healing & repair

Question 1

describe resolution

Answer 1

Initiating factor removed
Tissue undamaged or able to regenerate

Question 2

describe repair

Answer 2

initiating factor still present
tissue damaged and unable to regenerate

Question 3

how does repair work

Answer 3

Replacement of damaged tissue by fibrous tissue
Collagen produced by fibroblasts

Question 4

what is Lobar pneumonia

Answer 4

Affects a lobe of the lung rather than the whole thing (bronchopneumonia)

Alveoli filled with neutrophil polymorphs (acute inflammation) rather than air

Pneumocyte that line the alveoli can regenerate so the lung can be regenerated – the pneumocytes divide and reline the alveoli

Question 5

examples of repair

Answer 5

Heart after myocardial infarction
Brain after cerebral infarction (fibrosis in the brain -> gliosis)
Spinal cord after trauma

Question 6

what are the most superficial skin wounds

Answer 6

abrasions eg road rash

Question 7

what are the steps of wound healing

Answer 7

Normal skin -> abrasion -> scab formed over surface -> epidermis growing out from adnexa, produced by scab -> thin confluent epidermis -> final epidermal regrowth

Question 8

how to treat incised skin wound

Answer 8

healing by 1st intention

Question 9

why are skin wounds treated by 1st intention

Answer 9

An incision causes very little damage to the tissues on either side of the cut, so if the two sides are brought together accurately the healing can proceed quite quickly.

Question 10

describe healing by 1st intention

Answer 10

1st detention – can suture up the cut

Incision -> exudation of fibrinogen -> weak fibrin join -> epidermal regrowth and collagen synthesis -> strong collagen join

Question 11

how to treat tissue loss

Answer 11

healing by 2nd intention

Question 12

why is tissue loss treated by 2nd intention

Answer 12

A tissue loss injury or another reason that the wound margins are not apposed requires another mechanism for repair.

occurs when the sides of the wound are not opposed, therefore healing must occur from the bottom of the wound upwards

Question 13

describe healing by 2nd intention

Answer 13

Can’t bring the skin edges together the cut is too deep

Loss of tissue -> granulation tissue -> organisation -> early fibrous scar -> scar contraction

Phagocytosis to remove any debris
Granulation tissue to fill in defects and repair specialised tissues lost
Epithelial regeneration to cover the surface

Question 14

which cells regenerate

Answer 14

Hepatocytes
Pneumocytes
All blood cells
Gut epithelium
Skin epithelium
Osteocytes – help remodel bone fractures

Question 15

which cells dont regenerate

Answer 15

Myocardial cells
Neurones

Question 16

what is organisation

Answer 16

the process whereby specialised tissues ae repaired by the formation of mature fibrovascular connective tissue.
It occurs by the production of granulation tissue and the removal of dead tissue by phagocytosis.

Question 17

what is granulation tissue

Answer 17

a repair phenomenon, it is loops of capillaries supported by myofibroblasts which actively contracts to reduce wound size; this may result in a structure later.