By Ghulam Rasool Baltistani

Anatomy Of Heart

The HeartA hollow muscular organ that pumps the blood through the circulatory system by rhythmic contraction and dilation. In vertebrates there may be up to four chambers (as in humans), with two atria and two ventricles.

Size of Heart• The heart is relatively small, roughly the same

size (but not the same shape) as your closed fist.

• It is about 12 cm long, 9 cm wide at its broadest point, and 6 cm thick.

• It has an average mass of 250 to 300 grams.

Location of Heart• The heart rests on the diaphragm, near the

midline of the thoracic cavity.• Heart lies in the thoracic cavity in the

mediastinum and between the lungs.• It lies obliquely, a little more (about 2/3) to left

than the right.• Present a base above and apex below

Organ Associated With The Heart

• Inferiorly:• The apex rest on the central tendon of the diaphragm.

• Superiorly:• The great blood vessel aorta is located.

• Posteriorly:• Esophagus, Trachea, Left and Right bronchioles,

Descending Aorta.

• Laterally:• Lungs

• Anteriorly:• Sternum, Ribs, Inter costal muscles.

Pericardium• The membrane that surrounds and protects

the heart is the pericardium.• It confines the heart to its position in the

mediastinum, while allowing sufficient freedom of movement for vigorous and rapid contraction.

• It consists of two main parts: – Fibrous pericardium– Serous pericardium

Layers of the Heart Wall• The wall of the heart consists of three layers – the epicardium (external layer)– the myocardium (middle layer)– the endocardium (inner layer).

• The epicardium is composed of two tissue layers. The outermost, as you just learned, is called the visceral layer of the serous pericardium.

• The middle myocardium is composed of cardiac muscle tissue. It makes up approximately 95% of the heart wall.

• The innermost endocardium is a thin layer of endothelium overlying a thin layer of connective tissue.

Layers of the Heart Wall

• “Tricuspid” valve– RA to RV

• Pulmonary or pulmonic valve– RV to pulmonary trunk (branches R and L)

• Mitral valve (the bicuspid one)– LA to LV

• Aortic valve– LV to aorta

Valves of The Heart

Chambers of the Heart

• Two atria-divided• by interatrial septum– Right atrium– Left atrium

• Two ventricles-divided by interventricular septum – Right ventricle– Left ventricle

ReferencesPrinciples ofANATOMY &PHYSIOLOGYGerard J. TortoraBergen Community CollegeBryan DerricksonValencia Community College

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