Immunology and Cancer Flashcards
(43 cards)
Describe acute inflammation
- sudden onset, short, usually resolves
* neutrophil reaction
Describe chronic inflammation
- slow onset (may follow acute inflammation), long, may never resolve
- lymphocyte and macrophage reaction
3 main cells from the inflammatory response
- neutrophils - pus cells
- macrophages - phagocytic
- lymphocytes - immunological memory
- (endothelial cells)
- (fibroblasts)
Describe neutrophils
- short lived
- first response for acute inflammation
- granular cytoplasm - contain lysosomes (enzymes) that digest bacteria
- usually does at the scene - become yellow
- release chemicals that attract other inflammatory cells
Describe macrophages
- live weeks to months
- phagocytic
- May present antigen to lymphocytes
- a few die at the scene
- (many types of macrophage, this is the generic name)
Describe lymphocytes
- live for years
- control inflammation - produce chemicals that attract other inflammatory cells
- immunological memory for past infections/antigens
Describe endothelial cells
- become sticky during inflammation so inflammatory cells stick to them
- become porous so inflammatory cells can pass into tissue
Describe fibroblasts
- long lived
- particularly present in chronic inflammation
- responsible for scarring (form collagen)
Define:
• B lymphocytes
• T lymphocytes
B lymphocytes - produce antibodies
T lymphocytes - memory cells that produce chemicals to draw other inflammatory cells in
Define
• regeneration
• repair
Regeneration - initiating factor removed OR damaged tissue can regenerate
Repair - initiating factor still present OR damaged tissue is unable to repair
(Tissue replaced with fibrous tissue and scarring)
2 types of skin wound healing
Healing by 1st intention - best possibility
• incision fills with fibrin and blood
• fibroblasts make collagen
• repair + scar
Healing by 2nd intention
• if can’t suture smoothly
• can grow across eventually, but repair is not upwards
• larger scar, paler tissue
Define:
• thrombosis
• embolus
Thrombosis - solid mass of blood constituents formed within intact vascular system during life
Embolus - mass of material in vascular system able to become lodged within a vessel and block it
Describe thrombus formation
- damaged endothelium of artery
- collagen underneath exposed
- positive feedback loop - placement activation factor makes more platelets stock
- disruption of laminar flow - RBCs may stick too
- fibrin deposited (positive feedback loop of fibrin from fibrinogen)
3 parts of Virchow’s triad
Any 1 or combination increases risk of thrombosis
Changes to:
• vessel wall
• blood flow
• blood constituents
4 potential outcomes if thrombus is not treated?
- lysis and resolution - thrombus breaks down, but still need to consider what that vessel was supplying
- organisation - repair and scar tissue (vessel becomes stuck to itself)
- recanalisation - return of blood flow after previous occlusion (scar and residual thrombus at site)
- embolism - usually if part of the thrombus breaks off and spreads to other places
3 ways to prevent thrombus formation
- exercise
- elastic circulation stockings - squeezes blood out of leg veins
- aspirin - inhibits platelet aggregation
Causes of embolus
- atheroma with thrombus
- atrial thrombus
- valve vegetation - growth of bacteria on a heart valve causing infection
- thrombus from old/recent myocardial infarct
Define:
• ischaemia
• infarction
Ischaemia
• reduction in blood flow
Infarction
• reduction in blood flow that causes cell death (subset of ischaemia)
What is reperfusion injury?
Ischaemia-reperfusion injury, IRI
- when tissue is damaged by return of blood supply after a period of ischaemia or lack of oxygen
- induces comas can help prevent this
Define
• end artery supply
• dual supply
End artery supply
• only one way in
• e.g. the heart is mainly end arteries (not watershed though)
Dual supply
• if one is blocked, blood can still get to the organ
• few organs have this
• (e.g. lungs and liver, therefore rarely get infarction in these organs)
Describe watershed areas/territories
- region of the body that receives dual blood supply from the most distal branches of 2 large arteries
- if blood supply is decreased in either vessel, this can be problematic (despite being dual supply)
- can cause watershed strokes in the brain
Define and describe atherosclerosis
- buildup of plaque on artery walls which can restrict blood flow - also comes with inflammation and fibrosis
- can be fats, cholesterols and other substances
- the plaque can burst, leading to thromboses
- almost all >70s will have it
Describe the distribution of atherosclerosis in the body
- very prevalent in systemic arteries (i.e. derive from aorta)
- often occurs at bifurcation of arteries
• does not occur in veins or pulmonary arteries - low pressure so thrombus forms rather than plaque
Risk factors for atherosclerosis
- smoking
- hypertension
- diabetes mellitus - only if poorly controlled
- hyperlipidaemia - high cholesterol
- more prevalent in more deprived, industrial areas
- more prevalent in men with ischaemic heart disease