Anatomy of the valves Flashcards
What is the tricuspid orifice?
- It is a large oval opening connecting the right atrium with the right ventricle
- It is surrounded by a fibrous tissue ring giving attachment to the tricuspid valve
- It lies behind the 4th intercostal space
What is the anatomical thorax relation of the tricuspid orifice?
4th intercostal space
Describe the tricuspid valve
- It is a valve that guards the tricuspid orifice formed of a fibrous ring and three cusps:
1) Anterior cusp: Between the tricuspid orifice and the infundibilem of the RA
2) Posterior cusp: At the inferior wall of the right ventricle
3) Septal cusp: Attached to the interventricular septum
What are the features of the tricuspid valve cusps?
1) Made of two layers of endocardium with a fibrous tissue in between
2) The cusp is avascular except at the circumference
3) The atrial surface of the cusp is smooth, while the ventricular surface is rough and has attachments for the chordae tendenae
What is the mitral orifice?
- It is an opening surrounded by a fibrous ring between the LA and the LV
- It is smaller than the tricuspid orifice
- It lies at the 4th costal cartilage
What is the anatomical relation of the mitral orifice in regard to the thorax?
It lies at the 4th costal cartilage
What is the mitral valve?
It is the valve that guards the mitral orifice formed of two cusps:
1) Anterior cusp: It is larger than the posterior one, lies at the anterior and towards the right
2) Posterior cusp: Smaller and lies posteriorly towards the left
What are the features of the mitral cusps?
- It consists of a double endocardium layer with fibrous tissue in between
- Its base is attached to a fibrous ring
- Its atrial surface is smooth while the ventricular surface is rough, the ventricular surface is attached to two papillary muscles in the ventricles which are fewer and stronger than those of the right ventricle
Describe the aortic and pulmonary (semilunar) valves
- It is guarded by three semilunar cusps
- In the aortic valve, one cusp is anterior (right), and ONE IS LEFT THE THIRD IS POSTERIOR
- In the pulmonary trunk, one cus is posterior and 2 are anterior (LEFT & RIGHT)
Describe the structure of the semilunar cusps
- The cusp is cup-shaped
- The cusps are projected into the arterial wall
- Their free edge is thickened forming the lunule
- Each lunule has an angulated free edge with a central fibrous nodule
What is the significance of the sinus in the tricuspid valve?
The wall of the artery is slightly dilated in each cusp preventing the cusp from sticking into the blood vessel, and thus failing to shut
- The Right anterior cusp has a right coronary artery opening, while the left posterior cusp has a left coronary artery opening
What is meant by aortic stenosis?
It is a condition where the valve cusps are fused, narrowing the central opening, which will require extra work from the heart that might lead to hypertrophy of the LV
What is meant by aortic incompetence?
It is when the aortic cusps fail to close completely, leading to the backflow of blood into the ventricles
Describe the skeleton of the heart
- They are fibrous rings that surround the AV canals and the AORTA & PULMONARY TRUNKS
- Right and Left Fibrous Triagones form connections between the rings
- It forms the membranous part of the interventricular septum
What is the function of the skeleton of the heart?
1) Keeps the tricuspid and mitral orifices patent all the time
2) Prevents the over-distention of the orifices
3) It provides attachment for the myocardium and the cusps of the valves
4) Acts as an electrical insulator between the atria and the ventricles so that they can contract independently