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75 Cards in this Set
- Front
- Back
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-HIGH capillary density -HIGH myoglobin concentrations -HIGH mitochondria density -Predominant energy source is AEROBIC -LOW ATPase activity -LOW velocity -HIGH efficiency -MODERATE force generation |
TYPE 1 FIBER |
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-MODERATE capillary density -MODERATE myoglobin concentrations -HIGH/MODERATE mitochondria -HIGH/MODERATE resistance to fatigue -AEROBIC/ANEROBIC energy sources -HIGH ATPase activity -INTERMEDIATE velocity -MODERATE efficiency -HIGH force generation -INTERMEDIATE velocity
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TYPE IIa fast twitch |
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-LOW capillary density -LOW myglobin concentrations -LOW mitochondria -LOW resistance to fatigue -ANEROBIC energy source predominantly used -HIGHEST ATPase activity -HIGHEST velocity -LOW efficiency -HIGH force generation |
TYPE IIx fast twitch |
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How do actin and myosin work together to produce skeletal muscle contraction and relaxation during exercise? |
Sliding filament theory
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Muscle fibers contract by shortening of their myofibrils due to actin sliding over myosin. |
sliding filament theory |
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What are the key cellular processes that are involved in skeletal muscle contraction during exercise? |
-motor neuron -neuro muscular junction -t-tubles -sarcoplasmic reticulum -excitation contraction coupling -relaxation |
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How is the process of of muscle lengthening different than muscle contraction? |
-There is no power stroke stopping the actin molecule from binding to fast. -external force is greater than the force generated by the muscle weight going down |
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When is the greatest amount of tension produced by a skeletal muscle fiber? |
-Optimal sarcomere length is between 2- 2.5 um -no tension for lengths above 3.6um
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The more myosin that's binded the more force that can be generated. |
Length Tension Curve |
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At what point is a sarcomere at optimal length and ready to produce the greatest amount of force? |
At rest. |
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Can fiber type be altered by endurance and resistance exercise training? |
Yes, studies have shown that Type I fibers increased and Type II fibers decreased. -type II was converted into Type I muscle fibers -mitochondrial biogenesis, ATP turnover, and calcium release are factors that allow conversion to happen. |
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Can fiber type go from slow to fast twitch? |
Experimental conditions -Buller and Eccles surgically switched Alpha motor neuron intervation -exercise can not convert slow to fast |
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How does resistance training increase strength if there is little evidence of a slow to fast conversion. |
-Fiber size increases not fiber numbers -increase in sarcomeres -more nuclei is created by satellite cells increasing hypertrophy of muscle |
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Mechanisms of hypertrophy |
-muscle stretch or force -satellite cells -IGF-1 role in protein synthesis |
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What happens to skeletal muscle when endurance and resistance training are done together? |
-AMPK from endurance pathway upregulated from endurance training, blocks IGF pathway for power in resistance training.
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What is VO2 |
The amount of oxygen utilized to produce ATP |
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What are the two variables of VO2 |
-Amount of O2 delivered to tissue -Amount of O2 extracted from blood by tissue in skeletal muscle |
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What is the fick equation |
VO2= CO x a-VO2 diff
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What is the equation for a-VO2 difference? |
Arteriol blood O2 - Venous blood O2 |
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What happens to a-VO2 difference when going from rest to exercise? |
The amount of O2 extracted from arteriol blood increases |
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Why does a-VO2 increase when going from rest to exercise? |
-it takes more O2 to make more ATP and O2 needs to bind with Hydrogen in the ETC - a greater ATP demand is needed to sustain muscle contraction. |
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How does chronic aerobic exercise training effect a-VO2 difference? |
- a-VO2 increases at maximal exercise in a trained individual because more O2 can be extracted from arteriol blood -mitochondria has gotten larger |
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How are arteriol and venous O2 content impacted by chronic aerobic exercise training? |
-arteriol O2 content stays the same because O2 can not increase saturation level from exercising -venous O2 content decreases because more O2 is extracted from arteriol blood and used in working SKM |
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What changes occur to the skeletal muscle after chronic aerobic exercise training that would facilitate oxygen extraction? |
-Mitochondrial biogenesis -Angiogenesis |
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Formation of new capillaries from existing capillaries |
Angiogenesis
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Formation of new arteries from smaller vessels such as capillaries |
Arteriogenesis |
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Creation of a wall in lumen of pre existing capillary |
Intussusception |
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Small bud formation on side of pre existing capillary |
Sprouting |
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What is the molecular signaling that provides stimulus for angiogenesis? |
Vascular Endothelial Growth Factor (VEGF) |
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Frictional force created by blood moving through capillaries |
Sheer force |
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Muscle contraction compressing around capillaries |
Compression |
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Increase in BP stretching walls of capillaries |
stretch |
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What are the three exercise stimuli that influence angiogenesis? |
-Sheer -compression -stretch |
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How does increasing capillary numbers facilitate the diffusion of oxygen from red blood cell to contracting skeletal muscle? |
-increased capillary density -increase transit time -decrease diffusion distance of O2 to capillaries |
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How does resistance training impact angiogenesis? |
-does not increase capillary density -Skeletal muscle density my dilute the increase in capillary numbers -exercise stimulus may not be long enough to cause angiogenesis |
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What is Total Peripheral Resistance (TPR)? |
The sum of all resistance in body and how they affect the systemic circulation |
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What are the physiological barriers that could influence or affect Total Peripheral Resistance? |
-size of blood vessel -length of blood vessel -blood volume |
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What is the Hagen- Poiselle Equation |
Resistance=(Length of vessel x viscosity of blood)/Radius of blood vessel^4 |
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Which variable in the Hagen- Poiselle Equation is most affected by exercise? |
-the radius of blood vessels has a large impact on other factors |
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During exercise, what happens to blood vessels in active skeletal muscle? |
-they dialate |
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During exercise, what happens to visceral organ blood vessels? |
-they constrict |
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Which blood vessel type contributes the greatest amount to the regulation of Total Peripheral Resistance? |
Arteriols are the greatest site of Blood pressure regulation and Total Peripheral Resistance because they are the between the arteries and the capillaries. |
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What can effect the viscosity of blood? |
-Dehydration -high altitude -blood doping |
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During exercise what happens to Total Peripheral Resistance? |
-dependent on muscle mass and intensity of exercise, -resistance decreases in SKM -resistance decreases in skin -resistance increases in visceral organs |
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The pressure exerted by circulating blood upon the walls of the blood vessels |
Blood pressure |
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Blood pressure during heart contraction phase |
Stystolic BP |
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blood pressure during heart relaxation phase |
Diastolic BP |
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What is the equation for Mean Arterial Pressure (MAP)? |
MAP=DBP+.33(SBP-DBP) |
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What is the equation for blood Pressure? |
BP=(HRxSTV)xTPR |
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What is the equation for Cardiac Output? |
Q=HRxSV |
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How are TPR and BP related? |
BP is a product of Cardiac Output and TPR -If HR or TPR changes during exercise, BP will be impacted. |
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What is the average resting BP and how is it regulated during rest? |
-120/80 -There are regulating systems that respond to changes in BP *reninangiotensin system in kidneys *baroreceptors in aortic and corotid arteries |
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If Blood pressure suddenly increases what happens to the sympathetic and parasympathetic nervous system and what happens to heartrate and artery dialation? |
-Baroreceptors signal: Sympathetic = decrease Parasympathetic = increase Heart rate = decrease Artery dialation = increases
-influencing BP to go down |
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If Blood pressure suddenly decreases what happens to the sympathetic and parasympathetic nervous system and what happens to heart rate and artery dialation? |
Baroreceptors signal : Sympathetic = increase Parasympathetic =decrease Heart rate =increase Artery dialation =decreases
-to influence increase in blood pressure |
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What happens to systolic, diastolic, and MAP during exercise? |
Systolic BP= increases Diastolic = no change or slightly decreases MAP = increases |
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Why do Baroreceptors not decrease exercising BP? |
because during exercise, baroreceptors reset themselves to higher levels in order to maintain a higher blood pressure. |
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Explain the changes that occur to systolic and Diastolic BP during exercise. |
HR=increase SV=Increase = increase in CO Length = same Viscosity = same Radius = decreases of stays the same = TPR same |
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How would Blood pressure response differ between arm and leg exercise at similar workloads?
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-Arm blood pressure would be higher than leg BP because there are less Blood vessels and less muscles in upper body -so at the same work load as the lower body, the TPR would increase as well as the BP |
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The amount of blood that's ejected from the left ventricle per minute |
cardiac output |
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What is the average resting cardiac output? |
4.5L female 5.0L Male |
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What happens to Cardiac output when going from rest to exercise? |
it increases because it needs to meet the O2 demands of contracting skeletal muscle
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What happens to Heart Rate when going from rest to exercise? |
-heart rate increases linearly with increasing exercise intensity |
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What causes increase in heart rate? |
the autonomic nervous system interacts with the SA node |
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The ejected amount of blood from the left ventricle with 1 beat |
Stroke volume |
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What happens to stroke volume when going from rest to exercise? |
it increases up to 40% and then plateaus because ventricular filling time decreases with increased heart rate. -no time to fill ventricle since heart is beating so fast |
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What variables contribute to the increase in Stroke Volume with exercise? |
-End Diastolic Volume -Strength of ventricular contraction -Aortic blood pressure |
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the amount of blood that can get back to left ventricle prior to beat |
pre loading |
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Strength of ventricular contraction |
contractility |
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pressure in the aorta that the ventricle has to exceed to get blood out to the systemic system. |
After load |
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Increase cross bridges formed with increased stretch of ventricle produces more forceful contraction. |
Frank Starling Law |
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How does exercise increase preload? |
-venous constriction- SNS engages and causes veins to constrict -skeletal muscle pump- contraction of skm moves blood back to the heart -respiratory pump- negative pressure in the aorta and thoracic cavity produced by breathing, brings blood back to heart |
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How does exercise increase contractility? |
sympathetic stimulation- increased release of epinephrine causes heart muscle to contract harder |
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What impact does duration of exercise have on cardiac output, SV, and HR? |
-Cardiovascular drift *decrease plasma volume via sweat *decrease SV *increase HR to maintain CO |
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What factors influence recovery time after exercise? |
-fitness -duration/intensity -ambient air temp |
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What impact does endurance exercise training have on cardiac output? |
resting- no change submaximal- no change maximal - increase |
