3.1.2 e,f,g and h the heart

Question 1

what is the heart made of?

Answer 1

cardiac muscle

Question 2

what supplies blood to the cardiac muscle?

Answer 2

coronary arteries

Question 3

what is the heart surrounded by and why is it there?

Answer 3

inelastic pericardial membranes which help prevent the heart from over-distending with blood

Question 4

where does the blood go after the right atrium?

Answer 4

slight pressure builds as blood flows in until the atrioventricular valve/ tricuspid valve opens to let blood flow into the right ventricle

Question 4

where does deoxygenated blood enter the heart?

Answer 4

right atrium from the superior vena cava and the inferior vena cava

Question 5

what happens when both the right atrium and ventricle are filled?

Answer 5

atrium contracts forcing all the blood into the right ventricle and stretching the ventricle walls

Question 6

what happens when right ventricle starts to contract?

Answer 6

tricuspid valve closes to prevent any back flow of blood into the right atrium

Question 7

what do the tendinous cords do?

Answer 7

make sure the valves are not turned inside out by the pressures exerted when the ventricles contract

Question 8

what happens when the right ventricle contracts fully?

Answer 8

deoxygenated blood is pumped through the semilunar valves into the pulmonary artery which transport it to the capillary beds of the lungs

Question 9

where does blood from the lungs go?

Answer 9

enters the left atrium from the pulmonary vein

Question 10

what happens when pressure in the left atrium builds?

Answer 10

bicuspid valve opens so left ventricle fills with oxygenated blood

Question 11

what happens when both left atrium and left ventricle are full?

Answer 11

atrium contracts forcing all the oxygenated blood into the left ventricle

Question 12

what happens when the left ventricle contracts?

Answer 12

oxygenated blood is pumped through the semilunar valves into the aorta and around the body

Question 13

what side of the heart has a thicker muscular wall?

Answer 13

left side has to produce sufficient force to overcome the resistance of the aorta and the arterial systems of the whole body and move blood everywhere in the body

Question 14

what is the septum?

Answer 14

inner dividing wall of the heart which prevents the mixing of deoxygenated and oxygenated blood

Question 15

what does the cardiac cycle describe?

Answer 15

the events in a single heartbeat which lasts about 0.8 seconds in a human adult

Question 16

what does the heart do in diastole?

Answer 16

heart relaxes and the atria and the ventricles fill with blood
volume and pressure of the blood in the heart build as the heart fills but the pressure in the arteries is at a minimum

Question 17

what does the heart do in systole?

Answer 17

atria contract and ventricles contract so pressure inside the heart increases and blood is forced out of the heart
volume and pressure of blood is low at the end of systole and blood pressure in arteries is at its maximum

Question 18

what is atria contraction called?

Answer 18

atrial systole

Question 19

what is ventricular contraction called?

Answer 19

ventricular systole

Question 20

what is cardiac muscle?

Answer 20

myogenic

Question 21

what does myogenic mean?

Answer 21

muscle is able to contract without an external stimulus

Question 22

what is the basic rhythm of the heart maintained by?

Answer 22

wave of electrical excitation

Question 23

where does the wave of electrical excitation begin and what happens?

Answer 23

begins in the pacemaker area called the Sino-atrial node causing the atria to contract which initiates the heartbeat

Question 24

what separates the atria and the ventricles in terms of electrical conduction?

Answer 24

layer of non-conducting tissue

Question 25

what picks up the wave of electrical activity from the SAN and what happens?

Answer 25

atrio-ventricular node picks it up and AVN imposes slight delay before stimulating the bundle of His

Question 26

what is the bundle of His made from and what does it do?

Answer 26

made from a bundle of conducting tissue made up of Purkyne fibres which penetrate through the septum between the ventricles splits into two branches and conducts the wave of excitation to the apex of the heart

Question 27

what happens at the apex?

Answer 27

Purkyne fibres spread out through the walls of the ventricles on both sides and the spread of excitation triggers the contraction of the ventricles starting at the apex

Question 28

what is the recording of electrical activity of the heart called?

Answer 28

electrocardiogram

Question 29

what is tachycardia?

Answer 29

heartbeat is very rapid, over 100 bpm may be caused by problems in the electrical control of the heart

Question 30

treatments for tachycardia?

Answer 30

relaxation therapy beta-blockers

Question 31

what is bradycardia?

Answer 31

heart rate slows down to below 60 bpm many people have it because they are fit or caused by drugs severe may need a pacemaker

Question 32

what is ectopic heartbeat?

Answer 32

extra heartbeats that are out of the normal rhythm

Question 33

what is heart block?

Answer 33

separation of the p wave and the qrs complex delay in conduction between atria and ventricles

Question 34

what is hypertrophy?

Answer 34

p wave and atrial contraction is normal qrs complex is distorted due to hypertrophy of one side of the heart hypertrophy means enlargement could be caused by high blood pressure

Question 35

what is ventricular fibrillation?

Answer 35

cardiac muscle is contracting normal ventricles contract but it is not coordinated

Question 36

what is a flat line?

Answer 36

no electrical activity in the heart

Question 37

what is a hole in the heart?

Answer 37

have it at birth between atria or ventricles allows mixing of oxygenated and deoxygenated blood dangerous if not treated as pressure is reduced and less O2 is carried so less respiration