Wound Healing Flashcards
What is the basic plan for the healing of every wound?
1) Close the gap
2) Repair it with a scar
(The smaller the scar the better)
What are the processes involved in wound healing?
1) Haemostasis - as vessels are open
2) Inflammation - as there has been tissue injury
3) Regeneration and repair - as structures have been injured or destroyed
What is regeneration?
Restitution with no, or minimal, evidence that there was a previous injury
What is the difference between an abrasion and an ulcer?
Abrasion - superficial damage to the skin, no deeper than the epidermis
Ulcer - goes far deeper, into the submucosa
What are stem cells?
Cells with prolonged proliferative activity
What is meant by asymmetric replication of stem cells?
When they divide, one of the cells remains a stem cell while others mature into a cell of some type
Where are stem cells in the epidermis?
Basal layer adjacent to basement membrane
Where are stem cells in the intestinal mucosa?
Bottom of crypts
Where are stem cells in the liver?
Between hepatocytes and bile ducts
What are unipotent cells?
Most adult stem cells - only produce one type of differentiated cell
What are multipotent cells?
Cells that can produce several types of differentiated cell eg haematopoietic stem cells
What are totipotent cells?
Cells that can produce any type of cell and therefore any tissues of the body
(Embryonic stem cells)
What are labile tissues?
Contain short-lived cells that are replaced from cells derived from stem cells
What are stable tissues?
Contain cells with a low level of replication but if necessary can undergo rapid proliferation, both stem cells and mature cells proliferate
What are permanent tissues?
Contain mature cells that can’t undergo mitoses and no or only a few stem cells
What are some examples of labile tissues?
Surface epithelia, haematopoietic tissues
What are some examples of stable tissues?
Liver parenchyma, bone, fibrous tissue, endothelium
What are some examples of permanent tissues?
Neural tissue, skeletal muscle, cardiac muscle
What is a scar?
Healing with formation of fibrous connective tissue
What determines whether an injury will lead to regeneration or fibrous repair?
Whether or not the collagen framework is still intact and whether there is on-going chronic inflammation