7 structure of the heart Flashcards
Where does the heart lie?
behind the sternum in the mediastinum. behind ribs 2-5.
Where is the apex of the heart located?
Behind the 5th rib along the midclavicular line
What protects the heart?
- ribs
- sternum
- fibrous periacardum
What is the job of the fibrous pericardium
- tough unstretchy bag that stops the heart from over filling
- attached to the diaphragm and fused to the great vessels
- to anchor the heart in place
What is the structure of the fibrous pericardium?
- visceral and parietal pericardium
- parietal attached to the fibrous
- FP made of dense CT
- visceral (epicardium) attached to the heart wall
- serous fluid between the membranes makes movement frictionless
- gap between membranes = parietal cavity
What are the layers of the heart wall?
- epicardium/visceral pericardium
- myocardium
- endocardium
What does the epicardium contain?
lots of fat and blood vessels
What does the myocardium contain?
Lots of muscle - very thick layer
What does the endocardium consist of?
simple squamous endothelial cells for a smooth interior of the heart wall
What is another name for the visceral pericardium?
Epicardium
What is the name of the gap between the visceral and parietal pericardium?
Parietal cavity filled with serous fluid so two pericardial layers can glide on each other with no friction
Where is the bi cuspid valve?
between the left ventricle and atria
Where are the mitral valves?
between the ventricles and atria
Where are the semilunar valves?
Between the ventricles and aorta/pulmonary artery
Where are the atrioventricular valves?
where do you think, stupid?
Where is the tricuspid valve?
between the right ventricle and atrium
Talk about the action of the AV valves…
- conncted to papillary muscles by chordae tendinae
- as atria fills and pressure builds they open into ventricles
- as ventricles fill and pressure builds they are pushed back up and try to open into the atria causing eversion
- papillary muscles tense up and pull chordae tendinae tight preventing them from doing this
Whats eversion?
Flow of blood back into the atria due to backwards valves
Action of the semilunar valves:
- pushed open when ventricular pressure exceed aortic pressure
- during diastole they are pushed shut by blood pooling in the cusps
How are the coronary vessels fed?
- when systole the semilunar valves cover the entrance to them
- during diastole blood pooled on the cusp flows into the vessels to feed heart
- better this way coz otherwise vessels would be all squeezed up
What are the coronary vessels?
LCA -anterior inter ventricular vessel -circumflex RCA -posterior interventricular vessel -marginal
Which artery does the anterior interventricular vessel come off
LCA
Which artery does the posterior interventricular vessel come off
RCA
Where is the circumflex
vessel that wraps from the front of the hear round the back around aorta
