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Know the flow of blood thru the heart.
From veins, into the atria, through the AV valves, into the ventricles, up the semilunar valves, into arteries.
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Function of the Heart and Arterial System.
The heart is a pump for blood as it transports O2 and other things like hormones all over the body using the arterial system.
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What's the Fick equation? How does it relate to VO2?
- It measures cardiac output.
- Cardiac output is masured through oxygen consumption and average VO2.
- q= VO2/Average VO2
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What is Cardiac Output? What two parameters determine it?
- Cardiac output is the amount of blood pumped by the heart during a 1 minute period.
- Q=HR X SV
- Output from the heart depends on its rate of pumping and quantity of blood ejected with each stroke.
Increase in VO2max= Increase in Q max
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How does HR increase? SV?
They increase through exercise, catecholamine release, emotion, nerves that modulate arterial resistance.
SV increases through a higher filling of the blood htorugh EDV B/c SV= EDV-ESV
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Explain Frank Starling Mechanism.
As stroke volume increases, End Diastolic Volume increases, which is an increase of blood in the heart.
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How do catecholamines affect HR and SV?
Catecholamine release in physical activity enhances myocardial contractile force to augment stroke power and facilitate systolic emptying.
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How is Venous Return maintained during exercise?
When venous return increases through enhanced diastolic filling, catecholamines released in physical activity enhances systolic emptying to maintain venous return.
Muscle pump.
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How do heart size and body size relate to fatigue resistance?
- heart size is proportional to body size, and energy used to pump blood or move the body is proportional to fatigue resistance. Small body + heart, higher fatigue resistance.
- Right?
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Explain HR response to a maximal graded exercise test. What about steady state exercise?
heart rate plateaus and stays steady and normal after 3-5 minutes
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What is plasma?
- Plasma is mostly water
- Composes 55% of blood.
- Volume increases with training as the most immediate adaptation.
- Increased PV= Dec. Hematocrit- hallmark of a trained athelete.
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What is a RBC? Why is it important in O2 Transport?
- A red blood cell is a cell in the blood, takes up some % of blood.
- RBC has hemoglobin which picks up 4 O2s.
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What is a hematocrit? What is the normal value for it?
45% is the normal value, atheletes have lower, but not past 40%.
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What change do we observe in hematocrit with chronic training? How do you explain the hematocrit response?
3 months of training causes decerase in hematocrit
Large hemodilution- bad! Overtrained.
blood
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What is systolic BP? Diastolic BP? What do they represent?
- SBP- estimate of work of the heart and the force that blood exerts against the arterial walls during ventricular systole.
- DBP- during the cardiac cycle's resting phase, DBP indicates the ease with which blood flos from the arterioles into the capillaries.
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What is the MAP? How is it calculated?
- Mean arterial pressure, how much pressure in the system at all times on average. @ rest=93 mmHg
- MAP= 2/3 DBP + 1/3 SBP
- Q= MAP/TPR
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What does the calculation of MAP tell us about the systolic and diastolic time period?
Diastolic filling time period is longer than systolic. We know this because DBP takes up 2/3rds of MAP.
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What is the procedure for measuring blood pressure?
Place cuff over upper right arm. Inflate cuff to 20-30 mmHg above last known BP or 160-200 mmHg. place stethoscope inbetween arm and cuff and listen for Korotkoff sounds during deflation.
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What are the Korotkoff sounds?
- When measuring BP, you hear an initial 5 sounds.
- 1st- Blood rushing into closed arterial valve, which is the SBP
- 2nd
- 3rd
- 4th- DBP, a bit muffled.
- 5th- disappearance of sound means DBP @ rest.
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What is the normal blood pressure response to exercise? Use Poiseulle's/Ohms Law to explain.
The nomal blood pressure response to exercise is an increase in Systolic Blood Pressure.
- Poiseulle's law= Ohm's Law
- Change in P= fluid viscosity multiplied by cardiac output and length of vessel/radius of vessel
- We can change our fluid viscocity and vessel radius. Vasodilation have a more profound effect than viscosity.
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What is heart rate drift?
- A drop in SV and an increase in HR in ambient heat.
- This is why working out in hot areas decrease intensity so SV does not drop.
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Explain why heart rate is a good parameter to use for exercise training.
HR gives us the rate of perceived exertion.
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Explain the potential limitations to HR monitoring during exercise.
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What is proprioception? How is it important in exercise and sports performance?
Highly specialized sensory receptor sensitive to stretch known as proprioceptors located in muscles and tendons. They relay info about muscular dynamics and limb movememnt to conscious and subconscious portions of the CNS. Allows continual monitoring of progress of any sequence of movement.
Helps with refinement of movememnts and storage of motor patterns "muscle memory" in the cerebellum.
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How is a nerve impulse transmitted down the axon of a neuron? What role does myelin play?
- It's transmitted through an electron gradient.
- Myelin sheath increases the speed of the impulse.
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What is the motor end-plate?
AKA Neuromuscular junction. Interface between the end of a motor neuron and muscle fiber. Nerve impulse is transmitted across the synaptic cleft and reaches the muscle for action.
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What is the neurotransmitter released from the motor neuron?
Acetylcholine!
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Explain the stretch reflex. How can it act as a protective mechanism
- The muscle spindle detects, responds to and modulates changes in the length of the extrafusal muscle fibers.
- Muscle spindle responds to stretch.
- afferent nerve fiber carries sensory impulse from the spindle to the spinal cord.
- Efferent spinal cord motor neuron that activates the stretched muscle fibers.
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How is the stretch reflex utilized to enhance conditioning?
Muscle spindle detects stretch in muscle and assists contraction.. Allows muscle to adjust automatically to differences in load and length.
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Why does repetitive heavy muscle contraction cause a heterogenous blood flow to the muscle?
- Blood vessels run parallel to muscles. Arterioles and capillaries (get bigger through training).
- Heavy repetitive can cause intramuscular pressure to collapse.
- Blood flow becomes heterogenous which mean blood flow goes up and down all the time.??
- Accelerates glycolysis/phosphagen during contraction to keep ATP Pool.
- A good example of this is bicycling.
- Need help o this.
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What is myoglobin? How is it different from hemoglobin?
- Myoglobin is found in the muscle. It stores O2.
- Designed for low PO2
- Doesnt let go until PO2 drops below 5 mmHg
- No Bohr's effect
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What are T-tubules?
Areas in muscle where electron gradient is increased. shoots up action potential.
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What is the sarcoplasmic reticulum? What is its role during muscular contraction?
- Provides structural integrity to the mmuscle cell. It allows the wave of depolarization to spread rapidly from the fiber's outer surface to its inner environment through the T-tubule system to initiate muscle contration.
- It pumps out the Sarcoplasm's Ca+.
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What is a sarcomere?
A sarcomere unit lies between two Z lines with an M band inn the middle. It consists of Myosin (thick filament) and actin (thin filament) and tropomyosin.
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How are myosin and actin configured relative to one another?
Know the cross bridge cycle.
Explain the roles of troponin and tropomyosin in muscular contraction.
- Myosin and Actin attach to each other, which is muscle contraction.
- CrossBridge cycle:
- Activated myosin head connects to actin unveiled by tropomyosin when troponin attaches to Ca+
- actin and myosin bind, releasing ADP + P
- Powerstroke
- Actin and mYosin detach when ATP binds to myosin head.
- Energy from myosin head splitting ATP causes it to be activated and strained, closing the cycle.
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Explain ATP's role in muscular contraction, and how a low ATP pool could induce fatigue.
ATP is required for Myosin and actin to detach. if you cant get them to death, the cycle will slow. ATP pool must be maintained. Atp induce fatigue?
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What are three motor unit types?
Slow Oxidative, Fast oxidative glycolytic, fast glycolytic
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What are the three motor unit types nerve characteristics? How do these nerve characteristics explain the performance of the fiber types?
- SO or I:
- Small, less fibers, very fatigue resistant, oxidative.
- FOG or IIa:
- Medium, medium fibers, fatigue resistant, oxidative and glycolytic.
- FG or IIb:
- Large, more fibers, not very fatigue resistant, glycolytic
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Which are recruited first, SO or FG motor units? Why?
- ON TEST! SO > FOG > FG!!!
- WHy?
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What are the metabolic characteristics associated with the motor unit types? Structural characterisitics?
Darker due to a lot of mitochondria?
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How does chronic endurance training change motor unit characteristics?
Normal sized muscle fibers. tendency toward enlargement of the slow twitch fibers.
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What types of atheletes would have large percentages of slow twitch fibers? Fast twitch?
I would wanna say endurance runners for slow. And weight lifter for fast
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What is rhabdomyolysis? If you have symptoms, what should you do?
- Myoglobin in Urine due to muscle damage. Caused by New exercise, long exercise or "heavy Negative"
- It's lethal, can cause kidney failure and disturbs potassium balance, blood clots.
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How has muscle fiber typing potentially skewed our understanding of muscle adaptation?
We think people are "fast twitch" or "slow twitch" based on their performance, when in ...
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What are myosin light chains?
Proetin associated with myosin head. Involved in power stroke. COntraction force (favors) and velocity. 3 types.
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Can slow twitch fibers have Type IIa Myosin Heavy Chains in them?
Yes. What? How?
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What do current training studies tell us about Myosin heavy Chain composition in response to training stimuli?
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What effect would you expect on MHC composition if a patient was put on bed rest for two weeks? What about if an athelete began an extensive resistance exercise program?
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