Prac 4: Cardiac Flashcards
What is the most important mechanism via which cardiac myocytes can obtain additional oxygen?
Autoregulation of vascular restistance
What do we see in a histological section of coagulative necrosis?
Lost nuclei, outlines retained
65yo. woman, central chest tightness and shortness of breath (settling on resting). ST depression in lateral leads. What would we find in the coronary artery supply this area?
Atherosclerotic narrowing of the lumen greater than 70% (stable angina)
65 yo. woman, presents to ED with several hours of constant central chest pain and shortness of breath. ECG: ST elevation, loss of amplitude of R, small Q wave in inferior leads (II, III and aVF) What would we find in the coronary artery supplying the area of myocardium visualised by these leads?
Atherosclerosis with thrombosis (R coronary)
What are common causes of ischaemic events in the brain?
Thrombo-emboli and athero-emboli
What more common in the heart, thrombotic occlusion or thrombo-emboli?
Thrombotic occlusion
Which part of the heart is most susceptible to ischaemia?
Subendocardial muscle (severe coronary atherosclerosis causing great narrowing)
What areas of the heart does the LAD supply?
The anterior LV myocardium, anterior 2/3rds of IV septum
What allows rapid depolarisation to spread within the cell?
T tubules
What is the endothelial layer on a histological section of the heart?
Extremely thin layer on outside
In a normal myocardium, what do the intercalated discs look like?
Areas of vertical lines in muscle
What do desmosomes do?
Anchors cytoskeletal elements
What do gap junctions do?
Allow the passage of ions and small molecules between cells
What do tight junctions do?
Prevents exchange between apical/basolateral membranes and controls paracellular diffusion
What can haemopericardium be caused by?
Cardiac tamponade from ventricular wall rupture following MCI
What does infarcted myocardium appear like on a slide -larger features (3)
More eosinophilic
Areas of haemorrhage
Inflamed
What does infarcted myocardium look like (microscopic features) (4)
Elongated nuclei Smudged chromatin (kayolysis) NPs and haemmorhage
What does the presence of widespread granulation tissue suggest?
The process is at least 1-2 weeks old
Does pericarditis cause death?
No
What are the SA and AV nodes supplied by?
RCA
What is the name given to finely granular yellow-brown pigment?
Lipofuscin (residues of lysosomal digestion)
After an MCI, when does rupture generally occur?
10-14 days post infarction
In an infarcted myocardium, what would we see an accumulation of?
Calcium in the cytoplasm
Which part of the heart contains adipose tissue?
Epicardium
