Coronary artery circulation Flashcards
how many coronary arteries are there?
2
how many cardiac veins are there?
3
what do coronary arteries do?
supply the myocardium with oxygen
what do cardiac veins do?
drain deoxygenated away from the myocardium
what are the 2 coronary arteries?
left and right coronary arteries
left coronary artery
arises from the aorta above the left cusp of the aortic valve
supplies the left side of the heart
branches into 2 or 3 arteries
right coronary artery
originates from above the right cusp of aortic valve
travels down the right coronary sulcus, towards the crux of the heart
what are the coronary arteries?
right and left coronary arteries anterior interventricular artert circumflex artery posterior interventricular artery - posterior descending right and left marginal artery
branches of left coronary artery
left anterior descending
left circumflex > left marginal
branches of right coronary artery
75% of people it gives off posterior descending artery
right marginal
sinoatrial nodal artery
atrioventricular nodal branch
coronary sinus
collection of veins joining together, draining blood from myocardium
drains into right atrium at coronary sinus orifice
where is the coronary sinus orifice
between inferior vena cava and tricuspid valv
what are the tributaries of the coronary sinus?
great cardiac vein
middle cardiac vein
small cardiac vein
what does the great cardiac vein drain?
apex of heart, left atrium and both ventricles
what does the middle cardiac vein drain?
posterior right atrium and ventricle
what does the small cardiac vein drain
begins at apex
electrical conduction in the heart
- SAN generates impulses
- impulses pause at AVN for 0.1seconds
- AVN connects the atria and ventricles
- bundle branches - bundle of his conduct the impulses through the interventricular septum
- purkinje fibres depolarise the contractile cells of both ventricles
how is heart rate controlled?
carotid body - contain chemoreceptors near the bifurcation of carotid artery. They detect changes in ppO2 and ppCO2
send feedback via branches of glossopharyngeal nerve
aortic body - chemoreceptors in aortic arch sends feedback via afferent branches of vagus nerve
carotid sinus - baroreceptors at base of internal carotid artery - innervated by a branch of glossopharyngeal nerve
where in the brain controls the heart rate?
receptors send feedback to cardiorespiratory centres in medulla oblongata
which regulates autonomic control of heart rate and blood pressure via parasympathetic and sympathetic nerves
what does the P wave represent?
atrial depolarisation
what does the QRS complex represent?
ventricular depolarisation
what does the T wave represent?
ventricular repolarisation
How to treat an acute MI?
PCI - percutaneous coronary angioplasty
what is PCI used for ?
open a blocked coronary artery - treat stenosis and restore arterial blood flow to heart tissue
what is involved in a PCI?
coronary catheterisation - see vessels on x-ray
coronary angioplasty - balloon inflation to treat narrowing
stenting - keep vessel open
where can a cardiac catheter be inserted?
groin or wrist
arterial route of catheter via groin
femoral, external iliac, common iliac, aorta, left coronary and left anterior descending arteries
arterial route of catheter via wrist
radial, brachial, axillary, subclavian, aorta, left coronary and left anterior descending arteries
what is the widow maker?
blockage of left main coronary artery or left anterior descending artery
usually fatal
treating MI/ blockage of coronary arteries
surgery to restore blood flow via CABG
CABG
surgery to restore coronary artery blood flow
- left internal mammary artery is diverted to left anterior descending artery
- great saphenous vein is removed from a leg, one end is attached to the aorta and the other is attached to the obstructed artery immediately after the obstruction to restore blood flow
what is cardiomegaly?
abnormal enlargement of the heart
ECG for MI
ST elevation
ECG for atrial fibrillation
no P waves
QRS normal but irregularly irregular
