Sliding Filament Theory

Complete the chart of participants of the sliding filament theory:

Number the statements in the proper sequence to describe excitation-contraction coupling. Step 1 has been numbered for you.

___1____ 1. Acetylcholine is released by the axon terminal, diffuses to the muscle cell and attaches To ACh receptors on the sarcolemma.

________ 2. The action potential, carried into the cell via the T-tubules, causes the SR to release Calcium ions.

________ 3. Ach-E breaks down Ach, which separates from its receptors.

________ 4. The muscle cell relaxes and lengthens.

________ 5. The calcium ion concentration at the myofilaments increases; the myofilaments slide Past one another and the cell shortens.

________ 6.
Depolarization occurs and the action potential is generated along the sarcolemma.

________ 7.
Within 30 ms after the AP ends, Ca2+ concentration at the myofilaments decreases.

Number the events in correct order for the cross-bridge formation and cycle. The first step is indicated with (number 1).

________ 1. Myosin heads bind to active sites on actin molecules

________ 2. ATP is hydrolyzed.

________ 3. Myosin heads return to their cocked position ready for the next working stroke.

___1____ 4. Calcium ions bind to troponin.

________ 5. Cycling continues until calcium ions return to the SR.

________ 6. Myosin cross bridges detach from actin.

________ 7. Troponin changes shape.

________ 8. ADP and inorganic phosphate are released from the thick filament.

________ 9. Myosin heads pull on the thin filaments, sliding them toward the center of the sarcomere.

________ 10. ATP binds to the thick
filament.

________ 11. Tropomyosin moves, exposing active sites on actin.

COMPLETE THE FOLLOWING:

______________________ _____________________: the minimal amount of stimulus from a neuron that will initiate a contraction from a muscle cell; linked to the amount of neurotransmitter required to stimulate a contraction of a motor unit so observable contraction is evident.

____________________________________________: 1 neuron + all the skeletal muscle cells it innervates

____________________________________________: the additive effect to strength caused when additional motor units are stimulated.
The # of motor units determines the amount of strength brought to a particular action.

____________________________________________: energy source for muscle contraction

____________________________________________: the less moveable point of attachment

____________________________________________: the more moveable point of attachment

_____________________________________________: agonist; moves the body away from anatomical position

_____________________________________________: reverses motion of agonist; approximates anatomical position

MUSCLES OF MASTICATION:

MUSCLES OF FACIAL
EXPRESSION:

MUSCLES OF RESPIRATION:

MUSCLES OF THE ROTATOR CUFF:

MUSCLES OF THE ANTERIOR COMPARTMENT OF THE LOWER LEG:

COMPLETE THE COMPARISON CHART BELOW:

Skeletal
Cardiac
Smooth
CT Components

Sarcomeres

SR

Contraction Regulation

Contraction Initiation

Rhythmic Contractions

Shape of Muscle Cell

Location

Nucleus (Nuclei)

List some of the ways muscles are named. Give an example for each.