Musculoskeletal injury and repair

Question 1

Function of ECM

Answer 1

embeds muscle capillaries, allows blood supply and neuronal connections

Question 2

Muscle fascicle

Answer 2

bundles of muscle cells, surrounded by perimysium (ECM) allowing space for other cells.

Question 3

Muscle satellite cells

Answer 3

type of stem cell derived from mesenchymal stem cells that create new muscle myoblasts, myofibrils and full muscle fibres

Question 4

Muscle stem cells

Answer 4

1. go through proliferation
   2.self renewal- produce new muscle stem cells which are produced when there are injuries or further injuries

Question 5

Myofibril

Answer 5

long fibres of repetitive units of sarcomere

Question 6

1st phase after muscle injury :necrosis

Answer 6

necrosis-dying of muscle fibrils +formation of haematoma

Question 7

2nd phase after muscle injury:phagocytosis

Answer 7

phagocytosis-eating of dead cells and gets rid of damage

Question 8

3rd phase after muscle injury :activation and differentiation

Answer 8

activation and differentiation:muscle satellites into myoblast and fusion in myofibrils then form muscle

Question 9

how muscle cells get activated:neutrophil

Answer 9

neutrophil:immune cells get activated when they see damaged cells

Question 10

how muscle cells get activated:macrophage

Answer 10

sense damage of muscle fibres and production of DAMPS

Question 11

DAMPS

Answer 11

communications to and stimulates muscle satellite cells

Question 12

Erythrocyte

Answer 12

red blood cells -produces oxygen to tissue

Question 13

White blood cell

Answer 13

wait to be recruited into damaged cell if stimulated to do so

Question 14

cytokines

Answer 14

small soluble molecules which go back into capillary then immune cells will flood into damaged tissue to help phagocytosis

Question 15

1st wave after injury

Answer 15

infiltration:inflammatory cells and stimulation of M1 macrophages, responsible for latter stages, stimulation of new muscle stem cells to differentiate into new muscle

Question 16

2nd wave after injury

Answer 16

M2 macrophages -responsible for differentiation -of myoblast into myocyte +stimulates other cells e.g parasite which regenerate capillaries and fibre

Question 17

after few days of injury

Answer 17

m1 resident macrophage starts muscle satellite cells to create myoblasts+trigger myoblast proliferation

Question 18

After 2-4 days after injury

Answer 18

polarisation from M1 to M2 macrophages stimulates process of angiogenesis

Question 19

Adipose genic fibroblasts

Answer 19

generates ECM in mature muscle

Question 20

Transient collagen deposistion

Answer 20

provides framework for all various muscle and immune cells to function during inflammation, repair and remodelling process

Question 21

fibrosis

Answer 21

ECM should be removed and replaced with proper ECM around health muscle

Question 22

What happens in bone fracture?

Answer 22

-haemotoma is formed:rbc+wbc flood into break site

Question 23

Day 3-5 after fracture

Answer 23

mesenchymal stem cells enter site and differentiate into osteoporosis progenitor cells

Question 24

5-10 days after fracture

Answer 24

chondrocytes +osteoblasts start to secrete ECM -provides fibre cartilage

Question 25

osteo projenitor cell

Answer 25

type of cell that produce both bone+cartilage, then differentiate into chondrocytes which make cartilage and osteoblasts

Question 26

Fibro cartilage

Answer 26

mineralised cartilage -allows cells to work within that environment +ensures bone is made in the right place -also formation of new capillaries

Question 27

Haematopoietic stem cells

Answer 27

dissolving ECM of bone

Question 28

Tendinopathy tendons

Answer 28

restoration of structure of the tendon has not gone away-structure is less resistant to for force resistance than normal tendon

Question 29

fibronectins

Answer 29

disulphide linked dimers, with each polypeptide composed of a number of binding domains joined together by short flexible segments