Anatomy - Internal Heart and Posterior Mediastinum Flashcards
What are the 2 main branches the LCA gives rise to?
- Circumflex artery 2. Anterior interventricular artery (left anterior descending artery)
What does left circumflex artery then give rise to?
Marginal branch
What does the left anterior interventricular artery give rise to?
Diagonal branch
What does left anterior interventricular artery supply?
Predominance of left ventricle
What is the slight indentation on the intertartrial septum?
Fossa ovalis
What is the fossa ovalis?
Remnant of vascular shunt bypassing lungs (foramen ovale in foetal)
What is the rough part of the atrial wall?
Pectinate muscles
What separates the smooth from the rough parts of the atrial wall?
Crista terminalis (muscular ridge)
Why is the left atrium smoother than the right?
Pulmonary veins have been encompassed into the left atrial wall
What attach the edge of the cusps and anchor valves to ventricular wall?
Chordae tendinae
What are chordae tendinae held in place by?
Papillary muscles
What are papillary muscles elevations from?
Trabeculae carnae
What is the trabeculae carnae?
Roughened musculature of ventricles
Are trabeculae carnae more prevalent in left or right ventricle?
Left
Function of papillary muscles?
Contract to prevent tricuspid valve from prolapsing back into right atrium during diastole
What is the ‘moderator band’?
Just before impulse from SA node causes ventricular systole, there is some nervous tissue/Purkinje fibres that project through moderator band to papillary muscles a millisecond before ventricular systole. Enables papillary muscles to contract and pull on chordae tendinae to keep tricuspid valve taught during ventricular systole (stops prolapsing)
What does the trachea bifurcate into?
Right and left primary bronchi
What structure causes constriction of oesophagus?
Left bronchus crosses muscular tube (oesophagus) behind it, causing constriction
What is the ‘carina’?
A ridge of cartilage in the trachea that occurs between the division of the two main bronchi
What drains the thoracic cage?
Azygos vein which eventually empties into SVC
What drains all the lymph from the lower half of the body?
Thoracic duct
What is function of thoracic duct?
Drains lymph from lower half of body
Where does thoracic duct empty into?
Area where subclavian and jugular vein merge to make brachiocephalic vein
What can damage to thoracic duct lead to?
Lymph within thoracic cavity
Where does the trachea bifurcate?
At the carina
What is a chylothorax?
Accumulation of lymph fluid in the thoracic cavity due to damage to the thoracic duct
Papillary vs pectinate muscles?
Pectinate –> elevations from atria wall (form rough part of atria)
Papillary muscles –> elevations from trabeculae carnae, attach to chordae tendinae and then to cusps of valves
How does the trachea deviate?
Deviates slightly towards the right as it descends –> left primary bronchus causes obstruction of oesophagus
