practical 5: ECG and the anatomy of the heart

Question 1

this is a band 1 practical is medical supervision required

Answer 1

no

Question 2

what are the two stages of contraction of the heart muscle

Answer 2

systole of the atria followed by systole of the ventricles

Question 3

what is followed by systole

Answer 3

diastole (relaxation)

Question 4

what is function of the fibrous pericardium

Answer 4

a tough fibrous sac which the heart is enclosed within that prevents overdistension of the heart

Question 5

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 ______

Answer 5

right atrium

tricuspid

arteries

Question 6

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

Answer 6

veins

left atrium

mitral

pulmonary

Question 7

what are the three layers of the heart wall

Answer 7

endocardium
myocardium
epicardium

Question 8

what is the endocardium

Answer 8

the innermost layer that consists of a layer of simple squamous endothelium with an underlying basement membrane

Question 9

myocardium

Answer 9

the middle layer which consists of cardiac muscle cells

Question 10

epicardium

Answer 10

the outermost connective tissue layer (visceral layer of the serous pericardium)

Question 11

what is the coronary sinus

Answer 11

a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium)

Question 12

purpose of auricle

Answer 12

two pouches connected to the hearts atrium, transfer blood into the left and right ventricles

Question 13

what was the former role of the fossa ovale

Answer 13

foramen ovale, allows blood to pass from right atrium to left atrium, bypassing the non functional fetal lungs

Question 14

why is the wall of the left ventricle thicker than the right

Answer 14

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

Question 15

what is the role of the chordae tendinae

Answer 15

flexible strands in the heart that regulate the opening and closing of the flaps of the atrioventricular valves

Question 16

coronary veins drain into where

Answer 16

the coronary sinus, a large vessel that empties into the right atrium

Question 17

what is the first lub due to

Answer 17

the closure of the mitral and tricuspid valves

Question 18

what is the second dub due to

Answer 18

the closure of the aortic and pulmonary valves

Question 19

if we can hear murmurs what does this mean

Answer 19

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

Question 20

for the hearts electrical activity what coes ffirst repolarisation or depolarisation

Answer 20

depolarisation first

Question 21

where are myocytes (pacemaker cells) found

Answer 21

sino atrial node in the right atrium

Question 22

what does the SA node connect with

Answer 22

the atrioventricular node situated between the atria and the ventirlces

Question 23

how does electrical activity travel from the av node to the right and left ventricles

Answer 23

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

Question 24

what is an electrocardiogram

Answer 24

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

Question 25

what is the intial p wave

Answer 25

the spread of depolarisation across the atria

Question 26

QRS complex

Answer 26

spread of depolarisation across the ventricles

Question 27

T wave

Answer 27

repolarisation of the ventricles

Question 28

how did the heart rate change during inspiration andwhy

Answer 28

heart rate increases, more oxygen to body

Question 29

do the lengths of the ecg intervals remain the same when the heart rate changes

Answer 29

no, intervals get smaller as heart rate increases, more bets per minute, more intervals per minute

Question 30

pq segment

Answer 30

end of p tp beginning of QRS

Question 31

st segment

Answer 31

end of s to start of t

Question 32

pr interval

Answer 32

beginning of P to beginning of QRS

Question 33

qt interval

Answer 33

beginning of q to end of t

Question 34

tp interval

Answer 34

end of T to beginning of P