Sem 1 - Vascular histo and path Flashcards
where are the elastic lamina when present
Either side of the tunica media.
tunica intima> internal elastic lamina> tunica media > external elastic lamina > Tunica Adventitia
which vessels dont contain smooth muscle (3)?
capillaries, post capillary venules and small lymphatics
How can a small arteriole be distinguished from a muscular venule?
Muscular venules have a larger lumen relative to their wall thickness.
name 3 places with fenestrated capillaries
heart, liver, bone marrow
what is a fenestrated capillary? how is it different to a sinusoidal?
Fenestrated capillaries have pores in the endothelial cells - allow small molecules and limited amounts of protein to diffuse.
Sinusoidal are a special type of fenestrated capillaries that have larger openings in the endothelium. Allow red and white blood cells and various serum proteins to pass
what is a pericyte?
supportive cells with a smooth muscle cell-like phenotype that is normally located in and around the basement membrane of capillaries and venules?
Endothelial cells of most blood vessels are held together by which type of tight junction?
Fascia occludens (discontinuous tight junctions found between most endothelial cells)
LEAST likely to be seen within an atherosclerotic plaque? why?
neutrophils, as Atherosclerosis is a chronic inflammatory disease process
Name the arteries in the body that are elastic in type?
major distribution vessels: the aorta, brachiocephalic, subclavian and common carotid, and most of the large pulmonary arteries.
What is the function of vasa vasorum? Why is this necessary
supply oxygen and nutrients to the outer media in vessels with thick walls as the distance is too great for adequate perfusion from the vessel lumen.
what part of vessels do dissection tracks usually occur?
outer media
describe organisation in an adventita
The adventitia would be very cellular with prominent capillaries. The predominant cells would fibroblasts with very plump nuclei.
Select the two most likely complications that could develop as a result of an aortic atherosclerotic plaque. why?
thrombosis (loss of endothelium over plaque may activate haemostasis leading to thrombus formation over the plaque,).
Embolism - Bits of plaque may flick off and embolise into bloodstream.
explain claudication including likely arteries
Atherosclerosis leads to stenosis of the femoral and/or popliteal arteries in the leg with a subsequent reduction in blood flow and blood pressure distally.
typical way to tell dif b/w SMALL artery and vein on histo
a thicker wall than the accompanying vein and an internal elastic lamina
Why does the aorta have abundant elastic tissue in the media? (3 marks)
the aorta expands and moderates the rise in blood pressure during systole, then recoils, a function of the elastic tissue, during diastole. The recoil helps to maintain the pressure and forward flow of blood in diastole, despite there being no cardiac output during diastole.
Keywords: elastic/elastin, recoil, pressure
Explain the pathogenesis of arteriolar hyalinisation in aging or systemic hypertension. (4 marks)
Haemodynamic stress (with advancing age and aggravated by systemic hypertension), results in increased endothelial permeability to plasma proteins e.g. albumin and fibrinogen which deposit in the arteriole wall. Also stress and age lead to deposition of more extracellular matrix. Over time the build up thickens the wall and can narrow the lumen.
Hyalinisation of arterioles leads to what
Hyaline arteriolosclerosis can lead to narrowing and/or weakening of the vessel wall. Narrowing occurs gradually and can lead to chronic ischaemia with subsequent atrophy. Weakening can lead to rupture (and/or exudation of fluid).
at autopsy, a focal red haemorrhagic area was identified within an organ. the lesion was wedge-shaped with its base along the outer surface of the organ. what kind of pathology? and where most likely? most likely cause?
wedge shaped haemorrhagic area based on the outer surface of the organ is likely to be a haemorrhagic infarct. occur commonly in brain, intestine and lung.
