The Heart and Coronary Arteries Flashcards
how many layers does the pericardium have? what are they?
function? (5)
- *- 3 layered sac:**
i) fibrous pericardium
ii) visceral layer - attached to surface of the heart
iii) parietal layer - attached to fibrous layer - *- function:**
i) protec from infections from other organs
ii) attached to great vessels
iii) attached to diaphragm: anchors heart in place & limits movement
iv) prevents excessive dilation of heart in cases of acute volume overload
v) lubrication: allows free movement of heart within the pericardial sac
what is pericardial effusion?
what does it lead to?
difference between acute and chronic pericardial effusion?
- is the buildup of too much fluid between the viseral and parietal pericardium
- leads to pericardial tamponade (when it cant beat)
- the heart normall fills the pericardial sac with a small amount of fluid and doesnt need much space to expand. but when get pericardial effusion, heart has no where to go - cant beat as efficiently: might get collapse of chambers of heart.
acute pericardial effusion: can only accumulate about 150ml before cardiac output is reduced
chronic pericardial effusion: can accumlate about a litre before compromised
when cardiac tamponade occurs - which ventricle is effected?
what can result in ?
- impairs diastolic filling of both ventricles. BUT: the right ventricle is more severely effected bc has thinner ventricle wall
- reduces cardiac output, which can lead to: hypotension / shock
- also causes an increase in venous pressures, pulmonary congestion (blood pools in lungs)
how do you manage cardiac tamponade?
management: pericardiocentesis Pericardiocentesis is a procedure done to remove fluid that has built up in the sac around the heart (pericardium). It’s done using a needle and small catheter to drain excess fluid.
what is difference in cardiac output when have cardiac tamponade, for inspiration and exhlation?
amount of blood that leaves the heart is improved during expiration
during inspiration, diaphragm goes down = less space available. cardiac output is worsened
DURING CARDIAC TAMPONADE, CARDIAC OUTPUT IS WORSENED IN INSPIRATION C.F. EXPIRATION
what are the dfferent layers of heart wall?
epicardium: visercal layer of serous pericardium
myocardium: cardiac muscle fibers. arrnaged in bundles. squeezes blood out of heart
endocardium: continious with endothelium. line chambers and the heart
is the volume of the blood propelled by the right ventricle the same as that propelled by left ventricle in one heart beat?
within a few mls: YES
label the different heart chambers pls xox
on external surface of the heart, what seperates the atria from the ventricles?
whats in them?
where do u find the anterior and posterior interventricular sulcus?
- *coronary groove (aka atrioventricular sulcus)**
contains: coronary arteries and veins
anterior and posterior interventricular sulcus: seperates the right and left ventricles
which BV go into the right atrium and left atrium?
(which BV go leave the right ventricle and left ventricle?)
this is wrong lol
right atrium: SVC, IVC and coronary sinus
left atrium: 4 pulmonary veins - back from lungs to heart, left auricle
right ventricle: 2/3 anterior, pulmonary trunk leaves it
left ventricle: apex (left border), inferior surface (2/3 post), aorta leaves
what are the internal landmarks of the right atrium?
- posterior wall: smooth. thumb sized depression: fossa ovalis
- *- anterior wall:** rough, due to pectinate muscle
- *- sino atrial node:** base of SVC (*)
- atrioventricular node: inferior to coronary sinus (#)
what is the function, location and appearance of the moderator band?
moderator band: Function: provides a shortcut between the anterior and posterior papillary muscles : gives them coordinated contraction during systole and efficient closing of the tricuspid valve.
- Location*: spans between the interventricular septum and the anterior wall of the right ventricle.
- Appearance*: does not seem to be attached to one single side, but rather crossing the lower portion of the right ventricular chamber.
what are the walls of the left atria like compared to the right atria?
- left atria walls are entirely smooth, apart from left auricle, where have pectinate muscle
- right atria: only the posterior wall is smooth, non smooth has pectinate muscle
describe important structures of the left atrium and ventricle xo
where does it go to?
- *left atrium**
- fossa ovalis (?)
- between left atrium and left ventricle: mitrial valve. attached by chordae tendineae and papillary muscles
- *left ventricle**
- thicker myocardium
- tranbeculae carnae: irregular muscular columns which project from the whole of the inner surface of the ventricle
- goes into ascending aorta and aortic semilunar valve
which are the first vessels to branch off the aorta?
what do they branch off into and supply? - what determines dominance between them?
left and right coronary arteries - supply atria and ventricles with o2 blood fo
- Left coronary arteries: supplies / turns into left anterior descending, supplies the left ventricle
- right coronary artery: supplies the posterior descending and posterior lateral
- dominance determined on the posterior lateral and posterior descending artereis and whether come from left or right coronary arteries
what are aortic sinuses?
what is located next to the RCA?
- The aortic sinus, or bulb of the aorta (sinus of Valsalva), is a dilation of the aorta at its origin, from which the coronary arteries arise.
- Get right, posterior and left aortic sinus. left and right go into left and right CA.
- the atrioventricular node is located close (and supplied by the) RCA .
describe the paths of th coronary arteries - what do they both anastmose with?
RCA: anastomoses with circumflex branch of LCA: gives rise to posterior interventricular artery
LCA: loops around apex and branches into left anterior descending (LAD). anastamoses with posterir interventricular artery
what is dominance of coronary arteries determined by?
what % of pop are right, left and co-dom?
- by the arteries that supply the posterior and inferior wall of the left ventricle
- approx. 60% of pop are right dominanted, 25% are co-dom and 15% are left dom
what is the first branch of the RCA?
what is another important thing supplied by the RCA?
why is this imporant
sinus node artery - goes to the sinus atrial node
also supplies the atrio-ventrocular node
RCA is important bc it supplies the two parts of the conducting system: the sino atrial and atrioventricular nodes
where do myocardial infarctions predominately occur?
- *LCA:** ~ 60%
- *RCA:** ~ 30-40%
- *Circumflex of LCA:** ~ 15-20%
what can happen if RCA has myocardial infarction?
- bc the RCA supplies both the SA and AV nodes - can get heart block ( when the electrical signal that controls your heartbeat is partially or completely blocked)
what need to know about coronary veins? where does it drain into ? (2)
- coronary veins drains into the coronary sinus on posterior surface of heart
- THEN, coronary sinus drains into right atria
what type of tissue and what is the function of fibrous skeleton of the heart? (4)
- dense CT surrounds AV and outflow of vessel valves (semi-lunar valves)
-
fuses together and merges with interventricular septum:
i) supports the valves
ii) prevents overstretching of the valves
iii) insertion point of cardiac muscle bundles
iv) electrical insulator between atria and ventricles - gives small delay between atria and ventricles to allow ventricles to fill before ventricles contract
