The Heart Flashcards
How do you know if a heart is enlarged when looking at an x-ray?
>50% of the lateral distance of the front view (inspiration) at the diagram.
Where is the apex beat?
L5icsmcl (left 5th intercostal space, midclavicular line).
What are the layers of the pericardium?
Parietal which attaches to the mediastinum.
Visceral which attaches to the heart.
How is the heart orientated in the chest?
Tilted backward and rotated anticlockwise (looking down on it).
This is why the left atrium is the most posterior portion of the heart.
What are the two different muscle tissue types in the right atrium and what is the structure which separates them?
Atrium proper: anterior and contains the pectinate muscles.
Sinus of venae cavae: posterior and has a smooth wall.
Crista terminalis is the point where the two merge, it extends from the superior vena cava to the inferior vena cava
What is the fossa ovalis?
Large oval like structure which sits at the intra-atrial septum (left and right atrial wall). Was the foramen ovalae which was a foramen which allowed oxygenated blood which has arrived in the right atrium from the placenta to be diverted directly toward the systemic circuit. At birth this fuses with connective tissue.
What is the function of the valve of inferior vena cava and valve of coronary sinus?
They direct blood flow toward the left ventricle chamber.
Name the cusps of the
- Tricuspid valve.
- Pulmonary valve.
- Mitral/bicuspid valve
- Aortic valve.
- Tricuspid valve: Anterior, septal and posterior cusp.
- Pulmonary valve: Anterior, right and left cusp.
- Mitral valve: Anterior and posterior cusp.
- Aortic valve: Left, right and posterior cusp.
Label.
Each leaflet from the AV valves are associated with ______ _______ which are connected to _________ muscles.
Chordae tendinae, papillary muscles.
How many pulmonary veins drain into the right atrium?
4 pulmonary veins.
What chamber are we looking at?
What is the point in the cordae tendinae?
The left ventricular chamber (only 2 cusps).
Chordae tendinae are important in co-ordinating the closing of the mitral valve during systole, prevents prolapse.
What are the layers to the leaflets of the semilunar valves?
The most outerlayer facing the ascending aorta is the layer rich in collagen connective tissues: lamina fibrosa. Lamina ventricularis is the area facing the ventricle, the layer in the middle is the lamina spongiosa.
The lamina fibrosa is rich in collagen therefore keeping the structure.
The lamina ventricularis is contains a lot of elastin therefore when the leaflet is forced toward the ascending aorta that area is stretched and can recoil bringing the leaflet back toward the midline. The spongiosum just connects the two layers.
How do semilunar leaflets work?
What happens if they are calcified.
They have nodules at the point where they meet which allows the free edges to come together.
Calcification of the lamina fibrosa deforms the shape of the leaflet. If you get whole leaflet calcification then the free edges can start to fuse.
Where would you auscultate the praecordium for each of the valve sounds?
Just upstream from the valve.
Where do the left and right coronary arteries start?
Explain where the arteries run, what are the associated veins and the drainage system back to the heart?
Just above the right and left cusps of the aortic valve.
Run in the grove between the atria and the ventricles.
Cardiac veins into the coronary sinus which drains into the
How do purkinje cells differ from contractile tissue?
- Larger than contractile cells
- Lots of intercalated discs but contain a lot of gap junctions.
- Maintains some contractility (peripheral myofibrils).
Explain the sympathetic and parasympathetic innervation of the heart? Explain why pain in chest and arm when there is a stimulus from the heart.
Parasympathetic: Vagus nerve directly to the SA node (decrease the rate).
Sympathetic: Sympathetic chain ganglia. T2, T3, T4 and T1 associated with sensory neurons from the heart (via an interneuron).
Why would someone who has a stimulus on the pericardium will experience neck and jaw pain?
Compression of the phrenic nerve.
