processes by which O2 and CO2 are transported and expelled
1. Pulmonary Ventilation (external)
2. Pulmonary Diffusion (external respiration)
3. Transport of gases via blood
4. capillary diffusion (internal respiration
50
what is pulmonary ventilation
process of moving air into and out of the lungs
1. transport zone
2. exchange zone
51
what is the pathway of pulmonary ventilation
1. nose/mouth
2. nasal conchae
3. pharynx
4. larnyx
5. trachea
6. bronchial tree
7. alveoli
52
Pulmonary Ventilation- Inspiration
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
53
what additional muscles are used in forced inspiration
scalenes
sternocleidomastoid
pectorals
54
Pulmonary Ventilation- Expiration
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)
55
what muscles are involved in the active process of expiration
1. internal intercostals pull ribs down
2. latissimus dorsi
3. quadratus lumborum
4. abdominal muscles force diaphragm back up
56
what is the normal atmospheric pressure
760 mmHg
57
what is the intrapleural pressure
756mmHg
58
how are pulmonary volumes measured
spirometry
- lung volume capacities, flow rates
- tidal volume
- vital capacity
- residual volume
- total lung capacity
59
what is the total lung capacity the sum of
Vital capacity and Residual Volume
60
define vital capacity
greatest amount of air that can be expired after a maximal inspiration
61
define tidal volume
amount of air entering and leaving the lungs with each normal breath
62
define functional residual capacity
volume of air remaining in the lungs after normal expiration
63
define residual volume
amount of air remaining in the lungs after MAXIMAL expiration
64
define pulmonary diffusion
gas exchange between alveoli and capillaries
65
what is the inspired air path for pulmonary diffusion
bronchial tree and it arrives at alveoli
66
what is the blood path for pulmonary diffusion
right ventricle to the pulmonary trunk to the pulmonary arteries to the pulmonary capillaries
(capillaries surround alveoli)
67
2 major functions of pulmonary diffusion
1. replenishes blood oxygen supply
| 2. removes carbon dioxide
68
at rest how much blood do the lungs receive every minute
4-6L
69
what 2 things are equal at rest with regards to pulmonary diffusion
Lung blood flow=systemic blood flow
70
what is the respiratory membrane within pulmonary diffusion
(alveolar-capillary membrane) the surface across which gases are exchanged
(300 million alveoli)
71
what are the partial pressures of:
1. Nitrogen
2. oxygen
3. carbon dioxide
1. Nitrogen 79.04%
2. Oxygen 20.93%
3. Carbon Dioxide 0.03%
72
what is daltons law
total air pressure =PN2+PO2+PCO2
73
what is Henry's Law and what does it depend on
1. gases dissolve in liquids in proportion to partial pressure
2. depends on specific fluid medium and temperature
74
what is Fick's law
rate of diffusion proportional to surface area and partial pressure gas gradient
PO2 gradient is 65mmHg
PCO2 gradient is 6mmHg
75
At rest, why is oxygen diffusion capacity limited
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
during exercise why does oxygen diffusion capacity increase
increase is due to more even lung perfusion
| 1. systemic blood pressure increases causing the top 2/3s of the lungs to perfuse
77
how many mL of oxygen can be carried in 100mL of blood
20mL
1L O2/5L blood
78
what percent of oxygen is bound to hemoglobin
98%
other 2% dissolved in plasma
79
what does the hemoglobin saturation depend on
depends on PO2 and affinity between oxygen and hemoglobin
80
Hemoglobin Saturation:
| what happens when there is high PO2 in the lungs
1. loading portion of oxygen-hemoglobin dissociation curve
| 2. SMALL change in Hb saturation per mmHg change in PO2
81
Hemoglobin Saturation:
| what happens when there is low PO2 in body tissues
1. unloading portion of oxygen-hemoglobin dissociation curve
| 2. large change in Hb saturation per mmHg change in PO2
82
2 factors affecting hemoglobin saturation
1. blood pH
| 2. blood temperature
83
Factors affecting hemoglobin saturation:
Blood pH
more acidic causes the O2-Hb curve to shift to the right
- bohr effect
- more O2 unloaded at acidic exercising muscle
84
Factors affecting hemoglobin saturation:
blood temperature
warmer temperatures causes O2-Hb curve to shift right
promotes tissue O2 unloading during exercise
85
what percent of hemoglobin is saturated at rest
98-99%
86
does hemoglobin have higher or lower saturation during exercise
lower
87
3 ways that carbon dioxide is carried in the blood
1. as bicarbonate ions
2. dissolved in plasma
3. bound to hemoglobin (carbaminohemoglobin)
88
60-70% of CO2 in blood is carried to the blood by what
bicarbonate ions
89
what two compounds form carbonic acid (H2CO3)
CO2 and water
90
what is carbonic acid catalyzed by
carbonic anhydrase
91
what does carbonic acid dissociates into
bicarbonate
Hydrogen ions then bind to Hb and triggers bohr effect
bicarbonate ion diffuses from RBC into plasma
92
what percent of CO2 is dissolved in plasma
7-10%
93
what percent of CO2 is transported bound to Hb
20-33%
94
what part of hemoglobin does CO2 bind to
the globin portion
95
what affects the CO2-Hb binding
the partial pressure of CO2
1. increased PCO2 makes it easier for binding
2. decreased PCO2 makes it easier for dissociation
96
what transports oxygen within the muscle
myoglobin
| -higher affinity for oxygen
97
what are 3 factors influencing oxygen delivery and uptake
1. . O2 content of blood
2. blood flow
3. local conditions (pH, temperature)
98
what is the O2 content of blood represented by and what does it create
1. represented by PO2, Hb percent saturation
| 2. creates arterial PO2 gradient for tissue exchange
99
how does blood flow affect the oxygen delivery and uptake
1. as blood flow decreases, the opportunity to delivery oxygen to tissue also decreases
2. exercise increases blood flow to muscle
100
how do pH and temperature influence oxygen uptake and delivery
shift O2-Hb dissociation curve
decrease pH, and increased temp promote unloading in tissue
101
how does CO2 exit the cell
simple diffusion
1. driven by PCO2 gradient
- tissue PCO2 high
- blood PCO2 low
102
what are the 2 central mechanisms of regulation
1. respiratory centers
| 2. central chemoreceptors
103
what are the respiratory centers
- where are they located
- function
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
```
function of central chemoreceptors
-stimulated by what
```
1. increases rate and depth of breathing to remove excess CO2 from body
2. stimulated by increased CO@ in cerebrospinal fluid
105
list the 2 peripheral mechanisms of regulation
1. peripheral chemoreceptors
| 2. mechanoreceptors (stretch)
106
where are the peripheral chemoreceptors located and what are they sensitive to?
1. in aortic bodies and carotid bodies
| 2. sensitive to blood PO2, PCO2, H+
107
where are the mechanoreceptors located and what happens if there is excessive stretch
1. in pleurae, bronchioles, alveoli
| 2. excessive stretch results in reduced depth of breathing
108
why does the heart generate pressure
to drive blood through vessels
109
what must blood flow meet
metabolic demands
110
4 main aspects of the heart
1. four chambers
2. pericardium
3. pericardial cavity
4. pericardial fluid
111
relationship between blood viscosity and blood plasma
as blood viscosity increases, blood plasma decreases
112
what is the muscle within the heart called
myocardium
113
which ventricle has the most myocardium and why
Left ventricle
1. must pump blood to entire body and must do so against the force of gravity
2. thickest walls,
114
how many muscle fiber types are in the heart
1
- has high capillary density
- high number of mitochondria
- striated
115
purpose of desmosomes in cardiac muscle fibers
hold cells together
116
purpose of gap junctions in cardiac muscle fibers
rapidly conduct action potentials
117
what does the right coronary artery supply and what does it divide into
1. supplies right side of heart
| 2. divides into marginal, posterior inter-ventricular
118
what does the left main coronary artery supply and what does it divide into
1. supplies left side of heart
| 2. divides into circumflex, anterior descending
119
what is the name of coronary artery disease
atherosclerosis
120
what is spontaneous rhythmicity
special heart cells generate and spread electrical signal
121
what are the 4 special heart cells that generate and spread the electrical signal
1. sinoatrial node (SA)
2. atrioventricular node (AV)
3. Av bundle (bundle of His)
4. purkinje fibers
122
what is the intrinsic heart rate
100beats/min
123
what initiates the contraction signal and what else does it do
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
what does the AV node do
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
what does the AV bundle do
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
what do the purkinje fibers do
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
how does the parasympathetic nervous system reach the heart
via the vagus nerve
| 1. carries impulses to Sa, AV nodes
128
when the vagus nerve relays impulse to the heart, what happens
1. releases acetylcholine, which hyperpolarizes cells
2. decreases HR, force of contraction
3. decreases HR below intrinsic HR
129
what is the range of normal resting HR
60-100 bpm
130
what happens when the sympathetic nervous system reaches the heart
1. releases norepinephrine which facilitates depolarization
2. increases HR, force of contraction
3. endocrine system can have similar effect
131
what is the maximum possible HR
250 bpm
132
what does ECG stand for
electrocardiogram
133
what does the ECG do
record the hearts electrical activity
134
how many leads and electrodes does the ECG use and why
10 electrodes
12 leads
this is so we can monitor and see the different electrical views from all angles
135
what are the 3 basic phases that he ECG picks up
1. P wave: atrial depolarization
2. QRS complex: ventricular depolarization
3. T wave: ventricular repolarization
136
when does ventricular systole occur on an ECG
QRS complex to T wave
| 1/3 of cardiac cycle
137
when the heart contraction begins, what occurs
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
when does the ventricular diastole occur in an ECG
t wave to the next QRS complex
139
when relaxation (diastole) occurs in the heart, what happens
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
what is stroke volume
volume of blood pumped in one heartbeat
141
what is the equation for stroke volume
EDV-ESV=SV
142
what is the ejection fraction
percent of EDV pumped
143
what is the equation for the ejection fraction
Sv/EDV=EF
144
what is cardiac output
total volume of blood pumped per minute
| Q=Hr*SV
145
what is the average resting heart rate
70 beats per minute
146
function of arterioles
control blood flow, and feed capillaries
147
function of capillaries
site of nutrient and waste exchange
148
venules function
collect blood from capillaries
149
what are the 3 pressures associated with the heart
1. systolic
2. diastolic
3. mean arterial pressure
150
what is the equation for blood flow
delta P/R
151
what is intrinsic blood flow
1. ability of local tissues to constrict or dilate arterioles that serve them
2. alters regional flow depending on need
152
3 types of intrinsic control
1. metabolic
2. endothelial
3. myogenic
153
what are the metabolic mechanisms (VD) in intrinsic control
1. buildup of local metabolic by-products
2. decreased oxygen
3. increased CO2, K, H, and lactic acid
154
what are the endothelial mechanisms (mostly VD) in intrinsic conrol
1. substances secreted by vascular endothelium
| 2. nitric oxide, prostaglandins, EDHF
155
what are the myogenic mechanisms (VC, VD) in intrinsic control
1. local pressure changes can cause vasoconstriction or dilation
if pressure increases, VC increases
if pressure decreases, vasodilation
156
what occurs during extrinsic neural control of blood flow
1. redistribution of flow at organ
| 2. sympathetic nervous system innervates smooth muscle in arteries and arterioles
157
relationship between sympathetic activity and VC and VD
1. as sympathetic activity increases, vasoconstriction increases
2. as sympathetic activity decreases, vasoconstriction decreases
158
at rest, how much of the blood volume do the veins contain
2/3 blood volume
159
why can the veins contain 2/3 of blood volume at rest
1. high capacity to hold blood volume
2. elastic, balloonlike vessel walls
3. serve as blood reservoir
160
how can the venous reservoir be liberated and sent back to the heart
1. sympathetic stimulation
| 2. venoconstriction
161
what is integrative control of blood pressure
1. blood pressure maintained by autonomic reflexes
| 2. baroreceptors
162
function of baroreceptors
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
3 mechanisms that assist venous return to the heart
1. one way venous valves
2. muscle pump
3. respiratory pump
164
3 major functions of blood
1. transportation of nutrients
2. temperature regulation
3. acid base balance
165
what percent of blood volume is made up from plasma
55-60%
166
what percent of blood is made up from formed elements
40-45%
167
what is your hematocrit level
total percent of volume composes of formed elements
168
life span of RBC
roughly 4 months
169
what is the condition know as Varicose Veins
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
where do varicose veins usually occur
in the surface veins of the lower extremities
171
what activities should people with varicose veins avoid
avoid static, straining type exercises that accompany resistance training
172
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?
increases total peripheral resistance and reduces muscle perfusion
173
3 layers of the veins
1. tunica adventitia
2. tunica media
3. tunica intima
174
what organ kills old red blood cell
spleen
175
List the intrinsic control of the heart/heart rate
1. spontaneous rhythmicity
- SA node
- AV node
- Bundle of His
- purkinje fibers
176
what is the extrinsic control of the heart
1. sympathetic
- causes the release of norepinephrine from the SA node to facilitate depolarization
2. Parasympathetic
