Sliding Filament Theory
These two protein filaments are primarily responsible for muscle contraction.
Actin & Myosin
This type of muscle is under voluntary control and is attached to bones.
Skeletal Muscle
This is the basic functional unit of a muscle fiber.
Sarcomere
This process occurs when a muscle shortens to produce movement.
Muscle Contraction
This upper-arm muscle bends the elbow.
Biceps Brachii
During muscle contraction, this structure shortens while the A band remains the same length.
Sarcomere
This muscle type is involuntary and found in the walls of hollow organs such as the stomach and intestines.
Smooth Muscle
This long, cylindrical cell makes up a muscle fiber and contains myofibrils.
Myofibrils
This ion is released inside the muscle fiber to allow contraction to begin.
Calcium
This muscle on the front of the thigh extends the knee.
Quadriceps femoris
This molecule binds to myosin heads and provides the energy needed for the power stroke.
ATP
This muscle type is involuntary, striated, and found only in the heart.
Cardiac Muscle
This connective tissue layer surrounds individual muscle fibers.
Endomysium
This step of contraction occurs when myosin heads pull actin filaments toward the center of the sarcomere.
Power Stroke
This large chest muscle moves the arm across the body.
Pectoralis major
This regulatory protein complex blocks myosin-binding sites on actin until calcium ions bind and shift it out of the way.
Troponin-Tropomyosin Complex
Skeletal and cardiac muscle share this structural feature that smooth muscle lacks.
Striations
This structure anchors actin filaments and defines the boundary of each sarcomere.
Z Line (Z discs)
This regulatory protein moves when calcium binds, exposing the myosin-binding sites on actin.
Troponin
This broad muscle of the back pulls the arms downward and toward the body, such as during a pull-up.
Latissimus dorsi
When calcium ions are released from this organelle, they initiate the chain of events that leads to muscle contraction.
Sarcoplasmic Reticulum
This muscle classification is characterized by spindle-shaped cells, a single nucleus, and the absence of sarcomeres.
Smooth Muscle
This connective tissue layer surrounds the entire muscle and helps attach it to tendons.
Epimysium
This sequence of repeated events involving myosin binding, pivoting, and releasing actin produces muscle shortening.
Cross-Bridge Cycle
Originating on the anterior inferior iliac spine and inserting on the tibial tuberosity via the patellar ligament, this muscle extends the knee and flexes the hip.
FINAL JEOPARDY
Rectus femoris