Sliding Filament Model
This is the structure that shortens during muscle contraction as actin filaments slide over myosin.
What is a sarcomere?
This muscle type is voluntary, striated, and attached to bones to produce body movement.
What is skeletal muscle?
This large, fan-shaped chest muscle is responsible for flexion, adduction, and medial rotation of the arm.
What is the pectoralis major?
This muscle of the upper arm is responsible for flexing the elbow and is commonly flexed when showing strength.
What is the biceps brachii?
This immediate energy source stored directly in muscle cells powers contraction for only a few seconds.
What is ATP (adenosine triphosphate)?
These are the thin filaments that slide inward toward the center of the sarcomere during contraction.
What are actin filaments?
This muscle type is found only in the heart and is responsible for pumping blood throughout the body.
What is cardiac muscle?
This deep chest muscle lies beneath the pectoralis major and helps stabilize the scapula by pulling it forward.
What is the pectoralis minor?
This muscle located in the cheek allows you to smile by pulling the corners of the mouth upward.
What is the zygomaticus?
This high-energy compound stored in muscles rapidly regenerates ATP without requiring oxygen.
What is creatine phosphate (phosphocreatine)?
These projections on the thick filament attach to actin to pull it inward.
Question: What are myosin heads (cross-bridges)?
What are myosin heads (cross-bridges)?
This muscle type is non-striated, involuntary, and found in the walls of organs such as the stomach and intestines.
What is smooth muscle?
This broad back muscle is used during movements like pull-ups and is responsible for extension, adduction, and medial rotation of the arm.
What is the latissimus dorsi?
This large muscle on the back of the upper arm is responsible for extending the elbow joint.
What is the triceps brachii?
This anaerobic process breaks down glucose to produce ATP and lactic acid when oxygen is scarce.
What is glycolysis?
This ion is released from the sarcoplasmic reticulum and allows myosin to bind to actin.
What is calcium (Ca²⁺)?
These two muscle types are considered involuntary because they function without conscious control.
What are cardiac and smooth muscles?
This large upper back muscle helps elevate, retract, and rotate the scapula and is commonly strengthened by shoulder shrugs.
What is the trapezius?
This powerful muscle in the front of the thigh helps extend the knee and is used when kicking a ball.
What is the quadriceps femoris?
This aerobic pathway occurring in the mitochondria produces the largest amount of ATP using oxygen.
What is cellular respiration (aerobic respiration)?
This energy molecule is required for the myosin head to detach and reset during contraction.
What is ATP?
This feature is shared by both skeletal and cardiac muscle but not by smooth muscle.
What are striations?
These muscles are located between the ribs and assist with breathing by expanding and contracting the rib cage.
What are the intercostal muscles?
This calf muscle helps you stand on your tiptoes and is important for walking and running.
What is the gastrocnemius?
During prolonged exercise, this stored energy source in muscles and the liver is broken down to supply glucose for ATP production.
What is glycogen?