healing and repair

Question 1

What will contribute to resolution rather than repair?

Answer 1

1. initiating factor removed

2. tissue undamaged/able to regenerate

Question 2

What will lead to repair rather than resolution?

Answer 2

1. initiating factor still present

2. tissue damaged and unable to regenerate

Question 3

What are the features of repair?

Answer 3

1. replacement of damaged tissue by fibrous tissue

2. the collagen is produced by fibroblasts

Question 4

Give examples of repair

Answer 4

1. heart after myocardial infarction
2. brain after cerebral infarction
3. spinal cord after trauma

Question 5

Which cells can regenerate?

Answer 5

hepatocytes
pneumocytes
all blood cells 
gut epithelium
skin epithelium
osteocytes

Question 6

Which cells do not regenerate?

Answer 6

cardiac myocytes
neurones
(striated muscle cells)

Question 7

What two pt populations suffer with poor wound healing?

Answer 7

elderly

diabetics

Question 8

What is healing?

Answer 8

restoration with no/minimal residual defect:

• superficial skin abrasion
• healing by 1st intention

Question 9

Is healing by second intention classified as healing or repair?

Answer 9

repair

Question 10

Describe healing from skin abrasion

Answer 10

1. cells proliferate and spread out as a thin sheet until the defect is covered
2. stimulus to proliferate is switched off by contact inhibition
3. epidermis is rebuilt from the base upwards
   the scale is a layer of fibrin that protects the epidermis as it grows
   cells from sweat glands and hair follicles can contribute to healing

Question 11

What is organisation?

Answer 11

repair of specialised tissues by the formation of a fibrous scar

Question 12

What happens in organisation?

Answer 12

1. granulation tissue is formed and then contracts and accumulates collagen to form a scar
2. dead tissue is removed by phagocytosis

Question 13

what is granulation tissue made of and how is it formed?

Answer 13

capillary loops and myofibroblasts
capillary endothelial cells proliferate and grow into the area
fibroblasts divide and secrete collagen and ECM
collagen forms a scar

Question 14

why does a wound contract?

Answer 14

Contraction of myofibroblasts in granulation tissue to reduce the volume tissue for repair

Question 15

What is a disadvantage of granulation tissue?

Answer 15

contraction of scar tissue around a lumen causes stenosis/stricture and contracture in muscles

Question 16

Explain healing by first intention

Answer 16

• made by a scalpel
• causes little damage to tissues on either side of the cut
• the two sides of the wound are brought together accurately
• coagulated blood forms a scab and helps keep the wound clean
• capillaries proliferate
• fibroblasts secrete collagen
• only the elastin in the dermis is not restored
• a thin layer of fibrin joins the edges. This is replaced by collagen and covered by epidermis

Question 17

Explain healing by second intention

Answer 17

• happens when there is tissue loss
• this prevents the two sides of the wound coming together
• phagocytosis to remove debris
• granulation tissue to fill in defects
• epithelial regeneration to cover surface

Question 18

why does liver cirrhosis result?

Answer 18

The hepatocytes AND the architecture have been damaged

Question 19

Vascular smooth muscle cannot be regenerated as muscle is a permanent population. T or F?

Answer 19

False

Question 20

What happens when peripheral nerves are damaged?

Answer 20

Wallerian degeneration