Pathology - Tissue Damage

Question 1

What factors influence the severity of tissue injury?

Answer 1

Duration

Nature

Proportion of cells affected

Regenerative capacity

Topography

Question 2

What type of necrosis does this show?

Answer 2

Bridging necrosis

Question 3

What type of cell injury does this image show?

Answer 3

Fatty change

Question 4

What is necrosis?

Answer 4

Pathological death of tissue eliciting an adjacent tissue response

Question 5

What are the patterns of necrosis?

Answer 5

Coagulative

Colliquative

Caseous

Fibrinoid

Fat necrosis

Gangrenous

Question 6

What type of necrosis does this show?

Answer 6

Coagulative necrosis

Question 7

What sort of necrosis does this show?

Answer 7

Caseous necrosis

Question 8

What sort of necrosis does this show?

Answer 8

Fibrinoid necrosis

Question 9

What sort of necrosis does this show?

Answer 9

Fat necrosis

Question 10

What are the functions of inflammation?

Answer 10

Part of the process of repair

Destroy, dilute or wall of injurous agent

Question 11

What are the physical characteristics of inflammation?

Answer 11

Rubor (redness)

Calor (heat)

Tumor (swelling)

Dolor (pain)

Loss of function - movement consciously and reflexly inhibited by pain

Question 12

What causes the rubor of inflammation?

Answer 12

Dilatation of small blood vessels in damaged area

Question 13

What causes the heat of inflammation?

Answer 13

Increased blood flow through the region - hyperaemia

Question 14

What causes the swelling of inflammation?

Answer 14

Accumulation of fluid in extravascular space

Question 15

What causes the pain of inflammation?

Answer 15

Stretching and distortion of tissues caused by increased fluid

Chemical mediators such as bradykinin

Question 16

What are the features of the fluid exudate in inflammation?

Answer 16

Immunoglobulins

Fibrinogen

Question 17

Which mediators bring about increased vascular permeability in inflammation?

Answer 17

Histamine

Bradykinin

Question 18

How are endothelial gaps formed to bring about increased vascular permeability? Where does this occur?

Answer 18

Contractile proteins in endothelial cells pull open transient intercellular pores

Confined to the post-capillary venules

Question 19

What is the diagnostic feature of acute inflammation?

Answer 19

Neutrophil accumulation in extracellular space

Question 20

What is healing by first intention?

Answer 20

Restitution with no, or minimal, residual defect

e.g. incised wound

Question 21

What is healing by second intention?

Answer 21

Repair of tissue loss

Question 22

What happens in tissue desctruction and how is it repaired?

Answer 22

Parenchymal cells and stromal framework are lost

Replaced by connective granulation tissue, producing fibrosis and scarring

Question 23

What does repair by connective tissue fibrosis involve?

Answer 23

Angiogenesis

Migration and proliferation of fibroblasts

Deposition of extracellular matrix

Remodelling of fibrous tissue

Question 24

Which factors stimulate angiogensis?

Answer 24

Vascular Endothelial Growth Factor

Platelet Derived Growth Factor

Question 25

Which factors stimulate fibrosis?

Answer 25

Fibroblast Growth Factor Platelet Derived Growth Factor --- produced by platelets, inflammatory cells and activated endothelium

Question 26

What are the characteristics of Type I collagen?

Answer 26

Bundles of banded fibres with high tensile strength Found in skin, bones, tendons and most organs

Question 27

What are the characteristics of Type II collagen?

Answer 27

Thin fibrils, structural protein Found in cartilage and vitreous humor

Question 28

What are the characteristics of Type III collagen?

Answer 28

Pliable thin fibrils Found in uterus, skin, vasculature

Question 29

What are the characteristics of Type III collagen?

Answer 29

Amorphous Found in all basement membranes

Question 30

What happens during tissue remodelling?

Answer 30

Granulation tissue -\> Scar --- Changes in the composition of extracellular matrix Degradation of collagen by metalloproteinases Remodelling of connective tissue framework Wound debridement by collagenases and inhibitors

Question 31

What are the features of scar tissue?

Answer 31

Firmer than normal Puckered Shrunken

Question 32

Which systemic factors influence wound healing?

Answer 32

Nutrition Metabolic status (e.g. diabetes) Circulatory status Hormones

Question 33

What is a keloid scar?

Answer 33

One with excessive formation of repair components

Question 34

What are the stages in repair of a fracture?

Answer 34

**Early fracture** Haemorrhage filling fracture gap and surrounding area of injury **Inflammatory phase** Removal of necrotic tissue and organisation of haematoma Capillaries grow into haematoma with fibroblasts and osteoblasts **Reparative phase** Osteoblasts lay down irregularly woven bone - callus Mesenchymal cells differentiate into chondoblasts and lay down cartilage which undergoes endochondral ossification **Remodelling phase** Woven bone replaced by more orderly lamellar bone Lamellar bone remodelled according to direction of mechanical stress Medullary cavity is restore

Question 35

What is an amputation neuroma?

Answer 35

In amputation or poor realignment of cut axons, production of a disordered and tangled mass of axons

Question 36

Which type of cells proliferate in response to neuronal injuery?

Answer 36

Glial cells