Cardio Flashcards
What is the pericardium?
serous membrane that surrounds and protects the heart
What is the function of pericardial fluid?
reduces friction between layers
What is another name for the tricuspid valve?
atrioventricular valve
what is another name for the pulmonary valve?
semilunar valve
what is another name for the bicuspid valve?
mitral valve (atrioventricular valve)
what is another name for the aortic valve?
semilunar valve
What valves have chordae tendinae and papillary muscle?
tricuspid and bicuspid
Where does the blood circulates starting with the right atrium?
Right atrium through the tricuspid valve into the right ventricle through the pulmonary valve, into the pulmonary trunk and pulmonary arteries into the pulmonary capillaries, to the pulmonary veins into the left atrium through the bicuspid valve into the left ventricle then through the aortic valve into the aorta and systemic arteries to tissues. Then blood is brought back to the Right atrium by the coronary sinus, inferior vena cava, and the superior vena cava.
Through which vessels does blood enter the right atrium?
superior vena cava, inferior vena cava, and the coronary sinus
Through which vessels does blood enter the left atrium?
pulmonary veins
Is blood leaving the left ventricle oxygenated or deoxygenated?
oxygenated
Is blood leaving the right ventricle oxygenated or deoxygenated?
deoxygenated
Is blood entering the right atrium oxygenated or deoxygenated?
deoxygenated
What is meant by the term “systemic circulation”?
the system of carrying oxygenated blood to tissues and the deoxygenated blood back to the heart.
what vessel does the right and left coronary arteries branch off of?
the ascending aorta
What area of the body does the brachiocephalic trunk, left common carotid artery, and the left sub-clavian artery supply blood to?
brain
what are of the body do the right and left common iliac arteries supply blood to?
organs
where is the SA node located?
top of the right atrium
where is the AV node located?
bottom right of the right atrium
where is the bundle of His located?
behind the AV node
What is the mechanism by which valves open and close?
pressure
which valves have papillary muscle and chordae tendinae associated with them?
Atrioventricular valves (tricuspid and bicuspid)
What is the function of papillary muscle and chordae tendinae?
keep valves from opening backwards
What are the five phases of the cardiac cycle?
Atrial contraction, isovolumetric contraction, ejection, isovolumetric relaxation, ventricular filling
What happens to left ventricular volume during each of these phases?
Stays the same during isovolumetric contraction and relaxation. Increases during filling and atrial contraction. Decreases during ejection
What happens to left ventricular pressure during each of these phases?
Pressure remains constant during ventricular filling and atrial contraction. Pressure increases during isovolumetric contraction, decreases during isovolumetric relaxation. During ejection there is a period where the pressure increases then it will decrease.
Describe when the mitral valve closes during the cardiac cycle?
The mitral valve closes when the pressure in the left ventricle is higher than that of the left atrium. It closes during at the beginning of the isovolumetric stage.
Describe when the aortic valve opens during the cardiac cycle.
The aortic valve opens when the pressure in the left ventricle is greater than that of the aortic and systemic arteries. This is during the ejection phase and through the isovolumetric relaxation phase.
Describe when the aortic valve closes during the cardiac cycle.
The aortic valve closes at the end of the isovolumetric relaxation phase. This is due to the pressure in the left ventricle being lower than the pressure in the aortic artery.
does atrial contraction force the AV valves to open?
no
What is the definition of preload?
the stretch state before a ventricle contracts
what is the definition of afterload?
the pressure the heart has to overcome to eject the blood
what is the definition of contractility?
the ability for cardiac muscle to produce tension
how does an increase in venous return affect preload of the left ventricle?
the farter the cardiac muscle stretches the greater activation caused
how does aortic pressure affect afterload of the left ventricle?
the left ventricle has to pump harder to eject the blood
If preload and contractility both affect strength of contraction, what is the difference between them?
pre-load is dependent on sarcomere length
What is the function of the atria?
to enhance the amount of blood in ventricles, which enhances ventricular pumping
What is the function of the ventricles?
to pump blood through pulmonary circulation and systemic circulation
what can occur with damage to chordae tendinae or papillary muscle?
results in backward flow of blood as ventricles contract and could be lethal
What occurs during atrial contraction?
AV valve is open; atrium pumps blood into ventricle
what occurs during period of isovolumetric contraction?
Ventricle begins to contract-once pressure in ventricle exceeds that of atrium the AV valve will close. This period of contraction while the AV valve and semilunar valve are closed is the isovolumetric contraction phase. Once the pressure in the ventricle exceeds that of the aorta then the semilunar valve will open.
What occurs during the period of ejection phase?
as ventricular pressure rises above arterial pressure, semilunar valve opens and blood is ejected out of ventricles
what occurs during the period of isovolumetric relaxation?
ventricle begins to relax; pressure begins to drop within ventricles, as pressure drops below arterial pressure, semilunar valve closes. This period of relaxation while both valves are closed is the isovolumetric relaxation phase. ventricle continues to relax and eventually the pressure drops below that of atrium and therefore the AV valve opens.
What occurs during the ventricular filling phase?
passive filling of ventricle
what is systolic blood pressure?
the pressure in the systemic arteries while the left ventricle is contracting and ejecting blood
what is the diastolic blood pressure?
the pressure in the systemic arteries while the left ventricle is relaxing and not ejecting blood
What is end diastolic volume?
the amount of blood in the ventricle before it contracts (110ml)
What is End systolic volume?
the volume of blood in the ventricle at the end of systole (40ml)
How will an increase in afterload affect ESV?
Increase it due to more blood being left behind in the ventricle
How would aortic stenosis affect afterload?
increase it
What effect does increased afterload have on SV?
Decreases it due to slower volume
What is stroke volume?
The volume of blood pumped out of the left ventricle per contraction (70ml)
What is ejection fraction?
the fraction of EDV that was pumped out of the left ventricle per contraction (55-70%)
Ejection fraction =?
(SV/EDV)*100
What is cardiac output?
the amount of blood pumped out of the left ventricle per minute?
CO=?
HR * SV
What is venous return?
the amount of blood returned to the heart
what is the primary determinant of preload?
EDV
what is the primary determinant of afterload?
aortic pressure
In order to increase contractility, does there have to be an increase in EDV?
No, it is independent of fiber length or stretch
What is cardiac reserve?
The work that the heart is able to perform beyond that required of it under basal/resting conditions (300-400%)
Presence of what heart sounds may be an indication of an abnormality?
S3: vibrations during rapid phase of ventricular filling.
Where does gas exchange occur?
pulmonary capillaries
which of the types of vessels have smooth muscle and thus are capable of constriction and dilation?
muscular arteries
are arteries or veins more compliant?
veins
define blood pressure?
a measure of the force that the blood exerts on the vessel walls
how do you calculate MAP from blood pressure?
MAP=DBP + (1/3) (SBP-DBP)
Why does MAP represent the pressure gradient in the systemic circulation?
due to the pressure in the right atrium being nearly 0mm Hg
how does an increase in CO affect MAP?
increase it
how does an increase in TPR affect MAP?
increase it
What is another name for TPR?
systemic vasculature resistance
does TPR represent venous resistance or arterial resistance and why?
arterial resistance because veins are so compliant
What effect does Ang II directly have on CO and TPR?
increases both by increasing arterial pressure
what effect does aldosterone directly have on CO and TPR?
no effect directly
what effect does ADH have on CO and TPR?
increases vasoconstriction which will increase blood volume
what effect does ANP directly have on CO and TPR?
increases vasodilation which will decrease blood volume
what effect does the SNS directly have on CO and TPR?
Increases vasoconstriction and increases blood volume
what effect does the PNS directly have on CO?
decreases CO through a decrease in heart rate and decrease in stroke volume
Does the PNS directly affect TPR?
No, has no affect on vasculature dilation or constriction
What is the baroreceptor reflex?
senses pressure change of blood and oxygen, CO2, and H+ levels
What will the baroreceptors do when they notice a decrease in blood pressure?
In a decrease of BP the would decrease firing rate which will increase SNS which in turn increases activation of alpha one and beta one receptors to ultimately increase pressure
What is the function of arteries?
transport of oxygenated blood
what is the function of arterioles?
act as valves for entry into capillaries
what is the function of capillaries?
gas and nutrient exchange
what is the function of venules?
collects blood from capillaries
what is the function of veins?
carry deoxygenated blood back to the heart.
Do capillaries have smooth muscle?
No, they are unable to constrict or dilate
Can arterioles and venules constrict or dilate?
yes, they have smooth muscle
why do veins contain valves?
to prevent backflow of blood
MAP=?
CO * TPR
Pulse pressure =?
SBP-DBP
Greater stroke volume results in ____ pressure rise with each heart beat?
greater
Lower compliance of artery results in a ____ pressure rise with every beat?
greater
What is TPR?
the resistance to blood flow through all of the vasculature in the body (represents arterial vasculature)
What is the venous pump?
rhythmic contraction of skeletal muscle helps to push blood in the veins towards the heart; thus it increases venous return
What is the respiratory pump?
during inspiration, abdominal pressure increases and intrathoracic pressure decreases
What is RAAS?
Activation of the RAAS system will increase blood pressure
What does Ang II cause?
vasoconstriction
What does ADH do?
increases blood pressure through vasocontriction
What does the V1a receptor cause?
vasocontriction
what do the V2 receptors do?
mediate antidiuretic effects in the kidney
What does ANP do?
lowers blood pressure through vasodilation
What does the alpha-1 adrenergic receptor do?
causes constriction of most vessels of the body
Stimulation of beta two receptors causes what?
vasodilation
generalized activation of the SNS will increase blood pressure and decrease organ perfusion throughout the body except where?
in the heart and brain
Majority of blood vessels are/are not innervated by PNS?
are not
what are baroreceptors?
stretch receptors located in walls of large arteries
What are chemoreceptors?
carotid bodies and aortic bodies sense decrease in oxygen and CO2 and H+ content
What are atrial and pulmonary stretch receptors?
detect changes in pressure in low pressure areas
Is blood flow to each organ equal?
No
At rest, what gets the most blood flow?
organs excluding the heart and brain
during exercise what gets the most blood flow?
skeletal muscle
does smooth muscle require an action potential, initiated by the nervous system, to contract?
no
what types of stimuli can stimulate contraction or relaxation of smooth muscle?
nervous signals, hormonal stretch/stimuli, and changes in environment chemically
what factors contribute to the increased blood flow to skeletal muscle during exercise?
increased O2 demand, arteriovenous O2 difference increases
Why does cardiac output increase during excercise
activation of the SNS
Why does stroke volume plateau with increasing intensity of exercise after an initial increase during exercise?
The heart has less time for filling thus will have a lower EDV and a limited SV
What is causing the SBP to increase during exercise?
The left ventricle is contracting harder to try and get more blood around the body
Why does DBP not change during exercise?
To increase space for increased blood flow the arteries dilate
What is the primary determinant of SBP?
CO
Why is the RPP (rate-pressure product) increasing during exercise?
HR, SPB, and MAP are increased
What is the primary determinant of DBP?
TPR
What determines TPR?
the tone of arterial vasculature
What can lactate cause?
vasodilation
What does endothelin do?
vasoconstriction
what does bradykinin do?
arteriole dilation and capillary permeability
what do prostaglandins do?
arteriole dilation and capillary permeability
what does histamine do?
arteriole dilation and capillary permeability
What is oncotic pressure?
pressure determined by protein concentration
what is hydrostatic pressure?
pressure exerted by a fluid
how would an increase in capillary/blood hydrostatic pressure affect the movement of fluid out of the capillary?
increase flow out
how would an increase in capillary/blood oncotic pressure affect movement of fluid out of the capillary?
decrease flow out (increase flow in)
At the arterial end of the capillary is net filtration or reabsorption favored?
net filtration
at the venous end of the capillary is net filtration or reabsorption favored?
reabsorption
is all of the fluid that was filtered at the arterial end then reabsorbed at the venous end?
no
what is the role of the lymphatic system in the process of capillary fluid movement?
carries away remaining fluid in the interstitial
what is edema and how does it develop?
rate of fluid that enters the interstitial is greater than what the lymphatic system can remove
what is the danger of edema?
gas exchange in the capillaries is compromised
Why are cells of the SA node autorhythmic?
Fibers of SA node are leaky to Na
By what mechanism does the SNS increase HR?
releases norepinephrine which increases Na permeability
By what mechanism does the SNS increase contractility?
releases norepinephrine which increases Na permeability
By what mechanism does the PNS decrease HR?
releases Ach which increases K permeability
What is the purpose of the long ARP of the ventricular myocyte action potential?
prevents development of a tetanic contraction
What does the P wave represent?
atrial depolarization
What does the QRS complex represent?
ventricular depolarization
What does the T wave represent?
ventricular repolarization
What does it mean when the QRS complex comes back to the baseline on the ECG?
both atria have fully depolarized
Why is the P-Q interval sometimes called the P-R interval instead?
There is not always a Q wave
What does the X-axis on the ECG represent?
Time
What does the Y-axis represent?
energy (mV)
Is a wave of depolarization a wave of positive or negative charges within the muscle cell?
positive
Is a wave of repolarization a wave of positive or negative charges within the muscle cell?
negative
A wave of positive charges moving towards a positive electrode would result in an upward or downward deflection on the ECG?
upward
A wave of positive charges moving towards a negative electrode would result in an upward or downward deflection on the ECG?
downward
A wave of negative charges moving towards a negative electrode would result in an upward or downward deflection on the ECG?
upward
What is a lead?
angle view of the heard using two different charged electrodes (different does not necessarily mean different charges)
Which leads are limb leads?
1, 2, 3, AVR, AVL, AVF
Which leads are chest leads?
V1-V6
In lead II of the ECG, the QRS complex should be upward or downward?
upward
In lead aVR of the ECG, the QRS complex should be upward or downward?
downward
In lead aVF of the ECG, the QRS complex should be mostly upward or downward?
upward
Chest leads run horizontal through the chest: True or False?
TRUE
Why is the transmission through the AV node slower?
due to smaller fibers and fewer gap junctions
What is the natural pacemaker of the heart?
the SA node
Fibers of the SA node connect directly to ____ ____ ____ of the atria.
regular myocardial fibers
How much time does each small box on the EKG show?
.04 seconds
How much time does each large box on the EKG show?
.20 seconds
How much voltage does each small box on the EKG show?
.10 mV
How much voltage does each large box on the EKG show?
.50 mV
How do you determine HR from an EKG?
Find R wave that falls on heavy black line and count off 300, 150, 100, 75, 60, 50 for each consecutive heavy line until you fine the next R wave
What is a PAC?
premature contraction…originates suddenly in an atrial ectopic focus and produces an abnormal P wave earlier than expected
What is a PVC?
premature ventricular contraction; QRS is very wide and deep, originates in actopic focus in a ventricle, occurs before a P wave can begin a new cycle
What is atrial flutter?
p waves occur in rapid succession and each is identical to the next
Why will an atrial flutter only occasionally produce a QRS complex?
due to the AV node not having enough time to repolarize
What is ventricular flutter?
ventricular flutter is produced by a single ectopic focus firing at an extremely rapid rate…forms no p or t waves
What is atrial fibrillation?
caused by many atrial ectopic foci firing at rapid rates causing an exceedingly rapid, erratic atrial rhythm…no true p wave just spikes, will not directly kill but blood may pool
what is ventricular fibrillation?
caused by a rapid-rate discharge from many foci, only depolarizes a small area and will not have effective pumping…will directly kill you (erratic EKG)
What is a sinus block?
the SA node stops its pacing activity for at least one cycle, p waves identical but one is missing every so often
what is an AV block?
delay in transmission, primary has a longer P-R interval, secondary has a progressive P-R prolongation until QRS is dropped, tertiary is a complete block
What does an EKG with bundle branch block look like?
it has “rabbit ears” as a QRS complex
what is ischemia/infarct?
inverted symmetrical T waves
What do elevated or depressed S-T segments show?
sign of acute injury, can return to baseline with time
what is significant about very significant Q waves?
these are used to make a diagnosis of an MI at some point
What is the difference between primary and secondary hypertension?
secondary is drug related
how would overstimulation of the SNS increase blood pressure?
Increase CO and TPR
How would increased activation of RAAS increase blood pressure?
Not enough excretion out of blood and too much reabsorption
What are some contributing mechanisms of how insulin resistance and hyperinsulemia increase blood pressure?
higher oncotic pressure
Why does an increase in blood volume increase blood pressure?
arteries and veins can only hold so much until volume can not change thus pressure will increase
How does decreased secretion of bradykinin and nitric oxide contribute to hypertension?
decreased vasodilation
How does increased secretion of endothelin contribute to hypertension?
increased vasoconstriction
Where in the body is cholesterol synthesized?
Liver
What enzyme converts HMG-CoA to mevalonate?
HMG-COA reductase
What is a lipoprotein?
carry cholesterols and triglycerides
What role does endothelial injury play in development of atherosclerosis?
formation of plaque
How does atherosclerosis alter blood flow?
increase pressure
List three things that can cause endothelial injury.
Shear stress, smoking, hypertension
How does hypertension contribute to atherosclerosis development?
shear stress
How does hypercholesterolemia contribute to development of atherosclerosis?
LDL can become oxidized and inhibit vessel protection
How does hyperglycemia contribute to atherosclerosis?
Decrease in Nitric Oxide and increase in cell proliferation
What is the mechanism of action of statins and how does this help in reducing risk of atherosclerosis?
HMG-CoA reductase inhibitor, less cholesterol in circulation
What are chylomicrons?
Transports dietary cholesterol and triglycerides to various tissue in body
what is VLDL?
very low density lipoprotein, transports mostly triglycerides from liver to adipose tissue
What is IDL?
intermediate density lipoprotein, remnant of VLDL after it delivers triglycerides to tissue, may be cleared from the blood via direct uptake by the liver or remodeled into LDL
what is LDL?
low density lipoprotein, transports mostly cholesterol from liver to various tissues of body
what is HDL?
high density lipoprotein, transports cholesterol from peripheral tissues back to liver where it can be excreted via bile
What characterizes heart failure?
failure to pump adequate blood to satisfy body’s needs
what types of conditions can cause heart failure?
disorder of coronary arteries, HTN, cardiomyopathy, heart valve disorder, abnormal heart rhythm
How can coronary artery disease cause heart failure?
decrease in CO and TPR
How can hypertension cause heart failure?
leads heart to hypertrophy where it will eventually wear itself out
What is the difference between systolic and diastolic heart failure?
systolic is a pumping problem where diastolic is a filling problem
what is the purpose of increased SNS and RAAS activation?
to increase blood pressure
How can chronic activation of the SNS cause progression of heart failure?
causes cardiac cell apoptosis, increase in BP, and increase in O2 uptake by other tissues
how can chronic activation of RAAS cause progression of heart failure?
arrhythmias, cardiac fibrosis
define decompensation
loss of cardiac reserve
Why does tachycardia occur in heart failure?
increased heart rate to try and increase the CO
why does a decrease in cardiac reserve occur?
weakening of the heart muscles
why does SOB occur in heart failure?
less oxygen available to tissues
Why does edema occur in heart failure?
less reabsorption in the pulmonary capillaries
How does failure of the left ventricle lead to failure of the right ventricle?
Right ventricle has to overcome increased pressure because the left ventricle cannot pump enough blood out, overtime the right ventricle will weaken as well
