Structure and Function of Muscular, Nervous, and Skeletal Systems

Epimysium

Connective tissue surrounding the muscle belly.

Perimysium

Connective tissue surrounding a fasciculus.

Endomysium

Connective tissue surrounding individual muscle fibers.

Sarcoplasm

Cytoplasm of muscle fibers containing energy sources.

Myofibril

Contractile unit of muscle fibers.

Myosin

Thick filament involved in muscle contraction.

Actin

Thin filament that interacts with myosin.

Tropomyosin

Covers myosin binding sites on actin.

Troponin

Regulatory protein that binds calcium.

Sliding Filament Theory

Mechanism of muscle contraction via filament sliding.

Action Potential

Electrical signal triggering muscle contraction.

Neuromuscular Junction

Site where motor neuron meets muscle fiber.

Muscle Spindle

Sensory receptor detecting muscle length changes.

Golgi Tendon Organ (GTO)

Receptor preventing excessive muscle force.

Stretch Reflex

Involuntary response to muscle stretching.

Cortical Bone

Dense outer layer of long bones.

Cancellous Bone

Spongy interior of bones, site of hematopoiesis.

Tendons

Connect muscle to bone, withstand tensile forces.

Ligaments

Connect bone to bone, contain elastin.

Osteoporosis

Condition of weak, brittle bones.

Wolff's Law

Bone adapts to stresses placed on it.

Type 1 Muscle Fibers

Slow oxidative, fatigue-resistant muscle fibers.

Type 2A Muscle Fibers

Fast oxidative glycolytic, moderate fatigue resistance.

Type 2X Muscle Fibers

Fast glycolytic, highly fatigable muscle fibers.

Delayed-Onset Muscle Soreness (DOMS)

Pain after exercise, primarily from eccentric actions.

Central Nervous System

Includes brain and spinal cord, creates impulses.

Peripheral Nervous System

Relays nerve impulses between limbs and CNS.

Somatic Nervous System

Controls voluntary skeletal muscle movements.

Autonomic Nervous System

Regulates involuntary body functions.

Sympathetic Nervous System

Prepares body for fight or flight response.

Parasympathetic Nervous System

Promotes rest and digest functions.

Motor Unit Recruitment

Activating more motor units for increased force.

Rate Coding

Increasing firing rate of active motor units.

Size Principle

Order of motor unit recruitment by size.