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ANATOMY OF HEART & BLOOD VESSELS

bydr. Rahmadini Djalal M.Biomed

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HEART (Cor, Cardia)• The heart is a hollow, fibromuscular organ of a

conical/pyramidal form, with a base, apex and a series of surfaces and ‘borders’

• It occupies the middle mediastinum between the lungs and the pleurae, enclosed in the pericardium

• It is placed obliquely behind the corpus sterni and adjoining left costal cartilages and ribs; approximately 1/3 lies right of the midline

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Location of the heart in the thorax

Mediastinum

Pericardium

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Middle mediastinum

• The middle mediastinum is centrally located in the thoracic cavity.

• It contains the pericardium, heart, origins of the great vessels, various nerves & smaller vessels

Pericardium• The pericardium is a fibroserous sac

surrounding the heart and the roots of the great vessels.

• The fibrous pericardium is a tough connective tissue outer layer that defines the boundaries of the middle mediastinum

• The serous pericardium is thin and consist of 2 parts :

The parietal layer lines the inner surface of the fibrous

The visceral layer (epicardium) of serous pericardium adheres to the heart and forms its outer covering

The pericardial cavity : is a narrow space created between the two layers of serous pericardium containing a small amount of fluid

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Subdivisions of the mediastinum Sagittal section of the pericardium

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Fibrous pericardium• is a cone-shaped bag with its

base on the diaphragm and its apex continuous with adventitia of the great vessels

• The base is attached to the central tendon of the diaphragm and to a small muscular area of the diaphragm on the left side

• Anteriorly, it is attached to the posterior surface of the sternum by sternopericardial ligaments

Serous pericardium• The parietal & visceral layers of

serous pericardium are continuous at the roots of great vessels. These reflections of serous pericardium occur in 2 locations : The first superiorly, surrounding

the arteries, the aorta and pulmonary trunk

The second more posteriorly, surrounding the veins, the superior and inferior vena cava and the pulmonary veins

The oblique pericardial sinus : the zone of reflection surrounding the veins is “J-shaped” & cul-de-sac formed within the “J”, posterior to the left atrium

The transverse pericardial sinus : a passage between the two sites of reflected serous pericardium

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Posterior portion of pericardial sac showing reflections of serous pericardium

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Surfaces of the heart• Anterior surface : consists mostly of the right ventricle with some of the right

atrium on the right and some of the left ventricle on the left• Diaphragmatic surface : consists of the left ventricle and small portion of the

right ventricle separated by the posterior interventricular groove. This surface faces inferiorly, rests on the diaphragm, is separated from the base of the heart by the coronary sinus & extends from the base to the apex of the heart

• Posterior surface (base) : the base of the heart is quadrilateral & directed posteriorly. It consists of : the left atrium, a small portion of the right atrium, the proximal parts of the great veins (superior & inferior vena cavae and the pulmonary veins)

From the base of the heart projects forward, downward, and to the left , ending in the apex. The apex of the heart is formed by the inferolateral part of the left ventricle ( is positioned deep to the left 5th intercostal space

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Anterior surface of the heart

Right atrium

Left ventricleRight ventricle

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Base of the heart

Left atrium

Inferior vena cava

Superior vena cava

Right atrium

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Diaphragmatic surface of the heart

Left ventricle

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Margins of the heart• Inferior margin (acute) is defined

as the sharp edge between the anterior & diaphragmatic surfaces of the heart. It is formed mostly by right ventricle and a small portion of the left ventricle near the apex

• The obtuse margin separates the anterior & left pulmonary surfaces. It is round and extends from left auricle to the cardiac apex. It is

formed mostly by the left ventricle and superiorly by a small portion of the left auricle

External sulci• The coronary sulcus circles the

heart, separating the atria from the ventricles. It contains the right coronary artery, the small cardiac vein, the coronary sinus & the circumflex branch of the left coronary artery

• The anterior & posterior interventricular sulci separate the two ventricles. The anterior interventricular sulcus contains the anterior interventricular artery & the great cardiac vein. The posterior interventricular sulcus contains the posterior interventricular artery & the middle cardiac vein

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HEART CHAMBERS

Right Atrium Externally, there is no outstanding feature except : the right auricle, a small flap

shaped like a dog’s ear (auricle = little ear) that projects from the superior corner of the atrium

Internally, it has two parts : a smooth-walled posterior part & an anterior part lined by horizontal ridges called : the pectinate muscles

A large C-shaped ridge called : the crista terminalis separates the two parts of the atrium

Posterior to the end of this crista is the : fossa ovalis, a depression in the interatrial septum that mark the spot where an opening existed

in the fetal heart (foramen ovale) Inferiorly & anteriorly, the right atrium opens into the right ventricle through the

tricuspid valve (right atrioventricular valve)

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Crista terminalis

Pectinate muscles

Fossa ovalis

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Right Ventricle

• Receives blood from the right atrium and pumps it into the pulmonary circuit via an artery called the pulmonary trunk

• Externally, the right ventricle forms most of the anterior surface of the heart• Internally, its walls are marked by irregular ridges of muscle, called trabeculae

carnae. Additionally, cone-shaped papillary muscles (anterior, posterior & septal) project from the walls into the ventricular cavity.

• Thin, strong bands called chordae tendineae project superiorly from the papillary muscles to the flaps (cusps) of the tricuspid valve

• A single specialized trabeculum: the septomarginal trabecula (moderator band) forms a bridge between the lower portion of the interventricular septum and the base of the anterior papillary muscle → carries a portion of the cardiac conduction system, right bundle of the atrioventricular bundle to the anterior wall of the right ventricle

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Left Atrium• It forms most of the heart’s posterior

surface, receives oxygen-rich blood from the lungs through two right & two left pulmonary veins

• The only part of the left atrium visible anteriorly is its left auricle.

• Internally, most of the the atrial wall is smooth, with pectinate musle lining the auricle only

• The left atrium opens into the left ventricle through the mitral valve

Left Ventricle• It forms the apex of the heart,

pumps blood into the systemic circuit.

• Like the right ventricle, it contains trabecula carneae, papillary muscles, chordae tendineae & the cusps of mitral valve.

• Superiorly, the left ventricle opens into the aorta through the aortic semilunar valve

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HEART VALVES

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HEART VALVESAortic valve

• It consists of three semilunar cusps with the free edge of each projecting upward into the lumen of the ascending aorta

• Between the semilunar cusps and the wall of the asc.aorta are pocket like sinuses – the right, left and posterior aortic sinuses

• The right and left coronary artery originate from the right and left aortic sinuses

Pulmonary Valve• It consists of three semilunar cusps

with free edge projecting upward into the lumen of pulmonary trunk

• The free superior edge of each cusp has a middle, thickened portion : the nodule of the semilunar cusp, and a thin lateral portion : the lunule of semilunar cusp

• Relative to their fetal position before rotation of the outflow tracks, the cusps are named the left, right and anterior semilunar cusps

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HEART VALVESAortic Valve Pulmonary Valve

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Points on the anterior thoracic surface where sounds of the heart valves are heard most clearly

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CARDIAC SKELETON

• The cardiac skeleton is a collection of dense, fibrous connective tissue in the form or four rings with interconnecting areas in a plane between the atria & the ventricles

• The four rings of the cardiac skeleton surround the two atrioventricular orifices, the aortic orifice and opening of the pulmonary trunks

• They are the annulus fibrosus• The interconnecting areas include :• The right fibrous trigone, which is a thickened area of connective tissue between the

aortic ring and right atrioventricular ring• The left fibrous trigone, which is a thickened area of connective tissue between the

aortic ring and left atrioventricular ring

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Cardiac skeleton

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Coronary arteries

Right coronary artery• Originates from the right aortic

sinus of the ascending aorta.• It passes anteriorly and to the right

between right auricle & pulmonary trunk, then descends vertically in the coronary sulcus, between right atrium & right ventricle

• It branches : atrial branch, right marginal branch and posterior

interventricular branch

Left coronary artery• Originates from the left aortic

sinus of the ascending aorta.• It passes between the pulmonary

trunk and the left auricle before entering the coronary sulcus

• While still posterior to the pulmonary trunk, it divides into its two terminal branches : the anterior interventricular branch and the circumflex branch

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Cardiac VeinsGreat cardiac vein

• It begins at the apex of the heart, it ascends in the anterior interventricular sulcus, reaching the coronary sulcus then it turns to the left and continues onto the base of the heart. At this point, it is associated by circumflex artery

• Continuing along its path in the coronary sulcus, it gradually

enlarges to form the coronary sinus , which enters the right atrium

Middle cardiac vein

• It begins near the apex of the heart and ascends in the posterior interventricular sulcus toward the coronary sinus. It is associated with the posterior interventricular branch of the right coronary artery

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Cardiac veinsSmall cardiac vein

• It begins in the lower anterior section of the coronary sulcus between the right atrium and right ventricle

• It continues in this groove onto the base of the heart where it enters the coronary sinus at its atrial end.

• It is accompanied by the right coronary artery throughout its

course and may receive the right marginal vein

Posterior cardiac vein

• It lies on the posterior surface of the left ventricle just to the left of the middle cardiac vein

• It enters the coronary sinus directly or joins the great cardiac veins

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Other cardiac veinsThe anterior veins of right ventricle (anterior cardiac vein)

• Are small veins that arise on the anterior surface of the right ventricle. They cross the coronary sulcus and enter the anterior wall of the right atrium. They drain the anterior portion of the right ventricle

Venae cordis minimae / Veins of Thebesius

• A group of smallest cardiac veins• Draining directly into the cardiac

chambers, they are numerous in the right atrium and right ventricle, are occasionally associated with the left atrium, and are rarely associated with the left ventricle

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Coronary blood vessels

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THE BLOOD VESSELS• The complex system of blood vessels in the body called the vascular system

has two basic circuit : the pulmonary circuit & the systemic circuit• The pulmonary circuit carries blood to and from the lungs for the uptake of

oxygen and the removal carbon dioxide from body tissues• The systemic circuit carries oxygenated blood throughout the body and picks up

carbon dioxide from body tissues• THE SYSTEMIC CIRCULATION : The systemic arteries The systemic veins

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The systemic arteries• Aorta • Arteries of the head and neck• Arteries of the upper limb• Arteries of the thorax• Arteries of the abdomen• Arteries of the pelvis and lower limbs

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Major arteries of the systemic circulation

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Arteries of the head and neck

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Arteries of the right upper limb and thorax

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Arteries of the lower limb

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Major veins of the systemic circulation

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Veins of the head and neck

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Veins of the right upper limb and thorax wall

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