Pathology of CVS Flashcards
what is arteriosclerosis
the thickening and hardening of the walls of the arteries, occurring typically in old age
- not as big a concern
- mainly affects small blood vessels
- hyperplasia of smooth muscles
- inflammation
what is atherosclerosis
a disease of the arteries characterised by the deposition of fatty material on their inner walls.
a chronic inflammatory process followed by healing response
what are non-modifiable factors that cause atherosclerosis
- genes
- gender
- age
what are lifestyle choices that cause atherosclerosis
smoking
diet
obesity
what is hyperlipidaemia
an abnormally high concentration of fats or lipids in the blood.
what is the most important risk factor of atherosclerosis
hyperlipidaemia
what is formed in atherosclerosis
an atheroma
what size of blood vessels does atherosclerosis usually affect
larger blood vessels
coronal vessels
what is vascular pathology
either stenosis or obstruction or the weakening of the walls leading to dilation or rupture (aneurism)
what does stenosis mean
the abnormal narrowing of a passage in the body
how can genes cause atherosclerosis
> familial hypercholesterolaemia = mutation of LDL receptor gene
- LDL = low density lipoprotein (bad cholesterol),
found in liver cells
in healthy people the LDL receptor will take up circulating LDL and process it in the liver
in people with a mutation of this gene it doesnt work as well so the individual is at a higher risk of atherosclerosis
how does gender affect your risk of atherosclerosis
males are at a higher risk and women who have undergone menopause
before undergoing menopause women have a high level of oestrogen in the blood which keeps the blood vessels open so they are at a lower risk of getting the disease but after menopause women lose this protection
how does age affect the risk of atherosclerosis
older people are more likely to develop this disease so they are at a higher risk
can occur in any age though even children
where are LDL receptors present
in many cell types including
- smooth muscle cells
- fibroblasts
- adrenocortical cells
what are endothelial cells like in the basal state (normal)
[factors affecting endothelial cells]
- normotension
- laminar flow
- growth factors eg VEGF
[what endothelial cells are like as a result]
- non-adhesive
- non-thrombogenic surface
- smooth cells
what are endothelial cells like in an activated state (pathology)
[factors affecting endothelial cells]
- turbulent flow
- hypertension
- cytokines
- complement
- bacterial products
- lipid products
- advanced glycation end products
- hypoxia
- acidosis
- viruses
- cigarette smoke
[what endothelial cells are like as a result]
- increased expression of procoagulants, adhesic molecules and pro-inflammatory factor
- altered expression of chemokines, cytokines and growth factors
what are the 2 stages of atheroma
- chronic inflammation phase
- healing response phase
what happens in the chronic inflammation phase
- chronic inflammatory response to lipoproteins (something damages the endothelial cells)
- endothelial cells change surface cell receptors and become more permeable to lipids
- change cell adhesion molecules for monocytes so attach to endothelium and move into blood vessel walls
- monocytes include macrophages and T cells
- macrophages become foam cells and release lipid deposits from dead cells
what happens to macrophages do during the formation of an atheroma
they undergo phagocytosis and ingest lipids
they are big and pale in colour
a whole group of these together are called soap cells
lipid can’t be digested by the cell so it remains within the cell until the macrophage dies
then the lipid is released into circulation again
what are foam cells
Foam cells are a type of macrophage that localize to fatty deposits on blood vessel walls, where they ingest low-density lipoproteins and become laden with lipids, giving them a foamy appearance.
These cells secrete various substances involved in plaque growth and their death promotes inflammation, thereby contributing to cardiovascular disease.
what happens in the healing response phase
- proliferation of smooth muscle cells (tunica media thickening and cap formed over the cholesterol)
- fibrous tissue formation
- growth factors such as PDGF, FGF, TGF-alpha are produced
- a fibro fatty plaque is formed with a central mass of lipid and necrotic tissue
- neovascularisation may be seen at the periphery of the plaque
- haemorrhage can occur into the plaque (increase in size = fatal consequences)
- calcification of the lipid and necrotic tissue can sometiimes occur
what is the 5 stages within the phases of the formation of atheroma
- chronic endothelial cell injury
- permeability increase
- macrophages move in
- smooth muscle proliferation
- healing process
how can chronic endothelial cell injury occur
- genetic mutation
- inherited
- hypertension
what does the increase permeability in the formation of atheroma allow for
lipid to be deposited in the intimal layers
allows for movement
causing damage to the endothelial cells
what happens in the formation of an atheroma when macrophages move in
foam cells are formed
fatty steaks are formed (yellow streaks in wall of blood vessel)
may regress - if patient is aware and takes the steps to change their risk factors it can at least be held in check
what happen during smooth muscle proliferation during the formation of an atheroma
macrophages produce IL-1 which activates T cells
more cytokines, chemokines, ROS activate more inflammatory cells PLGF, FGF, TGF-alpha
what happens in the healing process of the formation of an atheroma
fibrous tissue is formed over the lipid
a fibro fatty atheroma is formed (plaque)
dystrophic calcification may occur at late stages
what do the effects of atherosclerosis depend on
the size of the blood vessel and the extent of the obstruction and what organ is affected
what are the effects of atherosclerosis
- decreased blood supply to tissue/organ (ischaemia)
- complete occlusion of the blood vessels lead to infarction
- thrombosis
- embolism