Posted by matt Oglesby on August 23, 2009 at 00:20:10:
In Reply to: Heart posted by isz on August 21, 2009 at 21:11:07:
I only answered a portion of these questions.
If you know the ones I left blank, post some knowledge.
If you dont like what I wrote, or would like to expand on it, feel free to make all necessary follow up changes.
1. What is the apex and base of the heart? How are they oriented in the body?
apex is on the atrial side, which is pointing dorsally to the right side of the body.
base is on the ventricular side, facing ventrally and pointing left.
2. Define the pericardium - fibrous coat and serous pericardium.
its a bilayer of serous membrane mesothelial tissue.
the fibrous coat provides connective tissue attachments on the outer aspect of the parietal layer of the pericardium.
the serous pericardium is the mesothelial layer which produces pericardial fluid to fill the cavity between the visceral and parietal layers of the pericardium.
3. What "anchors" the heart in the thorax?
the fibrous coat of the pericardium attaches collagenous fibers to the diaphragm (specifically the central tendon thereof). It also grabs onto the Inf. Vena Cava and the great blood vessels superiorly.
4. What is venous mesocardium?
5. What is arterial mesocardium?
6. What is the transverse sinus?
refers to a groove anterior to the entering point of the Sup. Vena Cava (in the R. Atrium) and posterior to the Pulm Trunk & Ascending Aorta.
7. What is the oblique sinus?
8. What is epicardium? Myocardium? Endocardium?
Epi = outer layer of heart wall. synonymous with visceral layer of pericardium.
myo = muscular layer of heart.
endo = innermost layer of heart, lines the chambers.
9. What is the blood supply to the heart?
off the Ascending Aorta = R/L coronary arteries.
RCA branches into the marginal artery on the R side of the heart. The RCA goes posteriorly and in the post. interventricular septum to form Posterior Interventricular Artery.
LCA is short. Dives down ant. interventricular septum to form the LAD. Runs laterally to the left (as the circumflex artery) and around to the posterior.
The venous system consists of a Greater Cardiac Vein (anterior venous analog to the LAD), and the Lesser Cardiac Vein (posterior venous analog to the Post. Interventricular Artery). They each drain into the Coronoary sinus.
10. In the right atrium, define the: crista terminalis, sulcus terminalis, pectinate muscles, coronary sinus, fossa ovalis.
11. In the right ventricule, define the : trabeculae carnae, papillary muscles, chordae tendinae, moderator band, conus arteriosus/infundibulum.
trabeculae carnae = beams of meat. these are muscles of the chamber walls.
The moderator band is a misnomer and is referred to as the septomarginal trabecula. It is a specialized stream of myocytes that is used for propagating electrical conduction.
papillary muscles hold onto the cusps of the AV valves via chordae tendinae to prevent prolapse during ventricular contraction.
12. Contrast the right atrium with the left atrium in terms of structure.
13. Contrast the right ventricle with the left ventricle in terms of structure.
left is bigger to allow for systemic perfusion.
14. What is the interventricular septum?
wall between the ventricles.
15. Discuss the structure and function of the atrioventricular valves.
right has a tricuspid valve.
left is a bicuspid. AKA mitral valve.
function is allow blood to trickle into ventricles during diastole, and to prevent regurgitation of blood back into the atria during systole.
16. Discuss the structure and function of the semilunar valves.
no chordae tendinae needed. operate on the basis of utilizing weighting nodules which push the cusps together when faced with pressurized backflow of blood on the "cupped" side of the valves.
17. Define the skeleton of the heart.
18. Define the SA node, AV node, AV bundle, moderator band, and Purkinje fibers.
SA node is a site of specialized muscle cells called myocytes which set the pace of the contractions.
AV node at the AV line and receives signal from the SA node. Passes it along through AV bundle, moderator band, and up the ventricular walls via the Purkinje Fibers.
19. Discuss the cornary arteries of the heart.
20. Discuss the coronary veins of the heart.
21. What is the cardiac cycle - systole/diastole?
systole = .4 sec = atrial/ventricular contraction
diastole = .4 sec = atrial/ventricular relaxation
22. Why is there no correlation to the thoracic projections of the valves of the heart with the sites of auscultation?
sound will carry more through certain structures such as ribs.
23. What is the ductus venosus?
embryonic shunt from the PA to the Arch of the Aorta.
24. What is the foramen ovale?
embryonic shunt of blood from RA to the LA. Avoided RV (since it would have sent the blood to the lungs) IF blood was sent to the RV, the ductus venosous would work to shunt it out of the PA and to the Asc. Aorta.