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46 Cards in this Set

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  • Back
what does CVD mean
cardio vascular disease, it includes the heart and all major blood vessels. Key components of CVD assessment is:
a health history
a physical
monitoring lots of lab and diagnostic test results
where is the heart located?
between the lungs (mediastatnum) and rests on the diaphram. Weighs about 10.6 ozs.
Systole is is contraction
Diastole is relaxation.
So what is happening during diastole?
the heart chambers fill with blood to prepare for its ejection. During Systole, the chambers of the heart smaller as the blood is ejected.
normal heart at rest will beat b/t 60 - 80 times a minute. It will eject around
70 ml of blood per beat and outputs 5 liters a minute.
the heart has 3 layers:
the inner layer=endocardium
the middle layer=myocardium
the exterer=epicardium
so what does the indocardium consists of?
endothelial tissue duh, and
this endothelial tissue lines the inside of the heart and valves. thats it!
then what does the myocardium do?
myocardium is made up of muscle and fiber responsible for the pumping action
what is the thin fiberous sac around the heart called?
pericardium and has 2 layers.
remember the epicaridum? the outside layer? adhering to it is the visceral pericardium.
Enveloping the visceral pericardium is the parietal pericardium, a tough fiberous tissue attached to the:
great vessels, diaphram, sternum, verteral column, and supports the heart in the mediastinum.
there is a space b/t the 2 layers that encase the heart. its filled w/ fluid. about 30ml of fluid. why is that fluid there?
lubs the surface of the heart and reduces friction during systole.
there are 4 heart chambers. duh. the right side is made up of right atrium and right ventricle. what do these do?
distributes venous blood (deoxynigenated) to the lungs via the pulmonary artery (this is the pulmonary circulation).
what 3 things feed the right atrium?
the superior vena cava (head, neck, upper extremitites)
inferior vena cava (trunk, lower extremities)
coronary sinus (coronary circulation) ((the heart itself))
the left side of the heart has the left atrium and left ventricle. what does the left side of the heart do for us?
distributes oxygenated blood to the remainder of the body via the aorta (systemic circulation). The left atrium receives o2 blood from pulmonary circulation via pulmonary veins.
the walls of the heart are different in their thickness. why is this
well, the heart is thin in the atriums b/c this is where blood returns. The ventricles are thicker b/c blood is pumped from there during systole.
what does the right venticle have to push against?
right ventricle has to push against low pulmonary vascular pressure so isn't as thick as its left ventricle brother's walls. which has walls 2 1/2 thicker because of the high systemic pressures it pumps against. Look at a picture and see how much thicker the L venticle is compared to the R ventricle.
Dig this. the heart is rotated for some reason SO, if you shoot someone thru the heart, the bullet goest thru what part first?
the bullet would go thru the right ventricle first (its just behind the sternum) and the left ventricle is behind that. So pictures of the heart distort this fact.
there are 4 valves in the heart. blood should only flow in one direction, the right direction. there are 2 types of valves. Name them and win a million dollars
atrioventicular valves
semilunar valves
what are atrioventricular valves?
the valves that seperate the atria from the ventricles. thats it! Ex. the tricuspid valve has 3 cusps or leaflets, seperates the R atrium from the R venticle. The mitral (bicuspid) valve, lies b/t the L atrum and L ventricle. so, thats the Tri and Mi are atrial/venticle valves, got it?
OK OK these atrial ventricle valves close, there are 2 deals in there that help with this valve closing. what?
1) papillary muscles
2) chordae tendineae

these 2 things help maintain valve closure.
OK during systole, contraction causes the papillar muscles the chordae tendineae to become taut, keeping the valve leaflets approximated & closed.
what do the semilunar valves do?
there are 2 semilunar valves. One is b/t the R ventricle and pulmonary artery called the pulmonic valve. The valve b/t the L ventricle and aorta is called the aortic valve.
so what do the coronary arteries do? First of all there are left and right coronary arteries. They originate from the aorta. The heart is a huge o2 user, extractly around ...
70% to 80% of the o2 delivered. other organs usually require only 25% of the delivered o2 !
The heart is weird. The coronary arteries are perfused during diastole. (Diastole is the period of time when the heart relaxes after contraction. Ventricular diastole is when the ventricles are relaxing, while atrial diastole is when the atria are relaxing.) how are you going to remember what diastole means?
die = stop
so diastole means to take a break, die down, relax
there is venticular diastole and atrium diastole.
think about this one:
an increase in heart rate shortens diastole and can decrease ...
myocardial perfusion. Patients w/ CAD (coronary artery disesase) can devlope myocardial ischemia (low o2 supply) when the heart rate accelerates.
the L coronary artery has 3 branches.
L main coronary artery
L anterior descending coronary artery
whats the other L coronary artery called?
the circumflex coronary artery
kind of wraps around the side of the L side of the heart
the R side of the heart has the R coronary artery
and the ...
posterior descending coronary artery.
the heart itself is a muscle, the myocardium muscle basically, a specialized muscle. resembles striated muscle like skeletal muscle, a muscle under conscious control. But functionally, ...
the heart muscle resembles smooth muscle b/c if contractions are involuntary. The myocardial muscle fibers are arranged in interconnected manner called syncytium that allows for coordinated myocardial contraction and relaxation. The sequential pattern of contraction/relaxation of individual muscle fibers ensures rhythmic behavior of the myocardium as a whole
3 things going on with the firing of the heart.
automatically: initiate impl
excitablility: ability to resp
and ...
conduitibility: ability to Transmit electrical impulse
the speicailized cells in the heart coordinate the transmission of electrical impulses to the myocardial cells. what is the result?
sequential atrioventicular contraction.
SA node = sinoatrial node. referred to as the primary ...
pacemaker of the heart.
at the junction of the superior vena cava and right atrium. in a normal resting heart has a firing rate of 60 to 100 impulses per minute, but can change for any metabolic reason.
So the SA initiates electrical impulses along the myocardial cells of the atria via specialized tracts called ...
internodal pathways. These impulses are directed down these pathways to the AV node, the Atrioventricular node. Its located in the R atrial wall near the Tricuspid
valve.
what does the AV valve do?
the AV node co ordinates the incoming electrical impules from the SA and after a slight delay, relays the impulse to the ventricles. this impulse is conducted by the bundle of HIS, a specialized conduction cells that travel in the septum seperating the L and R ventricles. The L conducts to the L ventricle and R conducts to the R ventricle.
To transmit impulses to the largest chamber of the heart, the L bundle bifurcates in to the L anterior and L posterior bundle branches. So, what determines the heart's firing rate?
the myocardial cells w/ the fastest inherient firing rate. The SA is always the fastest, then the AV node the next fastest rate. If the SA malfunctions, the AV b/c the pacemaker. If BOTH fail, a pacemaker site in the ventricule will fire at a bradycardia rate of 30 - 40 impulses per minute!
The transmission of electrical current in the heart is known as Cardiac ...
cardiac action potential
ions charged particels like potassium, sodium, calcuim. A charged cardiac cell (has potential, has a charge or difference devolped) b/t a - charged inside and a + charged outside of the cell membrane. remember the charged cell inside is - neg.
as a charge impulse starts, cell permibility changes...
then sodium moves rapidly into the cell, while potassium exists the cell. This ion exchange begins ...
depolarization
converting the internal charge of the cell to a postive one. Contraction of the myocardium follows depolarazation. This means the inside cell charge changes from - to a + charge. This Depolarization is just one specialized cell continues until depolarization and contraction continues until the whole myocardium has contracted.
So what is Repolarization?
return to the cell to its resting state. so what?
the cell returns to its baseline or resting state, this corresponds to relaxation of myocardial muscle.
where exactly is the SA node located?
at the junction of the superior vena cava and the R atrium. The firing of electrical impulses causes contraction of the atria.
where is the AV node located? (atria/ventricular node)
in the right atrial wall near the tricuspid valve and consists of another group of specialized cells similar to those of the SA node
What bundle of specialized conductions cells connectes the AV node to the R and L ventricles?
the bundle of HIS connects the electrical pathway from the AV node to the Venticles. This pathway is in the septum wall that seperates the L and R ventricles. HIS divides into a bundle branch to the R and a bundle branch to the L ventricle. Its important to note the L side (b/c the ventricle is so big) has a further dividing into the L anterior and L posterior bundle branches.
These electrical signals will terminate at a point at which the myocardial cell ae stimulated causing ventricular contractin. what is this point called?
Purkinje fibers

Purk in je fibers are the terminating point of the electrical impulses from the SA node, AV node, thru the bundle of His to the Purk inje fibers.
muscle how?
during the prolonged refactory period, it cannot be restimulated to contract. Skeletal muscle isn't like that. 2 phases of refactory period:
1) absolute refactory period- time during which the heart cannot be restimulated to contract regardless. This period corresponds w/ depolarization and early part of repolarization. The latter part of repolarization, if the electrical stimulus is stronger than normal, the myocardium can be stiulated to contract. This short period is called the RELATIVE REFRACTORY PERIOD
what do refractioniness do for the heart?
protect it from sustained contraction (tetany) which could cause sudden cardiac death!
what fluid is crucial for the electomechanical coupling & contraction of the heart?
the interstitial fluid surrounding the heart muscle cells does this. So, the composition of this fluid is based on the blood's composition that supplies this. A change in the calcium in this blood can alter contraction of the heart muscle fibers. A change in the potassium concentration affects the voltage of the cells.
an important concept in the heart is the concept of blood flow from a region of hi pressure to low pressure. What happens at the start of systole?
blood pressure rises rapidly
this forces the AV valves to close, this stops blood from flowing from the atria into the ventricles. Rapid rise of pressure inside R and L ventricles forces pulmonic and aortic valves to open. and blood goes into pulmonary artery and aorta.
What happens at the end of systole?
pressure in the R and L ventricles drops and this lowers pulmonary and aortic pressures, this causes the closure of the semilunar valves. This marks the onset of diastole.
which are relaxed during diastole?
the ventricles are relaxed at diastole, the atrio ventricular valves are open SO blood returning from the veins flows into the atria and then into the ventricles.
what event causes the atria muscles to contract in response to a electrtical impulse?
the SA node firing an electrical impluse does this, causes the atria muscles to contract
what is cardiac output?
amt of blood pumped by each ventricle during a given period. Cardiac output when the heart is at rest is around 5 liters. Caridac ouptut is figured by multiplying stroke vol. by heart rate.
what is stroke volume?
amt of blood ejected per heart beat. ave. around 70 mL.