Anatomy of heart

Anatomy of heart

Location: middle mediastinum

Anatomic position: left ventricle and small portion of right ventricle (separated by posterior interventricular groove) rests on the diaphragmatic surface

flow of the blood:

Four chambers: left and right atria & ventricles

Right atrium:

1. Receives blood from superior & inferior venae cavae and coronary sinus

2. Blood passes into right ventricle through right atrioventricular orifice.

3. Sulcus terminalis cordis separate the atrium externally

4. Interior of right atrium is divide by crista terminalis

5. Anterior to the crista is “atrium proper”, its wall is covered by musculi pectinati

6. Interatrial septum separate left/right atrium

a. Depression called fossa ovalis (oval fossa) with prominent margin (limbus fossa ovalis)

Right ventricle:

1. Conus arterious (infundibulum) is the outflow tract to pulmonary trunk

a. Has smooth walls

b. Derives from the embryonic bulbus cordis

2. Trabeculae carneae (papillary muscles)

a. Irregular structure muscle at inflow portion of the wall

b. One side attach to the ventricular surface, the other attach to the chordae tendineae

c. Three types of papillary muscle: anterior, posterior and septal papillary muscle

d. Septomarginal trabecula: carries right bundle of the atrioventricular bundle to the anterior wall of the right ventricle.

Left atrium:

1. embryologically derived from two structure

a. posterior half

i. receives the four pulmonary veins

ii. smooth walls

iii. derives from proximal parts of the pulmonary veins

b. anterior half

i. contains musculi petinati

ii. derives from embryonic primitive atrium

2. valve of foramen ovale

a. opposite the floor of fossa ovalis

b. prevents blood from passing from left to right atrium

c. may not be fused

Left ventricle:

1. blood enters through left atrioventricular orifice

2. thickesr layer of myocardium

3. aortic vestibule (outflow tract) has smooth walls and derived from embryonic bulbus cordis

4. trabeculae carneae are fine and delicate

a. anterior/ posterior papillary muscles

interventricular septum

1. muscular part: thick, major part

2. membranous part: thin, upper part of the septum

Tricuspid valve:

1. right atrioventricular valve

2. fibrous ring surrounds the atrioventricular orifice

3. named: anterior, septal posterior cusps

a. attach to chordae tendineae which helps prevent seperation of the cusps

Pulmonary valve:

1. three semilunar cusps

2. middle, thickened portion (nodule) and thin lateral (lunule)

3. named: left, right and anterior

4. form pocket-like sinus

5. blood fills pulmonary sinuses and force it to close after ventricular contraction

Mitral valve:

1. left atrioventricular valve aka bicuspid valve (anterior/ posterior)

2. secured by fibrous ring

3. similar to tricuspid valves

Aortic valve:

1. semilunar cusps

2. pocket-like sinuses + two opening for left/right coronary arteries

3. named: right, posterior (aka noncoronary), left

4. similar to pulmonary valve

a. but blood is forced into coronary arteries when it fills the aortic sinuses.

Cardiac skeleton:

1. fibrous rings

2. annulus fibrosus:

a. right/left fibrous trigone: thickened area of connective tissue between fibrous rings

b. maintain the opening

c. separates the atrial and ventricular musculature

Coronary vasculature

1. coronary arteries

a. supply the muscle and other tissue of the heart

b. circle in the coronary sulcus

c. empty into coronary sulcus (btwn left ventricle and atrium) then to right atrium

d. right coronary artery branch:

i. sinu-atrial node branch

ii. right marginal branch

iii. posterior interventricular branch

e. left coronary artery branch

i. anterior interventricular branch

ii. circumflex branch

iii. left marginal branch

2. cardiac veins

a. coronary sinus receives blood from great, middle, small, posterior cardiac veins

Cardiac conduction system

1. sinu-atrial node

a. pacemaker

b. superior end of the crista terminalis

2. atrioventricular node

a. near the opening of coronary sinus

3. atrioventricular bundle

a. direct continuation of atrioventricular node

4. the Purkinje fibre

Pericardium

1. fibroserous sac surrounding the heart

2. fibrous pericardium

a. tough connective tissue outer layer

3. serous pericardium

a. thin

b. parietal and visceral layer