Lab 7: Muscles and Muscle Tissue

Study Notes

Lab 7: Muscles and Muscle Tissue

Submitting Answers: Submit answers to the untimed quiz on Blackboard. Work through the quiz beforehand, writing answers on paper or a document. Afterward, open the online quiz to fill it out and submit.
Muscle Structure:
- Connective Tissue Surrounding Bundle: Epimysium
- Bundle of Muscle Fibers: Fascicle
- Smallest Contractile Unit: Myofibril
- Connective Tissue Around Entire Muscle: Perimysium
- Connective Tissue Surrounding Each Muscle Fiber: Endomysium
- Plasma Membrane of Muscle Fiber: Sarcolemma
- Organelle in Muscle Fiber: Sarcomere
- Actin or Myosin Structure: Myofilament
- Collagen Fiber Attaching Muscle to Bone: Tendon
Muscle Fiber Components:
- I band: (light band)
- A band: (dark band)
- Z disc:
- H zone:
- M line:
- Sarcolemma:
- Triad (tubules of SR)
- Myofibrils:
- Mitochondria:
Thin Filament Components:
- Actin Subunits:
- Portion of Thin Filament
- Troponin and Tropomyosin: (regulatory proteins)
Thick Filament Components:
- Myosin Molecules:
- Portion of Thick Filament
- Heads:
- Flexible Hinge Region:
Neuromuscular Junction:
- Motor Neuron:
- ACh: (neurotransmitter)
- Cytoplasm of Skeletal Muscle Fiber:
- Sarcolemma:
Excitation-Contraction Coupling:
- Action Potential (AP): arrives at axon terminal, enters motor neuron, opens voltage-gated channels, causes calcium release, diffuses, binds to ACh receptors, etc.
- Neurotransmitter (ACh): Released into synaptic cleft, binds to receptors; resulting in membrane potential shifts to become negative (end-plate potential).
Muscle Twitch (Isometric):
- Phases: Three phases visible on a myogram (graph).
- Isometric Contraction : muscle length stays the same.
- Concentric Contraction: Muscle shortens while doing work
- Eccentric Contraction: Muscle lengthens while doing work.
Sarcomere Length:
- Optimal Sarcomere Length: 80%-120% of resting length, optimal for tension and force generation.
- Changes in Sarcomere Length affect tension generation.