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Foundations 2 - Week 3 > Pathology > Flashcards

Pathology Flashcards

1
Q

What are the 5 types of wounds?

A
  1. Lacerations
  2. Abrasions
  3. Contusions
  4. Avulsions
  5. Punctures
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2
Q

What are the 3 main ways wounds can heal?

A
  1. Primary Intention - epidermis is brought together (ie-sutures). Fast healing.
  2. Secondary Intention - wound is allowed to granulate
  3. Tertiary Intention - wound is debrided and allowed to remain open for a number of days, before closure.
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3
Q

What are the 4 phases of wound healing?

A
  1. Hemeostasis
  2. Inflammation
  3. Proliferation
  4. Remodeling
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4
Q

Describe the first phase of wound healing, hemostasis?

What occurs? What is the function? What cells are involved? What growth factors are involved?

A

Hemostatis is the first phase of wound healing. It begins with the formation of the fibrin clot. This serves a number of fuctions, including:

  • Protective barrier to the external environment
  • Scaffolding for cell migration/proliferation
  • Resovior of growth factors that are released during degranulation of platelets.

Platlets are the main cell involved in hemostasis. They release growth factors PDGF, TGF-beta, and EGF which attact other cells, and start cell proliferation.

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5
Q

Describe the second phase of wound healing, inflammation?

What occurs? What is the function? What cells are involved? What growth factors are involved?

A

The following events occur during the inflammatory phase of wound healing.

  • Vasoconstriction and Vasodilation
  • Innate Immune Response
  • Macrophages arrival/activation
  • Neutrophil arrival/activation
  • Decline or Resolution of Inflammatory Phase

Many cells are involved - macrophages, fibroblasts, neutrophils, mast cells, keratinocytes, endothelial cells

Many growth factors are involved - VEGF, FGF, TGF-beta, TNF-alpha, EGF, etc.

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6
Q

Describe the third phase of wound healing, proliferation?

What occurs? What is the function? What cells are involved? What growth factors are involved?

A

The following events take place during the proliferation phase:

  • Angiogenesis
  • Granulation (ECM) of Tissue - fibroblasts, etc.
  • Collagen Deposition - fibroblast
  • Epithelialization - kerakinocytes
  • Contraction - myofibroblasts

Many cells are involved, including: Macrophages, fibroblasts, myofibroblasts, endothelial cells, keratinocytes.

MMPs are also involved.

Many growth factors are involved, especially VEGF for angiogenesis

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7
Q

Describe the final phase of wound healing, remodeling?

What occurs? What is the function? What cells are involved? What growth factors are involved?

A

During the remodeling phase of wound healing, following events take place:

  • Type 3 collagen is replaced by type 1.
  • The disorganized collagen is reorganized along tension lines
  • The collagen is cross-linked to improve tensile strength
  • The scar is flattened

Fibroblasts are the main cell involved in reshaping the wound. No growth factors are involved.

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8
Q

What is the definition of an infected wound– how many colony forming units (CFL) per gram of tissue are required?

A

10^5 (100,000)

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9
Q

What is the gold standard for diagnosing infected wounds?

A

Tissue biopsy

Physicians have a 50:50 chance of diagnosing an infected would by observation alone.

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10
Q

What is biofilm? What is one challenge of biofilms in wound healing?

A

Biofilm is a group of microorganisms in which cells stick to each other on a surface. These adherent cells are frequently embedded within a self-produced matrix of extracellular polymeric substance (EPS).

Immune cells have difficultly killing pathogens that reside wihitn the biofilm structures.

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11
Q

What are Venous Ulcers? Where do they typically occur?

A
  • Wounds that occur due to improper functioning venous valves, usually in the legs
  • A full-thickness defect of the skin, most frequently in the ankle region, common over the medial malleolus
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12
Q

What are Arterial Ulcers? Where do they typically occur?

A
  • A full-thickness defect of the skin, most frequently in the ankle region, common over the medial malleolus
  • Most common cause is atherosclerosis
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13
Q

What are diabetic Ulcers?

A
  • Most common foot injuries leading to lower extremity amputation
  • Peripheral neuropathy, peripheral vascular disease, and infection combine to lead to these ulcers and amputation
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14
Q

What are pressure ulcers?

A
  • Localized injury to skin or underlying tissue, usually over a bony prominence, as a result of unrelieved pressure.
  • Common among bedridden elderly
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15
Q

What are the 3 cornerstones of wound management?

A
  1. Moist Wound Healing
  2. Exudate Wounds - remove fluid
  3. Debridement - remove necrotic tissue and foreign materail.
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16
Q

Name some methods of debridement?

A
  • Mechanical - scrub the wound
    • Hydrotherapy - rinse the wound
    • Wet-to-dry dressing
  • Autolytic – use bodies own moisture and enzymes to liquify wounds
  • Enzymatic- use of topical agens to break down necrotic tissue (collagenase, fibrinogen)
  • Biological such as Maggot therapy
  • Chemical
  • Surgical Sharp Debridement - cut the wound out
17
Q

What are the benefits of using moisture in wound healing?

A
  • increase epithelialization, promote dermal matrix synthesis and improve the patient’s comfort.
18
Q

What are the benefits of exudating (removing fluid) a wound?

A
  • Wound fluid can inhibit the production of certain wound healing cells (keratinocytes, fibroblasts, epithelial cells, etc.)
  • Would fluid contains MMPs, which inhibit wound healing.
19
Q

What is the growth factor PDGF?

What does it do?

What type of receptors does it act on?

What cells secrete it?

A

PDGF - Platlet Derived Growth Factor

PDGF is a dimer (homo and hetero)

Functions:

  • Chemotactic for macrophages, fibroblasts
  • Activates macrophages
  • Mitogenic for fibroblasts
  • Stimulates matrix production

Acts on Tyrosine Kinase Receptors

Secreted mainly by:

  • Platelets
  • macrophages
  • keratinocytes
20
Q

What is the growth factor VEGF?

What does it do?

What type of receptors does it act on?

What cells secrete it?

A

VEGF - Vascular Endothelial Growth Factor

VEGF Fuctions:

  • Angiogenesis

It works on tyrosine kinase receptors

It is secreted by keratinocytes and macrophages

21
Q

What is the growth factor TGF-Beta?

What does it do?

What type of receptors does it act on?

What cells secrete it?

A

TGF-Beta - Transforming Growth Factor Beta

TGF-beta functions:

  • Chemotactic for macrophages and fibroblasts
  • Keratinocyte migration
  • Stimulates matrix production by fibroblasts

TGF-beta works on serine-threonine kinase receptors

TGF-beta is secreted by platlets and macrophages

22
Q

Is TGF-Beta secreted in an active or inactive form?

What type of receptors and signaling does TGF-beta induce?

A

Inactive.

It reguires the cleavage of beta-binding proteins and latent associated protein (LAP).

TGF-beta (isoforms 1 and 2) activates tyrosine kinase receptors which trigges SMAD signlaing proteins which induce gene transcription

23
Q

What is the growth factor FGF?

What does it do?

What type of receptors does it act on?

What cells secrete it?

A

FGF - Fibroblast Growth Factor

Function:

  • Mitogenic for fibroblasts
  • Angeogenic

FGF acts on tyrosine kinase receptors

FGF is produced by macrophages and damaged endothelial cells

24
Q

What is the growth factor FGF?

What does it do?

What type of receptors does it act on?

What cells secrete it?

A

EGF -Epidermal Growth Factor

Function:

  • Migration of Keratinocytes
  • Mitogenic for Keratinocytes

EGF acts on tyrosine kinase receptors

EGF is produced by platlets

25
Q

What are 5 functions of the Extra Cellular Matrix (ECM)?

A
  1. Mechanical Support
  2. Embryonic Development
  3. Pathways for cellular migration
  4. Wound Healing
  5. Management of Growth Factors
26
Q

What types of molecules make up the soluble portion of the ECM?

A

Proteoglycans

27
Q

Proteoglycans are composed of what two molecules?

What is their function in the ECM and Basal Lamina?

A
  • A core proteins + a glycosaminoglycan (GAG)
  • Mechanical Support, Cushion, and limit permeability of ions.
28
Q

Name 4 glycosamnioglycans?

A
  • heparan sulfate
  • chondroitin/dermatan sulfate
  • keratan sulfate
  • hyaluronan (HA).
29
Q

How is Hyaluron differnt from the other glycosaminoglycans (GAGs)?

A

Unlike the other GAGs, Hyaluron is not linked to a core protein. It is a huge molecule of linked saccharides that acts as a gel and retains water.

30
Q

What are the 4 insoluble components of the basal membrane and the ECM?

A
  1. Collagen
  2. Elastic Fibers (elastin)
  3. Fibronectin
  4. Laminin
31
Q

What are MMPs?

What is their function?

Name the different types?

What fiber is resistant to MMPs?

A

MMP - Matrix Metalloproteinases

MMPs breakdown the ECM

Types:

  • collagenases
  • gelatinases,
  • stromelysins
  • matrilysins
  • membrane-type MMPs, and macrophage metalloelastases

Undenatured triple-helix collagen is reistant to MMPs

32
Q

What is fibronectin?

A

A dimeric protein that bind many different molecules togehter in the ECM and basal membrane

33
Q

What is laminin?

A

A heterotrimer that associates with integrin and other connective molecules in the basal lamina. It looks like a cross.

34
Q

What is entactin?

A

A monomer that associates with laminin and collagen IV fibers in the basal lamina.

35
Q

What type of collagen fiber is mostly found in the basal lamina?

A

Type IV

36
Q

What is elastin?

A

A elastic fiber that resides mostly in the ECM. It forms cross-linked covalent bonds with it self. This creates an elastin network. It is very similar to collagen, except that it is not glycosylated.

Foundations 2 - Week 3 (4 decks)

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