Acute inflammation 2

Question 1

what is opsonization?

Answer 1

The process of coating a particle to target it for phagocytosis

Question 2

what allows microorganisms to be recognised?

Answer 2

coated with opsonins

Question 3

what do opsonins do?

Answer 3

bind to specific receptors on leucocytes and greatly enhance phagocytosis

Question 4

what is phagocytosis?

Answer 4

the complex process by which phagocytes such as neutrophils and macrophages engulf and ingest microorganisms or other cells and foreign particles

Question 5

what are the 3 steps of phagocytosis?

Answer 5

i. Recognition and Attachment
ii. Engulfment
iii. Killing and Degradation

Question 6

what occurs of phagocytosis ?

Answer 6

neutrophils undergo apoptosis

Question 7

Describe recognition and attachment.

Answer 7

Although attachment to specific receptors is not an absolute requirement, phagocytosis is typically initiated by recognition of particles by leucocyte surface receptors
Efficiency of phagocytosis is greatly enhanced when particles are opsonized

Question 8

Describe engulfment.

Answer 8

Engulfment involves cytoplasmic extensions to flow around the particle resulting in complete ‘engulfment’ of the particle within a phagosome made by the cell membrane
This phagosome membrane then fuses with lysosomal membrane, resulting in discharge of the lysosome content into the phagolysosome

Question 9

what two mechanism doe s killing of infectious agents occur?

Answer 9

• oxygen-dependent

- oxygen- independent

Question 10

Describe the mechanism of oxygen-dependent?

Answer 10

Phagocytosis results in products of oxygen reduction which cause intracellular killing of micro-organisms

Question 11

Describe the mechanism of oxygen-independent?

Answer 11

Via the action of substances in leucocyte granules eg Lysozyme which attacks bacterial coat
Defensins that are cytotoxic to microbes Acidic pH inside phagocytic vacuoles

Question 12

after killing, what degrades the microorganism inside the phagolysosome?

Answer 12

acid hydrolase

Question 13

where are the leucocytes products released to?

Answer 13

extracellular space aswell as the phagolysosome

Question 14

what are the key products in neutrophils and macrophages?

Answer 14

1. Lysosomal enzymes
2. Oxygen derived active metabolites
3. Products of arachidonic acid metabolism including prostaglandins and leukotrienes

Question 15

what are the effects of lysosomal product release?

Answer 15

1. ActivatescoagulationfactorXII
2. Attracts other leucocytes into the area
3. Damageslocaltissues
4. Increases vascular permeability
5. Pyrogens producing systemic fever

Question 16

what are the macroscopic appearances of acute inflammation?

Answer 16

Necrotising – septic necrosis, bacterial putrefaction • Serous – thin protein rich fluid exudate
• Catarrhal – mucus hypersecretion
• Fibrinous – exudate contains plentiful fibrin
• Suppurative – production of pus
• Membranous – epithelium coated by fibrin

Question 17

what is suppuration and what causes it?

Answer 17

Formation of pus –neutrophils, bacteria, cellular debris
• Causative stimulus almost always infective agent, eg pyogenic
bacteria such as staphylococci

Question 18

what is an ulcer?

Answer 18

An ulcer is a local defect, or excavation, of the surface of an organ or tissue that is produced by the sloughing of inflammatory necrotic tissue

Question 19

where are ulcers most frequently found in?

Answer 19

1. Mucosa of the mouth, GI tract, GU tract

2. Low limbs (chronic ulcers) in those with circulatory disturbance

Question 20

what are the beneficial effects of acute inflammation?

Answer 20

1. Dilution of toxins- can be carried away by lymphatics
2. Entry of antibodies- due to increased vascular permeability
3. Stimulation of the immune response- fluid exudate containing antigens reaches local lymph nodes
4. Fibrin Formation – impedes movement of micro-organisms 5. Delivery of nutrients and oxygen - aided by blood flow
5. Transport of drugs – eg antibiotics

Question 21

what are harmful effects of acute inflammation?

Answer 21

Digestion of normal tissues
• Swelling – eg laryngeal oedema, brain swelling
• Inappropriate inflammatory response – eg type I hypersensitivity

Question 22

what are systemic effects of acute inflammation?

Answer 22

1. Fever
2. Constitutional Symptoms
3. Weight Loss
4. Reactive Hyperplasia of the Reticuloendothelial System
5. Haematological Changes

Question 23

what do most bacterial infections produce?

Answer 23

neutrophilia

Question 24

what can viral infections produce?

Answer 24

lymphocytosis

Question 25

what can be produced in allergic disorders and parasitic infections?

Answer 25

eosinophilia

Question 26

what is the sequelae of acute inflammation?

Answer 26

resolution, suppuration, chronic inflammation, organisation