muscular system

Three types of muscle tissue

Skeletal, cardiac, smooth

Skeletal muscle

Voluntary muscle type attached to bones

Cardiac muscle

Muscle type found only in the heart

Smooth muscle

Involuntary muscle type found in walls of hollow organs

Main function of skeletal muscles

Movement of the skeleton and posture maintenance

Function of cardiac muscle

Pump blood through the heart and circulatory system

Function of smooth muscle

Control movement of substances through hollow organs (e.g., intestines, blood vessels)

Tendon

A connective tissue that connects muscle to bone

Basic functional unit of a skeletal muscle

Sarcomere

Protein filaments that make up the sarcomere

Actin (thin filament) and myosin (thick filament)

Cause of muscle contraction

Sliding filament theory — actin and myosin filaments slide past each other

Role of calcium in muscle contraction

Calcium binds to troponin, allowing actin and myosin interaction

Neurotransmitter that stimulates muscle contraction

Acetylcholine

Muscle fatigue

A decrease in muscle's ability to generate force due to prolonged activity

Difference between isotonic and isometric contractions

Isotonic involves muscle length change; isometric involves tension without length change

Origin in muscle terminology

The fixed attachment point of a muscle

Insertion

The movable attachment point of a muscle

Hypertrophy

Increase in muscle size due to exercise

Atrophy

Decrease in muscle size due to disuse

Biceps brachii

Muscle that helps flex the forearm at the elbow

Triceps brachii

Muscle that helps extend the forearm at the elbow

Antagonist muscle

The muscle that opposes the action of the agonist (prime mover)

Synergist muscle

A muscle that assists the agonist in performing an action

Function of the diaphragm

Main muscle responsible for breathing (inhalation)

Smooth muscle in the eye

Controls pupil size in the eye

Muscle tone

Continuous, passive partial contraction of muscles for posture and readiness