Healing And Repair

Question 1

Define Repair

Answer 1

Involves regeneration and scar formation and therefore the associated fibrosis

Question 2

What are the three parts of the wound healing process

Answer 2

Heamostasis, inflammation and regeneration

Question 3

What are the three different types of tissues

Answer 3

Labile, Stable and Permemant

Question 4

What type of cell division do stem cells display?

Answer 4

Asymmetric division

Question 5

What do growth factors do?

Answer 5

Promote proliferation in the cell population

Question 6

What are two of the factors controlling regeneration?

Answer 6

Contact between basement membrane and adajecent cells

Question 7

How does contact with the basement membrane affect cell regeneration

Answer 7

Loss of contact inhibition between cells encourages the proliferation of different cell types, and there is often signalling throughout he different adhesion moelcules involved

Question 8

what factors determine whether aa tissue wil resolve after injury or not.

Answer 8

Whether the necrosis was of labile, stabile or permenant cell popultions, and whether the collagen framework remains intact

Question 9

What are the key components of fibrous repair?

Answer 9

Angiogenesis, cell migration, extracellular matrix production and remodelling

Question 10

What are the different stages of angiogenesis?

Answer 10

Endothelial proteolysis of the basement membrane, migration of Endotheial cells via chemotaxis, migration of endotehail cells via chemotaxis, endotheial proliferation, endothaiel maturation and tubular remofdeelin and recruitment of periendotheiel cells.

Question 11

What are some disorders of collagen syntehsis?

Answer 11

Vitamin C deficeincy, Ehlers Danos Syndrome, Scurvy

Question 12

What are the 3 overarching stages of the mechanism of fibrous clot repair?

Answer 12

The inflammatory cell infiltrate, the clot replacement by granulation tissue, Maturation of the clot.

Question 13

What is involved in the inflammatory cell infillrate stage of fibrous clot repair?

Answer 13

Blood clot forms, there is the development of chronic inflammation, macrophages and lymphocytes migrate into the clot.

Question 14

What are the details of the granulation tissue stage of fibrous repair?

Answer 14

Angiogenesis, Myofibroblasts migrating and differentiating, extracellular matrix is produced by Myofibroblasts.

Question 15

What are the details of the maturation stage of fibrous clot repair>

Answer 15

Comparitley long lasting, the cell population falls, collagen increases, matures nd remodes, vessels differentiate and are reduced and you are left with a fibrous scar.

Question 16

What are the two mechanisms of repair of skin?

Answer 16

Healing by primary intention and healing by secondary intention.

Question 17

What are the features of a wound which heals by primary intention?

Answer 17

Clean wounds that have opposed edges, icisionol, closed, and non infected wounds

Question 18

What are the features of a wound that heals by secondary intetnion?

Answer 18

Excisional wounds with tissue loss and unopposed edges.

Question 19

What are some stages of the process of wound healing by secondary intention?

Answer 19

Open wound filled with abundant granulation tissue from the edges, considerable wound contraction is needed to close the defect, which is firstly caused by the contraction and shrinkage of the scab, and after a week the Myofibroblasts invade and contract.

Question 20

What are the stages of healing a bone fracture?

Answer 20

Formation of a heamotoma, formation of a firbin mesh and then graunlation tissue, formation of a soft callus, then a hard callus or a bony callus, formation of lamellar bone, remodelling based on Mechinal stresses

Question 21

Name some of the local factors that influence healing and repair?

Answer 21

Size, location and type of wound, blood supply, denervation, locl infection, foreign bodies, heamotoma, mechinal stress, necrotic tissue

Question 22

What re the systemic factors that influence healing and repair?

Answer 22

Anemia, Hpoxyi, hypovalvima, obesity, diabetes, malgiancy, genetic disorders, malnution.

Question 23

What are some of the possible complications of fibrous repair?

Answer 23

Formation of firbos adhesions, loss of function(due to loss of specialised parenchymal tissue), disruption of complex tissue , obstruction to tubes (Contractures)

Question 24

What are the healing features of cardiac tissue?

Answer 24

Limited if any regenerative capcity, therefore a myocardial infraction is often followed by the formation of scar tissue

Question 25

What are the healing features of the liver?

Answer 25

The liver has a remarkable capacity to regenerate, and if the liver is removed compensatory growth occurs, resortaton of the liver lobes by enlargemern, and almost all cells are involved in regeneration.

Question 26

What are the healing features of the periphral nerves?

Answer 26

Proximal stumps sprout and enlarge, and elongate, and the Schwann cells are used to guide the severed nerve back to the tissue.

Question 27

What are the healing features of carlitage?

Answer 27

Does not heal well due to lack of blood supply, lymphtic drainge and innervation.

Question 28

Wht are the healing features of the CNS?

Answer 28

The cells in the CNS cannot be repair, and therefore the cells are often repaired by glial cells.

Question 29

Define regeneration

Answer 29

Replacement of the dead and differentiated cells by functional differentiated cells