Sem 1 - Cardio Flashcards
by how far does the lumen need to narrow in a coronary artery for stable angina to occur?
70%
most common cause of MI?
atherosclerosis with thrombosis
what is cardiac tamponade?
In cardiac tamponade, also known as pericardial tamponade, blood enters the pericardial sac and causes an increase in pericardial and thus intracardiac pressures. This impairs filling and cardiac output becomes inadequate
features of healthy myocytes (3)?
oval shape, fine chromatin, inconspicuous nucleoli
Why is rupture more likely at 2-4 days with say 3 or 6 weeks following an infarct? (2 marks)
rupture is more likely at this time as the necrotic muscle is weak and being phagocytosed. As time goes on more collagen (or fibrous tissue) is laid down which strengthens the wall.
without intervention what changes would occur over time in the affected artery? (has a thrombus in it)
Over time, a thrombus will undergo organisation and recanalisation.
what are organisation and recanalisation?
Organisation is the process of the formation of scar tissue via the formation of granulation tissue, which in this case will replace the thrombus.
Recanalisation refers to the formation of new vessels in the granulation and later scar tissue through the occluded lumen.
Explain the role of troponin (in general, needn’t give details of all 3 subunits) in normal contraction. (5 marks) (no keywords here but please attempt an answer)
Troponin (3 subunits), tropomyosin, actin and myosin are regulatory and contractile proteins involved in contraction. Troponin and tropomyosin are linked and lie along the actin filaments. Tropomyosin inhibits the interaction between actin and myosin. Calcium released from the sarcoplasmic reticulum by depolarisation binds to one of the subunits of troponin, inducing a conformational change in tropomyosin, enabling interaction between actin and myosin and thus contraction.
what part of the heart does the LAD supply?
apex and anterior wall of the left ventricle, and the anterior two-thirds of the interventricular septum.
A 74-year-old man with an old inferior myocardial infarction died of unrelated causes. Describe the macroscopic abnormalities expected to be seen in this man’s left ventricular myocardium. (3 marks)
The inferior left ventricular myocardium and posterior one third of the interventricular septum would be very pale, almost white and the wall thinned.
in the above case What would you most expect to see macroscopically in the coronary artery supplying the abnormal area?
scar tissue
in the above case Which coronary artery is most likely to be occluded? which is also possible
Right. Circumflex
