Wound Healing

Question 1

List the 4 stages of wound healing

Answer 1

Haemostasis
Inflammation
Proliferation
Remodelling

Question 2

Signs of inflammation

Answer 2

Pain
Swelling
Heat
Loss of function

Question 3

List 2 phases of acute inflammation

Answer 3

Vascular
Cellular

Question 4

Function of vascular acute inflammation

Answer 4

Prevent further injury, dilutes toxins & bacteria

Question 5

Approximate time scale for vascular acute inflammation

Answer 5

Almost immediate - 3/5 days

Question 6

what causes mast cells to burst

Answer 6

damaged tissue

Question 7

what causes vasodilation in wound healing

Answer 7

histamine

Question 8

when mast cells burst what do they release

Answer 8

histamine, serotonin

Question 9

what causes stimulation of pain receptors

Answer 9

pressure from swelling

Question 10

What 2 functions does platelets, histamines and serotonin have in wound healing

Answer 10

Causes vasodilation (heat/redness)
Increased vascular permeability (swelling/pain)

Question 11

how does proteins and plasma move into intracellular spaces

Answer 11

osmosis

Question 12

what sensitises pain receptors

Answer 12

bradykinin and prostaglandins

Question 13

what does vasodilation do

Answer 13

increase blood flow

Question 14

what happens when endothelial cells lose their tight junctions

Answer 14

blood vessels become leaky - increased permeability

Question 15

when does the area become hypotoxic

Answer 15

when blood supply has been lost in the injury

Question 16

what does histamine stimulate

Answer 16

endothelial cells to lose their tight junctions

Question 17

After 12 - 24 hours which phase starts

Answer 17

Cellular

Question 18

Functions of cellular acute inflammation

Answer 18

Removes bacteria, cleans up tissue and prepares for wound repair

Question 19

Identify the cells involved in cellular inflammation

Answer 19

Neutrophils
Macrophages

Question 20

explain the role of macrophages at end of inflammation

Answer 20

they release proinflammatory cytokines or anti inflammatory cytokines and growth factors that progress the wound

Question 21

What is angiogenesis

Answer 21

New blood vessel growth

Question 22

What is the function of neutrophils in wound healing

Answer 22

Phagocyte - Bacterial destruction and clean up

Question 23

What is the function of macrophages in wound healing

Answer 23

Phagocyte - bacterial clean up, damaged tissue removal and dead neutrophils, release growth factors

Question 24

How do neutrophils die

Answer 24

Apoptosis

Question 25

What is apoptosis

Answer 25

When neutrophils fill their self up with bacteria

Question 26

What is a monocyte

Answer 26

Immature macrophages

Question 27

What are the 5 stages of how cells travel from the blood to the site of injury (cellular phase)

Answer 27

Margination Rolling / pavementing Adhesion Diapedesis Chemotaxis

Question 28

Explain margination

Answer 28

As blood flow becomes congested, phagocytes drop the margins

Question 29

explain rolling / pavementing

Answer 29

weak attraction and rolling along the endothelial cells

Question 30

explain adhesion

Answer 30

phagocytes attaches strongly to special attachment proteins

Question 31

explain diapedesis

Answer 31

phagocyte squeezes through leaky membrane into intracellular spaces

Question 32

explain chemotaxis

Answer 32

cells move to area of damage following cytokine concentration gradient, cell debris

Question 33

describe what happens to epithelial cells in early proliferation

Answer 33

loss of contact stimulates epithelial cells to replicate macrophages release growth factors epithelial cells replicate

Question 34

how do epithelial cells replicate

Answer 34

leap frog over each other process repeats until they meet in the middle

Question 35

describe the role of fibroblasts in early proliferation

Answer 35

fibroblasts migrate into the wound they make ground substance and type 3 collagen

Question 36

what characteristic does type 3 collagen have compared to type 1

Answer 36

it is much weaker less organised easily broken

Question 37

explain how blood vessels grow into the wound during early proliferation

Answer 37

fibroblasts and epithelial tissue quickly use up local oxygen levels m2 macrophages release growth factors this stimulates endothelial cells of blood vessels to replicate

Question 38

which direction does endothelial cells grow

Answer 38

towards hypotoxic areas

Question 39

which tissue is present at the end of proliferation

Answer 39

granulation

Question 40

list the components of granulation tissue

Answer 40

fibroblasts ground substance (proteoglycans) type 3 collagen macrophages new blood vessels new epithelial tissue

Question 41

when does a fibroblast make smooth muscle actin (myofibroblasts)

Answer 41

when physical stress on the new tissue stimulates the fibroblast

Question 42

what causes reduction in wound size

Answer 42

myofibroblasts attached to collagen bundles and which contracts to pull inwards

Question 43

what happens at the end of proliferation

Answer 43

epithelial cells have recovered the site invading blood vessels are now organised fibroblasts have filled the wound with type 3 collagen and ground substance