Heart & Heart Disease (2/3)

Front 1

Valves

Back 1

- direct blood flow through heart

- located entrance/exit of each ventricle
- 4 in total

Front 2

Atrioventricular valves

Back 2

ENTRANCE valves

Front 3

Semilunar valves

Back 3

EXIT valves

Front 4

Right atrioventricular (entrance) valve

Back 4

- tricuspid

- 3 flaps that open/close
- when open, blood flows from right atrium to right ventricle

Front 5

Left atrioventricular (entrance) valve

Back 5

- bicuspid/mitral

- permits blood to flow from left atrium to left ventricle

- ensures forward blood flow into aorta

Front 6

chordae tendinae

Back 6

- thin fibrous threads to papillary muscles arising from walls of ventricles

- function: stabilise valve flaps when ventricles contract to prevent backflow of blood when heart beats

Front 7

Pulmonary valve (exit)

Back 7

- located between right ventricle & pulmonary trunk

- prevents blood from returning to ventricle

Front 8

Aortic valve (exit)

Back 8

- located between left ventricle and aorta

- prevents backflow of blood from aorta into ventricle

Front 9

coronary circulation

Back 9

is the blood supply to myocardium

composed of:

- left coronary artery
- right coronary artery
- coronary sinus

Front 10

left coronary artery

Back 10

branches into circumflex artery and left-anterior descending artery

Front 11

right coronary artery

Back 11

snakes around heart inferior to right atrium
- gives off branch called posterior descending artery

Front 12

coronary sinus

Back 12

dilated vein that opens into right atrium near inferior vena cava
- blood collects in coronary sinus after passing through capillaries in myocardium

Front 13

cardiac cycle (heartbeat)

Back 13

Heart muscle contraction begins in thin-walled atria, followed by contraction of thick muscle in ventricles.

Front 14

systole

Back 14

contraction

Front 15

diastole

Back 15

resting phase

Front 16

cardiac output

Back 16

volume of blood pumped by each ventricle in one minute

CO = HR x SV

Front 17

stroke volume

Back 17

volume of blood ejected from ventricle with each beat

Front 18

heart rate

Back 18

number of times heart beats per minute

Front 19

Heart conduction system

Back 19

heart muscle stimulated to contract by electric energy passing along cells
- this action potential is generated by specialised tissue within heart - 2 nodes
- and other specialised fibers branching through myocardium

Front 20

Nodes (2 types)

Back 20

sinoatrial node
atrioventricular node

Front 21

sinoatrial node

Back 21

- initiates heartbeats by generating action potential at regular intervals
- pacemaker
- located upper wall of right atrium in small depression described as sinus

Front 22

atrioventricular node

Back 22

- conducts the normal electrical impulse from the atria to the ventricles

- located in interatrial septum at bottom right atrium

Front 23

Specialised fibers (3 types)

Back 23

• Atrioventricular bundle (bundle of His)
  
• Purkinje fibers
• Intercalated disks

Front 24

Atrioventricular bundle (bundle of His)

Back 24

fibers travel down both sides of interventricular septum in groups called right and left bundle branches

Front 25

Conduction pathway (sinus rhythm)
SAAIBBV

Back 25

• Sinoatrial node
• Atria
• Atrioventricular node
• Internodal pathways
• Bundle of his
• Bundle branches and Purkinje fibers
• Ventricles

Front 26

Sinus rhythm

Back 26

normal heart rhythm originating at sinoatrial node