CHPT 5 - Muscular System Flashcards
Muscular System
Links the nervous and skeletal systems and generates force to move the human body.
Excitation-Contraction Coupling
Steps in the muscle contraction process involving the nervous and muscular systems. Electrolyte calcium and neurotransmitter acetylcholine are involved as well.
All or Nothing Principle
Describes how a motor unit either maximally contracts or does not contract at all.
Type 1 Muscle Fibers
Slow-twitch, muscle fibers are smaller in size, produce less force, and are fatigue resistant.
Type 2 Muscle Fibers
Fast-twitch, muscle fibers are larger in size, produce more force, and fatigue quickly.
Three types of muscles:
Skeletal, cardiac, and smooth.
Skeletal Muscle
The type of muscle tissue that connects to bones and generates the forces that create movement.
Fascia
Connective tissue that surrounds muscles and bones.
Epimysium
Inner layer of fascia that directly surrounds an entire muscle, commonly referred to as the “deep fascia.”
Fascicles
Largest bundles of fibers within a muscle. Fascicles are surrounded by perimysium.
Perimysium
Connective tissue surrounding a muscle fascicle.
Endomysium
Connective tissue that wraps around individual muscle fibers within a fascicle.
Tendons
Connect muscles to bones. Commonly discussed tendons include the Achilles tendon at the ankle and the patellar tendon of the knee. When a tendon is overstretched or torn, this is known as a strain.
Ligaments
Connect bones to bones. A commonly discussed ligament is the anterior cruciate ligament of the knee that connects the tibia to the femur. When a ligament is overstretched or torn, it is known as a sprain.
Myofibrils
The contractile components of a muscle cell; the myofilaments (actin and myosin) are contained within a myofibril.
