Heart (2) : Innervation, Vasculature & Valves
Heart (2) : Innervation, Vasculature & Valves
Heart (2) : Innervation, Vasculature & Valves
Conducting System
Sino-Atrial node (SA node) Atrio-Ventricular node (AV node) Atrio-Ventricular Bundle & branches (bundle of His) Purkinje fibers (subendocardial plexus)
A-V Node
The pulse conductor Lower part of atrial septum (above septal cusp)
AV bundle (septum) Right (moderator) & Left bundle branches Purkinje fibers
Autonomic Innervation
To SA & AV nodes
Arterial Supply
Coronary arteries: Right & Left (larger) From ascending aorta & just above the valve
Divides to: 1. ant. interventricular a. 2. circumflex a 3. SA nodal (35 - 40%) through which branch?
Circumflex Artery
Pass in left AV groove winding around the heart in a circle anastomoses with Rt. coronary posteriorly
Gives rise to left marginal artery
Venous Drainage
3 main veins Coronary Sinus
1. Great: Ant. 2. Middle: Post. 3. Small: Rt. Margin
Angina Pectoris
Angina = G, strangling, Pectoris= L, chest Severe chest pain due to O2 shortage to the heart wall (ischemic heart disease) Cause: Partial obstruction or spasm of a coronary artery (arteriosclerosis) Symptoms: chest discomfort (pressure, heaviness or tightness) substernal pain specially after ? referred pain over the left arm, neck & lower jaw
Myocardial Infarction
Interruption of bld. Supply to a part of the heart leading to death of heart muscle on that region.
Heart Valves
4 valves:
- 2 semilunar: Aortic & Pulmonary - 2 A-V: Tricuspid & Mitral
Semilunar Valves
Pulmonary:
3 semilunar cusps (2 ant. & 1 post.)
Cusp: folding of endocardium with C.T. inside
Aortic :
similar to pulmonary
Tricuspid Valve
Rt. A-V orifice 3 cusps: 1. ant. 2. post.
3. septal
Mitral Valve
Left A-V orifice 2 cusps (bicuspid): Ant. & Post.
Pulmonary (P)
Heart Position
Behind the sternum & slightly to the left strong sounds = left to the sternum Dextrocardia: The heart is on the right side of the chest heart sounds = right to the sternum