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59 Cards in this Set
- Front
- Back
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what about the pulmonary circuit of the heart? |
-right side of the heart -pumps deoxygenated blood to the lungs via pulmonary arteries (from the body system) -returns oxygenated blood to the left side of the heart via pulmonary veins |
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what about the systemic circuit? |
-left side of the heart -pumps oxygenated blood to the whole system body via arteries (aorta) -returns deoxygenated blood to the right side of the heart via veins (vena cava) superior = above heart// inferior= below heart |
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what is the myocardium? |
-the heart wall -receives blood supply via coronary arteries--high demand for oxygen and nutrients |
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what is myocardial infarction? |
-blockage in coronary blood flow results in cell death/damage -exercise training protects against heart damage during MI - this is because exercise helps to increase the number of capillaries |
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what is the epicardium, myocardium, pericardium, and endocardium responsible for? |
epi- protective in nature myo- is the function of the muscle endo- protective as well peri- fluid filled sack that lubricates the heart |
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what is systole? |
contration phase -ejection of blood -2/3 blood is normally ejected from ventricles per beat/less than 2/3 if unhealthy -at rest, diastole is longer than systole during exercise, both systole and diastole are shorter |
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what is diastole? |
relaxation phase -filling with blood -at rest, diastole is longer than systole during exercise, both systole and diastole are shorter |
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what does muscle pump and increased diaphragm help? |
helps pump blood back to the heart |
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what about the pressure changes during diastole? |
-pressure in ventricles is low -filling with blood from atria -AV valves open when ventricular pressure is less than atrial pressure -this allows blood to flow from atria to ventricle |
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what about the pressure changes during systole? |
-pressure in ventricles rises -blood ejected in pulmonary and systemic circulation -semilunar valves open when ventricular pressure is greater than aortic pressure -allows blood to flow from LV to aorta |
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what are the heart sounds heard during pressure changes during the cardiac cycle? |
first- closing of the AV valves/ prevents back flow into atria second: closing of aortic and pulmonary valves/ prevents back flow to lungs and aorta |
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generally speaking, what is normal systole and diastole? what is systolic pressure? what is diastolic pressure? |
120/80 mmHg -systolic is pressure generated during ventricular contraction -diastolic pressure in the arteries during cardiac relaxation, there should be very little pressure generated by the heart during relaxation |
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what is pulse pressure? |
difference between systolic and diastolic (SBP-DBP) |
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what is MAP |
mean arterial pressure -average pressure in the arteries (at rest) during exercise the .33 becomes .5 - MAP = DBP +33(SBP-DBP) |
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what are some of the determinants of mean arterial pressure? |
-cardiac output= HR(bpm) times SV(ml/beat)=ml/min -total vascular resistance- resistance in system/ resistance aorta has to overcome- diastolic blood pressure MAP=cardiac output times total vascular resistance |
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what about short term regulation for arterial blood pressure? |
-sympathetic nervous system -baroreceptors in aorta and carotid arteries (pressure receptors) -increase in BP = decreased SNS activity - decreases BP - Decrease in BP = increased SNS activity - increase BP |
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what about long term regulation for arterial blood pressure? |
-kidneys (fluid/H2O control) if a lot of water is in system, increases blood pressure - via control of blood volume |
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what does contraction of the heart depend on? |
electrical stimulation of the myocardium |
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what makes up the conduction system? |
-sinoatrial node- pacemaker, initiates depolarization by opening Na gates -atrioventricular node- passes depolarization to ventricles, brief delay to allow for ventricular filling (diastole > systole) -bundle branches- to left and right ventricles -purkinje fibers- throughout the ventricles |
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what is cardiac output? |
the amount of blood pumped by the heart each minute -product of heart rate and stroke volume |
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what exactly is heart rate? |
each contraction of the LV (number of beats per minute) |
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what exactly is stroke volume? |
amount of blood ejected in each LV contraction |
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what is Q? |
HR times SV |
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what does cardiac output depend on? |
training state and gender -resting HR will decrease and SV will increase; men have larger hearts |
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what is the average cardiac output for humans? what does it mean to have an increased Stroke Volume? |
5 L/min larger chamber size |
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what does the parasympathetic division of the nervous system do to regulate HR? |
-via Vagus nerve -slows HR by inhibiting SA and AV node- decreased depolarizing rate |
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what does the sympathetic division of the nervous system do to regulate HR?
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-via cardiac accelerator nerves -increases HR by stimulating SA and AV node |
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what about the regulation of heart rate? |
-low resting HR due to parasympathetic tone -increase in HR at onset of exercise -initial increase due to parasympathetic withdrawal-- up to 100bpm -later increase due to increased SNS stimulation (E/NE) |
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in regards to the regulation of stroke volume, what about the End-Diastolic Volume (EDV) |
volume of blood in the ventricles at the end of diastole (filling) Diastole ("preload") |
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what is the average aortic blood pressure resistance? |
-pressure the heart must pump against to eject blood ("after load") |
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what is the mean arterial pressure at rest? at exercise? |
rest- DBP + 1/3 (PP) exercise- DBP + 1/2(PP) |
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how is the strength of the ventricular contraction enhanced? |
-circulating E and NE - direct sympathetic stimulation of the heart |
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what is the Frank Starling Mechanism? due to what? dependent on what? |
greater EDV results in a more forceful contraction -due to stretch of ventricles -dependent on venous return |
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how is the venous return increased? |
venoconstriction -via SNS increase DBP Skeletal muscle pump -rhythmic skeletal muscle contractions force blood in the extremities toward the heart -one way valves in veins prevent back flow of blood Respiratory pump -changes in thoracic pressure pull blood toward the heart |
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what are some of the physical characteristics of blood? |
plasma -liquid portion of blood -contains ions, proteins, hormones cells -RBC -contain hemoglobin to carry oxygen WBC -important in preventing infection Platelets -important in blood clotting Hematocrit -percentage of blood composed of cells (solid portion of blood) |
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what is blood flow? |
-directly proportional to the pressure (difference between 2 ends of the system) -inversely proportional to the resistance (flow increase = resistance decrease) blood flow = change in pressure/resistance |
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what is blood pressure? |
-proportional to the difference between MAP and right atrial pressure (change in pressure) vena Cava |
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in regard to hemodynamics (blood movement), what does resistance depend on? |
-length of the vessel -viscosity of the blood -radius of the vessel Resistance = length x viscosity/radius^4 |
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what are sources of vascular resistance? |
MAP decreases throughout the systemic circulation -largest drop occurs across the arterioles -arterioles are called "resistance vessels" |
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Oxygen demand by muscles during exercise is ___ greater than at rest? |
15-20 times |
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during exercise, increased O2 delivery accomplished by? |
-increased cardiac output -redistribution of blood flow--from inactive organs to working skeletal muscle |
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why does cardiac output increase during exercise? |
increased HR - linear increase to max increased stroke volume -increase, then plateau at 40% of VO2 max |
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for adults, what is the max HR? |
220-age(years) plus/minus 15bpm this is 80% of adults |
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for children, what is the max HR? |
208-0.7 x age (years) |
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during exercise, what about the arteriovenous difference? |
there is a higher difference -amount of O2 that is taken up from 100ml blood -increase due to higher amount of O2 taken up -used for oxidative ATP production |
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what is the Fick Equation? |
math equation for VO2 -relationship between cardiac output (Q), a-vO2 (arteriovenous) difference, and VO2 |
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what does VO2 equal? |
VO2=Q x a-vO2 difference VO2= HR x SV x aVO2 difference |
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know figure 9.22 |
figure 9.22 |
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regarding the redistribution of blood flow during exercise, what happens? |
increased blood flow to working skeletal muscle -at rest, 15-20% of cardiac output to muscle -increases to 80-85% during maximal exercise -Decreased blood flow to less active organs-- liver, kidneys, and GI tract -redistribution depends on metabolic rate--exercise intensity |
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what happens to local blood flow during exercise? |
skeletal muscle vasodilation -autoregulation -bloodflow increased to meet metabolic demands of tissue (deliver oxygen) due to changes in O2 tension, CO2 tension, nitric oxide (vasodilator), potassium, adenosine, and pH Vasoconstriction to visceral organs and inactive tissues -SNS vasoconstriction |
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what are some of the circulatory responses to exercise? what does it depend on? |
-changes in HR and BP depends on- -type, intensity, and duration of exercise (arm vs leg exercise) -environmental condition (hot/humid vs cool) -emotion influence (can raise pre-exercise HR and BP) |
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what happens at the onset of exercise? |
-rapid increase in HR (up to 100bpm, withdrawal parasympathetic/ past 100, sympathetic stimulation) SV (muscle pump, resp. pump), cardiac output - plateau in submaximal (below lactate threshold) |
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what happens during recovery? what does it depend on? |
decrease in HR, SV, and cardiac output toward resting values -depends on duration and intensity of exercise and training state of subject (fit recover faster) |
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during incremental exercise, what happens to HR and cardiac output? |
-increases linearly with increasing work rate -reaches plateau at 100% VO2 max |
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during incremental exercise, what happens to BP? |
mean arterial pressure increases linearly -systolic BP increases -diastolic BP remains fairly constant or may decrease in fit person |
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during incremental exercise, what is a double product (rate-pressure product)? |
-increases linearly with exercise intensity -indicates the work of the heart |
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arms vs legs at the same O2 uptake, arm work results in higher? |
HR -due to higher sympathetic stimulation (b/c arms have smaller musculature) BP -due to vasoconstriction of large inactive muscle mass/ not working legs |
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regarding intermittent exercise, what does recovery of HR and BP between bouts depend on? |
-fitness level -temp and humidity- if higher, increased time of recovery -duration and intensity of exercise |
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during prolonged exercise, what happens? |
-cardiac output is maintained/sub max steady state -gradual decrease in SV--due to dehydration and reduced plasma volume -gradual increase in HR-- cardiovascular drift |
