Heart structure, cardiac cycle and vessels Flashcards
Where does the apex beat?
Left 5th intercostal space, mid-clavicular line.
Where does right heart border run? Where does left heart border run?
From SVC to right atrium.
Aortic knuckle– left pulmonary artery– LA appendage– left ventricle.
Anteriorly? Posteriorly?
Mainly right ventricle. Mainly left atrium and pulmonary veins.
Plane between what 2 things divides superior and inferior mediastinum? Pericardium divides what?
Sternal angle and T4/5.
Anterior, middle and posterior mediastinum.
What is cardiac tamponade?
Rapid collection of pericardial fluid is restrictive and impairs filling.
What allows drainage drainage of pericardial fluid from left of xiphisternum?
Pleural reflection.
What attach to atrioventricular valves via chordae tendinae? How many pulmonary veins drain into left atrium?
Papillary muscles.
Usually 4.
Coronary sinus drains blood from heart muscle into where? What 2 portions does the right atrium have? Separated by what?
The right atrium.
Smooth (from sinus venosus) and trabeculated (from original atrium.)
Crista terminalis.
What is fossa ovalis the remains of?
The foramen ovale which was patent in foetal life.
Left main coronary artery divides into what? Where does LAD run? Gives off septal and diagonal branches where to?
Left anterior descending (LAD) and circumflex (Cx) branches.
In anterior inter ventricular groove.
To septum and left ventricular myocardium.
Where does circumflex artery run? Gives off obtuse marginal branches to where? In 10%, also provides what?
In left atrioventricular groove.
Posterolateral LV wall. Posterior descending artery (PDA.)
Where does right coronary artery run? Usually supplies what? Branches to where?
In right atrioventricular groove. Sinus node, AV node.
Anterior RV wall.
Posterior descending artery runs where?
In posterior inter ventricular groove and supplies inferior septum and left ventricle.
70% of people are what? 20% are co-dominant are what? 10% are what?
Right dominant- RCA supplies PDA. Co-dominant- RCA and circumflex both supply the PDA.
Left dominant- circumflex supplies the PDA.
Systole involves what?
Ventricular contraction and blood ejection- 0.3 seconds.
What is isovolumetric contraction?
Contraction of the ventricles where there’s an increase in pressure but the volume remains the same since the valves remain closed.
Only time when all the valves of the heart are closed?
Isovolumetric contraction and relaxation.
Once pressure in the ventricles exceeds that in the aorta and pulmonary trunk what happens? What don’t the ventricles completely do during contraction?
The aortic and pulmonary valves open and maximal ejection from the ventricles into the arteries occurs.
Empty.
What is diastole?
Ventricular relaxation and blood filling= 0.5 seconds.
What is there a phase of? What valves close?
Reduced ejection. The semilunar valves.
At this time the atrioventricular valves are closed- known as what?
Isovolumetric ventricular relaxation (decrease in pressure but volume remains the same.)
What causes rapid ventricle filling and ventricle suction?
Blood in atria are slightly pressurised due to venous return and there is lower pressure in ventricles= mitral and tricuspid valves open..
What is diastasic? What is happening at this point?
Pressure between atrium and ventricle equalise thus slows filling.
The AV node is delaying the stimuli from the SAN to allow full ventricular filling.
What is the atrial booster?
Atrial contraction increases pressure enabling ventricles to be actively filled.
What is the first heart sound? Second? Third?
Lub= closure of atrioventricular valves. Dub= closure of aortic and pulmonary valves. Third= sounds of blood rushing into the left ventricle.
What 3 main things do arteries contain? What is the intima composed of?
Elastic, collagen and smooth muscle.
An inner surface lining of endothelial cells and a small amount of collagen.
What does the adventitia mainly show? How many elastic laminae are there?
Collagenous connective tissue. 2- one at interface of intima and media and the other on the outer edge of the media.
What 2 layers may be obvious in arterioles? What may smaller arterioles show?
The media and adventitia. A few medial cells with a poorly defined elastic lamina.
What 2 things also exist in arterioles?
A thin adventitia and a normal intima.
What is the endothelium? What things exist in it?
A single layer or spindle cells with tight adhesions between adjacent cells.
Little cytoplasm, intra-cellular organelles but gap junctions are prominent.
What might the endothelium be? Especially in what organs?
Fenestrated- liver, kidney glomeruli and endocrine tissues.
What are capillaries? What do pericytes do?
Tubes of endothelial cells (one cell thick wall) bound to a basement membrane with co-existing pericytes.
Muscle fibres and may regulate blood flow.
What do veins generally have?
Collagen and little muscle and elastic with the wall and single internal elastic lamina.
What are some veins surrounded by?
Skeletal muscle which contracts to increase vein pressure and ensure blood flows back tot he heart.
