Satia Cellula Injury

Question 1

What are the two major forms of cell death?

Answer 1

Necorsis and apoptosis

Question 2

What is coagulative necrosis?

Answer 2

Desaturation of intracytoplasmic proteins

dead tissue is firm then soft

typically in ischaemic injury EXCEPT THE BRAIN

Question 3

WHAT IS COLLQUATIVE NECROSIS?

Answer 3

Seen in brain e.g. stroke

glial reaction at periphery with cyst formation

Question 4

What is caseous necrosis?

Answer 4

Characteristic of TB
macro - cheese like
micro - no structure

Question 5

What is gangrenous necrosis?

Answer 5

Necrosis with putrefaction of tissues due to certain bacteria e.g. Clostridia or Streptococci

Question 6

What makes tissue black in gangrenous necrosis?

Answer 6

Iron sulfide from degraded haemoglobin

Question 7

What causes gas gangrene?

Answer 7

C perfringens

Question 8

What type of necrosis is seen in malignant hypertension?

Answer 8

Fibrinoid necrosis

Question 9

What are some mediators of apoptosis?

Answer 9

p53
bcl-2
fas (CD 95)
Caspases

Question 10

How is bcl-2 related to tumours

Answer 10

inhibits apoptosis, therefore expression leads to failure of initiation of apoptosis

overexpressed in neoplasia

Question 11

What is pyknosis

Answer 11

nuclear shrinking

Question 12

what is karyorrhexis

Answer 12

nuclear fragmentation

Question 13

What disease increase apoptosis?

Answer 13

HIV
Neurodegenerative diseases

Question 14

What are labile cells?

Answer 14

Good capacity for regeneration
e.g. surface epithelial cells constantly being replaced by cells from deeper

Question 15

What are stable cells?

Answer 15

divide at a slower rate under physiological conditions
replaced by mitotic division of mature cells and lost cells are rapidly replaced e.g. liver and renal tubular epithelium

Question 16

What are permanent cells?

Answer 16

Never divide in post natal life cannot be replaced if lost

e.g. nerve cells

Question 17

Outline the process of organisation

Answer 17

Fibrinous exudate
Removal of fibrin and dead tissue by phagocytes
Migration of fibroblasts and capillaries forming granulation tissue
Replacement of exudate by vascularised fibrous tissue
eventually a collagen rich scar develops

Question 18

Describe the formation of granulation tissue

Answer 18

Capilary endothelial cells grow into the area to be repaired
Fibroblasts are stimulated to divide
Fibroblasts secrete collagen and matrix components
Fibroblasts acquire muscle filaments and become myofibroblasts

Question 19

What is proud flesh?

Answer 19

excessive granulation tissue protruding above the wound surface

Question 20

Issues with organisation

Answer 20

Fibrous adhesions in the peritoneum ma cause intestinal obstruction

obliteration of the pericardial space - constrictive pericarditis

Question 21

Issues with wound contraction

Answer 21

Stenosis
Stricture
Scarring in muscle = contracture
Contractures following burns

Question 22

Describe healing by primary intention

Answer 22

Edges opposed
Fibrin helps to stick the edges together
Capillaries bridge the gap
Fibroblasts invade fibrin network
After 10 days wound is strong and sutures can be removed
remodelling

Question 23

Describe healing by secondary intention

Answer 23

Tissue loss
Phagocytes remove debris
Formulation of granulation tissue at base of wound
Myofibroblasts cause contraction
Re-epithelialisation
Tissue deficit replaced by scar tissue

Question 24

What is keloid?

Answer 24

Excessive fibroblast proliferation and collaagen production
Collagen deposits beyond and above wound
covered by normal epithelium

Question 25

Describe Hyperophic scar

Answer 25

Does not extend beyond wound borders

Question 26

Describe bone repair

Answer 26

Haematoma
Macrophages invade haematoma with polymorphs and fibroblasts
new vessels grow
Fibrosis by the end of the week
Osteoblasts grow into haematoma and form trabeculae of woven bone
The new bone is called callus
Internal callus is within the medullary cavity
External callus is related to the periosteum
Woven bone replaced by lamellar bone
Remodelling takes place in the direction of mechanical stress

Question 27

What factors affect bone remodelling?

Answer 27

Movement
misalignment
interposition of soft tissues
infection
pre-existing bone disease

Question 28

What is wallerian degeneration

Answer 28

Is the process that occurs when a nerve is cut or crushed.
- It occurs when the part of the axon separated from the neuron’s cell nucleus degenerates.
- It usually begins 24 hours following neuronal injury and the distal axon remains excitable up until this time.
- The degeneration of the axon is followed by breakdown of the myelin sheath, a process that occurs by infiltration of the site with macrophages.
- Eventually regeneration of the nerve may occur although recovery will depend on the extent and manner of injury

Question 29

What is Neuropraxia?

Answer 29

Nerve intact but electrical conduction is affected
Full recovery
Autonomic function preserved
Wallerian degeneration does not occur

Question 30

What is neurotmesis?

Answer 30

Disruption of the axon, myelin sheath and surrounding connective tissue.
Wallerian degeneration occurs

Question 31

What is axontmesis

Answer 31

Axon is damaged and the myelin sheath is preserved. The connective tissue framework is not affected.
Wallerian degeneration occurs

Question 32

Erosion vs Ulcer of GIT

Answer 32

Erosion is loss of part of thickness of mucosa

Ulcer is loss of full thickness

Question 33

Where in the GI tract do anastomoses heal the best?

Answer 33

Upper

Question 34

What tumours are produced by UV light?

Answer 34

BCC SCC and malignant melanoma