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
1.Right Atrium
2.Right Ventricle
3.Left Atrium
4.Left Ventricle
Chambers of Heart
Internal Structure of Heart
Right Atrium
1. Rough
anterior part.
Crista Terminalis
2. Smooth
posterior
part.
1
2
Musculi pectinati
(Pectinate muscles)
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
1. Right Atrioventricular
(Tricuspid)
2. Left Atrioventricular
(Bicuspid or Mitral)
3. Pulmonary
3
4. Aortic
1
4
2
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
Thank You