Repair and Regeneration

Question 1

What are the 2 forms of healing?

Answer 1

Regeneration and repair

Question 2

What is healing by regeneration?

Answer 2

Cells replaced by like cells and tissue regains function

Question 3

What is healing by repair?

Answer 3

Cells cannot be replaced by like cells and so fibrosis and scarring occur. There is a loss of specialised function.

Question 4

What are the characteristics of labile cell populations?

Answer 4

High turnover
Active stem cell population
Excellent regenerative capacity

Question 5

Name a location where labile cell populations are found

Answer 5

Epithelia

Question 6

What are the characteristics of quiescent cell populations?

Answer 6

Low turnover
Good regenerative capacity
Turnover can massively increase if required

Question 7

Name two locations where quiescent cell populations are found

Answer 7

Liver

Renal tubules

Question 8

What are the characteristics of permanent cell populations?

Answer 8

Zero turnover
Zero regenerative capacity
Long life span

Question 9

Which condition observes a collapse of reticular framework in the liver?

Answer 9

Cirrhosis

Question 10

What are the characteristics of stem cells

Answer 10

A prolonged self renewal
An asymmetric replication
Crucial to regeneration

Question 11

When does repair occur?

Answer 11

When the normal structure cannot be replaced

Question 12

What are the consequences of healing by repair?

Answer 12

Functional

Question 13

What are the characteristics of healing by repair?

Answer 13

Basic stereotyped pathological process
Repair of specialised tissue by formation of fibrous scar
Granulation tissue in abundance

Question 14

What are the three components of granulation tissues?

Answer 14

New capillary loops
Phagocytic cells (Neutrophils and macrophages)
Myofibroblasts

Question 15

What are the steps of new vessel formation?

Answer 15

Endothelial cell proliferation
Buds
Canalisation
New vessels

Question 16

What is the function of phagocytes in granulation tissue?

Answer 16

Remove dead/damaged tissue

Question 17

What is the function of myofibriblasts in granulation tissue?

Answer 17

Synthesis collagen and ECM

Question 18

What 3 categories can oesophageal peptic ulcers be grouped into?

Answer 18

Intrinsic diseases

Extrinsic diseases

Functional

Question 19

What is the pathophysiology of intrinsic forms of oesophageal peptic ulcers?

Answer 19

Narrow the lumen through inflammation, fibrosis or neoplasia

Question 20

What is the pathophysiology of extrinsic forms of oesophageal peptic ulcers?

Answer 20

Compromise the lumen by direct invasion or lymph node enlargement

Question 21

What is the pathophysiology of functional forms of oesophageal peptic ulcers?

Answer 21

Disrupt oesophageal peristalsis

Lower oesophageal sphincter function

Both via affects on smooth muscle and it’s innervation

Question 22

What are some causes of oesophageal peptic ulcers?

Answer 22

Acid
Infectious
Congenital
Drug induced
Autoimmune
Iatrogenic
Radiation

Question 23

As vascularity and cellularity of granulation tissue decrease, what increases?

Answer 23

Collagen
ECM
Wound strength

Question 24

What are some local factors inhibiting healing?

Answer 24

Infection
Haematoma
Foreign bodies
Mechanical stress
Blood supply

Question 25

What are some systemic factors inhibiting healing?

Answer 25

``` Age Drugs Anaemia Diabetes Malnutrition Catabolic states Vitamin C deficiency Trace metal deficiency ```

Question 26

What are the predisposing factors to healing by first intention?

Answer 26

Clean, uninfected surgical wound Good homeostasis Edges opposed with sutures or staples

Question 27

What are the predisposing factors to healing by second intention?

Answer 27

Wound edges unopposed | Greater extensive scarring

Question 28

What are the steps to fracture healing?

Answer 28

Removal of necrotic fragments Osteoblasts lay down woven bone Remodelling according to mechanical stress Replacement by lamellar bone

Question 29

What causes non-union of fractures?

Answer 29

``` Misalignment Infection Movement Pre-existing bone pathology Interposed soft tissue ```

Question 30

What is different about healing in the brain compared to healing in other tissues?

Answer 30

Supporting tissue is giant cells rather than collagen and fibroblasts, hence damaged tissue is removed often leaving a cyst Gliosis rather than scarring

Question 31

Generally, is EGF secreted from and what is its function?

Answer 31

Secreted from: macrophages and platelets Function: Stimulates granulation tissue formation

Question 32

Generally, where is TGF secret from and what is its function?

Answer 32

Secreted from: Macrophages and platelets Function: Chemotactic agent and inhibits production of MMPs

Question 33

Generally, where is platelet derived growth factor secreted from and what is its function?

Answer 33

Macrophages and platelets Chemotactic agent and stimulates angiogenesis

Question 34

Where is TNF secreted from and what is its function?

Answer 34

Macrophages, mast cells and T Lymphocytes Activates macrophages and regulates other cytokines