Lab 6 Terms and Lesson Flashcards
What is the muscle formed of?
Formed by groups of fasciles
What is the epimysium?
Dense irregular connective tissue (tissue that resists tensions from all directions) surrounds muscles.
What is a facicle?
A bundle of individual muscle fibers
What is perimysium?
Dense irregular connective tissue surrpunds fascicles.
What is a muscle fiber (aka muscle cell/myocyte)
An elongated, contractile cell that is a bundle of myofibrils
What is the endomysium?
Layer of connective tissue surrounding individual muscle fibers
What are tendons formed by?
Formed from endomysium, perimysium, and epimysium that extend beyond each muscle fiber that attach the muscle to bone.
What is the structure of the muscle?

Name all parts of a sarcomere on a myofibril

- Z disk
- M line
- Thick filament
- Thin filament
- I band
- A band
- H zone
- Zone of overlap

What is the zoomed in sarcomere on a microfibril look like?

What do the following look like?
- Zone of overlap
- H zone
- Z disc
- M line
- A band
- Halves (2) of I bands


What do the following look like?
- Myosin heads
- Troponin
- Actin
- Tropomyosin


What is muscular dystrophy?
Muscular dystrophy (MD) is classified as a group of inherited diseases in which voluntary muscles weaken over time.

What are four different types of muscular dystrophy? And what two are associated with heart problems?
- Duchenne
- Becker
- Duchenne and Becker are associated with heart problems
- Myotonic (Steinart’s Disease)
- Congenital

What is Duchenne Muscular Dystrophy?
Most common in children, many young boys need a wheelchair by age 12, life expectancy = late teens, early 20s
What is Becker Muscular Dystrophy?
Similar to Duchenne but less severe. Symptoms can be later (as late as 25), can usually walk until 30’s live longer.
What is Myotonic (Steinart’s Disease) Muscular Dystrophy?
Most common in adults, affects CNS, heart, GI tract, eyes, hormone-producing glands.
- Causes myotonia - inability to relax muscles after they contract
What is Congenital Muscular Dystrophy?
Occurs around birth, muscles shrink and cause joint problems, some can die in infancy
What are causes of muscular dystrophy?
- Caused by mutations on X chromosome
- Women have a 50% chance of passing it to their sons
- Caused by absense of dystrophin, which is vital for proper muscle function
What are risk factors of muscular dystrophy?
- Depends on the type…
- Duchenne: young boys
- 3 Risk factors that led to early death for those with Duchenne
- Being underweight (measured from BMI)
- Poor lung function
- High blood concentration of a protein linked to cardia damage
- Family history of muscular dystrophy
What are some symptoms of muscular dystrophy?
- All sorts, very depending on type
- Trouble walking
- Difficulty standing up
- Loss of reflexes
- Scoliosis
- Heart and lung problems
- Issues with swallowing
What are some diagnoses of muscular dystrophy?
- DNA Testing
- Muscle biopsy
- To show if dystrophin is absent or abnormal
- Electromyography or nerve conduction tests
- Blood enzyme tests
- Look for creatine kinase, which deteriorates muscle fibers
What are some treatments for muscular dystrophy?
- Corticosteroids (for short term only)
- Heart medications (i.e. ACE inhibitors)
- Physical therapy (walking and swimming)
- Ventilator for breathing assistance
- Canes/wheelchairs/walkers
- Pacemaker for cardiac abnormalities
What are some complications of muscular dystrophy?
- Contractures: Shortening of tendons, ligaments, and muscles around joints
- This can lead to immobility
- Severe breathing problems
- Heart problems
- Can lead to death





































































