Inflammation, Repair/Regneration, and Thrombosis Flashcards
What are 3 characteristics of acute inflammation?
- sudden onset
- short duration
- usually resolves
Example of acute inflammation?
Appendicitis
Which cells involved in acute inflammation?
Neutrophil-mediated
3 characteristics of chronic inflammation?
- slow onset or sequel to acute
- long duration
- may never resolve
Example of chronic inflammation?
Tuberculosis
What cells involved in chronic inflammation?
Macrophages and Lymphocytes
What is the difference between good and bad inflammation?
good response is to infection or injury, bad response is autoimmunity or over-reaction to stimulus
Lifespan of neutrophils?
short, 2-3 days
How do neutrophils work?
phagocytosis and have lysosomes that contain bacteria killing enzymes. also release chemicals that attract other inflammatory cells
When do neutrophils appear on site of acute inflammation?
first
Lifespan of macrohpages and lymphocytes?
longer
Function of macrophages?
transport material to lymph nodes (secondary immunity), ingest bacteria
Function of lymphocytes?
Produce chemicals to attract other inflammatory cells and have immuniological memory
Where are endothelial cells located?
capillary blood vessel lining
How do endothelial cells respond to inflammation?
become sticky and porous so inflammatory cells stick and pass into tissues
How do endothelial cells respond to damage?
grow into areas to form new vessels
What happens to capillary sphincters during inflammation?
Open, causing redness. Arterioles leak and cause swelling
What do fibroblasts form?
long lived, collagen in areas of chonic inflammation and repair
What are the 5 cardinal signs of inflammation?
- redness
- swelling
- heat
- pain
- loss of function
What are the 3 stages of inflammation?
- change in vessel calibre and flow
- increased vascular permeability and formation of fluid exudate
- formation of cellular exudate
How is cellular exudate formed?
emigration of neutrophil polymorphs into extravascular space
What is a granuloma?
Specific type of chronic inflammation with collections of macrophages surrounded by lymphocytes
What is resolution (brief)?
Complete restoration
What is suppuration?
Formation of pus: mix of living and dead neutrophils, bacteria, cellular debris, and lipid globules
What is organisation?
Tissue replacement by granulation
Give 5 treatment options for inflammation
- Ice
- Antihistamines
- Ibuprofen (inhibits prostaglandin)
- Corticosteroids
- Aspirin
What is the definition of resolution?
When initiating tissue factor is removed, tissue is undamaged or able to regenerate
Example of resolution in the lungs?
Lobar Pneumonia affects a lobe rather than the whole lung
What happens in lobar pneumonia?
Alveoli fill with neutrophil polymorphs instead of air. Pneumocytes that line alveoli can regenerate
Why is cirrhosis not an example of resolution?
Forms fibrous tissue between regenerative tissue
What is an abrasion?
Superficial skin wound
How does an abrasion heal?
scab forms –> epidermis grows from adnexa –> thin confluent epidermis –> final epidermal regrowth
What is healing by 1st intention?
An incision where the sides of the wound can meet so healing can be quick
What is the process of healing by 1st intention? (5 steps)
Incision –> exudation of fibrinogen –> weak fibrin join –> epidermal regrowth and collagen synthesis –> strong collagen join
What is healing by 2nd intention?
Wound margins can’t be brought together
Stages of healing by 2nd intention? (5 steps)
loss of tissue –> granulation tissue –> organisation –> early fibrous scar –> scar contraction
What is organisation?
Specialised tissues repaired by fibrovascular connective tissue - occurs with production of granulation and removal of dead tissue
What is granulation tissue?
Loops of capillaries supported by myofibroblasts that contract to reduce wound size
What is the definition of repair?
Initiating factor is still present so tissue is damaged and unable to regenerate
In repair, what is damaged tissue replaced by?
fibrous tissue made up of collagen, produced by fibroblasts
Example of repair?
heart attack after myocardial infarction
Which cells can regenerate? (6)
- hepatocytes
- pneumocytes
- gut epithelium
- skin epithelium
- osteocytes
- all blood cells
Which cells can’t regenerate? (2)
- mycoardial
- neurones
Why don’t blood clots form all the time? (2 reasons)
Laminar flow - cells travel in centre of vessel
Endothelial cells - line vessels and are not sticky when healthy
Definition of thrombosis?
Formation of a solid mass from blood constituents in an intact vessel during life
What are the stages of a thrombus forming? (4)
- vascular spasm and endothelial damage exposes collagen
- platelet aggregation: platelets release chemicals that cause more platelets to stick
- clotting cascade produces fibrin which entraps RBCs in mesh and forms clot
- aggregation and cascade are positive feedback loops
What are the 3 components of Virchow’s triad?
- change in vessel wall
- change in blood flow
- change in blood constituents
Example of something that could change vessel walls?
cigarette smoking and vaping
Example of that changes blood flow?
stasis - blood flow is slow and not laminar so platelets drag along endothelial cells
What inhibits platelet aggregation at a low dose?
aspirin
Definition of an embolism?
process of a solid mass in the blood being carried to a place where it gets stuck and blocks vessel
What are causes of an emboli other than a thrombus?
air, cholesterol crystals, tumour, amniotic fluid, fat
Difference between an arterial and venous embolism?
arterial: systemic, downstream of entry point
venous: vena cava –> right side of heart –> pulmonary arteries
Why are the lungs a filter for emboli?
the emboli is too big to get into the capillaries
Definition of ischaemia?
A reduction in blood flow to a tissue without other implications
Definition of infarction?
A reduction in blood flow that causes subsequent death of tissue cells
What is infarction usually caused by?
thrombosis of an artery
What is end artery supply?
organs supplied by only one main artery, meaning they are more susceptible to infarction
Which organs have dual supply so are less susceptible to infarction?
liver, lungs, brain
