Nov 4 - Anatomy of the Heart and Great Vessels Flashcards
What is the heart?
Muscular, 4-chamber pump that propels blood throughout the systemic and pulmonary circulation
Where is the heart?
It is found within a pericardial sac in the middle mediastinum
What controls the heart?
It has it’s own pacemaker. Autonomic innervations (sympathetic and parasympathetic) modulate the heart’s actions
Describe how the heart is connected to the lungs?
In the hilum of each lung, one pulmonary artery enters the lung and two pulmonary veins leave the lung and enter the heart
Describe the position of the heart?
The apex of the heart, formed by the left ventricle, is shifted anteriorly left. All the valves, found at the base of the heart, are shifted obliquely (making it hard to listen)
Where is the base of the heart found?
Behind the sternum
Why does the heart move up and down?
The pericardium, or pericardial sac, is attached to the central tendon of the diaphragm
Name the layers of the pericardium from superficial to deep
The fibrous pericardium, the parietal layer of the serous pericardium, the pericardial cavity, the epicardium (visceral layer of the serous pericardium), the myocardium and the endocardium
Describe the fibrous pericardium
The outer layer of the pericardium. It is very tough and non elastic. It attaches to the diaphragm inferiorly
Describe the serous pericardium
Two layers: the parietal layer is attached to the fibrous pericardium and the visceral layer or epicardium lines the surface of the heart. The pericardial cavity contains fluid
What is the role of the pericardium?
It gives the heart room to move independently and reduces friction
Name the two recesses/sinuses
The oblique sinus, behind the heart and the transverse pericardial sinus
Describe the location of the transverse pericardial sinus
Posterior to the pulmonary trunk and the the ascending aorta. It separates the outgoing and incoming vessels of the heart (surgeon’s landmark)
What structure is posterior to the heart
The esophagus is found posterior to the heart
What attaches the aortic arch and the left pulmonary trunk?
The ligamentum arteriosum
What creates the brachiocephalic vein?
The junction of the right subclavian and the right internal jugular
Describe the positions of the main bronchi in the left and right hilum of the lung in relation to the pulmonary artery
The left main bronchus is inferior to the pulmonary artery and the right main bronchus is posterior to the pulmonary artery
How does the heart sit in the mediastinum
More on its posterior inferior surface against the diaphragm (often referred to as the diaphragmatic surface). The apex is to the left (the heart doesn’t stand on its apex)
Why can’t you see the right ventricle in a chest X-ray
Because it’s not border forming (anteriorly)
What separates the left and right ventricles?
The interventricular septum (IVS)
Which ventricle has a thicker myocardium? Why?
The left ventricle because it’s pumping blood into the systemic circulation (whereas the right ventricle pumps blood into the pulmonary circulation)
How is the myocardium arranged?
In a spiral way starting from the apex and then pushing the whole volume of blood upward
Name the contents of the ventricles
Trabeculae carneae, the papillary muscles, chordae tendinae, atrioventricular valves (AV valves), semilunar valves
What is trabeculae carneae?
It’s the rugged surface of the ventricles