practical 5: ECG and the anatomy of the heart Flashcards
this is a band 1 practical is medical supervision required
no
what are the two stages of contraction of the heart muscle
systole of the atria followed by systole of the ventricles
what is followed by systole
diastole (relaxation)
what is function of the fibrous pericardium
a tough fibrous sac which the heart is enclosed within that prevents overdistension of the heart
deoxygenated blood enters the _______ ______ of the heart via the superior and inferior venae cavae. it passes through the _______ valve into the pulmonary trunk and then goes to the lungs via the right and left pulmonary ______
right atrium
tricuspid
arteries
oxygenated blood returns to the heart via the pulmonary _____ into the ____ ________. it passes through the _______ valve into the left ventricle. on ventricular systole the blood passes through the ________ valve into the aorta to be pumped around the body
veins
left atrium
mitral
pulmonary
what are the three layers of the heart wall
endocardium
myocardium
epicardium
what is the endocardium
the innermost layer that consists of a layer of simple squamous endothelium with an underlying basement membrane
myocardium
the middle layer which consists of cardiac muscle cells
epicardium
the outermost connective tissue layer (visceral layer of the serous pericardium)
what is the coronary sinus
a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium)
purpose of auricle
two pouches connected to the hearts atrium, transfer blood into the left and right ventricles
what was the former role of the fossa ovale
foramen ovale, allows blood to pass from right atrium to left atrium, bypassing the non functional fetal lungs
why is the wall of the left ventricle thicker than the right
so it can generate sufficient pressure to pump blood throughout the body (but nnot the lungs). right ventricular wall is thinner because it doesn’t need to pump blood in high pressure
what is the role of the chordae tendinae
flexible strands in the heart that regulate the opening and closing of the flaps of the atrioventricular valves
coronary veins drain into where
the coronary sinus, a large vessel that empties into the right atrium
what is the first lub due to
the closure of the mitral and tricuspid valves
what is the second dub due to
the closure of the aortic and pulmonary valves
if we can hear murmurs what does this mean
heaet valves are damaged and become stenosed and/or leaky permitting gurgitation (turbulent blood flow), blood flows turbulently through the stenosis or regurgitates back through the valve
for the hearts electrical activity what coes ffirst repolarisation or depolarisation
depolarisation first
where are myocytes (pacemaker cells) found
sino atrial node in the right atrium
what does the SA node connect with
the atrioventricular node situated between the atria and the ventirlces
how does electrical activity travel from the av node to the right and left ventricles
conducts down a collection of cardiac musle fibres called the bundle of His, these then separate into the left and right bundle branches within the interventricular septum. the depolarisation rapidly extends across the ventricles via purkinje fibres
what is an electrocardiogram
non invasive method of recording the electrical activity (depolarisation and repolarisation) as it spreads across the heart. this activity is detected using several electrodes on the surface of the body
