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what does cardio mean?
what does vascular mean?
- vascular=blood vessels
what are the 4 components of the cardiovascular system?
what do they do?
- - heart: provides continuous linkage with other 3 components
- - arteries: acts as a high pressure distribution gradient
- - capillaries: act as exchange vessels
- - venous system: is a low pressure collection and return circuit
characteristics of the myocardium (heart/cardiac muscle)
- -short branched fibers with transverse striations that are connected by intercalated disks
- -nucleus is single and central
- -strong quick rhythmic contractions; pumps blood from the heart
- -involuntary: intrinsically stimulated by the autonomic nervous system
what are the 3 functions of the heart?
- -main transport system
- -circulates blood
- -relates blood flow
specifically, what is the function of the left ventricle? right ventricle?
*really understand heart structure. pg 304
- right: receives blood returning from the body and pumps the blood for gas exchange (aeration) in the pulmonary circulation (capillaries)
- left: receives oxygenated blood from the lungs and pumps it into the aorta for distribution throughout the body (systemic circulation)
What do arteries do? Does gas exchange happen in arteries? why/why not?
What are arterioles? what characteristics make them important? why?
Arteries distribute oxygenated blood to the body. Gas exchange doesn't happen because the walls of them are so thick
they're smaller branched arteries made of smooth muscles that relax and contract to regulate blood flow through the vascular unit. this is important because they make sure muscles used during physical activity are well oxygenated by redirecting blood flow
what is blood pressure
where does blood pressure come from? (the cause) what is a pulse?
- since vessels dont carry blood as quickly as it ejects from heart, the aorta swells and stores a portion of the blood creating a pressure gradient for the arterial system. a pulse is a wave of pressure caused by the stretch and recoil of the arterial walls during cardiac cycles
- pulse rate=heart rate
blood pressure=cardiac output x total peripheral resistance
what is cardiac output?
what 2 factors determine cardiac output?
How do you measure it?
the volume of blood pumped by the heart (pressure through the arterial system) per minute
- Heart rate: the number of time a person's heart beats per minute
- Stroke volume: the amount of blood exiting the ventricle (usually referring to left) during systole (contraction)
CO=HR x SV
does systolic vs diastolic mean?
remember, generally in reference to left ventricle of the heart
- systole- contraction phase
- diastole- relaxation phase
what is systolic blood pressure and purpose of measuring?
what is the average?
where is the best place to measure?
- -the pressure generated by contraction of the left ventricle
- -the purpose is to see how much the heart is working and the amount of force put on the arteries during ventricular contraction
- -120 mm Hg
- -the brachial artery
what is diastolic pressure measuring?
what is average?
- -the amount of flow (or resistance) from the arteries to the capillaries during diastole (relaxation of the ventricles)
- -average is 80 mm Hg
What does MAP stand for? what is it for?
Why is MAP so much closer to diastolic pressure rather than systolic pressure?
what is average MAP?
- -mean arterial pressure
- -measures average pressure in a person's arteries
- -the heart stays in diastole longer than systole
- -93 mm Hg
what effects pulse pressure?
SV and compliance of arteries
how do you measure MAP?
MAP= SBP+ (DBPx2) /divided by 3
ex. if blood pressure is 83mmHg/50mmHg then the MAP would = 61mmHg
how do you measure pulse pressure (PP) and stroke volume (SV)?
- systolic BP, diastolic BP
- end systolic volume, end diastolic volume
what is total peripheral resistance?
the resistance of arteries to blood flow. when they constrict there is more resistance/less flow, when they relax there is less resistance/more flow.
what is the relationship between cardiac output and peripheral resistance? (how to calculate each)
What happens to resistance during exercise versus during rest? why?
CO=MAP/total peripheral resistance
*total peripheral resistance=MAP/cardiac output pg. 309
ex. if at rest you have BP of 120/80 (MAP=93.3), and CO of 5.0Lpermin, then total peripheral resistance would be 18.7mmHg per L per min
ex. if in strenuous exercise you have BP of 210/90 (MAP=130), and CO of 35.0Lpermin, then total peripheral resistance would be 3.7mmHg per L per min
- resistance in the arteries decreases significantly to allow more blood flow during strenuous activity
- systolic pressure rises considerably more than diastolic (less rest time, more pump is happening) and there is more cardiac output.
what is the important relationship between stroke volume and exercise intensity?
what 2 ways do you affect SV? explain
increase in exercise activity=increase in SV
Frank-starling mechanism: changes in EDV (the ability to stretch to hold more blood) causes an increase in increase in contractility for a higher stroke volume
Frank starling is for stretch that leads to contractility! Frank starling isnt contractility!
*the heart can change its force of contraction in response to venous return
what is the Fick equation? write it, explain it
what are the factors that affect it?
what is VO2 and VO2 Max
- -measurement of O2 consumption is the product of 2 factors: the cardiac output and the difference in the artery O2 and the vein O2
- VO2=Q x a-vO2 diff
- -affected by central and peripheral factors
-determines the rate at which a person uses oxygen in their body: O2 transport, or VO2
- -VO2: the volume of oxygen uptake
- -VO2 max: the max amount of oxygen uptake
what does VO2/VO2 max functionally represent?
the ability to create ATP!
understand relationships of VO2 max, stroke volume, max HR, and cardiac output
Our stroke volume can increase to our highest VO2 max and our max heart rate reflects our max cardiac output
discuss the importance of the heart size
- -the heart size generally reflects heart size
- -big body explains more hemoglobin, more blood volume
- the key here is bigger body=higher VO2 max
- its important that there is a good ratio of large heart size compared to body size
- -this leads to more fatigue resistance
describe the function of capillaries at rest compared to during exercise
what causes this?
During rest, fewer capillaries are utilized than available. But when exercise intensity increases, the driving force of increased blood pressure (perfusion) in the muscles and local metabolites (vasodilation) cause an increased use of capillaries to deliver oxygen to that muscle
this is why larger muscles develop more capillaries. they need more oxygen
what causes varicose veins?
when the valves in veins fail to maintain their one way blood flow, blood gathers in them and causes them to be back up and distended.
what contributes to most of venous return?
muscular activity and the compression (milking type of contractions) to the veins
how does lack of venous return effect cardiac output? result?
is lowers cardiac output and MAP, so the heart tries to pump faster because its trying to get blood moving and causes people to faint
what is hypertension? what can cause it?
-increased blood pressure
"hardening" of fatty materials in the vessels, creating a thicker layer
excessive peripheral resistance to blood flow because of malfunction in kidneys or neronal hyperactivity
-lifestyle changes and medication
what effects blood pressure?
- the type/mode of exercise you're doing
- -resistance, steady-rate, graded exercise, upper body exercise, and recovery
how does resistance exercise effect blood pressure?
resistance exercise causes straining that compresses the arterial vessels that supply the muscle. This means there is an increase in total peripheral resistance and a lowering of muscle perfusion.
to combat this and restore muscle flow, the sympathetic nervous system, cardiac output, and MAP increases (BP increases)
how does endurance (rhythmic) training effect blood pressure?
- endurance training encourages vasodilation, so there is less total peripheral resistance. the contraction and relaxation of the muscles creates a good pump that encourages venous return. systolic pressure will initially increase, but then level off again because the arterioles have dilated.
- diastolic, unchanged
how does graded exercise effect blood pressure?
systolic blood pressure will initially rise dramatically from rest, but then it'll steadily increase while diastolic BP stays stable (doesn't really change)
there won't be in increase in total peripheral resistance, but systolic pressure is increased because of a high cardiac output. more graded leads to higher HR.
how does upper body physical activity effect blood pressure compared to lower body?
there is a smaller muscle mass and vasculature in the upper limbs compared to the lower limbs. so when this is more isolated, there is a greater resistance to blood flow for blood supply to the muscles
how do you estimate max HR?
what is the better formula to use?
better way? 206.9-(0.67xage)
how does recovery from exercise effect blood pressure?
blood pressure falls below the pre-exercise BP
what does EPOC stand for
excess post oxygen consumption
what is the relationship between VO2 and HR?
as heart rate increases, VO2 increases
how is the heart internally regulated?
the sinoatrial (SA) node, or pacemaker, repolarizes and depolarizes to create a simulus for heart action impulses
what is the impulse pathway of the heart?
SA node, atria, AV node, AV bundle (purkinje fibers), ventricles
what does the heart do during depolarization and repolarization? which is diastolic and systolic?
- depolarization-contraction (systolic)
- repolarization-relaxation (diastolic)
what is the time frame called when there is ventricular filling during diastole
what is the function/purpose to extrinsic heart regulators?
in relation to exercise
extrinsic controls accelerate the heart in anticipation of exercise then rapidly adjusts according to the intensity of the physical effort
which N.S. nerve fibers occupy the atria and ventricles?
- atria- parasympathetic and sympathetic
- ventricles- sympathetic
what hormones cause more rapid depolarization?
is this sympathetic or parasympathetic?
epinephrine and norepinephrine
associated with vasodilation
what hormone slows the HR
how is this significant in speeding up the HR
-its the inhibition of this hormone that causes the heart to speed up during exercise
what peripheral input affects the heart's rate?
chemoreceptors, mechanoreceptors, and baroreceptors in the muscles and vascular system create afferent impulses
what are the 3 most common methods of measuring cardiac output
- Direct ficks
- Indicator dilution
- CO2 rebreathing
what two variables must we know for the direct fick method when calculating cardiac output
- -the amount of oxygen being consumed in one minute
- -average difference between the oxygen content of arterial and venous blood (a-vO2 diff)
what is the indicator dilution method?
it is used to measure cardiac output
a green dye is inserted into a large vein, which goes through the body, lungs, and out of the heart where is is seen by a photosensitive device showing the CO of the arteries
CO=amount of injected dye/dye concentration in the curve x duration of curve
What is the CO2 rebreathing method?
measures cardiac output by doing a breath by breath analysis of gas exchange (v-aCO2 diff)
what 2 factors explain why endurance athletes have such high stroke volumes and low heart rates
- - they have an increase in parasympathetic tone and a decrease in sympathetic drive, which slows the heart
- - the high compliance (stretch) of their heart causes a higher contractility, and increased stroke volume = high CO
what are the 3 ways you can enhance stroke volume?
- increase ventricular filling during diastole (increased stretch/compliance.. think frank starling mechanism) preload
-increase the contraction/ejection in the myocardium during systole. afterload
-training adaptions that expand/increase blood volume and reduce resistance to blow flow in peripheral tissues (encourages compliance)
What is cardiovascular drift?
-cardiovascular drift: slight increase in HR even though exercise is constant, and reduced stroke volume
when the body's heat rises during exercise, blood moves to the periphery to encourage heating. decrease in blood plasma leads to the decrease in venous return to the heart causes an initial decline in stroke volume. The heart begins to compensate by increasing the heart rate to maintain a nearly constant cardiac output as activity progresses an body temp increases.
What are the effects of cardiovascular drift on exercise? (2)
- -if CV drift didn't occur, we would have to exercise at even lower intensities that we do at higher temperatures (allows us to maintain intensities at high temps)
- -CV drift (inc HR+dec SV) leads to decrease in VO2 max. Causes a decrease in performance or max power output
What is HR a good marker for? Like, what is a good use, what is it a reflection of or telling us
total body stress
not exercise intensity
since HR tells us more about the body's stress, rather than the intensity of exercise.. what are some good ways to indicate intensity?
pace, power output, RPE (rate of perceived exertion)
Describe the distribution of CO, or blood plasma throughout the body during rest versus exercise
what is the exception?
- rest- blood is flowing to kidneys, brain, liver, etc
- exercise- up to 84% (or just most of it), goes to the muscles
blood flows to the tissues in proportion the metabolic demands of the body during various activity
heart and brain, actually increases
what does the body circulate more oxygenated blood than it utilizes?
it is a kind of oxygen reserve as a margin of safety between the transition of rest to maximum physical effort (dramatic changes like getting up and sprinting)
if a person has a low VO2 max, what could you assume about their CO?
it is also low
if a person has a low CO, what could you assume about their max VO2?
it is also low
what is unique about woman and teen's cardiac output compared to men, regardless of their hemoglobin count
- women have 10% less hemoglobin than men, and generally exercise submaximally, but still have higher cardiac output
what 2 mechanism increases the consumption of oxygen during exercise
- -increased cardiac output, or total volume of blood pumped by the heart
- -increased use of oxygen already held in the blood (expanded a-vO2 diff)
what is hemoconcentration?
what 2 mechanisms cause this?
-the increase of hemoglobin (RBCs) in the blood because of the decrease in plasma volume that is moving to the interstitial space of the tissues
- 1) increase in capillary hydrostatic pressure as blood pressure rises
- 2) metabolic byproducts that osmotically draw fluid into tissue spaces from the plasma
what factors affect the a-vO2 diff during physical activity?
- -some central tissues decrease blood supply to supply active peripheral tissues during exercise
- -some muscles have a greater size and number of capillaries to fibers ratios, which increases the use of oxygen in the blood in order to create more ATP (certain muscles have more mito, also influenced by training)
what are the differences in O2 consumption, HR, and pulmonary ventilation during upper body exercises compared to lower body exercises during maximal exercise? why?
there is about 20 to 30% lower oxygen consumption in the upper limbs, and a lower maximal HR and pulmonary ventilation because there is generally a smaller muscle mass. which means less mitochondria
what are the differences in O2 consumption, HR, and pulmonary ventilation during upper body exercises compared to lower body exercises during submaximal exercise? why?
why is there such a change in oxygen cost? 2 reasons
- -submaximal efforts show that since there is a much lower mechanical efficiency of the upper body compared to lower body, so it uses more energy
- -when you use the upper body during submaximal efforts you end up recruiting additional musculature to stabilize the torso
physiologically, why does the upper body cause more strain during submaximal efforts than the lower body? (increased HR, more O2 consumption, more pulmonary ventilation, and more perceptions of effort)
- theres a larger muscle mass being used*
- 1) greater feed-forward stimulation from the brain's central command to the medulla
- 2)increased feedback from the active tissue to the medulla (greater strain=more feedback to medulla... the medulla increases HR and BP)
what is the role of the medulla during exercise?
increase HR and BP
physiologically, why does the upper body cause more strain during maximal efforts than the lower body? (dec HR, less O2 consumption, less pulmonary ventilation, and less perceptions of effort)
- There is a lower muscle mass being used*
- 1)less feed forward stimulation from brains central command to medulla
- 2) less feedback from active tissue to medulla (less strain)
what is the pattern of the number of muscle mass activation in the upper body during maximal efforts vs submaximal efforts?
- max efforts=less muscle activation
- submaximal efforts=more muscle activation
why do lower limbs use more oxygen than upper limbs during submaximal exercise?
but what is the main point to remember, generally?
At submaximal effort, the lower limbs are more efficient=less strain and less consumption. Where as, to perform at the same level, the arms have to put in way more work than the legs=more oxygen consumption. But at a higher level, max exercise, obviously our legs are way stronger than our upper limbs, regardless of how many muscles the upper limbs activate to help. So, in that case at max effort the lower limbs use more oxygen.
*the upper limbs consume and need more oxygen supply than the lower limbs
what was the old knowledge of stroke volume in comparison to HR?
what do we know now?
they thought SV maxed about 120 bpm because at 120 bpm, there wasn't enough time to fill ventricles with blood. so if you wanted to maximize SV you had to train at 120bpm. thinking was the CO (or Q) could only be increased by the HR, and that SV couldnt get bigger. Balke thought that at 180bpm, CO went down.
this isn't true during exercise. SV doesn't stop at 180 bpm. SV can be increased all the way to VO2 max (CV capacity) in highly trained people. Max HR=Max Q (cardiac output)
what is the ratio of hematocrit
- 55% plasma
- 45% cells/protein- most is RBCs, 1% is white cells and platelets
Are you getting an A on this exam?
understand what hematocrit of normal vs anemia vs blood doping vs dehydration
what is the most adaptable portion and most immediate of the blood and most immediate change during exercise training? how fast? what happens?
plasma volume, increases in 2-3 days of hard training.
what happens to hematocrit when plasma volume is increased during exercise training
what the "fine line" message to take away about increases in increased PV? think about relation to VO2
how does the enhanced blood volume a good thing? (what is this called)
- increase of plasma volume=decrease in RBS (hematocrit) (goes away quickly too)
- MILD RBC increase with it
an increase of plasma volume vs hematocrit is a good thing, it increases VO2. But too much of an increase of plasma volume to the point of anemia, is actually a bad thing and causes a decrease in VO2.
it encourages venous return, which causes increased EDV (frank starling stretch mechanism), greater CO. sports anemia. Increase of plasma in BV, not decrease in hematocrit
what is the LIMITING factor of VO2 max?
- -Central factors, or Cardiac output (HRxSV), how much oxygen we can deliver 70%. 30% is the ability of the muscle to extract O2 from blood
- -to increase VO2 we have to increase CO
what kind of central adaptions happen with training?
- -your heart rate decreases when you exercise submaximally and during rest. thats why athletes have to exercise at max, intensity is important
- -the max HR increases minimally. if your max HR starts going down, you're being overtrained
sign of over training?
-the max HR increases minimally. if your max HR starts going down, you're being overtrained