The Embryonic Development of The Skeletal Muscles
Main Ideas and Talking Points
Duchenne Muscular Dystrophy (DMD)
- Muscular dystrophy is the collective name for a group of genetic diseases that cause the progressive break down of muscle in the body. The diseases lead to weakness and subsequent loss of mobility. The heart, diaphragm, and gastrointestinal muscle may also be affected.
Bibliography
Myopathy
- http://www.depts.ttu.edu/meatscience/docs/Myogenesis_1.pdf
- http://embryology.med.unsw.edu.au/embryology/index.php?title=Musculoskeletal_System_-_Muscle_Development
- http://www.anatomyexpert.com/structure_detail/5250/1468/
- http://discovery.lifemapsc.com/in-vivo-development/skeletal-muscle
- http://ps.fass.org/content/86/5/1050.abstract
- Myopathy is a muscular disease in which the muscle fibers do not function for any one of many reasons, resulting in muscular weakness.
- There are several different types of myopathic diseases and each have a different cause
Diseases
- Duchenne Muscular Dystrophy (DMD)
- Myopathy
- Muscular fibrosis
Quiz
Muscular fibrosis
1. What are the four steps in the process of myogenesis?
2. Name one of the two muscle groups and where they are located.
3. Name one of the diseases and their result.
- Muscular fibrosis is the excessive formation of fibrous bands of scar tissue in between muscle fibers.
- The abnormal development of muscular fibrosis may cause muscle weakness, fatigue, and an inability to perform simple daily activities.
Epaxial Muscle
- Developed from the somite myotome
- Located on dorsal (posterior) side of vertebral column
- Small muscle group formed by the transversospinalis, longissimus, and iliocostalis muscles
Muscle Groups
- Epaxial Muscle
- Hypaxial Muscle
Hypaxial Muscle
Myotubes
- Developed from the somite myotome
- Located on the ventral (anterior) side of the vertebral column
- Form in the trunk (body) which consist of three muscle layers
- Also form in the limbs which consist of the extensor and flexor muscle groups
- Play an important role in vocalization, respiration, urinization, and defecation
- Myogenesis
- Muscle Groups
- Diseases
Myoblasts
- They are multinucleated with thousands of nuclei per cell
- Their nuclei are unable to divide (post-mitotic)
- They are also able to synthesize actin and mysin
- They mature into myofibers
- Myoblasts are the first identifiable muscle cells
- They are able to synthesize myofibrillar proteins such as myosin and actin
- They line up and fuse together with other myoblasts to form myotubes
Myogenesis
Myofibers
- The fibers can no longer divide and the formations are complete at birth
- The fiber number is now fixed at birth
- Myogenesis is the formation of muscular tissue, particularly during embryonic development
- It has four different stages: From somites to myoblasts to myotubes to myofibers
Somites
- A somite is a division of the body of an animal.
- They are ball-like clusters of mesodermal cells
- They are also in the majority of the skeletal muscles