Responses to cell and tissue injury

Question 1

What is an acute cell injury?

Answer 1

when the environmental changes exceed cells capability to maintain normal homeostasis

Question 2

What is sublethal injury?

Answer 2

damage is caused to cell but no death

Question 3

What are the types of sublethal injury?

Answer 3

• hydropic change

- fatty change

Question 4

WHat are the types of irreversible cell injury?

Answer 4

• necrosis

- apoptosis

Question 5

What are the types of irreversible cell injury?

Answer 5

• necrosis

- apoptosis

Question 6

What is hydropic change?

Answer 6

• accumulation of water in the cell

- early sign of cellular degeneration

Question 7

What is fatty change?

Answer 7

“steatosis”

- abnormal retention of lipids in a cell

Question 8

What is oncosis?

Answer 8

Oncosis refers to a series of cellular reactions following injury that precedes cell death. -non-apoptopic

Question 9

What is necrosis?

Answer 9

cell death following bioenergetic failure and loss of plasma membrane integrity
- induces inflammation and repair

Question 10

What is apoptosis?

Answer 10

• the death of cells which occurs as a normal and controlled part of an organisms growth or development
• breaks up into tiny fragments

Question 11

What does reduced apoptosis result in?

Answer 11

cells don’t die when they should - cancer

• neoplasia
• autoimmune disease
• virus infection

Question 12

What does increased apoptosis result in?

Answer 12

neurodegenerative disorders

HIV infection of T lymphocytes

Question 13

What causes apoptosis and necrosis?

Answer 13

a- physiological or pathological

n - pathological

Question 14

What does apoptosis and necrosis effect?

Answer 14

a - single cells

n - cell groups

Question 15

What happens in apoptosis and necrosis?

Answer 15

a - energy dependent fragmentation of DNA

n - abnormal ion homeostasis

Question 16

What happens to the cell membrane integrity in apoptosis and necrosis?

Answer 16

a - maintained

n - lost

Question 17

What happens to the morphology of cells in apoptosis and necrosis?

Answer 17

a - cell shrinkage and fragmentation

n - cell swelling and lysis

Question 18

What is the inflammatory response of apoptosis and necrosis?

Answer 18

a - none

n - usual

Question 19

What is the fate of dead cells in apoptosis and necrosis?

Answer 19

a - phagocytosed by neighbouring cells

n - phagocytosed by inflammatory cells

Question 20

Coagulative necrosis?

Answer 20

coagulation of cellular proteins

• commonest type
• inflammatory response
• initially firm but later soft

Question 21

Colliquative necrosis?

Answer 21

liquidfication of tissue

Question 22

Caseous necrosis?

Answer 22

tissue becomes cheese like

- tuberculosis

Question 23

Gangrenous necrosis?

Answer 23

necrosis with putrefaction

- wet and dry forms

Question 24

Fibrinoid necrosis?

Answer 24

accumulation of material in tissue with tissue similar to fibrin

Question 25

Pyroptosis?

Answer 25

part apoptosis but then necrosis

Question 26

What happens after cell injury?

Answer 26

- death - healing - complete resolution - repair - second best option

Question 27

Labile tissues?

Answer 27

continuously dividing tissues | - blood, skin, gut

Question 28

Stable tissues?

Answer 28

only divide when needed - after injury potential for complete repair - liver, kidney

Question 29

Permanent tissues?

Answer 29

limited capacity to restore -scar

Question 30

What are factors favouring resolution?

Answer 30

- minimal cell death and tissue damage - occurrence in an organ or tissue with regenerative capacity - rapid destruction of the casual agent - rapid removal of fluid and debris by good local vascular drainage

Question 31

What is organisation?

Answer 31

``` repair of specialised tissue by formation of a scar involves: - formation of granulation tissue - removal of dead tissue by phagocytosis - wound contraction and scarring ```

Question 32

What factors favour organisation?

Answer 32

- large amounts of fibrin - substancial necrosis - exudate and debris cannot be removed or discharged

Question 33

What is granulation tissue?

Answer 33

``` an intermediate substance - loops of capillaries - myofibroblasts - collagen - inflammatory cells organised by deposition of collagen and contraction ```

Question 34

What is healing by first intention?

Answer 34

- course in wounds with edges close together - healing usually faster than healing by secondary intention - end result 0 return to function and minimal scarring

Question 35

What is healing by second intention?

Answer 35

sides of wound are not opposed so the healing must occur from the bottom of the wound upwards - wound contraction reduces size of defect - presence of myoofibroblasts

Question 36

What are the stages of healing by first intention?

Answer 36

Haemostasis - haemotoma forms to prevent blood loss (platelets and cytokines) Inflammation - removes any pathogens or cell debris Proliferation - cytokines released by inflammatory response drive proliferation of fibroblasts and formation of granulation tissue Remodelling - devascularisation occurs and the fibroblasts undergo apoptosis

Question 37

What are the stages of healing by second intention?

Answer 37

Haemostasis - large fibrin mesh fills the wound Inflamation - debris and pathogens are removed - larger amount of debris present so inflammatory response is more severe Proliferation - granulation tissue forms at the bottom of the wound Remodelling - wound contraction can occur

Question 38

What are keloid scars?

Answer 38

excessive fibroblast proliferation and collagen production leads to a raised scar

Question 39

How does bone healing occur?

Answer 39

- repair, remodelling, resolution - haemotoma at fracture site gives a framework for healing - replaced by fracture callus - replaced by lamellar bone - remodelled to restore normal trabecular pattern of bone

Question 40

How does healing in the liver occur?

Answer 40

- necrosis, regeneration, fibrous scarring, architectural disruption chirrhosis - scarring of the liver

Question 41

What are the factors that influence wound healing?

Answer 41

``` systemic - age - nutrition - metabolic status - circulatory status - hormones Local - infection - mechanical factors - foreign bodies - size, location and type of wound ```

Question 42

What are the properties of an abnormal wound?

Answer 42

- deficient scar formation - ulceration, dehiscence - excessive formation of repair components - keloid scar - formation of contractures

Question 43

What are the advantageous effects of scars?

Answer 43

- provides a permanent patch | - allows surrounding tissues to continue to function

Question 44

What problems can scars cause?

Answer 44

- cosmetic | - functional - site, size