Repair Flashcards
What is an abnormal connection between any 2 things in the body? Where is it inevitable?
Adhesion
side-effect of surgery
What is a common complication of adhesions requiring surgery?
intestinal obstruction
What is the process of replacing damaged tissue. Is it healing?
Repair
Repair is healing
What the are two forms of repair?
regeneration and scarring
What is repair with the growth of fully functional tissue to replace injured or dead tissue?
regeneration
T/F Total pure regeneration is rare.
true
What does regeneration require?
an intact connective tissue scaffold or only superficial injury (epidermal or epithelial layer only)
Healing with scarring replaces the injured or dead tissue with what? What is the function thereafter?
fibrous tissue lacking the specialized function of the tissue it replaces
Removal of one kidney causes compensatory hyperplasia and hypertrophy of the remaining kidney, which doubles in size
T/F this is regeneration
false, this is not regeneration
Removal of one lobe of the liver causes compensatory hyperplasia and hypertrophy of the remaining lobe, which generates the same volume of fully functional liver tissue as pre-removal
T/F this is regeneration
true
What is an excavation (a local defect) in the surface of an organ or tissue produced by sloughing (shedding) of inflamed necrotic tissue?
an ulcer
What is erosion?
superficial sloughing of mucosa (or epidermis)
T/F An ulcer is deeper than than an erosion
true
Why is it for physicians to know the difference bw erosion and ulcers?
Erosions heal by regeneration.
Ulcers are too deep to heal by regeneration and they scar.
Organs within the abdominal cavity are normally separated by what?
the peritoneal space
Lungs are normally separated from the chest wall by what?
the pleural space
heart is normally surrounded by what? Is it connected to it?
the parietal pericardium
not connected
Inflammatory material can create what between the surroundings of the organs if the spaces are compromised? If early, what are they composed of? later?
adhesions => abnormal connections between these things
early => adhesions are composed primarily of fibrin and are referred to as fibrinous
late => fibroblasts deposit collagen within them and they become fibrous
What is an abnormal opening between two places in the body?
fistula
What is a surgical connection between two things, commonly tubular structures?
anastomosis
A surgical anastomosis between tubular structures is usually not called a fistula except for the anastomosis between what?
anastomosis between an artery and vein in the arm created for the purpose of hemodialysis
Where do adhesions commonly occur?
between loops of bowel, bowel and peritoneum, fallopian tube and ovary, and lung and pleura
What type of adhesions are an inevitable side-effect of surgery?
fibrous adhesions
What is a common complication of fibrous adhesions tethering and kinking the bowel, with resultant loss of the lumen?
How is this treated?
intestinal obstruction
Regeneration requires what?
of stem cells
What has self-renewal capacity not present in mature cells?
stem cells
What type of replication do stem cells undergo? describe it
asymmetric replication:
in every cell division, one daughter cell retains self-renewing capacity and the other enters a differentiation pathway to a mature cell.
Describe the different types of stem cells
- Embryonic stem cells can give rise to any tissue (are pluripotent)
- Adult stem cells can only give rise to a limited number of tissues
- Induced pluripotent stem cells are derived from patient cells with embryonic stem cell genes introduced
Tissues can be categorized as labile, stable or permanent based on what?
the replicative capacity of their cells
Describe labile tissues
give examples of labile tissues
continuously lose cells and replace them by proliferation of mature cells and replacement of mature cells by stem cell proliferation
skin and the linings of the mouth, gastrointestinal tract, bladder, vagina, cervix, uterus, fallopian tubes and exocrine gland ducts, as well as the bone marrow, are all labile tissues
Describe stable tissues
give examples
composed of quiescent cells capable of proliferation, but not normally called on to proliferate
liver, kidney, pancreas, smooth muscle tissues, blood vessel linings and fibroblasts are stable cells and tissues
Describe permanent cells
give examples
do not proliferate except under extraordinary circumstances
parenchymal cells of the brain and heart (neurons and cardiac myocytes)
Continuously proliferating labile tissues are particularly vulnerable to what?
radiation injury
Radiation to skin causes what signs?
- erythema (redness),
- pruritis (itching)
- later desquamation (sloughing),
- and if hair-bearing, loss of hair
Radiation to the chest and abdomen causes what?
nausea, vomiting and diarrhea from the injury to the gastrointestinal tract.
Radiation to the bone marrow causes what?
leukopenia
What allows very high doses of radiation to be delivered to small areas in the treatment of malignant tumors, decreasing injury to surrounding tissue, but requiring computer-controlled multileaf collimators to precisely focus the radiation beam?
linear accelerators
Healing requires certain actions from a variety of cells. Name them
- monocyte migration to the site,
- fibroblast migration to the site,
- fibroblast proliferation,
- angiogenesis
- fibroblast collagen production
What orchestrates how tissues heal? Name them
- epidermal growth factor (EGF),
- fibroblast growth factor (FGF),
- platelet-derived growth factor (PDGF),
- transforming growth factor (TGF)
- vascular endothelial growth factor (VEGF)
What promotes fibroblast migration and proliferation?
EGF
What stimulates fibroblast migration and proliferation, as well as monocyte chemotaxis and angiogenesis?
FGF
What promotes fibroblast migration and proliferation along with monocyte chemotaxis and collagen making?
PDGF
What is the primary difference between PDGF and FGF?
PDGF is most prevalent early in the process when blood vessel disruption allows platelet contact with extracellular matrix
What stimulates fibroblast migration, monocyte chemotaxis and collagen making?
When is it most prevalent?
TGF-beta
more prevalent later in the course of repair
Monocyte chemotaxis is mediated by what?
- PDGF,
- FGF
- TGF-beta,
- other molecules
Fibroblast migration is promoted by what?
- PDGF,
- EGF,
- FGF
- TGF-beta
(EGF apparently being more repair-minded than inflammatory)
Fibroblast proliferation is mediated by what?
- PDGF,
- EGF,
- FGF,
- TGF-beta
Angiogenesis is promoted by what?
- FGF
- VEGF
Collagen synthesis is stimulated by what?
PDGF
TGF-beta
What prevents deficiency of any one growth factor from being rate-limiting?
Most growth factors have multiple roles and most roles can be played by multiple growth factors, so there is extensive redundancy,
Repair requires the production
extracellular matrix
What does the ECM consist?
basement membrane (underneath epithelium and around blood vessels) and interstitium, which is the supporting tissue between epithelium and vessels and between cells in connective tissue such as bone and cartilage