Cardiovascular Anatomy Flashcards
What is rate of diffusion proportional to?
Square of the distance
What does rate of diffusion depend on?
Area available for exchange - a tissue which is more metabolically active will have more capillaries, and thus larger area of exchange
Diffusion resistance - nature of the molecule, the barrier, the path length
Concentration gradient - gradient level depends on rate of use by tissue and rate of blood flow
State the normal cardiac output and for an average adult male at rest and during exercise
5l/min for a 70kg person at rest
24.5 l/min during exercise
Describe the position of the heart in situ
Heart sits behind sternum, with the apex pointing to the left, inferiorly and anteriorly
Base of posterior surface is formed by atria (mainly left)
Anterior surface mainly shaped by right atrium and right ventricle
Inferior surface formed by ventricles - mainly left ventricle and lies above diaphragm
Describe the layers of the pericardium
Has a thick fibrous layer on the outside
Pericardial layer contains fluid which is contained within the parietal and visceral walls (epicardium)
Myocardium and then endocardium inside
Explain the problems associated with fluid accumulation in pericardial sac
If excess fluid builds up relatively rapidly, this can compress the heart due to the inextensible fibrous pericardial layer
Compression can lead to cardiac tamponade - prevents ventricles from expanding fully and thus blood isn’t pumped sufficiently around the body
Could be cancer or bacterial infection that causes fluid to build up or blood from the heart can also enter
Needle can be entered into pericardium to test what fluid is inside or to relieve compression (pericardiocentesis)
Where do surgeons clamp the heart during surgery
Transverse pericardial sinus due to heart folding
Cardiac surgeons clamp the aorta and vena cava in this space
Once clamped, blood will not flow to the heart
Exterior machines are run to keep lungs, brain and other vital organs running
What does right coronary artery divide into and supply
Right coronary artery arises from the right aortic sinus
Branches into right marginal artery and posterior interventricular artery
Supply blood to the sinoatrial and AV nodes
What does the left coronary artery divide into and supply
Left coronary after arises from the left aortic sinus
Separates into circumflex branch, left marginal artery and anterior interventricular artery
Left anterior interventricular artery commonly blocked in myocardial infarction
Supplies both sides of the heart - septum and both ventricles
Also known as left anterior descending artery (LAD) or widow-maker
State the main venous drainage of the heart
Coronary sinus - drains into right atrium
