Download Chambers Valves, Conduction System, Coronary Circulation

Cardio 2a – Chambers, Valves, Conduction System, Coronary Circulation
Anil Chopra
1. Understand the circulatory pathway through the heart. Vessels that enter the
heart and vessels that leave the heart.
Lungs
Pulmonary Vein
Pulmonary
Trunk
Right Atrium
Left Atrium
Right Ventricle
Left ventricle
Vena
Cava
Aorta
Body
2. a) Understand the Chambers of the heart
Right Atrium:
- Appendage and venous components.
- Appendage is large
- Venous component receives blood from vena cavae and
coronary arteries.
- Leads to tricuspid valve
Left Atrium:
- Appendage and venous components.
- Appendage is small and finger-like
- Venous component receives blood from the pulmonary veins.
- Leads to mitral valve
Right Ventricle
- Elliptical in shape.
- Inlet is tricuspid valve
- Output is infundibulum that supports pulmonary valve.
- Supraventricular crest separates pulmonary and tricuspid
valve.
- Trabecular portion (inside connective tissue and framework)
is rough, project into the cavity and are made from irregular
muscle bundles.
Left Ventricle:
- Conical in shape with rounded cross-section.
- Thicker walled than right ventricle.
- Inlet is mitral valve.
- Aortic and mitral valve and are adjacent.
- Output is aortic valve and is in between ventricular septum
and mitral valve.
- Trabecular portion in apex. It comprises of criss-crossing
bundle fibres.
b) Understand the components of the septum.
Atrial septum: between left and right atria. It contains the oval fossa where the septum
is thin. It is noticeable on the right atrium.
Ventricular septum: runs obliquely between left and right ventricles. It is mainly
muscular but also contains Purkinje Fibres. A small part of the ventricular septum is
membranous.
c) Understand the components of heart valves.
Atrioventricular Valves:
 between atria and ventricles.
 prevent backflow of blood in ventricular systole.
 have hinge like attachments which attach tendons to papillary muscles.
Tricuspid Valves:
 has 3 cusps (leaflets), antero-superior, mural, septal.
 between right atria and ventricles.
Mitral (bicuspid) Valves:
 has 2 cusps between left atria and ventricles, anterior and posterior.
Arterial Valves (semilunar)
 prevent reflux from arteries into ventricles
 oven when ventricles contract in systole.
 3 semilunar leaflets not attached to chords.
 have nodules in the middle of each of the leaflets.
 fills with blood in diastole as the valve closes.
Pulmonary Valves:
 right infundibulum
Aortic Valve:
 Left side of heart in junction between aorta LV.
d) Understand the conduction system.
(1) Sinus Node (SAN) – initiates the conduction of impulses.
(2) Atrioventricular Node (AVN) – amplifies current down septum through the
bundle branches of the Purkinje network.
e) Coronary Circulation.
Consists of:
Right: Right coronary artery
Left: Anterior descending, posterior descending, circumflex arteries.
NB: If the right coronary artery supplies the posterior descending coronary
artery than it is RIGHT CORONARY DOMINANCE (90%)
If the left coronary artery supplies the posterior descending artery it is LEFT
CORONARY DOMINANCE.
Venous return consists of great,
middle and small cardiac veins
which all drain into the coronary
sinus which returns blood to the
right atrium. Thebesian veins also
drain directly into chambers.