4 Healing & repair Flashcards
Whatever the wound, basic ‘plan’ is the same, what is this basic ‘plan’ ? Involving …. Gap, repair it with …. / ….. and the smaller the scar the ….
- close the gap
- repair it with normal tissue
- repair it with a scar
- the smaller the scar the better
5 steps involved in wound healing ?
- haemostasis - blood vessels are bleeding
- inflammation - been tissue injury
- proliferation of injured tissues
- regernation / resolution / restitution and / or repair (organisation) of structures that have been injured or destroyed
- re-modelling: the return, if possible, to original form
Haemostasis happens within (time frame of injury)?
first few minutes of injury
What happens during haemostasis ?
- Platelets adhere to each other and to the injured site.
- They change into an amorphous shape, more suitable for clotting, and they release chemical signals to promote clotting.
- Activation and formation of a fibrin clot binding everything together to stop blood loss
- Vasoconstriction of arterioles and arteries
Inflammation increases local blood flow bringing …. to site of injury
- oxygen
- nutrients
- immune cells
In inflammation what is removed by phagocytosis ?
- damaged and dead cells
- bacteria and debris
Proliferation: growth of new tissue involves what ?
- regeneration of damaged tissues
- granulation tissue formation
- angiogenesis
- myofibroblasts close the gap
- cells die by apoptosis when process complete
Granulation tissue formation means what ?
fibroblasts grow and form/ repair a new, provisional matrix/scaffold
what is angiogenesis ?
new vessel formation
How do myofibroblasts close/decrease the gap ?
gripping the wound edge and contracting
In proliferation what do the original cells in a skin lesion do ? [aleter Q!]
multiply and grow across the wound bed
What is granulation tissue NOT ?
granuloma
What does granulation tissue have ?
granular appearance and texture
granulation tissue consists of ?
- Developing capillaries
- Fibroblasts and myofibroblasts
- Chronic inflammatory cells
Functions of granulation tissue ?
- Fills the gap
- Capillaries supply oxygen, nutrients and cells * Contracts and closes the hole
What is involved in the step regeneration/ resolution/ restitution ?
- proliferation, if possible, of the original cells e.g. epithelial cells
- other cells of tissue/organ to return the tissue/organ to a near normal and funcitonal state
If possible , what happens during re-modelling stage ?
return to original structure
What happens to collagen or bone during re-modelling stage ?
re-aligned along the original structure, for instance in the skin along the “tension lines”
or bone returns to its pre-existing form and strength
How are cells that are no longer needed removed ?
apoptosis
Timescales of healing of haemostasis
seconds - minutes
Timescales of healing of acute inflammation
minutes - hours
Timescales of healing of chronic inflammation
1-2 days
Timescales of healing of granulation tissue forms
3 days
Timescales of healing of early scar
7 - 10 days
Timescales of healing of scar maturation
weeks - 2 years
What may insults be ? give examples
anything that causes tissue damage:
* infection
* burn
* insult due to toxins e.g. paracetamol etc.
Regeneration invovles either …. or … insults
minor or more severe
Minor insult :
Restitution with ..1.. evidence that there was a …2… injury
A ..3.. injury with ..4… edges: Wound healing by ..5.. intention
- no, or minimal,
- previous
- superficial
- closely aligned
- primary
More severe insults involve …. injury , other …., edged ….. ?
wound healing by …. intention ?
- more severe injury
- other insult
- where edges are not closely aligned
- secondary intention
In regeneration of more severe insults:
1. tissue does not ….
2. gap is filled in …
- return to original structure
- by scar formation
Which cells are mainly derived from stem cells ?
new differentiated cells
Whic cells cannot divide ? [change answer]
Once terminally differentiated most terminally differentiated cells can’t divide
Stem cells:
1. activity ?
2. replicaiton shown ?
3. what system to do what ?
- ongoing/prolonged proliferative
- asymmetric replication
- ‘Internal repair system’ to replace lost or damaged cells in tissues
Stem cells vary between which tissues ? found where ?
LIE !!
Liver - between hepatocytes & bile ducts
Intestinal mucosa - bottom of crypts
Epidermis - basal layer adjacent to the basement membrane
Unipotent stem cells:
1. most …. cells
2. only produce ….e.g.
- adult stem
- one type of differentiated cell e.g. epithelia
multipotent
1. produce..
2. e.g.
- several types of differentiated cell
- haematopoietic stem cells
Pluripotent stem cells:
1. …. stem cells
2. can produce….
- embryonic
- any type of cell & therefore any tissues of the body
Totipotent stem cells:
1. what cells ?
2. can produce what ?
- embryonic stem cells & extra-embryonic including placental cells
- any type of cell and therefore any tissue of the body and placenta
- Can all tissues regenerate ?
- what does it depend on if all tissues regenerate ?
- no
- whether tissues are labile, stable, permanent
Tissues of the body are divided into 3 groups on the basis of their proliferative activity , what are these 3 groups ?
- labile
- stable
- permanent
What are labile tissues ?
- continuously dividing tissues
- proliderate throughout life replacing cells that are destroyed
Examples of labile tissues
- surface epithelia
- lining mucousa of secretory ducts of glands of the body
- columnar epithelia of GI tract and uterus
- transitional epithelium of urinary tract
- cells of bone marrow and haemotopoietic tissues