HEART ANATOMY

The Heart Wall

serous membrane

• A serous membrane consists of a single layer of flattened mesothelial cells applied to the surface of a thin layer of collagenous tissue that attaches to underlying fascia.

• The mesothelium of the serous membrane forms the lining of a closed serous membrane cavity.

• Serous membrane lining the wall of a serous cavity is designated parietal while that covering viscera is called visceral.

• Connecting serous membrane runs between parietal and visceral components.

• The myocardium. Note the endocardial layer, which consists of endothelium supported by a rather thick layer of subendocardial connective tissue (green). The ventricular lumen is indicated.

Valve

Lumen

HEART ANATOMY (EXTERNAL VIEW)

• The heart is a complex muscular pump that maintains oxygen and blood circulation through the lungs and the rest of the body through Both the systemic and the pulmonary cerculations.

• The heart pumps about 7200 liters/day.

• Is about the size of you clenched fist

the Heart ANTERIOR SURFACE

the Heart, POSTERIOR SURFACE

– Atria – separated by the interatrial septum

– Ventricles – separated by the interventricular septum

– Atrioventricular valves extend into the openings between the atria and ventricles permitting the blood to flow in one direction only.

– Contraction of the papillary muscles prevent the atrioventricular valves from folding back into the atria.

Internal Anatomy and Organization

– Receives blood from the superior vena cava (head, neck upper limbs, chest) inferior vena cava (rest of the trunk, lower limbs, and viscera), and coronary veins of the heart through the coronary sinus.

– Oval impression – Fossa Ovalis– Contains pectinate muscles with trabecule

Right Atrium

The Right Atrium

The distinction between the posteriorSmooth walled and the anterior trabeculatedappendage. The junction between the two is marked byThe formed muscle bundle, the cristaterminalis.

The trabeculae tend to run at right anglesto the crista.

The inside of the right atrial chamberpresents a

The posterior surface, a septal surface, and an anterior surface.

The floor of the chamber can beconsidered as tricuspid valveorifice orientated obliquely to the right

The inferior vena cava opens into thejunction of the posterior wallAnd the floor.  

CT

FOPost

Ant

Septal

IVC

Right Atrium, Extensive trabecular pouch found beneath the orifice of the inferior vena cava

(the so-called sub-eustachian sinus).

http://www.rjmatthewsmd.com/Definitions/anatomy_ofthe_heart.htm

IVC

SES

Right Ventricle

– Blood flows from the right atrium to the right ventricle through the cusps of the right atrioventricular valve known as the tricuspid valve.

– The tricuspid valve is attached by long tendons called chordae tendineae to the papillary muscles.

– When the right ventricle contracts, the tricuspid closes preventing blood from entering the right atrium. The chordae tendineae keep the tricuspid from folding back into the right atrium.

– Blood exits the right ventricle through the conus anteriosus as the pulmonary semilunar valve opens into the pulmonary trunk dividing into the right and left pulmonary arteries leading to the lungs.

The Right ventricle

PMPMCTCT

AVSAVS

PTPT

MBMB

Left Atrium

• Smaller than right atrium• Thicker walls than right atrium• 2 left & 2 right pulmonary veins• Oval impression – Fossa Ovalis• Atrial Appendage (longer & narrower)

– Receives oxygen rich blood from the two right and two left pulmonary veins.

– Blood passes from the left atrium to the left ventricle through the left atrioventricular valve or bicuspid.

Left Atrium

• The left atrium is rather smaller than the right, but its walls are thicker, measuring about 3 mm it consists, like the right,

• of two parts, a principal cavity and an auricula.– The principal cavity is cuboidal in form, and concealed, in

front, by the pulmonary artery and aorta; in front and to the right it is separated from the right atrium by the atrial septum; opening into it on either side are the two pulmonary veins.

– The auricula is somewhat constricted at its junction with the principal cavity; it is longer, narrower, and more curved than that of the right side, and its margins are more deeply indented. It is directed forward and toward the right and overlaps the root of the pulmonary artery.   35

The Left Atrium of the Heart (Principle Part)

• Contractions causes the bicuspid to close keeping the blood from backing up in the left atrium; distance between the apex and base increases; diameter of the ventricle chambers decrease.– Blood exits through the semilunar valve into the ascending

aorta.– Right and left coronary arteries originate at the aortic sinuses

and deliver blood to the heart.– Blood passes into the descending aorta and into the systemic

circuit.

Left Ventricle• Oval shaped• Larger than right • Walls 3 X thicker than

right• Smooth walls• Papillary muscles• Cordae tendinae

Valves of the HeartThe heart has four valves for: Pumping action of the heart. Maintaining unidirectional blood flow.

Tricuspid Valve

PMPM

CTCT

AVSAVS

PTPT

Bicuspid “Mitral” Valve

Oblique section (left)

Mitral Valve• 2 triangular leaflets• Larger, thicker, stronger than

tricuspid• Anterior leaflet (aortic or

septal)• Posterior leaflet (ventricular)• Papillary muscle – contraction

occurs during systole to shorten Cordae Tendinae – prevent MR during

ventricular systole

• 3 triangular shaped leaflets• Names

– Anterior– Septal– Posterior

• Papillary muscles & chordae tendinae are present but play a more important role in the high pressure chamber of LV

Tricuspid valve

Pulmonary semi-lunar valve

Aortic semi-lunar valve

Lt. Atrium

Pulmonary Valve Aortic Valve

Aortic Simi lunar Valve

Pulmonary valve

• 3 Semi-lunar cusps• Semi lunar shape• Attached to a fibrous ring

within the wall of pulmonary trunk

• Orientation:– Left anterior– Right anterior– Posterior

• 3 Similar to pulmonary• Leaflets - 3 • Semi lunar shape• Attached to a fibrous ring within

the wall of wall of aortic artery

• Orientation– Anterior– Left posterior – Right posterior

Aortic valve

Skeleton of the heart valves

Systole

Diastole