4. Healing

Question 1

labile cells

Answer 1

cells that multiply constantly throughout life

Question 2

stable celsl

Answer 2

cells that multiply when needed

Question 3

permanent cells

Answer 3

incapable of multiplication - cannot regenerate

brain cells and skeletal and heart muscles

Question 4

resolution

Answer 4

disappearance of a symptom or condition

Question 5

wound contraction

Answer 5

myofibroblasts decrease the size of the wound. grips wound edges and contracts. when cells roles are close to complete, unneeded cells undergo apoptosis

Question 6

wound contracture

Answer 6

excess wound contraction, leads to physical deformities characterized by skin constriction and functional limitations

Question 7

healing by primary intention

Answer 7

when wound edges are sutured/glued together so that they are adjacent to each other. minimal scarring

Question 8

healing by secondary intention

Answer 8

allowance of wound granulation –> broader scar, therefore healing process can be slow due to presence of drainage from infection

Question 9

adhesion

Answer 9

scar tissue in body cavities that joint issues or organs together that normally are not connected

Question 10

granulation tissue

Answer 10

new connective tissue and tiny blood vessels that form on the surfaces of a wound during healing

Question 11

keloid formation

Answer 11

scar formation that is composed of collagen (either type III [early] or type I [late]), result of overgrowth in granulation tissue (type III) at the site of healed skin injury –> slowly replaced by type I

Question 12

what can cause delay in wound healing? (5)

Answer 12

1 reduced blood supply
2 infection
3 foreign bodies
4 excessive movement
5 location of injury

Question 13

skin healing (3 steps)

Answer 13

1. inflammatory phase
2. proliferative phase
3. repair and remodelling phase

Question 14

explain what happens in the inflammatory phase

Answer 14

bleeding leads to fibrin formation, resulting fibrin is semi-permanent and also acts to stop bleeding (clot)

Question 15

explain what happens in the proliferative phase (dermis and epidermis as well)

Answer 15

lots of growth factors released from the clot causing increased cell division

dermis: cell division of fibroblasts and endothelial cells
epidermis: cell division results in re-epithelialisation

Question 16

explain what happens in the repair and remodelling phase

Answer 16

emigration/chemotaxis of fibroblasts and endothelial cells, fibroblasts form collagen, angiogenesis
forms new tissue called GRANULATION TISSUE

Question 17

maturation process of granulation tissue

Answer 17

1. gap is closed between endothelial cells of blood vessels
2. fibroblasts transform into myofibroblasts to produce wound contraction
3. type I collagen progressively replaces type III collagen

Question 18

how does wound contraction work?

Answer 18

fibroblasts transform into myofibroblasts, the smooth muscle like cells link together and contract to produce tension in the wound which is necessary for type I collagen to form (initially there is no tension in the wound, which is why we only see type III/immature collagen formation)

Question 19

wound healing - granulation to scar tissue (3)

Answer 19

1. blanching (apoptosis of endothelial cells)
2. tensile strength increases (leading to decreased ability to pull wound apart)
3. wound contracture (late process of remodelling which causes shortening of collagen fibers in the scar. this can be detrimental, reducing function or even causing death)