Anatomy & Physiology I - Muscular System

These flashcards cover key terms and concepts related to the muscular system, focusing on muscle tissues, their characteristics, functions, and the structure of skeletal muscle.

Types of Muscle Tissue

Skeletal, Cardiac, and Smooth.

Four main characteristics of muscle tissues

Excitability, Contractility, Extensibility, and Elasticity.

Functions of muscles

Produce movement, Maintain posture and body position, Stabilize joints, Generate heat.

Components of Skeletal Muscle

Nerve supply, Blood supply (artery and veins), and Connective tissue sheaths.

Connective tissue sheaths surrounding muscles

Epimysium, Perimysium (fascicles), and Endomysium.

Cell of skeletal muscle

Muscle fiber.

Components of muscle fiber

Sarcolemma, Sarcoplasm, Glycosomes, Myoglobin, Myofibrils, Sarcoplasmic reticulum, T tubules.

Specialized structures of muscle fiber

Myofibrils, Striations, Sarcomeres, Myofilaments.

Muscle Interactions

Muscle collaborations that include Agonist (Prime Mover), Antagonist, Synergist, and Fixator.

Agonist (Prime Mover)

The muscle primarily responsible for a specific movement, such as the Biceps brachii for elbow flexion.

Antagonist

The muscle that opposes or reverses the action of the agonist, like the Triceps brachii during elbow flexion.

Synergist

Muscles that aid the prime mover by adding extra force or minimizing unnecessary movement.

Fixator

A type of synergist that immobilizes a bone or muscle’s origin, helping maintain posture.

Major Muscle Groups - Head/Neck

Includes Masseter, Temporalis, Sternocleidomastoid, involved in chewing and head rotation.

Major Muscle Groups - Thorax

Includes Pectoralis major and Rectus abdominis, responsible for arm flexion and trunk flexion.

Major Muscle Groups - Back

Includes Trapezius and Latissimus dorsi, aiding in scapula movement and arm extension.

Major Muscle Groups - Upper Limb

Includes Deltoid, Biceps brachii, and Triceps brachii, involved in abduction and flexion/extension of the elbow.

Major Muscle Groups - Lower Limb

Includes Quadriceps (4 muscles) and Hamstrings (3 muscles), responsible for leg movement.

Sarcomere

The functional unit of muscle contraction, composed of myofilaments.

Myofilaments

Includes Actin (thin filament) and Myosin (thick filament), crucial for muscle contraction.

Sarcoplasmic Reticulum (SR)

Stores and releases calcium ions (Ca2+) for muscle contraction.

Cross-Bridge Cycle

Occurs when Ca2+ binds to troponin, exposing actin sites for myosin binding and pulling.

Muscle Relaxation

Involves Ca2+ being pumped back into the SR and ATP breaking the cross-bridge.

Direct Phosphorylation

Uses Creatine phosphate to provide ATP for approximately 15 seconds.

Anaerobic Pathway

Glycolysis that produces lactic acid, supplying energy for about 30-40 seconds.

Aerobic Respiration

Generates 95% of ATP during rest and light-to-moderate exercise.