Path: Repair Flashcards
(120 cards)
Name the two forms of repair.
Regenerating and scarring
Describe the regenerating form of repair.
Repair with the growth of fully functional tissue to replace injured or dead tissue.
Total pure regeneration of injured tissue is rare. Explain why.
It requires an intact connective tissue scaffold or only superficial injury (epidermal or epithelial layer only).
Explain the process of scarring repair.
It replaces the injured or dead tissue with fibrous tissue lacking the specialized function of the tissue it replaces.
Name the one organ capable of regeneration to replace the function of excised tissue.
Liver. Amazing. The liver is Amazing.
T/F: erosions heal by regeneration.
True.
T/F: ulcers heal by regeneration.
False. Erosions are too deep to heal by regeneration alone and thus, they scar.
Describe……an adhesion!
An abnormal connection between any two things in the body. Like your nose to your elbow. That may be an adhesion secondary to PKU.
Describe the character of an early adhesion.
Early on, adhesions are composed primarily of fibrin and are referred to as fibrinous.
Describe the character of a late adhesion. Ready, GO!
Later, fibroblasts deposit collagen within them and they become fibrinous, requiring a scalpel or scissors or a broad sword to separate.
What is a fistula again?
An abnormal opening between two places in the body. Like your PP fossa to your elbow. Might be secondary to PKU as well.
What differentiates a fistula from an anastamosis?
An anastamosis is a surgically formed fistula. It belongs there. Unlike PKU.
WHO (cell type) IS RESPONSIBLE FOR ALL THIS SCAR TISSUE??
Wretched fibroblasts! Who hired those clowns? Was it you mesenchyme? You’re fired. You have until the afternoon to pack all your things. No, leave the ficus, that belongs to the office.
Who are the key players in repair?
Fibroblasts.
Why is the cytoplasm of fibroblasts so basophilic?
Has lots of RNA.
Let’s say a fibroblast is capable of contracting. Then what is it called? Also, why is this relevant to scars?
Myofibroblast. In the process of healing with scar, myofibroblasts contract and tighten up the evolving scar. As a result, scars are smaller than whatever they replace.
When their job is done, fibroblasts go into reserve mode or retire (with a great pension). What are these fibroblasts called?
fibrocytes. (kind of like osteocytes after osteoblasts are done laying down bone)
Regeneration requires the proliferation and differentiation of _____ cells.
Stem cells.
Describe the process of asymmetric replication and what cells undergo such a fascinating thing.
Stem cells undergo asymmetric replication: in every cell division, one daughter cell retains self-renewing capacity and the other enters a differentiation pathway to a mature cell (it will no longer be a stem cell).
Describe the 3 type of stem cells.
Embryonic: can give rise to any tissue (pluripotent)
Adult: can only give rise to a limited # of tissues
Induced pluripotent: derived from patient cells with embryonic stem cell lines introduced. The hope is to grow a pt’s own cells into replacement tissue/organs for any pt who needs replacement.
Tissues can be categorized as _______, ________ or _________ based on the replicative capacity of their cells.
labile, stable or permanent
Describe the replicative capacity of labile tissues. Give 3 examples of such tissue.
Labile tissues continuously lose and replace cells by proliferation of mature cells and replacement of mature cells by stem cell proliferation.
ex: GI tract, bladder, vagina, cervix, uterus, fallopian tubes, exocrine gland ducts, bone marrow.
Describe the replicative capacity of stable tissues. Give two examples.
Composed of quiescent cells capable of proliferation, but not normally called on to proliferate.
ex: Liver, kidney, pancreas, smooth muscle tissues, blood vessel linings, fibroblasts.
Describe the replicative capacity of permanent cells and give two examples.
Do not proliferate except under extraordinary circumstances.
ex: parenchymal cells of brain and heart
