Repair - Nichols Flashcards
What is the difference between regeneration and scarring?
Regeneration is repair with the growth of fully functional tissue to replace injured or dead tissue. It is rare. It requires an intact connective tissue scaffold or only superficial injury.
Scarring replaces dead tissue with fibrous tissue lacking the specialized function of the tissue it replaces.
What is an ulcer?
an excavation in the surface of an organ or tissue produced by sloughing of inflamed necrotic tissue. It is deeper than an erosion, which is superficial sloughing of mucosa.
What is the difference in the healing process of ulcers and erosions.
Erosions aren’t as deep as ulcers and heal by regeneration.
Ulcers are deeper and heal by scarring.
What is an adhesion?
an abnormal connection between any two things int he body.
What are adhesions predominantly composed of early on? Later?
fibrin. Later fibroblasts add collagen.
What is a fistula?
abnormal opening between two places in the body
What type of replication do stem cells undergo?
asymmetric replication: in every division, one daughter cell retains self-renewing capacity and the other enters a differentiation pathway to a mature cell.
What is special about embryonic stem cells?
they are pluripotent and can give rise to any tissue. Adult stem cells can only give rise to a limited number of tissues.
What are induced pluripotent stem cells?
Embryonic stem cells with a patients genetic material introduced via laboratory.
What are labile tissues?
tissues that continuously lose cells and replace them by proliferations of mature cells and replacement of mature cells by stem cell proliferation. Ex: linings of mouth, gastrointestinal tract, bladder, vagina, cervix, uterus, fallopian tubes, exocrine gland ducts, and bone marrow.
What are stable tissues?
Tissues composed of quiescent cells capable of proliferation, but not normally called onto proliferate. Ex: kidney, liver, pancreas, smooth muscle tissues, brain, and heart.
Which type of tissue would you expect to be vulnerable to radiation injury: labile, stable, or permanent?
Labile, because they are constantly reproducing.
What is epidermal growth factor (EGF)?
growth factor that promotes fibroblast migration and proliferation.
What does FGF do?
fibroblast growth factor stimulates fibroblast migration and proliferation, as well as monocyte chemotaxis and angiogenesis.
What does PDGF do?
platelet-derived growth factor promotes fibroblast migration and proliferation along with monocyte chemotaxis and collagen making. It is most prevalent early in the process when blood vessel disruption allows platelet contact with extracellular matrix.
What does TGF-beta do?
transforming growth factor stimulates fibroblast migration, monocyte chemotaxis and collagen making. It is more prevalent later in the course of repair.
Which growth factors is monocyte chemotaxis mediated by?
PDGF, FGF, and TGF-beta
Which growth factors is fibroblast migration promoted by?
PDGF, EGF, FGF, and TGF-beta
Which growth factors is fibroblast proliferation mediated by?
PDGF, EGF, FGF, TGF-beta
Which growth factors is angiogenesis mediated by?
FGF and VEGF
Which growth factors is collagen synthesis stimulated by?
PDGF and TGF-beta
What are basement membranes composed of?
type IV colagen, laminin, heparan sulfate and proteoglycans.
What does the interstitium underneath epithelium contain?
fibrillar collagen, fibrillin, elastin, hyaluronic acid and proteoglycans.
What are all types of collagen composed of?
3 polypeptide chains braided into a ropelike triple helix
What are fibrillar collagens strengthened by?
lateral cross-linking
What is Ehlers-Danlos syndrome?
disease from defective collagen (type V for weak joints, poor wound healing and hyperflexibility) (type III for vascular problems)
What is fibrillin? What is it secreted by?
glycoprotein secreted by fibroblasts.
What syndrome does a defect in fibrillin cause? Describe it.
Marfan’s syndrome: thin, elongated body habitus, abnormally long fingers, arms and legs. weak aorta, prone to dilation and rupture.
What type of inheritance do genetic defects in structural proteins tend to have? Defects in enzymes?
autosomal dominant for structures
Autosomal recessive for enzymes (there are still functional ones around)
What is granulation tissue?
healing tissue with residula chronic inflammatory cells (lymphocytes and macrophages), cellular debris, fibroblasts, neovascularization and new collagen. It is commonly red or pink, soft and granular.
What is organization as it refers to pathology?
process of replacing injured, necrotic and inflamed tissue by healing and scar tissue.
What is angiogenesis? What is it mediated by?
AKA neovascularizaiton. Is the formation of new blood vessels in healing tissue.
Mediated by VEGF
What induces production of VEGF?
TGF, PDGF and hypoxia.
how soon after injury does angiogenesis occur?
5 days.
What are the three phases of wound healing?
inflammation, proliferation, and maturation.
Which growth factors promote angiogenesis?
VEGF, which is promoted by TGF, PDGF, and hypoxia
What is the primary reason diabetes mellitus delays wound healing?
diabetes mellitus is usually associated with small blood vessel disease, reducing blood flow. There is also excess sugar in wounds, which provides food for infecting organisms.
