Muscle System Flashcards
Muscular Dystrophy
Inherited disorders, muscle enlarge due to increased fat and connective tissue, but fibers generate and atrophy over time
Duchenne MD
Most common; proteins to maintain sarcolemma not present so sarcolemma breaks down
Myasthenia Gravis
Problem with acetylcholine receptors because there aren’t enough or they don’t work
Treatment for MD
No treatment to stop/reverse; therapy, orthopedic appliances for support, medication, and corrective orthopedic surgery to slow it down
Sarcolemma
Specialized plasma membrane involved in muscle contraction
Sacromere
Contractile unit of muscle fiber
Myosin
Think muscle fiber in sacromere
Actin
Thin muscle fiber in sacromere
Flexibility
Bending something; decreasing angle of joint to bring two bones together
Extension
Increasing angle of joint
Abduction
Moving it away from midline
Addiction
Bringing it toward midline
Skeletal Muscle
Attached to bone by tendon; multinucleated; striated; voluntary; surrounded and bundled by connective tissue; tires quickly; generates great force
Smooth Muscles
No striations; spindle-shaped cells; single nucleus; mainly in walls of hollow organs; slow, sustained, tireless; involuntary
Cardiac muscles
Stirations; single nucleus; cells joined at intercalated discs; involuntary; only in heart; steady pace
7 Steps of Neuromuscular Contraction
1) signal from brain travels length of axon/nerve
2) calcium channels open and calcium diffuses into terminal end of axon
3) acetylcholine is released
4) acetylcholine binds to receptors on muscle (sarcolemma)
5) cation ion channels open
6) Na ions in, K ions out of muscle fibers
7) once action potential is reached, muscle contracts
Action potential
When the ratio of Na entering and K editing is great enough to cause muscle contraction
Frontalis
Raises eyebrows; wrinkles forehead
Obiclaris Occuli
Closes eyes; squinting
Obiculais Oris
Purses and puckers lips
Trapezius
Laterally rotates, elevates, and retracts scapula; extends and laterally rotates neck
Sternocleidomastoid
Flexes and laterally rotates cervical spine; protracts head; extends neck
Deltoid
Abducts arm; ant fibers- flex and medically rotate; post fibers-extend and laterally rotate
Pectoralis Major
Clavicular head- flexes and adducts arm; sternal head- afduxts and
Frontalis
Raises eyebrows; wrinkles forehead
Obiclaris Occuli
Closes eyes; squinting
Obiculais Oris
Purses and puckers lips
Trapezius
Laterally rotates, elevates, and retracts scapula; extends and laterally rotates neck
Sternocleidomastoid
Flexes and laterally rotates cervical spine; protracts head; extends neck
Deltoid
Abducts arm; ant fibers- flex and medically rotate; post fibers-extend and laterally rotate
Pectoralis Major
Clavicular head- flexes and adducts arm; sternal head- afduxts and
