A11 - Regeneration of muscle and neural tissue

Question 1

How many days after injury will normally regeneration of muscle tisse start?

Answer 1

4-5 days after injury. The regeneration peaks at 2 weeks and slowly finishes 3-4 weeks after injury.

Question 2

There are two outcomes of muscle regeneration:

Answer 2

1. Complete regeneration
2. Complete necroso

Question 3

What is complete regeneration?

Answer 3

Only possible in striated skeletal muscles, which will regenerate after a segmental necrosis.
The sarcolemma and satellite cells of the myocytes needs to be intact.

Question 4

What is complete necroso?

Answer 4

Happens in smooth and cardiac muscle

Question 5

What happens during a regeneration?

Answer 5

1. The cross striation is lost
2. Within 24-48 hours the macrophages appear to remove the debris (The fragments of a dead/damaged cell or tissue remains)
3. The satelite cells proliferate to form myoblast, which again form myotubes
4. the myotubes form cytoplasmic processes, which contact, fuse and rebuild the muslce
5. The cross striation reappears

Question 6

When will scar formation take place?

Answer 6

Always in case of cardiac and smooth muscles. Sometimes in striated muscles

Question 7

In case of striated muscles, when will scar formation take place?

Answer 7

1. The sarcolemma is destroyed, which happens in case of muscle rupture, contusion and complete necrosis.
2. The connection is no restored
3. The function may stay intact

Question 8

How does regeneration of neural tissue happens?

Answer 8

It refers to the biological process of restoring and repairing damaged nerves in the central and peripheral nervous systems. This complex process involves the removal of debris, production of growth factors, and the guidance of regenerating axons towards their targets

Question 9

Events following an injury of neural tissue:

Answer 9

1. Mylein sheets, neurofibrils and receptors becomes fragmented
2. Debris of Mylein sheets, neurofibrils and receptors is removed by histiocytes and schwann cells
3. Proliferation of schwann cells
4. Myelin sheets is built and then axons are built
5. If the stumps are too far apart, we see an amputation neuroma occurring

Question 10

In which scenarios will there be difficulties with regeneration of neural tisse?

Answer 10

1. The stumps are too far apart
2. Only connective tissue connects the ends
3. If schwann cells are destroyed = No regeneration
4. Schwann cells of the central part still proliferate
5. There are onion bulbs = formations are concentric layers of Schwann cell processes and collagen surrounding axons

Proliferate = Increase rapidly in number, they multiply