Week 1 CV Flashcards
What is the primary role of the cardiovascular system?
to transport nutrients to the body’s cells and remove waste products away from the cells
it regulates temperature, acid-base balance and the amount of fluid in the body
what is the role of each part of the cardiovascular system?
(heart, arteries, capillaries, and veins)
heart = pump
arteries = distribution system
capillaries = where the transactions or exchanges take place
veins = collection and return system
what does each side of the heart do?
right = receives blood from the body and brings it to the lungs
left = receives blood from the lungs and pumps it to the body
what is the order of flow through the heart?
system -> vena cava -> right atrium -> tricuspid valve -> right ventricle -> pulmonary valve -> pulmonary artery -> lungs -> pulmonary vein -> left atrium -> mitral valve -> left ventricle -> aortic valve -> aorta -> system
what do the lub and dub of the heart beat represent?
lub = tricuspid and mitral valve closing
dub = pulmonary and aortic valve closing
what are the differences between the artery and veins?
arteries = have thicker muscular and elastic walls to handle higher blood pressures and volume leaving the heart
veins = thin walls and lower blood pressure further away from the pump. have valves that help prevent back flow
what is the role of capillaries?
they are microscopic vessels between the arteries and veins whose walls only contain one layer of epithelial cells.
the walls allow blood cells to travel single file through them exchanging nutrients and waste between the blood stream and tissues
what does muscle pumping do for venous return?
prevents pooling and edema
directs blood back towards the heart
T/F: veins hold 65% of blood at rest
true
what is a varicose vein?
when a one-way valve becomes defective in the vein and leads to the pooling of blood
usually effects surface veins due to less musculature to help compress the vessels
what is phlebitis?
varicose veins with inflammation
what is isovolumetric relaxation?
when all four valves of the heart are closed
in relation to blood pressure what is systole?
when the aortic valve is open
the contraction phase
highest pressure
used to estimate work of heart
pumping into the system
in relation to blood pressure what is diastole?
when the aortic valve is closed
the relaxation phase
indicates peripheral resistance
the filling of the pump
what happens to blood pressure when a person has atherosclerosis or hardening of the arteries?
both systolic and diastolic BP increase due to the increased resistance, decreased elasticity, and endothelial dysfunction (vessel tone)
what is considered normal blood pressure?
either or
<120 systolic
<80 diastolic
what is considered hypertension blood pressure?
either or
>135 systolic
>85 diastolic
what are some treatments for hypertension?
-medications that decrease contractibility
-regular physical activity
-weight loss due to the decrease in the amount of tissue the heart has to supply decreasing stress on the heart
-stress management
-decreased sodium intake and decreased alcohol consumption due to the changes in osmolality of the blood and the amount of fluid in the cardiovascular system
what is the BP response to resistance exercise?
causes and increase in both systolic and diastolic BP due to straining
what happens to systolic pressure with steady rate exercise?
increases with increasing workload
increases quickly initially then there is a linear relationship between workload and systolic BP
what happens to diastolic pressure with steady rate exercise?
remains fairly constant
why does the diastolic blood pressure stay the same as exercise intensity increase?
more muscle fibers are active, more oxygen and blood supply is needed, vasodilation and closed precapillary sphincters open increasing blood flow surface area
what happens to BP during exercise recovery?
-following endurance exercise, there is a hypotensive response
BP temporarily falls below normal resting values
what is BP’s response to upper body exercise?
resistance to flow is increased
smaller vessels in the upper body compress more easily (needs higher pressure to push blood through)
blood pressure increases substantially more with the same workload
when is the heart supplied with blood?
when the aortic valve closes
T/F: the heart can work anaerobically
no it needs oxygen
at rest, what percentage of available O2 does the myocardium extract?
~70-80%
during exercises flow must increase to meet the O2 demand. how much does it usually increase?
4-6 times
the myocardium has a significantly higher mitochondrial density compared with skeletal muscle. this allows the heart to utilize:
glucose, fatty acids, and lactate (coming from working muscle)
how does endurance exercise effect myocardial metabolism?
it increased the ability to use lactate and fatty acids for fuel.
it increase mitochondria and aerobic enzymes
results in decreased reliance on carbohydrates
what is myocardial infarction?
death of the myocardium
results from impaired blood supply
what is the rate pressure product?
an estimate of myocardial work
= SBP x HR
what are the differences in cardiac muscle compared to other types of muscle?
it is striated
contains intercalated discs that allow the electrical signal that causes contraction to spread across the myocardium in a specific manner resulting in coordinated contraction
what is the path of depolarization of the heart?
-impulse spreads from the SA node throughout both atria
-reaches the AV node which delays the spread of the impulse and allows time for efficient blood flow
-travels into the left and right bundle branches then into the perkinje fibers
what does an EKG do?
records the signal of the heart depolarizing
what does each part of the EKG represent? (P wave, QRS complex, T wave)
p wave = depolarization of the atria
QRS complex = depolarization of the ventricles
T wave = repolarization of the ventricles as they recover from muscle contraction
what is intrinsic regulation of heart rate?
inherent rhythm of the SA node
(in a closed system ~100 BPM)
what is extrinsic regulation of heart rate?
neural: direction innervation
chemical: circulate via blood
what are the two extrinsic influences on BP?
sympathetic and parasympathetic
how does sympathetic affect the heart?
increases the work of the heart
catecholamines: chronotropic increase the rate, inotropic increase contractility
adrenergic fibers: key for smooth muscle tone
how does parasympathetic affect the heart?
the relaxation response
slows the heart rate
vagus nerve: cholinergic fibers release ACh, which slows HR
as exercise begins there is a decrease in parasympathetic activity
what determines the amount of blood flow?
the pressure differential from the beginning of the system to the end
what is the equation for blood flow?
pressure gradient x vessel radius4 / vessel length x viscosity
what can cause vasodilation?
temperature, CO2, pH, NO
what can cause vasoconstriction?
epinephrine and norepinephrine
what is nitric oxide?
produced and released by the vascular endothelium
causes relaxation of the smooth muscle and results in vasodilation
what is cardiac output?
volume of blood pumped in 1 minute
Q = HR x SV
what factors affect cardiac output (Q)?
venous return (amount of blood returning from the body)
diastolic filling (how much blood is in the heart chamber before contraction)
strength of contraction
parasympathetic nervous systems (slows HR)
mean arterial blood pressure
what is MAP and what is it used for?
mean arterial pressure: the amount of blood that is getting to the body
used to monitor perfusion of organs
what is normal MAP?
70-110 (need 60 to perfuse organs)
how is Q increased?
increasing preload, contractility and volume
what is preload?
pressure in the venous system that stretched the myocardium
what is ejection fraction?
the amount of blood ejected by the left ventricle during systole
total volume ejected by LV / amount left in LV
stroke volume / end diastolic volume
what is normal ejection fraction (EF)?
> or equal to 55-75%
what is EF in CHF?
~20%
what is dehydrations effect on Q?
leads to lower blood volume because of lower fluid. it decreases Q
what is the difference in cardiac output between men, women and children?
women have 10% lower hemoglobin level than men which results in 5-10% larger Q to compensate
children have a smaller volume
what is the a-vO2 difference?
the amount of oxygen that is extracted from the blood
what is normal a-vO2 difference during rest?
20 ml O2 * dl-1 arterial
15 ml O2 * dl-1 venous
what is normal a-vO2 difference during exercise?
20 ml O2 * dl-1 arterial
5-15 ml O2 * dl-1 venous
what is the V02 equation?
Q x a-vO2 difference
what factors affect the a-vO2 difference?
-redistribution of flow to active tissues during exercise
-increased capillary density due to training increase surface area and O2 extraction
-increased number and size of mitochondria
-increased oxidative enzymes
-vascular and metabolic improvements
how is the distribution of blood directed?
vasodilation and vasoconstriction
what is the difference between VO2max and VO2peak during aerobic or long term energy system?
VO2max = O2 consumption levels off despite an increase in exercise intensity, has been reached
VO2 peak = highest value of oxygen consumption measured during graded test exercise
what are the commonly used VO2max prediction tests?
walking tested - Reebok 1-mile
endurance runs - cooper test
step tests
2 or 6 min walk test
what is the resting value for cardiac output?
~5.0 L/min
cardiac output increases with increasing exercise intensity up to:
~20 to 40 L/min
how does VO2 differ with upper body exercises?
higher VO2 at given submax workload but max VO2 is ~20-30% lower than w/ LE exercises
submaximal arm exercise produces a greater:
HR
pulmonary ventilations
RPE
BP response
than comparable leg exercises
what is the effect of a cardiac transplant on HR response?
HR response is blunted with transplant
