Healing And Repair Flashcards
What r the 3 process of wound healing?
* Haemostasis – as vessels are open • Inflammation – as there has been tissue injury • Regeneration (also called resolution) and repair – as structures have been injured or destroyed.
Define regeneration?
-regeneration can occur as long as____cells r intact.
growth of cells and tissues to replace lost structures.
-regeneration can occur as long as the STEM CELLS R NOT DESTROYED!.
***it requires a connective tissue scaffold.
What is the difference between an abrasion and an ulcer? ana ulcer/abrasion goes all the way below the _____layer of skin
Ulceration is a severe form of an abrasion, its more deeper, and is difficult to see in skin, and injury that goes below muscularis muscosa
they r cells with long proliferative activity and show asymmetric replication
name it, and explain what is meant by asymmetric replication
STEM CELLS
in aysmetric replication> one daughter cell remains a stem cell, while the other differentiated into a mature nondiving cell
Where abouts in the tissues are the stem cells? (3)
intestinal mucosa> bottom of crypts
liver> btw hepatocytes and bile ducts
epidermis> basal layer next to to the BM
regeneration can tay place bs feeha shar6, name it
1) tissue damage should not be very EXTENSIVE> cuz u loose ur connective tissue SCAFFOLD and u need that for regeneraton to take place!
What is fibrous repair (organisation) and when does it occur?
Healing with formation of fibrous connective tissue = scar
* when a PERMANENT tissue is damaged> fibrous connective tissue will form in that area making SCAR.
describe the processes of Fibrous repair and name the cells involved!
- Phagocytosis of necrotic tissue debris by inflammatory cells
- Proliferation of endothelial cells which results in small capillaries that grow into the area (angiogenesis)
- Proliferation of fibroblasts and myofibroblasts >synthesise collagen, cause wound contraction (the repair tissue at this stage is called GRAN-ULTION TISSUE)
The granulation tissue becomes less vascular and matures into a fibrous scar
The scar matures and shrinks due to contraction of fibrils within myofibroblasts.
describe this image, what type of tissue is this? what does it consist of? why is it so very red? what is its function?
GRAN-ULATION tissue
- granular appearence & texture
- very red> bc it contains many developing capillaries, these r very delicate> easy to bleed
Consists of:
- Developing capillaries
- Fibroblasts and myofibroblasts
• Chronic inflammatory cells
Function
-fills gap> capillaries supply oxygen and nutrients and cells>contracts and closes hole.
Which cells are involved in fibrous repair?
-inflammatory cells -endothelial cells -fibroblasts and myofibroblasts
What is collagen? function? which type is most commonly found?
- most abudant protein in animals, type 1 is most common
- Provides extracellular framework for all multicellular organisms,
(i. e., responsible for holding body together, including the skeleton)
Type ______ collagen makes up basement membranes
4
four=floor
lol.
What (4) diseases are the result of defective collagen synthesis? which ones r inherited? aquired?
Aquired
-scurvy
Inherited
- ehlers-danlos syndrome
- osteogeniss imperfcta
- Alborts syndrome
Name disease caused by VC deficiency! name symptoms
SCURVYY
vitamen C deficiency > procollagen can’t do hydroxylation in ER > reduced cross- linking and defective helix formation > ppl unable to heal wounds 3adl>tendacy to BLEED
- bleeding gums
- loss of tooth
ppl had black bones when they died> bc there was a lot of bleeding in ur bones!
How are regeneration and repair triggered and controlled?
Cells communicate with each other to produce a proliferative response
Cell to cell signalling can be via:
- Hormones
- Local mediators (e.g. GF)
- Direct cell-cell or cell-stroma contact
Controlled?
via integrins and cadherin, if theyre not their, cells will divide.
Amongst local mediators, ______r the most important in regeneration and repair.
Growth Factors
considered as “local hormones” they act over a short distance.
Polypeptides that act on cell surface receptors
They kick start the cell cycle.
-they r coded by proto-oncogenes
Apart from cell proliferation, what other effects can growth factors have?
• Inhibition of division
- Locomotion
- Contractility
- Differentiation
- Viability
- Activation
- Angiogenesis
Types of growth factors and what produces them
- EGF
- VGEF
- PDGF
- TNF
Produced by cells such as platelets, macrophages, endothelial cells.
what is contact inhibition? how r malignant cells different in contact inhibition? what r the adhesion molecules found on cells?
most cells in the body dont like to be on their own, they’ll keep proliferating until they TOUCH other cells then they stop!>>this is called CONTACT INHIBTION
-they do they same but they just DONT FUCKING STOP.
- Cadherins bind cells to each other
- Integrins bind cells to the ECM
why do surgeons use sutures that dont have much of a surface area on them?
so bacteria wont grow there. since bacteria r attracted to foreign stuff.
What is healing by primary intention? when do we see it?
What is healing by secondary intention? whe do we see it?
NEAT inscisional,closed, non-infected wound> typical surgical wound
Excisional wound WITH tissue loss!, infected> ulcers, infarct, abcess
theres more to it alaa bs maly khlg aktb.
when performing a split skin graft, how does the donor site heal without making a scar?
when u do a split skin graft, u take off a peice of skin and then u put it in this machine) like speghetti machine, it’ll pierce holes in that skin peice (looks like net) >> then they put that on the area of burn>> it grows back quickly without making a SCAR bc u r splitting it a very SUPERFICIAL level, and we left the structures behind (hair, glands whatevs)
How does bone heal?
A fracture results in a:
haematoma>>>fills gap, surrounds the bone injury.
A fibrin mesh and then granulation tissue>>Platelets and inflammatory cells release cytokines>> activate osteoprogenitor cells to osteoclastic and osteoblastic activity.
Soft callus (also called procallus or fibrocartilagenous callus) >> consists of fibrous tissue and cartilage within which woven bone begins to form.
Hard callus (or bony callus) >>laid down by osteoblasts. The bone formed initially is woven bone. It is weaker as it is less organised than lamellar bone but it can form quickly.
Formation of lamellar bone which is more organised and stronger than woven bone.
Remodelling of the bone occurs in response to mechanical stresses placed on it. Bone not physically stressed is resorbed and the outline of the bone is re-established.
name tissues of the body r divided into 3 groups depending on their proliferative activity and examples:
Labile tissues: continuously dividing, proliferate in life replacing destroyed cells (ex:secretory glands of body, lining of GI and urinary, bone marrow cells.
Stable tissues (quiescent): cells that multiply ONLY when needed. They spend most of the time in the quiescent G0 phase of the cell cycle.
ex: kideny, liver, bone, pancreas (horse in stables. itha ba3’ainahum, 6ala3nahum)
permanent tissues (non dividing) : can’t undergo mitosis & only a few or no stem cells r present. heal with a SCAR.
Ex: neurons, cardiac muscle, skeletal muscle
REVIEW COLLAGEN ALAAA
OK OK
ok
it what cases does fibrous repair occur? regeneration?
why is this scar white? and why do scars stretch as they get older?
cuz sometimes u dont get regeneration of MELANOCYTES.
bc fibroblast and myofibroblasts cant lay down elastin!
why does this dude have no hair on the area of his scar?
bc Sweat glands and hair follicules can’t regenerate!
Name different types of collagen and explain where each one is seen?
what r 3 types of cell signaling?
PEA
paracrine
endocrine
autocrine
describe this image?
Which people are especially at risk for developing this complication?
Keloid scar
overgrowth of fibrous tissue due to overproduction of collagen 3. that exceeds the borders of the scars.
-African Caribbean
What is a pressure sore and why do they occur?
Which patients are most at risk?
How can they be prevented and treated?
occur when someone is admitted to hospital
Prevention is the best approach:
- Changing the patient’s position as much as possible.
- Pillows, regular turning, fleece under the heels, special mattresses and beds.
Treat the patient’s general condition.
Pain relief.
Dressings - particularly gel and foam-based dressings.
Antibiotics - may be needed if there are any signs of infection.
Surgery - sometimes needed to remove damaged or dead skin (debridement). Plastic surgery may be used to close a pressure ulcer that is not healing and skin grafts may be needed.
Describe the extracellular steps of collagen synthesis
