Heart & Diaphragm Flashcards
What are the three parts of the conducting system of the heart
Sinoatrial Node
Atrioventricular Node
Atriventricular bundle of HIS
What are the functions of the sinoatrial node
1: Pacemaker
2: Initiates cardiac impulse
3: Send the impulse from SA node to AV node
What are the functions of the atrioventricular node
Delays the contractions of the ventricles
Where is the atrioventricular node located?
In the right atrium in the lower part of the interatrial septum
Describe the atrioventricular bundle of HIS
It descends into the interventricular septum and divides into:
1: Right ventricular branch
2: Left ventricular branch
These branches descend in the interventricular septum. They then spread out in the walls of respective ventricles to end as Purkinje fibres.
Where does the blood supply to the heart come from
The right and left coronary arteries
What is the atrioventricular groove also called
Coronary sulcus
Atrioventricular sulcus
What is the auricle
The muscular pouch that expands the capacity of the atria
What is the origin of the right coronary artery
Right aortic sinus
What is the course of the right coronary artery
1: Between pulmonary trunk and right auricle, descends to the right in the coronary sulcus
2: Turns posteriorly at junction of right and inferior border
3: Continues along the posterior part of the coronary sulcus (and then anastomoses with branch of left coronary artery)
What are the branches of the right coronary artery
Artery to SA node (65% of cases)
Right marginal artery
Posterior interventricular branch
Conus artery
Atrial and ventricular branches
What are the areas supplied by the right coronary artery
Most of the right atrium
Right ventricle, except area adjoining anterior interventricular groove
Left ventricle adjacent to posterior interventricular sulcus
Posterior third of interventricular septum
SA node (in 65% of cases)
AV node
Bundle of HIS (except left branch of bundle of HIS)
What is the origin of the left coronary artery
Left aortic sinus
What is the course of the left coronary artery
1: Behind, then to left of pulmonary trunk to reach left part of coronary sulcus
2: Divides into:
- - Anterior interventricular artery
- - Circumflex artery
What are the braches of the left coronary artery
Anterior interventricular artery
Circumflex artery
Diagonal artery
Atrial and ventricular branches
What are the areas supplied by the left coronary artery
Left atrium
Left ventricle (except area adjoining posterior interventricular groove)
Right ventricle adjacent to anterior interventricular sulcus
Anterior two-thirds of interventricular septum
SA node (35% of cases)
Part of the left branch of bundle of HIS
How is coronary artery dominance determined
Whether the posterior interventriuclar artery is attached to the right coronary artery or the left coronary artery
What are the three ways that the heart is drained
1: Coronary sinus
2: Anterior cardiac veins
3: Venus cordis minimae
Where is the coronary sinus
In the posterior part of the coronary sulcus
What are the tricutaries of the coronary sinus
Great cardiac vein Middle cardiac vein Small cardiac vein Right marginal vein Oblique vein of left atrium Posterior ventricular vein
What are the anterior cardiac veins
Several small veins that drain anterior aspect of the right ventricle that open up into right atrium
What do the venus cordis minimae drain
Endocardium and deep myocardium
Where do the venus cordis minimae drain into
Open directly into each chamber of the heart
Explain the nerve supply of the heart
Carciac Plexus (Autonomic nervous system)
Made up of:
A: SYMPATHETIC FIBRES
-From the superior, middle and inferior cervical ganglia
-From the spinal segments (T1-T4)
B: PARASYMPATHETIC FIBRES
-Vagus nerve
