Human Anatomy: The Muscular System
Dive into the fascinating world of human muscles with this essential flashcard deck! Covering key structures, functions, and mechanisms of the muscular system, these cards are perfect for reviewing core concepts. Strengthen your understanding of how our bodies move and maintain posture.
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What are the three types of muscle tissue?
Skeletal (voluntary, striated), cardiac (involuntary, striated) and smooth (involuntary, non-striated).
What are the main functions of the muscular system?
Movement, posture, joint stability and heat production.
What are the four functional properties of muscle tissue?
Excitability, contractility, extensibility and elasticity.
How is skeletal muscle organized from largest to smallest?
Muscle → fascicle → muscle fiber (cell) → myofibril → sarcomere → myofilaments.
What is a sarcomere?
The basic contractile unit of striated muscle, running from one Z-disc to the next.
Which proteins form the thin and thick filaments?
Actin forms the thin filaments; myosin forms the thick filaments.
What does the sliding filament model say?
Myosin heads pull actin toward the center of the sarcomere, so filaments slide past each other and the sarcomere shortens.
Which neurotransmitter triggers skeletal muscle contraction at the neuromuscular junction?
Acetylcholine.
What does calcium bind to start contraction?
Troponin, which shifts tropomyosin off the myosin-binding sites on actin.
Where is calcium stored in a muscle fiber?
The sarcoplasmic reticulum.
What happens when ATP binds a myosin head?
The head detaches from actin; hydrolyzing the ATP then re-cocks it for the next stroke.
What is the difference between a muscle's origin and insertion?
The origin stays relatively fixed; the insertion is the attachment that moves.
What is the difference between an agonist and an antagonist?
The agonist (prime mover) produces a movement; the antagonist opposes it.
How do isotonic and isometric contractions differ?
Isotonic contractions change muscle length and move a load; isometric ones create tension without changing length.
What features are skeletal muscles commonly named for?
Location, shape, size, fiber direction, number of origins, attachments or action.