Wound healing

Wound healing

1. Induction of acute inflammatory response by the initial injury 2. Debridement (surgical or natural by phagocytosis) 3. Formation of a healthy granulation bed 4. Angiogenesis and fibroplasia 5. Epithelialization ("cover & seal", contact inhibition) 6. Wound contraction 7. Remodeling of tissue elements to restore function and to increase wound strength as much as possible

Proliferate and differentiate into myoblasts

Activation of satellite leads to?

oxygen, nutrients, and more phagocytic cells and chemical mediators

Angiogenesis allows the influx of blood with what?

Neovascularization

Angiogenesis is also called?

Fibrinolytic enzymes

Dissolution of fibrin clots by?

Make contact with similar cells

Epithelial cells make contact with ______ cells form all sides of the wound and seal it

Proteolytic enzymes

Epithelial cells us what enzymes to sever the connection between the clot and the wound surface?

Keeping the wound moist

Epithelialization can be aided by keeping the wound?

Contracture

Excessive wound contraction

Angioblasts, fibroblasts, & myofibroblasts

Granulation tissue contains what cells?

3-5 days

Granulation tissue forms in how many days?

Over time

Granulation tissue represents a temporary scaffolding that changes ___________ ___________

Reconstruction

Granulation ↔ ?

Suppresses adrenal gland and immune system

How can glucocorticoids/ steroids be bad?

Often continues for months

How long does the maturation phase of healing often continue for?

Become highly organized

In the Maturation phase of healing collagen fibers are initially almost random, but now become?

Repair promoting macrophage function

Perhaps anti-inflammatory drugs may not be such a good idea if they are inhibiting what?

Inflammation

Platelets, neutrophils, and macrophages

1. Inflammation 2. Proliferation 3. Remodeling/Maturation

What are the three phases of wound healing?

Glucocorticoids (aka steroids)

What are: •Anti-inflammatory drugs •Slow the migration of phagocytic cells to the site of injury •Cause phagocytic cells already in the area to become less active •Mast cells exposed to steroids are less likely to release histamine and other chemicals that promote inflammation

Satellite cells

What assist with repair of damaged fibers?

Some fibroblasts can

What can transition into myofibrils

Excessive bleeding

What causes clots, bacteria, infection, prolonged inflammation, exudation, pus?

Excessive fibrin deposition

What causes fibrous adhesions?

Stable cells

What cells are usually low level of replication, stimulation can lead to rapid division increases (quiescent)?

Permanent cells

What cells cannot reproduce themselves after birth, stop dividing during prenatal life (nondividing)?

Epithelial cells

What cells from the surrounding healthy tissue migrate into the wound

Continously Dividing cells

What cells proliferate throughout life (labile)?

Produce collagen which gradually develops more strength - for strong scar tissue

What do fibroblasts produce?

Influence wound healing

What do these influence? - site of the wound - mechanical factors - size of the wound - infection - circulatory status - nutritional and metabolic factors - age of patient or wound

Epithelialization

What does covering or sealing of the wound called?

- Filling in the wound defect - epithelization - contraction

What does repair involve?

• return to normal structure and function, minor damage w/o complications • can take up to 2 years

What happens to the structure and function if a wound has healed by regeneration?

Myofibroblasts

What have features of both fibroblasts and smooth muscle cells?

Ischemia

What impairs collagen synthesis, cell death, infection, prolonged inflammation?

First intention

What intention is regeneration/resolution?

Second intention healing

What intention of healing? • large, open defects and infected wounds • formation of granulation tissue

First intention healing

What intention of healing? • wounds with minimal tissue loss • always preferred IF possible

Sutured surgical wound

What is an example of first intention healing?

Cirrhosis of the liver

What is an example of internal contracture?

Degloving

What is an example of second intention healing?

Scar tissue

What is composed of collagen, restores strength but not function?

Angiogenesis

What is it called when capillary buds sprout out of vascular endothelial cells on wound margins?

Regeneration

What is it called when damaged tissue is replaced with healthy tissue - ideal "cure, good as new"

Resolution/ regeneration

What is it called when injured tissue is replaced by cells of the same type? - restoration of the OG function and structure

Dehiscence

What is it called when wound pulls apart (5-12 days after suturing) due to wound infection or excessive strain?

Repair

What is it called when: • destroyed tissue is replaced by connective tissue •fills in the lesion and restores tensile strength but can not carry out physiologic functions of the destroyed tissue - second best "fix-up, patch-up", "scar"

Contraction

What is shrinking of the wound called?

Natural debridement

What is slow, and uses inflammation and phagocytosis for debridement?

Debridement

What is the first absolutely essential step in wound healing?

"fill in, seal, and shrink the wound

What is the saying for wound healing

Phase 3 Maturation Phase of Healing

What is: - also called the scar remodeling phase - continuation of collagen deposition, tissue repair, and wound contraction - scar tissue is remodeled and gains its maximum strength

Keloid scar

What kind of scar raised, extends beyond original boundaries, invades surrounding tissue?

Remodeling and maturation phase

What phase has fibroblasts?

Proliferative phase

What phase: - macrophages, fibroblasts, lymphocytes - new tissue formation?

Inflammatory phase

What phase: - platelets, neutrophils, and macrophages - coagulation and hemostasis?

Multinucleated

What provide multiple copies of genes to speed up production of enzymes and structural proteins?

Granulation tissue

What tissue has a pink, soft, granular appearance?

Surgical debridement

What type of debridement speeds up healing?

Hypertrophic scar

What type of scar is raised, remains in original boundaries of the wound, regresses over time?

Fibroblasts

What: - enter the area and proliferate - deposit fibrous structural proteins

Type 3; Type 1

"immature" _________ collagen is replaced by stronger ________ collagen

Inflammatory process

Both resolution and repair begin early during what process?

1st Intention

Cannot do __________ __________________ now because epithelialization has caused wound edges to become sealed down; would need to create new wound edges

Angioblasts

Cells that form new blood vessels

Angioblasts and fibroblasts

Chemical mediators secreted by macrophages promote growth of

Phagocytosis

Clean up of particulate matter in the inflammatory exudate happens by?

0.5mm

Contraction alone may move the wound edge by ______mm per day

Remodeling/maturation

Just fibroblasts

Proliferation

Macrophages fibroblasts, and lymphocytes

Parallel lines

Most collagen fibers are in?

Wound bed

Myofibroblasts anchor themselves to the ___________ _____________ and exert pull on neighboring cells

Neighboring cells

Myofibroblasts establish connections with ___________?

+N*on-*S*teroidal *A*nti-*I*nflammatory *D*rugs

NSAID's

Macrophages and neutrophils

Proliferation stage has debridement by ______________ and _______________

Reconstruction and maturation

Repair involves what two overlapping phases?

Second intention

Repair is what intention

Repair is to 2nd intention

Resolution is to 1st intention a _________ is to _________

Stress

Tension lines orientation depends on the _________ placed on then skin during normal movement

False

True or False: There is greater granulation tissue and wound contraction in 1st intention healing

Myoblasts

What are embryonic cells which fuse to create the muscle fibers?

Diabetes mellitus, obesity, wound infection, inadequate nutrients, drugs (steroids, NSAIDs), tobacco smoke

What are some examples of predisposing disorders for dysfunctional wound healing?

Parenchymal of organs and mesenchymal cells

What are some examples of stable cells?

1. Inflammation 2. Proliferation 3. Remodeling & Maturation

What are the 3 phases of wound healing?

1. formation of a healthy granulation bed 2. filling in the wound defect 3. covering or sealing the wound (epithelialization) 4. shrinking the wound (contraction) 5. wound maturation

What are the 5 steps of wound healing?

- Ischemia - Excessive bleeding - Excessive fibrin deposition

What are the causes of dysfunctional wound healing?

C. Epithelial

Which cell type is most likely to lead to cell resolution? A. cardiac B. liver C. Epithelial

B. macrophages

Which cell types infiltrates a wound during both the inflammation phase and the proliferation phase? A. fibroblasts B. macrophages C. lymphocytes D. neutrophils E. platelets

↓ excess inflammation

Why are glucocorticoids/ steroids good?

Slower

Will wounds orthogonal to the tension lines will heal faster or slower?

Faster

Will wounds that are parallel to the tension lines heal faster or slower?

Migrate into the scaffolding and organize into vessels

With angiogenesis new endothelial cells migrate into the _________ and organize into ___________

Overlapping

Wound healing occurs in 3 ______________ phases

Fibrin and trapped cells

Wound is initially sealed off by a blood clot containing?