The basis of Disease

Transcription

1 General Curriculum The basis of Disease ZHOU REN 周韧 Prof., M.D., Ph.D. Institute of Pathology & Forensic Medicine Department of Pathology & Patho-physiology Zhenjiang University Judicial Evidence & Evaluation Center Zhejiang University School of Medicine

2 (2). Cell injury

3 Form and Morphology of cell injury 1. Intracellular Accumulations (degeneration) (1)Cellular swelling Conception: Influx of H 2 O and abnormal accumulation within cell whenever cells are incapable of maintaining ionic and fluid homeostasis. A common form of cell injury. The most often affected organ are liver, kidney, heart etc.

4 Causes and mechanism: hypoxia, intoxication, infection. G: Pallor, loss of normal glistening transluscency as if scalded in hot water.

5 H: Swollen of affected cells, with fine granules and vacuoles filling the cytoplasm. The severe form of this type of cell injury is known as hydropic change, even ballooning change.

6 (2)Fatty change Conception: Fatty change refers to any abnormal accumulation of fat within parenchymal cells. Most affected organ: liver

7 Causes and mechanism of fatty change of liver:

8 Morphology G: Liver enlargement, yellow in color

9 H: Small vacuoles in the cytoplasm. In severe case, the vacuoles coalesce to large vacuole pushing the nucleus against the cell membrane.

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11 Fatty change(sudaniii)

12 Fatty change of cardiac muscle G. Tigroid appearance. Fatty change is more severe in cardiac muscle remote from the blood vessel than in those near the vessel.

13 H. Fat globules within the muscle fibers.

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15 (3)Hyaline change Conception: Appearance of homogenous, refractive, eosinophilic, hyaline material in connective tissue, vascular wall and cell is known as hyaline change.

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18 (4)Amyloid change(amyloidosis) Conception: Amyloid is an abnormal proteinaceous substance which is deposited between cells in many tissue and organs in a variety of clinical settings. At one time it was thought to be starch-like substance, hence the designation amyloid, however, it is now known to be protein in nature.

19 Morphology: With usual tissue stains, amyloid appears as an intercellular pink translucent material.

20 Systemic amyloidosis: Follows chronic infection (osteomyelitis, tuberculosis). Spleen and kidney are the most prominently affected organs. Local amyloidosis: Occurs in sites with numerous plasma cell infiltration. (eyelid and upper respiratory tract).

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23 (5) Mucoid degeneration Mucoid accumulation mucin Myxedema The diseases usually involved are: Rhumatic disease Tumour

24 (6)Intracellular pigment accumulation (i)hemosiderin Conception: Hemosiderin is a goldenyellow to brown iron containing pigment readily visible with the light microscope and shows positive Prussian blue reaction.

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26 Morphology:

27 (ii)lipofuscin Conception: Lipofuscin is an insoluble pigment also known as wear-and tear or aging pigment. It represents the indigestible residues of autophagic vacuoles formed during aging or atrophy. Morphology:

28 (iii)melanin Conception: Melanin is an endogenous, nonhemoglobin-derived, brown- black pigment formed when the enzyme tyrosinase catalyzes the oxidation of tyrosine to dihydroxyphenylalanine(dopa). In humans, melanin synthesis is under adrenal and pituitary control. Albinos suffer from a hereditary lack of tyrosinase.

29 Morphology:

30 (7) Pathological calcification Conception: The deposition of calcium in cells and tissues other than bone, cartilage and teeth. (1)Dystrophic calcification: Deposition of calcium in dead or dying tissue despite normal serum calcium level and normal calcium metabolism

31 Course of Basic Medical Sciences Chapter 1

32 (2)Metastatic calcification: Metastatic calcification is always in association with deranged calcium metabolism, leading to hypercalcemia (hyperparathyroidism, widespread metastasis of bone cancers and vit. D intoxication).

33 2. Cell Death I. Necrosis Def. Necrosis may be defined as the morphology of cell death in living body. Autolysis Heterolysis

34 Fundamental changes 1Nuclear changes: Pyknosis, karyorrhexis, Karyolysis. 2Cytoplasmic changes: acidophilic, granular, opaque mass.

35 Gross appearances of necrosis in earlier stage

36 Classification of necrosis 1Coagulative necrosis 2Caseous necrosis 3Liquefactive necrosis 4 Fat necrosis Fibrinoid necrosis (Fibrinoid change ) Gangrene a)dry gangrene b)moist gangrene c)gas gangrene

37 1 Coagulative necrosis 2 Liquefactive necrosis 3 Types of Special necrosis Caseous necrosis Gangrene a) Dry gangrene b) Moist gangrene c) Gas gangrene Fat necrosis Fibrinoid necrosis (Fibrinoid change )

38 Types of necrosis. 1Coagulative necrosis Conception: Coagulative necrosis implies preservation of the basic outline of the coagulated cell for some days with the disappearance of fine structures (cellular details) within cell.

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42 Mechanism: Intracellular acidosis denatures not only structural proteins but also enzymic proteins and so blocks the proteolysis of the cell.

43 Morphology: 2Caseous necrosis Conception: A distinctive form of coagulative necrosis, most often occurs in tuberculosis. The term caseous is derived from the gross appearance of the necrotic area. i.e. white and cheesy. Characteristic morphology: disappearance of both basic outline and fine structures (cellular details) within cell of the affected cell.

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46 3Liquefactive necrosis Conception: The damaged cells are lysed by autolysis or heterolysis leaving amorphous, fluid or semifluid material. Morphology:

47 4 Fat necrosis a)enzymatic fat necrosis: In acute pancreatitis, activated pancreatic enzymes are released from pancreas resulting in destruction of fat tissue. b)traumatic fat necrosis: Trauma induce rupture of fat cells. The released fat causes chronic inflammation and foreign body reaction.

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49 Fibrinoid necrosis(fibrinoid change) Conception: Accumulation of pink staining homogenous masses of fibrin, immunoglobulins, and other plasma proteins within the vascular wall, connetive tissue is known as fibrinoid change.

50 Gangrene Def. Massive necrosis of body surface or organs with a passage to the body surface with putrefaction superadded is known as gangrene.

51 Classification: a)dry gangrene Conception: Dry gangrene occurs in the extremities due to occlusion of large artery with intact venous returns. The necrotic area is well dermacated black and mummification.

52 Morphology:

53 b)moist gangrene Conception: Blockage of venous return and artery supply massive necrosis followed by liquefaction caused by bacterial enzyme purplish black color with fouel smelling.

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55 c)gas gangrene Conception: A serious complication of war wounds. deep contaminated wound(massive necrosis) + clostridia group bacterial infection gas production through the action of saccharolytic and proteolytic enzyme released from bacteria.

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