Musculoskeletal System: Muscle Contraction Flashcards
(20 cards)
What are the major functions of the skeletal system?
Support, protection, movement, mineral storage, blood cell production, and energy storage.
Why is calcium important for the skeletal system?
It is essential for bone strength and various physiological processes like muscle contraction and blood clotting.
What are the three types of muscle tissue?
Skeletal, cardiac, and smooth muscle.
Where is skeletal muscle found?
Attached to bones for voluntary movement.
What is the function of cardiac muscle?
Pumps blood through the heart; involuntary.
What is the function of smooth muscle?
Found in walls of hollow organs; controls involuntary movements.
What are the main functions of muscles?
Body movement, posture, respiration, heat production, communication, and blood flow regulation.
What is the difference between the origin and insertion of a muscle?
Origin is the fixed attachment, and insertion moves during contraction.
Why do muscles pull but not push?
Muscle contraction shortens the muscle, pulling the insertion toward the origin.
What is a sarcomere?
The functional unit of a muscle fiber between two Z-lines.
What are the major proteins in the sarcomere?
Actin (thin filament) and myosin (thick filament).
What is the role of calcium in muscle contraction?
It binds to the troponin complex and triggers troponin to shift, exposing myosin-binding sites on actin and therefore allowing the attachment of the miasmal heads.
What is the role of ATP in muscle contraction?
Provides energy for myosin head movement and detachment from actin.
What is the contraction cycle?
Cross-bridge formation, power stroke, detachment, and reactivation of myosin heads.
What is isotonic contraction?
Muscle changes length to move a load (e.g., lifting a weight).
What is isometric contraction?
Muscle tension increases but length stays the same (e.g., holding a weight still).
What are slow-twitch muscle fibers?
Fibers with more mitochondria and myoglobin; fatigue-resistant but less powerful.
What are fast-twitch muscle fibers?
Fibers with many myofibrils, fewer mitochondria; powerful but fatigue quickly.
What is a motor unit?
A somatic motor neuron and all the muscle fibers it innervates.
How is fine control achieved in muscle movement?
By activating smaller motor units with fewer fibers.
