Wound Healing Flashcards

1
Q

Define Parenchyma

A

Organ specific cells related to function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define Stroma

A

‘Background’ tissue - provides the structure, mechanical and nutritional support to the organ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Name some functions of epithelia

A

Protection

Containment of body fluids

Absorption

Secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Name some functions of connective tissue

A

Mechanical reinforcement

Immune surveillance

Diffusion of nutrients and waste

Cells are not in close contact - embedded in the ECM

Vascularised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Name some functions of muscle

A

Specialised for gross movement through cellular contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Name some functions of nervous tissue

A

Responsible for rapid, long-distance signalling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Name 2 areas where connective tissue does not have to be vsacularised

A

Cartilage

Cornea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What 3 things make up the ECM?

Not the only 3 things in the ECM; lymphocytes, adipose and other cells found there also

A

Fibrous components - collagen and elastin

GAGs - to support collagen

Proteoglycans - GAGs attached to a core protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What determines the properties of a connective tissue?

A

The composition of the ECM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Name the 2 types of connective tissue?

A

Loose connective tissue

Dense irregular connective tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which type of connective tissue contain numerous cells, has a lose fiber arrangement in a viscous matrix?

Give some examples

A

Loose connective tissue

Haematopoietic/lymphatic tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What type of connective tissue has a dense woven network of collagen and fibres in a viscous matrix?

Give some examples

A

Dense irregular connective tissue

Joint capsules
Tendons and ligaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define ‘wound’

A

Injury or trauma to tissues that results in a disruption of the function and structure of a tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Name the 4 stages of wound healing

A

Haemostasis

Inflammation

Proliferation

Remodelling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens during the haemostasis stage of wound healing?

How long does this stage last?

A

Wound closed by clotting (coagulation cascade)

Platelets and fibrin adhere to site

Formation of a thrombus

<24 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What 3 cell types are present in the inflammatory stage of wound healing?

What do they do?

How long does this stage last?

A

Platelets - control bleeding

Macrophages - prevent infection

Neutrophils - inflammation

0-4 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens during the proliferative phase of wound healing?

How long does this stage last?

A

Angiogenesis

Epithelialisation

Contraction

Fibrous tissue formation

1-14 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens during the remodelling phase of wound healing?

How long does this stage last?

A

Maturation of cells

Collagen remodelling and realignment

Day 21 - years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Name the 2 types of tissue repair

A

Regeneration

Scar formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Define tissue repair

A

The restoration of the structure and function of a tissue

21
Q

What 3 molecules are present in the regeneration of tissue?

A

Platelet-derived growth factor (PDGF)

Vascular endothelial growth factor (VEGF)

Transforming growth factor-beta (TGF-B)

22
Q

TGF-B does what at a wound site?

How is it activated?

A

Lays down new collagen
-by converting fibroblasts into myofibroblasts

Activated by macrophages

23
Q

Give a brief description of labile tissues with some examples

A

Continuously proliferating to replace dead/sloughed off cells

Skin, GI tract, salivary gland tissues

24
Q

Give a brief description of stable tissues with some examples

A

Cells that normally exist in a non-dividing state, but can enter the cell cycle in response to injury

Normally not full regeneration, just compensatory growth

Parenchymal liver cells, kidney, pancreas

25
Q

Give a brief description of permanent tissues with some examples

A

Non-dividing cells that lead to scar formation if damaged

Cardiac and skeletal tissue

26
Q

What are growth factors?

A

Proteins that stimulate proliferation, migration, and differentiation of cells

Stimulate the entry of cells into the cell cycle

27
Q

Which cells produce growth factors?

A

Macrophages

Lymphocytes

As part of the inflammatory process

28
Q

What is the role of the ECM in regeneration?

A

Stores and presents growth factors

Acts as a scaffold for migrating cells to adhere to

29
Q

What happens in scar formation?

A

Replacement of damaged parenchymal cells with connective tissue

Incomplete restoration of architecture and function

30
Q

Where does scar formation occur?

A

Severe/chronic injuries that result in damage to parenchymal cells and connective tissue

Permanent non-dividing tissues

31
Q

Which growth factor stimulates angiogenesis?

A

VEGF

32
Q

How does angiogenesis occur?

A

Sprouting of new vessels from existing ones

Involves endothelial cell proliferation an migration

33
Q

Describe the formation of granulation tissue

A

Migration and proliferation of fibroblasts to the site of injury

Deposition of ECM proteins produced by these cells

Derived from growth factors - TGF-B

34
Q

What is involved in the degradation of collagens and other ECM components during the remodelling phase of wound healing?

A

Matrix metalloproteinases (MMPs)

35
Q

Depending on the nature and size of the wound, the healing of skin wounds occurs by:

A

First intention (primary union)

Second intention (secondary union)

36
Q

When does wound healing by first intention occur?

A

Healing of a clean, uninfected surgical incision

Epithelial regeneration is the principle mechanism of repair

37
Q

Outline the 6 stages of wound healing

A
  1. Incisional space fills with fibrin-clotted blood
  2. Neutrophils migrate from the incision margin to the fibrin clot
  3. Epithelial cells migrate and proliferate along the dermis
  4. Neutrophils have been replaced macrophages. Angiogenesis in full swing. Granulation tissue begins to invade space
  5. Collagen accumulation, fibroblast proliferation
  6. Remodelling continues to increase wound tensile strength
38
Q

When does wound healing occur by second intention?

A

Large wounds at sites of abscess formation, ulceration, infarction

Scar formation is followed by wound contraction - mediated by the action of myofibroblasts

39
Q

Give some differences between second intention and first intention healing

A

Second intention:
A larger clot or scab

Intense inflammation

Larger defects that require more granulation tissue

Wound contraction

40
Q

List the 6 stages of fracture healing

A

Haematoma

Granulation tissue

Callus formation

Woven bone

Lamellar bone

Remodelling

41
Q

Describe the haematoma stage of fracture healing

A

Bleeding from ruptured vessels

Inflammatory reaction - phagocytes move to area

42
Q

Describe the granulation tissue stage of fracture healing

A

Granulation tissue replaces the haematoma

Cell proliferation occurs in response to growth factors/cytokines

43
Q

Describe the callus stage of fracture healing

A

Formation of callus (irregular swelling at bone ends)

Initially made from fibrocellular material and cartilage

44
Q

Describe the woven bone stage of fracture healing

A

Osteoprogenitor cells proliferate and form woven bone

45
Q

Describe the lamellar bone stage of fracture healing

A

Woven bone is replaced by mature lamellar bone

46
Q

Describe the remodelling stage of fracture healing

A

Osteoclasts and osteoblasts remodel lamellar bone into a form related to function in response to stresses

Excessive callus is resorbed

47
Q

What 6 local factors could affect tissue repair?

A

Infection

Mechanical factors

Foreign bodies

Size of wound

Location of wound

Type of wound

48
Q

What 6 systemic factors could affect tissue repair?

A

Nutritional status

Metabolic status

Circulatory status

Hormones

Age

Collagen disorder

49
Q

Name the 3 complications of tissue repair

A

Inadequate formation - dehiscence

Excessive formation - keloid scars (excessive collagen), proud flesh (excessive granulation tissue)

Formation of contracture - fibrosis of connective tissue that prevents normal mobility of the tissue. Myofibroblasts play a role. Severe burns