The Heart And Great Vessels

Front 1

Mediastinum

Back 1

1) area bounded by pulmonary cavities (lateral), sternum (anterior), thoracic vertebrae (posterior), diaphragm (inferior) & level of 1st rib (superior)
2) plane of sternal angle divides mediastinum into:
a) superior mediastinum - above plane; contains great vessels & trachea
b) inferior mediastinum - below plane; contains pericardium & heart, descending aorta, azygos vein, esophagus, thoracic sympathetic trunk

Front 2

Pericardium (pericardial Sac)

Back 2

- has outer fibrous & inner serous layers
1) Fibrous Pericardium - forms tube running superior-inferior around heart
a) inferior end attached to diaphragm
b) superior end - merges into outer connective tissue layer of great vessels
2) Se3rous Pericardium - two parts
a) parietal layer of serous pericardium - lines inner wall of fibrous pericardium
b) visceral layer of serous pericardium - covers outer surface of heart
c) parietal & visceral layers connected at level of sternal angle (reflection of serous membrane between surface of heart and inner wall of fibrous pericardium)

Front 3

Heart Orientation

Back 3

1) base - superior end of heart; site of entry/exit of great vessels
a) located at mid-line, at level of 2nd intercostal space
2) inferior border - surface of right ventricle; sits on diaphragm
3) apex - inferior tip of heart (left ventricle); located 8 cm (3 in) lateral to left border of sternum at 6th intercostal space (behind left nipple of male)
a) long axis of heart (from base to apex) oriented diagonally, running down & to left side
4) left border - surfaace of left ventricle
5) right border - surface of right atrium; along line of junction for superior & inferior vena cava

Front 4

Great Vessels

Aorta

Back 4

1) Aorta - ascending aorta, arch of aorta and descending aorta divisions
a) ascending aorta - arises from left ventricle of heart
b) aortic arch - passes obliquely posterior and to the left to lie along left side of vertebral bodies; bottom of aortic arch located at plane of sternal angle
c) descending aorta - has thoracic aorta and abdominal aorta segments
1) thoracic aorta continues as abdominal aorta after passing through aortic hiatus of thoracic diaphragm (at T12 vertebral level)
2) in upper thorax, aorta runs along vertebral coumn, just to left of midline
a) thoracic aorta moves toward mid-line as it descends
b) passes through diaphragm at mid-line (anterior to vertebral bodies)

Front 5

Great Vessels

Branches of Aorta

Back 5

a) from ascending aorta:
1) right and left coronary arteries - to heart walls
b) from arch of aorta
1) brachiocephalic artery - divides into right common carotid & right subclavian arteries
2) left common carotid artery
3) left subclavian artery
c) from thoracic aorta
1) posterior intercostal arteries - one pair to each intercostal space of posterior thoracic wall

Front 6

Pulmonary Trunk

Back 6

a) rises from right ventricle of the heart & runs superiorly
b) immediately below aortic arch (at plane of sternal angle) - pulmonary trunk bifurcates (T-shaped division) into:
1) right & left pulmonary arteries - to right & left lungs

Front 7

Brachiocephalic Veins

Back 7

- right & left
a) formed by junctions of internal jugular & subclavian veins
b) left brachiocephalic vein crosses midline anterior to aortic arch & its arterial branches

Front 8

Vena Cava

Back 8

a) superior vena cava - formed by junction of right & left brachiocephalic veins
1) receives azygos vein from posterior thoracic wall
b) inferior vena cava - ascends from abdominal cavity through caval hiatus of diaphragm
c) superior & inferior vena cava empty independently into right atrium of heart

Front 9

Pulmonary Vein

Back 9

- two from each lung
a) all four drain independently into left atrium of heart
1) key landmark - plane of sternal angle: bottom of aortic arch, division of pulmonary trunk, bifurcation of trachea, and reflection of parietal & visceral layers of serous pericardium

Front 10

Surface markings of heart

x 5

Back 10

1) epicardium - outer surface layer of heart overlying muscular (myocardium) layer
a) consists of visceral pericardium, fat, coronary arteries, & veins of heart wall
2) apex of heart
a) left ventricle larger & more superior that right ventricle; extends down to include apex
3) left atrium - on dorsal (posterior) side of heart; receives pulmonary veins (4)
4) right atrium - on right side of heart; receives superior & inferior vena cava, and coronary sinus (venous return from heart wall)
5) Auricles - muscular pouches extending off of each atrium

Front 11

Arterial Supply to Heart Walls

Back 11

1) provided by Right & Left Coronary arteries - branch from ascending aorta
2) Right Coronary Artery
a) runs i groove between right atrium & right ventricle - passes to dorsal (posterior) side of heart
b) terminates as posterior interventricular artery on posterior heart
3) Left Coronary artery - comes off aorta behind pulmonary trunk; quickly divides into:
a)circumflex coronary artery - wraps around to dorsal side of heart, running in groove between left atrium & left ventricle
b) anterior interventricular artery - runs down anterio heart in groove between right and left ventricles

Front 12

Venous return from heart

Back 12

1) Great cardiac vein - runs up anterior heart in groove between ventricles, then passes around to posterior heart - drains into coronary sinus
2) coronary sinus - large venous sinus on posterior heart, in groove between atria and ventricels
a) receives venous drainage from all veins of heart walls
b) empties directly into right atrium

Front 13

Interior of Heart

Back 13

1) atrium - muscular walls of atria are thin compared to ventricular walls
a) inner atrial walls are smooth
b) inner walls of auricle have cords (strands) of muscle called pectinate muscle
2) ventricles - thicker walls than atria; walls of left ventricle musch thicker (3x) than right ventricle walls (left ventricle pumps blood to body)
a) left ventricle extends down as apex of heart
b) right ventricle forms inferior border of heart, but does not extend to apex
c) trabeculae carnae (little strands of meat) - muscular cords (strands) on inner walls of ventricles

Front 14

Atrioventricular (AV) Valve of heart

Back 14

1) one-way valves that prevent backflow of blood from ventricles into atria
2) consist of:
a) cusps (valve flaps) - when atrium contracts, cusps bend downward to allow flow of blood from atrium into ventricle; when ventricle contracts, cusps close off valve opening to prevent backflow of blood into atium
b) papillary muscle - muscle bundle extending up from inner wall of ventricle
c) chodae tendineae - thin fibrous strands connecting papillary muscle to ventricular side of valve cusp
3) papillary muscle & ventricular walls contract at the same time - papillary muscle pulls on cusps to keep valve closed (prevents backflow of blood from ventricles into atria)
4) Tricuspid valve - between right atrium & right ventricle; has three cusps (right = tricuspid [R/T])
5) Bicuspid (Mitral) Valve - between left atrium & left ventricle; has two cusps

Front 15

Semilunar Valve of Heart

Back 15

1) consists of 3 cusps attached to walls of ventricle - same structure for both valves
a) do not have papillary muscles or chordae tendineae
2) Pulmonary Semilunar valve - between right ventricle & pulmonary trunk
3) Aortic semilunar valve - between left ventricle & aorta

Front 16

Flow of Blood Through Heart
x 16

Back 16

1) Superior & Inferior Vena Cava
2) Coronary Sinus
3) Right Atrium
4) Tricuspid Valve
5) Right Ventricle
6) Pulmonary Semilunar valve
7) Pulmonary Trunk
8) Pulmonary Arteries
9) Lungs
10) Pulmonary Veins
11) Left Atrium
12) Bicuspid Valve
13) Left Ventricle
14) Aortic Semilunar Valve
15) Aorta
16) Body

Front 17

Flow of Blood Through Heart
1 of 16

Back 17

1) Superior & Inferior Vena Cava

Front 18

Flow of Blood Through Heart
2 of 16

Back 18

2) Coronary Sinus

Front 19

Flow of Blood Through Heart
3 of 16

Back 19

3) Right Atrium

Front 20

Flow of Blood Through Heart
4 of 16

Back 20

4) Tricuspid Valve

Front 21

Flow of Blood Through Heart
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Back 21

5) Right Ventricle

Front 22

Flow of Blood Through Heart
6 of 16

Back 22

6) Pulmonary Semilunar valve

Front 23

Flow of Blood Through Heart
7 of 16

Back 23

7) Pulmonary Trunk

Front 24

Flow of Blood Through Heart
8 of 16

Back 24

8) Pulmonary Arteries

Front 25

Flow of Blood Through Heart
9 of 16

Back 25

9) Lungs

Front 26

Flow of Blood Through Heart
10 of 16

Back 26

10) Pulmonary Veins

Front 27

Flow of Blood Through Heart
11 of 16

Back 27

11) Left Atrium

Front 28

Flow of Blood Through Heart
12 of 16

Back 28

12) Bicuspid Valve

Front 29

Flow of Blood Through Heart
13 of 16

Back 29

13) Left Ventricle

Front 30

Flow of Blood Through Heart
14 of 16

Back 30

14) Aortic Semilunar Valve

Front 31

Flow of Blood Through Heart
15 of 16

Back 31

15) Aorta

Front 32

Flow of Blood Through Heart
16 of 16

Back 32

16) Body

Front 33

Conduction System of the Heart

Back 33

1) depolarizing impulse for cardiac muscle contraction originates in Sinuatrial (SA) Node
a) located in wall of right atrium
b) depolarizing wave spreads downward through walls of right & left atria toward atrioventricular valves - wave of atrial contraction pushes blood through valves & into ventricles
3) Atrioventricular Bundle (Bundle of His) - pathway that carries depolarization from AV node to ventricles
b) bundle passes inferiorly within interventricular septum (insulated by surrounding connective tissue - depolarization doesn't spread to ventricle)
1) divides into right & left bundle branches - to right & left ventrilces
c) at apex of heart, branches turn superiorly & subdivide - innervate ventricular wall muscle and papillary muscles - contraction of papillary muscles closes AV valves
d) depolarization of ventricles begins at apex & spreads superiorly - produces wave of muscle contraction that squeezes blood toward semilunar valve and out of heart

Front 34

Fetal Circulation

1 of 2

Back 34

1) in fetus prior to birth, lungs do not function in gas (O2 - CO2) exchange
a) O2 & CO2 exchange occurs across placenta with maternal circulation
2) blood sent to placenta via 2 umbilical arteries - branches of internal iliac arteries
a) carry poorly oxygenated blood
3) blood returned from placenta via single umbilical vein
a) carries richly oxygenated blood
b) umbilical vein passes superiorly from umbilicus (running at inferior margin of falciform ligament) & enters liver
1) adult remnant of umbilical vein = round ligament of teh liver (ligamentum teres heaptica)
c) blood shunted through liver - joins with hepatic veins to drain into inferior vena cava

Front 35

Fetal Circulation

2 of 2

Back 35

4) majority of circulating fetal blood by-passes lungs via 2 shunts:
a) foramen ovale - opening through interarterial wall between right & left atrium
1) allows blood flow in right atrium to flow into left atrium
2) foramen ovale closes at birth - adult remnant = fossa ovalis
b) ductus arteriosus - connects top of pulmonary trunk to overlying arch of aorta
1) allows blood pumped into pulmonary trunk to flow into aorta
2) ductus arteriosus - connects top of pulmonary trunk to overlying arch of aorta
1) allows blood pumped into pulmonary trunk to flow to aorta
2) ductus arteriosus closes at birth; adult remnant = ligament arteriosum (fibrous cord that connects adult pulmonary trunk to inferior side of aortic arch)