Lecture 2 Flashcards
Describe the right hand internal anatomy of the heart?
The SVC, and the IVC and the coronary sinus drain into the RA. Thus the part where the veins drain into are smooth walled. The muscular wall part is the part that contracts. It is made up of the muscluli pectinati. The crista terminalis is the ridge that is between musculi pectinati and the smooth part of the RA.
What do you find between the LA and the RA?
Fossa ovalis. Oval fossa, that was the foramen ovale (direct connection between RA and LA).
Where is the right auricle?
It is a projection of the RA. The auricle itself has muscular walls which help with the contraction of the RA.
Describe the tricuspid valve?
This is a valve between the RA and the RV. It is attached within the ventricle. It has a cusp around the outside, then spider-like protections called the cordae tendinaea, which are attached to the papillary muscles (within the wall of the ventricle). When the papillary muscles contract they hold onto the cordae and stop the valve from blowing back.
Describe the cusps of the Tricuspid valve?
There is an anterior cusp, septal cusp, and posterior cusp.
Describe the septomarginal trabecula (moderator band)?
A little band of muscle that runs from the inter-ventricular septum. When the ventricles contract, the moderator band, takes a little shortcut from the IV septum,a cross the anterior wall of the ventricle. This is so that the electoral impulse gets to the anterior wall as the rest of the ventricle. The papillary muscles, contract just a little bit ahead of the rest of the ventricles in order to hold onto the valve cusps.
Describe the trabeculae carneae?
These are the muscles of the ventricular wall itself. These are thick, complex muscles.
Describe the posterior wall of the Left Atrium (LA)?
It’s very thin and smooth walled. It is the venous part of the left atrium, it is where all the pulmonary veins come into.
Describe the mitral valve?
Similar to the tricuspid valve. Has two cusps, which re attached to the cordeae tendinaea.
What is anterior to the aortic valve?
Pulmonary valve.
What valve is found on the RHS of the heart?
Tricuspid valve.
Describe the aortic valve?
The aortic valve has three cusps, and within two of the cusps are the openings of the coronary arteries (L and R).
How does the aortic and pulmonary valve work?
Blood will rush through them from the ventricles. Then as the ventricles stop contracting, the blood will then rush back and fill the semi-lunar flaps causing the valve to close.
Describe coronary arteries?
The coronary arteries fill in diastole. So the LV will pump and fill the whole aorta, as the aortic valve opens it closes off the openings to the aortic. When the aortic valve closes, the blood has no where else to go, so the blood is forced into the coronary arteries. You want them to fill when the ventricles are relaxed.
Describe sound projections?
When blood goes through a valve, the blood flow becomes slightly turbulent. You hear the blood best where the blood flows to.
Describe the conduction system of the heart?
The impulse is generated int he sinoatrial node (SA node). The impulse then passes out through the atrium until it hits the atrioventricular node (AV node) - this node is situated between the two atria and the two ventricles. The impulse passes down the AV bundle of His, where it divides into the right and left bundle branches. Each travels through the inter ventricular septum, where it then spreads out to the rest of the ventricles. It comes down the inter-ventricular septum (which is quite thick), the wall of the LV is densely packed with fibres where as the RV needs to have the moderator band (fibres can take a shortcut).
What is the important thing about the moderator band?
It primes the papillary muscles and the anterior wall of the RV so that they’re already to go before the actual signal comes through, so that the papillary muscles can hold onto the valve.
Which is more important: the left or the right coronary artery?
Right - this artery supplies the SA nodal branch, can cope without the node however the heart is not regular. It also gives off the marginal branch, posterior inter-ventricular, and the AV nodal branch. If the RCA gets blocked you will get rhythm disturbances, could do a pacemaker.
Left - this artery supplies atrium and the ventricle and the left anterior descending (runs straight down the front of the heart and supplies both ventricles). If the LCA gets blocked you will get pump failure. Could do an angioplasty, bypass grafting (i.e. triple bypass).
Describe the nerves of the heart?
There is a sympathetic system which will speed things up. The fibres come from T1-T5. Speed up HR, increase BP, make heart more contractile. The sympathetic fibres form a plexus with he parasympathetic fibres (from the vagus nerve - cranial nerve X).
