Internal features of Heart Dr. Sama ul Haque

Objectives List the chambers of the heart. Describe the internal features of right atrium. Describe the internal features of the right ventricle. Discuss internal features of the left atrium. Discuss the internal features of the left ventricle. Differentiate between right and left ventricles. Define conducting system of the heart.

Chambers of Heart Right Atrium Right Ventricle Left Atrium Left Ventricle

Chambers of Heart

Internal Structure of Heart

Right Atrium 1 2 Rough anterior part. Smooth posterior part. Crista Terminalis 1 Musculi pectinati (Pectinate muscles) 2

Right Atrium Posterior wall of the right atrium: • Opening of the superior vena cava • Opening and valve of the inferior vena cava • Opening and valve of the coronary sinus • Fossa ovalis and the limbus fossa ovalis Anterior wall of the right atrium: • Pectinate muscles • Crista terminalis

Right Ventricle

Right Ventricle Tricuspid valve has three cusps: anterior, septal, and posterior. Three papillary muscles: anterior, septal, and posterior. The anterior papillary muscle is the largest and most prominent. Trabeculae carneae (rough muscular ridges).

Right Ventricle The septomarginal trabecula (moderator band): extends from the interventricular septum to the base of the anterior papillary muscle. The conus arteriosus (infundibulum): is the cone-shaped portion of the right ventricle inferior to the opening of the pulmonary trunk. The pulmonary valve: consists of three semilunar cusps: anterior, right, and left.

Right Ventricle

Left Atrium Receives blood from lungs: Through 4 pulmonary veins (2 right & 2 left) Bicuspid valve: blood passes through it into left ventricle (mitral valve has two cusps).

Left Ventricle Aortic valve: has three semilunar valve cusps: right, left, and posterior. Left atrioventricular valve (bicuspid valve or mitral valve): has anterior & posterior cusps.

Left Ventricle Anterior papillary muscle and the posterior papillary muscle: the chordae tendineae of each papillary muscle attach to both valve cusps. Trabeculae carneae.

Left Ventricle have thick muscular wall

Valves of the Heart 3 4 2 1 Right Atrioventricular (Tricuspid) Left Atrioventricular (Bicuspid or Mitral) Pulmonary Aortic 3 4 2 1

Fibrous Skeleton of the Heart Dense collagenous fibrous tissue framework lies at the junction of the atria with the ventricles. Includes: 1-Tricuspid fibrous annulus: 2-Mitral fibrous annulus 3-Pulmonary fibrous annulus: 4-Aortic fibrous annulus Functions: 1-Supports the valves. 2-Electrically separetes atria from ventricles.

Valves of the Heart

Valves of Heart in Diastole (Viewed from base with atria removed)

Valves of Heart in Systole (Viewed from base with atria removed)

Direction of blood flow

Conducting system of Heart Sinu-Atrial Node (S-A Node) Atrio-ventricular Node (A-V Node) Atrio-ventricular Bundle Right and left Bundle branch Purkinje Fibers

Conducting system of Heart S-A Node A-V Node

Conducting system of Heart PF

Conducting system of Heart

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