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
What are some misconceptions and fun facts about muscular dystrophy?
- There are more than 30 different kinds of MD
- Dystrophin makes up .002% of total proteins in striated muscle
- DMD is the gene that encodes dystrophin, and is the largest known human gene
What is prevention for muscular dystrophy?
- There is no way to prevent MD, and there is also no cure
- Certain drugs and different kinds of therapy delay progression of symptoms and improve the affected person’s quality of life
Define origin
Nonmoving point of attachment when a muscle contracts
Define insertion
- Moves toward the origin
- Majority of tension developed when a muscle contracts is focused here
Define a muscle agonist
Prime mover
Define muscle Synergist
Helps the agonist
Define muscle antagonist
Works against the agonist
Define muscle fixator
Stabilizes the origin of the prime mover, providing efficiency
Move your head in hyperextension, extension, and flexion.
Move your arm hyperextension, extension, and flexion
Move your arm in abduction and adduction
Move your arm in circumduction
Move your forearm in flexion and extension
Move your hand in flexion, extension, and hyperextension
Move your hand in abduction and adduction
Move your digits in abduction and adduction
Move your thigh in hyperextension, extension, and flexion
Move your leg in extension and flexion
Move your thigh in abduction and adduction
Move your thigh in circumduction
Move your head in a rotation
Move your thigh of medial rotation and lateral rotation
Move your arm lateral rotation and medial rotation