week 8 Flashcards
1
Q
sequence of events for implant reaction
A
- implantation
- blood-biomaterial interactions
- provisional matrix formation
- acute inflammation
- chronic inflammation
- granulation tissue
- foreign body reaction
- fibrosis/ fibrous capsule development
2
Q
step 1
A
IMPLANTATION
3
Q
step 2
A
BLOOD-BIOMATERIAL INTERACTIONS
4
Q
what forms: PROVISIONAL MATRIX FORMATION
A
STEP 3 - forms within mins-hrs of implantation - fibrin ( blood coagulating protein- produced from fibrinogen) - inflammatory products (released by complement system) - activated blood platelets - inflammatory cells - endothelial cells
5
Q
what happens: ACUTE INFLAMMATION
A
STEP 4
- neutrophils arrive in vast numbers
- do a lightning immunological assault
- short duration (mins-days)
6
Q
main features: ACUTE INFLAMMATION
A
- release of fluid and blood plasma proteins
- arrival of leukocytes (initially neutrophils, later macrophages)
- resolves in a week –> longer = infection
7
Q
role of leukocytes: ACUTE INFLAMMATION
A
- adsorb to biomaterial
- frustrated phagocytosis
- -> particulate biomaterials/ wear debris, phagocytosis is successful
8
Q
draw the graph
A
insert?
9
Q
purpose of INFLAMMATION
A
- contain, neutralise, dilute or wall (ward) off injurious agent or process, setting off regenerative process
10
Q
cell mediators: role and examples
A
chemicals released by damaged cells that have a role in stimulating the inflammatory response
- histamine
- prostoglandins
- leukotrienes
- kinins
- complement
11
Q
what happens: CHRONIC INFLAMMATION
A
STEP 5
- macrophages (monocytes and lymphocytes) arrive –> DEFINING FEATURE
- proliferation of blood vessels and connective tissue
- less uniform histologically than acute
- long term presence of lymphocytes and monocytes may indicated long-standing infection
12
Q
what happens: GRANULATION TISSUE
A
STEP 6
- fibroblasts and endothelial cells arrive and healing begins
- scar tissue begins to form
13
Q
initiation: GRANULATION TISSUE
A
- 1 day post implant
- by action of monocytes and macrophages
14
Q
key features: GRANULATION TISSUE
A
- proliferation of small blood vessels –> neo-vasculatisation. angiogenesis –> proliferation, maturation and organisation of endothelial cells into capillaries
- proliferation of fibroblasts –> activley synthesise collagen and proteoglycans of CT
- macrophages present but not dominant
15
Q
what happens: FOREIGN BODY REACTION
A
STEP 7
macrophages form giant cells
- multinuclear macrophages
- components of granulation tissue
