Middle Mediastinum Flashcards
(44 cards)
Why is the pericardial sinus important?
deliniates aorta and pulmonary trunk, and diverts blood flow if something is placed in there. surgeon then has bloodless field in which to work.
P wave represents?
QRS complex?
T wave?
P wave- atrial depolarization
QRS complex- ventricular depolarization
T wave- ventricular repolarization
Explain the electrical aspect of the P wave. PR interval? QRS interval? ST interval? T wave?
P wave- SA node fires, atria contract, pulse sent to AV node
PR interval- AP is delayed at AV node, and depolarization of atria continues
QRS interval- Ventricular depolarization
ST segment- Beginning of ventricular repolarization.
T wave- ventricular repolarization.
What is the base of the heart?
The left atrium.
What makes up the diaphragmatic surface of the heart?
The ventricles.
Where do the aorta, inferior vena cava, and esophagus pierce the diaphragm?
Inferior vena cava- T8
esophagus- T10
Aorta- T12
What is the auricle of the heart, and what is its purpose?
Small muscular flap that increases blood flow capacity of the atrium.
What is the sinus venarum, and where is it?
It is a smooth surface on the posterior wall where the superior and inferior vena cava empty in to.
Where is the crista terminalis and what is it?
origin of the pectinate mm, on the anterior wall.
What is the sulcus terminalis?
External feature that marks the (internal) crista terminalis.
Where exactly is the SA node located?
At superior aspect of sulcus terminalis, and lateral/inferior to the opening of the superior vena cava.
Where is the fossa ovalis, and what was it in the fetus?
It is in the interatrial wall, and was the foramen ovale in the fetus.
What are the muscle ripples called in the ventricles?
Trabeculae carnae
What is the supraventricular crest?
separates the conus arteriosus from the rest of the right ventricle (separates inflow and outflow tracts)
What do the chorda tendinae attach to in the right ventricle?
The anterior, posterior, and septal cusps.
What is at the apex of the conus arteriosis? What level is this at?
The pulmonary valve. at the level of 3rd costal cartilage.
What is the aortic vestibule? How is it oriented anatomically?
Outflow area from left ventricle. Located antero-superior.
explain the point of papillary muscles
during ventricular systole, pressure in the atria is very low. Blood would backflow, but the papillary mm contract to keep the AV valves closed.
What is stenosis, and what happens? (mitral/aortic valve stenosis)
valve does not open fully, so less blood flows out of chamber.
What is insufficiency/regurgitation, and what happens?
Valve fails to close completely, so some blood goes back into previous spot.
What is a heart murmur?
Extra/unusual heart sound. Can be innocent or abnormal.
What does the RCA supply? (5-7)
The interventricular septum, left ventricle (diaphragmatic myocardium), right ventricle, right atrium, AV septum, and usually the SA and AV nodes
Which coronary artery is usually dominant? What makes one dominant?
The RCA is usually dominant. Dominance decided by which gives rise to the posterior descending artery.
Right coronary artery arises from? Gives what brr, and where? How does it travel? (include all the way to its anastomoses)
- Arises from right aortic sinus and travels down AV groove
- gives off marginal a. branch
- courses to posterior of heart, and gives off AV nodal branch at the crux (where all 4 chambers meet)
- Posteriorly, it gives off the posterior descending branch (posterior interventricular), which travels in posterior interventricular groove toward the apex of the heart.
- Also gives off perforating brr to supply ventricles, and the IV septal br to supply the IV septum.
- Continues to anastomose w/circumflex of the LCA.
