Skeletal muscle
What is acetylcholine and what is its purpose?
Acetylcholine is a neurotransmitter that helps nerves communicate with muscles. Function is to open ligand gated sodium channels so that sodium can flood in and depolarize the muscle, eventually allowing it to contract.
Per unit of force, which muscle is the strongest in the human body?
masseter
What is the action of the middle deltoid?
shoulder abduction
12-18 months
Name the 4 rotator cuff muscles.
supraspinatus, infraspinatus, teres minor, subscapualris
Contrast depolarization and repolarization.
Depolarization: charge in the cell gets more positive.
Repolarization: charge in the cell gets more negative/returns to baseline.
What is another name for a partial tear of a muscle?
strain
What is the origin of the wrist flexor muscles?
medial epicondyle
What is the origin of the wrist extensor muscles?
lateral epicondyle
What muscle is most likely implicated during a case of shoulder impingement?
supraspinatus
Resting membrane potential is about what voltage?
About -60 to -90 mV
What is the difference between the following 3: concentric, eccentric, isometric contraction.
Concentric: muscle shortens
Eccentric: muscle lengthens
Isometric: muscle stays same length
Name one action in daily life that would be impaired if extensor digitorum was paralyzed.
Extending digits to grip something. Can give many examples.
How do you stretch the scalenes?
Laterally flex to the opposite side and apply overpressure with your arm.
What muscle causes torticollis? How do you stretch to fix this?
SCM
To stretch, you laterally flex to the opposite side and rotate to the same side.
Draw an action potential voltage graph on the board.
Should be present: time on x, voltage on y.
Stimulus, threshold, depol, repol, hyperpol, return to resting state.
Your muscle is flexor carpi ulnaris. Demonstrate an eccentric contraction.
Slow control of extension and radial deviation (opposite of muscle actions)
FCR is paralyzed. What happens when you flex your wrist?
FCU is still working properly. When you flex your wrist, ulnar and radial deviation will no longer be neutralized. Every time you flex your wrist, you will also ulnar deviate, as the flexor carpi radialis will not be able to neutralize the pull of flexor carpi ulnaris.
Demonstrate the 3 actions of the trapezius and an exercise that can be done with each.
scapular elevation: shrugs
scapular retraction: rows
scapular depression: lat pulldown or Ys.
Demonstrate the 3 actions of the lat dorsi and an exercise to work the muscle.
Shoulder internal rotation, shoulder extension, shoulder adduction. Lat pulldown.
Draw and label a neuromuscular junction on the board.
Need: presynaptic and postsynaptic neuron, Na+, ligand gated channels, voltage gated channels, vesicles, ACh
What is the difference between the following fibers:
fast glycolytic
slow oxidative
fast oxidative
fast glycolytic: fibers have fast contractions and primarily use anaerobic glycolysis.
slow oxidative: fibers contract relatively slowly and use aerobic respiration (oxygen and glucose) to produce ATP.
fast oxidative: fibers have fast contractions and primarily use aerobic respiration, but because they may switch to anaerobic respiration (glycolysis), can fatigue more quickly than SO fibers.
Demonstrate an isometric contraction of semispinalis capitis.
Push head back into extension but leave muscle at same length/head in same spot. Example would be pushing head back into your hand or the wall for 3-5 second holds.
One group member has to come up to the front of the room. Act out a baseball pitch in slow motion. Discuss three anatomical movements that happen during the motion.
Many movements depending on which phase of throw. Can be wrist, fingers, elbow, forearm, shoulder.
What is the action of the left SCM?
lateral flex to left, rotate to right