The Heart Flashcards
What are the different surfaces of the heart and what are they made up out of?
Sternocostal/anterior - RV mainly but also RA and LV.
Diaphragmatic/posterior - Mainly LV but also RV.
R pulmonary - RA.
L pulmonary - LV.
What separates the diaphragmatic surface of the heart from the base?
The coronary sinus
Describe what the base of the heart is composed of and its positioning.
- LA, pulmonary veins and some RA.
- Fixed posteriorly to pericardium at level T6-T9 but when supine it is T5-T8.
Where is the position of the apex of the heart?
The left 5th intercostal space, 8-10cm left of the midline (midclavicular line) but in children it is more superior and lateral
Name the margins of the heart and what they are composed of (important)
Right margin - RA.
Left margin - LV and left auricle.
Inferior margin - RV and LV
Name the 3 external sulci
Coronary sulci, Anterior interventricular sulcus and the posterior interventricular sulcus
Name the function of the coronary sulcus and what runs through it
It separates atria frim ventricles. The right coronary artery, left circumflex artery and coronary sinus runs through it.
What runs through the anterior interventricular sulcus?
Anterior interventricular artery and the great cardiac vein (anterior interventricular vein)
What runs through the posterior interventricular sulcus?
Posterior interventricular artery and the middle cardiac vein (posterior interventricular vein)
Name the three septa of the heart
Interartrial septum, Interventricular septum and the atrioventricular septum (from RA to LV)
Where does the right atrium receive blood from?
SVC, IVC (both have no valves), coronary sinus (60%) and the smallest cardiac veins (40%) that open stright into atrium.
What separates the right atrium from the right auricle?
Internally a muscular ridge called crista terminalis but externally it is sulcus terminalis
What is the fossa ovalis? what is its margin called?
It is on the right side of the interatrial septum and is the site of the foramen ovale in fetus. The margin is called limbus fossae ovalis
What is the valve of inferior vena cava?
It directed blood to the foramen ovale from the placenta in fetus. Meaning oxygenated blood bypassed the under developed lungs
What is the function of the valve of coronary sinus?
It prevents regurgitation of blood when the atrium contracts
Describe features if the right auricle
It has a rough surface formed by pectinate muscles, the function of these is to provide some power of contraction without significantly thickening the cardiac wall
Where is the right ventricle situated?
It sits of the central tendon of the diaphragm
What connect the right ventricle to the pulmonary valve/trunk?
Infundibulum (conus arteriosus)
What is the direction does the blood have to flow in order to pass through the pulmonary trunk?
It flows upwards, backwards and to the left
Name the irregular muscular ridges of the walls of the RV
Trabeculae carnea
Name another muscle in the RV and its function.
Septomarginal trabeculae. It acts as a bridge between the interventricular septum and anterior papillary muscle
What is the function of papillary muscles and how many are there?
They attach to chorda tendinae which attach to the free edges of tricuspid valve cusps. There are three in the RV and two in the LV
What is the function of chorda tendinae?
They prevent the eversion of cusps and therefore prevent regurgitation of blood into the atria during ventricular systole. They can attach to more than one cusp.
What is the direction of blood flow through the tricuspid valve?
Forwards and medially.
The base of each valve cusp from the tricuspid and mitral valve is attached to what?
Right fibrous ring (anulus fibrosus) for tricuspid and Left fibrosus ring (anulus fibrosus) for mitral.
Name the features of the pulmonary valve
It is a tricuspid valve. Each cusp forms a pulmonary sinus. When these fill with blood it closes the valve after systole.
Name the depressed area on the IA septum in the left atrium and how it formed
Falx septi, it is caused by the fusion of foramen ovale.
Describe how blood flows to apex
Anteriorly
Name the two muscles in the LV
Muscular ridges names trabecula carnea and anterior and posterior papillary muscles
What si the outflow tract to the aprtic valve and how does blood flow through this valve?
Outflow - Aortic vestibule. And blood flows upwards, backwards and to the right side of this valve.
Describe the structure of the aortic valve
3 semi-lunar cusps at apex of aortic vestibule, right and left (coronary) and posterior. The right and left sinus give rise to the coronary arteries. Valves closed in diastole (blood to coronary arteries) OPEN IN SYSTOLE.
What is the fibrous skeleton of the heart?
It is a frame formed by a set of 4 fibrous rings around the AV, aortic and pulmonary valves. With two trigones, right and left.
Describe the functions of the fibrous skeleton of the heart
Points of attachment for cusps, maintains integrity of AV and semilunar orifices. Origin and insertions for artial and ventricular muscles and insulates the atria from the ventricles, allowing for independent contractions.
Describes the layers of the heart
ENDOCARDIUM - thin layer of endothelium that receives oxygen and nutrients directly from chambers.
MYOCARDIUM - Spiral and circular bundles of atrial and ventricular musculature.
EPICARDIUM - visceral layer of serous pericardium.
Explain why points of auscultation of heart sounds are different from the surface projection of the heart valves
All the surface projections of the heart valves are behind bone which makes them too difficult to listen too. They auscultation areas are in the direction of blood flow
