Muscular Dystrophy

Question 1

Duchenne Muscular Dystrophy

Answer 1

Most common form
Dystrophin gene
- sex-linked disorder affected males almost exclusively (X chromosome defect)
- Absence of dystrophin (localized on the inside of sarcolemma)
- symptoms appear before 6 years old and becomes worse with aging eventually degenerating muscles of diaphragm and heart starting by the age of 20

Question 2

Muscular Dystrophy

Answer 2

Groups of proteins: cytoplasmic, extracellular, and transmembrane that mediate interactions between intracellular cytoskeleton & ECM
Mutant proteins lead to loss in integrity of the muscle cells making one more vulnerable to damage

Question 3

Visualization of Duchenne’s MD

Answer 3

Differing cell sizes
Nuclei are centered
Build-up of connective tissue

Question 4

Visualizing early stages

Answer 4

Myonecrosis: muscle cell death
- deeply pink then macrophages enter and remove debris
Macrophages: engulf dying debris
Inflammation: fibroblasts are activated to secrete ECM - making muscles stiff

Question 5

DMD sarcomeres

Answer 5

Stair-step pattern