ICL 1.1: Heart & Pericardium Flashcards
when does the heart start to beat?
23 days
what is the pericardium?
double-walled fibroserous sac which surrounds and covers the heart and roots of great vessels
- serous pericardium (visceral and parietal)
- fibrous pericardium
what are the 2 divisions oft the serous pericardium?
- parietal layer = lines the inside of the fibrous pericardium
- visceral layer covers the outside of the heart and has a special name = epicardium
what is the fibrous pericardium?
connective tissue layer outside of the parietal serous layer that forms bulk of the gross pericardial sac
it’s fused to adjacent connective tissue planes
what are the 2 pericardial sinuses?
- oblique
- transverse
slide 9
what are the boundaries of the pericardium?
superiorly: fuses with adventitia of great vessels at level of the sternal angle
inferiorly: fuses with fascia of the diaphragm
laterally: fuses with mediastinal pleura
posteriorly: fuses with adventitia of esophagus –> the heart sits on the esophagus! the pericardium helps the heart not move and bounce around and crush the esophagus
what is the blood supply of the pericardium?
- pericardiacophrenic from internal thoracic**
- musculophrenic
- internal thoracic
- esophageal aa. from aorta
- bronchial aa.
- pericardial – directly from aorta
which nerve innervates the pericardium?
- phrenic nerves
- vagus nerves
- sympathetic trunk
what is the function of the pericardium?
the pericardium contains approximately 10 to 15 cc’s of serous fluid
the function of the pericardium is to limit or prevent acute pathological distension of the heart once the pericardial reserve volume has been used up and the pericardium is stretched
the pericardial attachments maintain the heart in its normal position and are so arranged that external forces exerted on the pericardium by respiration or changes in body posture tend to cancel each other and maintain a constant heart position
what is cardiac tamponade?
the pericardial sac allows for the heart to have free movement within the pericardium
if there’s a bleed in the pericardium, the collection of blood in the pericardial sac is a limiting factor for the heart beating because the pericardium can only be stretched so much
so the heart will be confined and the ventricles won’t be able to expand all the way due to the pressure buildup and cardiac output will be reduced
what are the layers of the heart wall?
- epicardium = visceral layer of the pericardium; external covering of heart
subepicardium = between epicardium and muscles; contains fat and major vessels to the heart
- myocardium = middle muscular layer; oblique fibers
- endocardium = inner lining layer composed of endothelium backed by thin connective tissue
subendocardium = just outside the endocardium and contains tissues of the conducting system
where is the apex of the heart?
5th intercostal space at the midclavicular line
where is the base of the heart?
it’s where you see the aorta, pulmonary trunk and superior vena cava
what are the various surfaces of the heart?
slide 20-23
where is the left atrium?
on the posterior surface of the heart!!
it sits on the esophagus!!!!!!!
where is the coronary sinus located?
between the left atrium and ventricle on the posterior surface of the heart
what are the 4 valves of the heart?
- tricuspid valve = right atrioventricular valve
- mitral valve = left atrioventricular valve
- pulmonary valve
- aortic valve
what is the tricuspid valve?
between the right atrium and right ventricle
what is the mitral valve?
between the left atrium and left ventricle
what is the pulmonary valve?
it closes the orifice of the pulmonary trunk, which consists of three semilunar valves, or cusps
what is the aortic valve?
it closes the aorta and also consists of 3 semilunar valves or cusps
what is the structure of the atrioventricular valves?
fibrous rings and chordae tendineae!
the chordae tendineae go from the valves and extend and attach to the papillary muscles
it’s like a parachute!
what is the function of the infundibulum?
it funnels all the blood from the right ventricle into the pulmonary trunk
inFUNdibulum FUNnnels blood
aka conus arteriosus which developed from the bulbis cordis –> the pulmonary trunk develops from the conus arteriosus
what are the semilunar valves?
the aortic and pulmonary valves!
right and left coronary artery openings are in the aortic valve along with the aortic sinus
where do you listen for the semilunar valves?
the 2nd intercostal space
aortic valve is on the right while pulmonary is on the left
slide 50
where do you listen to all the valves during a cardio exam?
there’s liquid flow of blood so when the sound is being propagated from the valve closing, the sound will follow the flow of the blood!! that’s why we listen to the valves in the spots that we do even though that’s not where the valve itself is
slide 50
what are the generic heart sounds and what do they represent? like which valves are opening/closing at each?
lub = first sound (S1) closure of a-v valves (tricuspid and mitral)
dub = second sound (S2) closure of semilunar valves (aortic and pulmonary)
no sounds associated with valves opening
systole between lub and dub
diastole between dub and next lub
what happens to the heart sounds during inspiration?
the lungs create a vacuum so instead of just lub dub, you have the S2 valve splitting the valve between what’s coming from the aortic and pulmonary valves
during expiration, it’s the normal lub dub!
what is the skeleton of the heart?
a fibrous connective tissue to which valves and muscles of the heart are attached
it provides support and rigidity and serves as an electrical insulator preventing conduction between atria and ventricles
what’s the difference in pressure between the right and left ventricle?
the BP in the left ventricle is SO much bigger than the right ventricle
what are the important structures in the right atrium?
- crista terminalis
- musculi pectinati
- fossa ovalis (previously the foramen ovale)
