Introduction to Pathology and Inflammation Flashcards

Question

What are Macrophages?

Answer 1

Play a small part in the acute inflammatory exudate. Macrophages are derived from monocytes in the circulating blood which migrate to the damaged area after later than neutrophils. The increase in numbers over time to facilitate elimination of dead material. Actively phagocytic Can survive for longer due to their capacity for oxidative metabolism. They also produce growth factor, cytokines which mediate some of the events in the inflammatory response. Macrophages have more important roles in chronic inflammation

Answer 2

Purulent – Neutrophils dominated and the material is liquefied to form pus Fibrinous Fibrin in abundance, seen in relation to serosal surfaces Serous when fluid is the major component

Answer 3

Acute Epiglottitis Acute Meningitis

Answer 4

Stored - Histamine Active Synthesis Prostaglandins Leukotriens Platelet Activating Factor Cytokines Nitric Oxide Chemokines

Answer 5

Kinin System Bradykinin Clotting Pathway Activated Hageman Factor Thrombolytic System Plasmin Complementary Pathway - C3a, C3b, C5a

Answer 6

Main pre formed mediator of inflammation Released from mast cells, basophils and platelets Causes transient dilation of arterioles, increases permeability in venules

Answer 7

Derived from local synthesis from arachidonic acid. (long chain fatty acid which are liberated from cell membranes by activation of the enzyme phospholipase Az.

Answer 8

Synthesis by mast cells / basophils Stimulated by IgE- Mediated release Also synthesized by platelets, neutrophils, monoctes and endothelium & specialized phospholipid compound which causes vasoconstriction, increased permeability and platelent aggregation - It’s a thousand times more potent than histamine!

Answer 9

A large group of polypeptide proteins of activated lymphocytes and monocytes Main ones in acute inflammation: Interleukin-1 Interleukin – 8 Tumour Necrosis Factor Alpha (TNFa) Which are responsible for: Induction of cell adhesion on endothelium Induction of prostacyclin synthesis Indution of PAF synthesis Fever, Anorexia and stimulation of acute phase protein synthesis by the liver Stimulation of fibroblast proliferation and secretory activity Attraction of neutrophils into the damaged area.

Answer 10

Secreted and leukocytes & endothelial cells in response to tissue damage During neutrophil rolling, chemokine receptors are activated and this signals the activation of leukocyte integrins, mediating adhesion and emigration.

Answer 11

A small molecule that is locally synthesied by the endothelium and macrophages through the activity of the enzyme, Nitric Oxide Synthase. A powerful cause of: vascular dilation & permeability Can also mediate cell and bacterial killing

Answer 12

Is compromised of a set of plasma proteins with important roles in immunity and inflammation. There is a cascade of activation which produces a number of intermediately activated peptides

Answer 13

Small peptides. Derived from plasma precursors Increase vascular permeability Cause pain and activates the compliment system

Answer 14

Responsible for coagulation of blood by the formation of fibrin from fibrinogen  thus forming fibrinopeptides Stimulates deposition of fibrin, activates the Kinins & thrombolytic pathway Causes vascular permeability

Answer 15

The enzyme plasmin is a proteolytic enzyme with several roles in inflammation Activates the complement system Activates Hageman Factor Lyses fibrin to form fibrin degradation products which increase permeability of vessels.

Answer 16

1) Toxins & Physical Agents May cause necrosis of vascular endothelium  leading to abnormal leakage (non- mediated vascular leakage) 2) Chemical mediators of acute inflammation cause retraction of endothelial cells, leaving intracellular gaps (mediated vascular leakage)

Answer 17

Immediate Response transient, lasts for 30-60mins Mediated by Histamine acting on the Endothelium Delayed Response Starts 2-3 hours after injury, lasts up to 8 hours Mediated by factors synthesized by local cells, e.g. bradykinin, factors derived from complement & from dead neutrophils in the exudate. Immediate Response that is prolonged for over 24 hours  Seen if there has been direct necrosis of endothelium e.g. a burn or chemical toxin

Answer 18

1 - Minimal cell death & tissue damage 2 - Rapid elimination of the causal agent e.g. bacteria 3 - Local conditions which favor the removal of fluid & debris

Answer 19

Lobar Pneumonia is a type of acute inflammation of the lung Caused by bacteria excreting toxins into the alveolar sacs, thus causing epithelial cell death (type 1 & type 2 pneumocytes). The body’s response is the produce an acute inflammatory exudate (components which are fluids, salt, fibrin / fibrinogen, proteins, neutrophils & macrophages). As the infection develops, the air in a large area of the alveoli is replaced by exudate. This tends to spread rapidly through alveolar sacs within a particular lobe of the lung. Patient’s gas exchange capacity is lost. Importantly, Although cells lining the alveoli die, the support stroma & vascular structure of the ling remain intact. Under favorable conditions, especially if the patient is treated with antibiotics, the neutrophils in the exudate phagocytose & destroy all the causative bacteria And thus the resolution process can begin. Enzymes released by neutrophils break up structural proteins (e.g. the Fibrin) & remnants of dead cells, rendering the exudate highly liquid. Some of it is coughed up in sputum But most of it is re-absorbed into the alveolar capillary network or into the pulmonary lymphatic system. Macrophages phagocytose any residual undigested debris, pass into the lymphatic system & are transmitted into regional lymph nodes. At the same time, remnant epithelial stem cells divide to re-line the alveolar air spaces, differentiating into new Type1 & Type 2 alveolar lining cells.

Answer 20

Is the formation of PUS Where pus accumulates, an ABCESS will form.

Answer 21

It is the initial protective response to tissue injury / infection with the aim to replace the damaged area by organized tissue, which is identical in structure and function to that originally present (termed restitution). Restitution is the ideal outcome. It can only be achieved if: the damaging agent is removed Cell debris is cleared from the site The specialized cells have the capacity to regrow / regenerate

Introduction to Pathology and Inflammation Flashcards

(45 cards)