CVS Flashcards
Where does the mediastinum lie?
Inferior surface of the diaphragm to the superior thoracic aperture, and from the sternum and costal cartilages anteriorly to the thoracic vertebra posteriorly
Where does the superior mediastinum occur?
T4
What structures are found in the superior mediastinum?
SVC Brachiocephalic v. Arch of aorta Vagus Phrenic nerve Trachea Oesophagus
What structures are found in the anterior mediastinum?
Sternopericardial ligament (anchors pericardium to sternum) Remnants of thymus gland which becomes fibrous and fatty after puberty
What structures are found in the middle mediastinum?
Heart
Ascending aorta
SVC
What structures are found in the posterior mediastinum?
Oesophagus
Thoracic aorta
Azygous and hemiazygous veins
What structure makes the base of the heart?
LA (T6-9)
What are the 4 surfaces of the heart?
Anterior - sternocostal
Inferior - diaphragmatic
Left - LV
Right - RA
What are the 4 borders of the heart?
Right: RV
Inferior: mainly RV and partly LV
Left: LV
Superior: RA and LA
What level is the heart located?
T5-8
How does the position of heart change with height?
Taller - more vertical
Smaller - more transversely placed
Describe layers to the pericardium
Fibrous outer layer
Serous inner layer: parietal, pericardial cavity, serous)
Describe endocarium
Simple squamous epithelium on BM adhered to connective tissue
Describe epicardium
Connective tissue, BM and simple squamous epithelium
Contains branches of the coronary arteries
Forms the serous visceral layer
Name the semi-lunar valves
Aortic and pulmonary (3 cusps)
Is mitral valve bicuspid or tricuspid?
Bicuspid
What is the annulus fibrosis?
A fibrous structural support for the heart chamber - supports the atrioventricular septum
Composed of dense connective tissue
What is the function of the chord tendineae?
Tendons that connect papillary muscles to valve cusps
What is the function of the papillary muscles?
Prevents inversion of valve
What is the function of the annulus fibrosis?
Keeps all valves open, preventing tears and back flow
Acts as an electrical insulator by preventing electrical impulses through atria and ventricles, so delaying contraction, to allow ventricles to fill up
What is the function of the coronary arteries?
Supply the myocardium and epicardium and are located deep in the epicardium, embedded in fat
Where do the coronary arteries arise from?
Aortic sinuses at the proximal part of the ascending
What does the RCA divide into further?
Sino-atrial (SA) nodal branch - SA node
R marginal branch - R of heart
AV nodal branch - AV node
Posterior IV branch - both ventricles
What does the LCA divide into further?
Circumflex
Anterior IV branch (LAD)
What are the two main sulci of the heart?
Coronary sulcus - between atria and ventricles
Interventricular sulcus - between ventricles
Where do the cardiac veins drain into?
Coronary sinus - a wide venous channel on the posterior side of the heart which feeds into the RA
What are the cardiac veins and what coronary aa. do they lie along?
Great cardiac vv. - LAD
Middle cardiac vv. - posterior descending aa.
Small cardiac vv. - R marginal aa.
At what level does the aortic arch lie?
T4
At what level is the bifurcation of abdominal aorta?
L4
At what level is the bifurcation of common iliac aa.?
L5
What are the 3 arteries that branch of the arch of the aorta?
Brachiocephalic trunk
L common carotid aa.
L subclavian aa.
What are the arteries that branch off the descending aorta?
Bronchial aa.
Oesophageal aa.
Pericardial aa.
Posterior IC aa. (only one indentifiable on wet specimen)
What are the tributaries of the SVC
L and R braciocephalic vv.
Azygous vv.
(Internal jugular vv. + subclavian vv. -> brachiocephalic vv.)
What is the function of the azygous vein?
Drain blood from the posterior IC veins to the SVC and found immediately to the right of the thoracic aorta