Muscle Physiology & Respiratory System

These flashcards cover key concepts in muscle physiology and the respiratory system for exam preparation.

Origin

The fixed end of a muscle where it attaches to a bone.

Insertion

The moving end of a muscle that is attached to a bone.

Flexors

Muscles that decrease the angle of a joint.

Extensors

Muscles that increase the angle of a joint.

Agonist

The prime mover muscle in a movement.

Antagonist

The muscle that opposes the action of the agonist.

Epimysium

The connective tissue surrounding the whole muscle.

Perimysium

The connective tissue that surrounds fascicles.

Endomysium

The connective tissue surrounding each muscle fiber.

Multinucleated

Having more than one nucleus, a characteristic of skeletal muscle fibers.

Striated cells

Muscle cells that have a striped appearance, indicative of skeletal muscle.

A band

The dark band in a striated muscle, made of thick and thin filaments.

I band

The light band in a striated muscle, composed of thin filaments only.

Z disc

The boundary of a sarcomere in striated muscle.

H zone

The area in the A band that contains thick filaments only.

Neuromuscular Junction

The synapse or junction where a motor neuron communicates with a muscle fiber.

Motor Unit

A motor neuron and all muscle fibers it innervates.

Small Motor Unit

A motor unit that allows for fine control, such as in the eye.

Large Motor Unit

A motor unit that generates strength, such as those found in the legs.

Actin

A protein that makes up the thin filaments in muscle fibers.

Tropomyosin

A protein that covers the binding sites on actin.

Troponin

A protein that binds calcium and induces a conformational change in tropomyosin.

Myosin

The protein that makes up the thick filaments and has ATPase activity.

Sliding Filament Theory

The mechanism explaining how muscles contract by the sliding of actin and myosin filaments.

Power stroke

The action during contraction when myosin heads pull actin filaments toward the center of the sarcomere.

Cross-bridge

The attachment of myosin heads to actin filament during muscle contraction.

Excitation-Contraction Coupling

The process linking action potentials to muscle contraction.

SERCA pump

The pump responsible for returning calcium ions to the sarcoplasmic reticulum.

Twitch

A single contraction of a muscle fiber.

Summation

When twitches combine and produce a stronger contraction.

Tetanus

A sustained muscle contraction resulting from many rapid stimuli.

Isotonic Contraction

A contraction where the muscle changes length while producing movement.

Concentric Contraction

A type of isotonic contraction where the muscle shortens.

Eccentric Contraction

A type of isotonic contraction where the muscle lengthens.

Isometric Contraction

A contraction generating tension without changing length.

Length-Tension Relationship

The relationship between muscle length and the force it can produce.

Type I Fibers

Slow oxidative fibers that are resistant to fatigue and used for endurance.

Type IIA Fibers

Fast oxidative-glycolytic fibers that provide both endurance and strength.

Type IIX Fibers

Fast glycolytic fibers that are used for quick bursts of power.

Muscle Spindle

A sensory receptor that detects muscle length and stretch.

Nuclear bag fibers

Type of fibers in muscle spindle that respond quickly to changes in length.

Golgi Tendon Organ

A sensory receptor that detects muscle tension.

Alpha Motor Neurons

Neurons that innervate extrafusal muscle fibers, generating force.

Gamma Motor Neurons

Neurons that innervate intrafusal fibers to maintain spindle sensitivity.

Monosynaptic Stretch Reflex

A reflex that involves a direct connection between a sensory neuron and a motor neuron.

Cardiac Muscle

Muscle tissue that is striated and intercalated with discs, crucial for heart function.

Gas Exchange

The process of exchanging oxygen and carbon dioxide during respiration.

Acid-base Regulation

The process of maintaining a stable pH in the body through respiration.

Conducting Zone

The part of the respiratory system that does not participate in gas exchange.

Respiratory Zone

The part of the respiratory system where gas exchange occurs.

Atmospheric Pressure

The pressure exerted by the weight of air in the atmosphere.

Intra-Alveolar Pressure

The pressure inside the alveoli during the breathing cycle.

Intrapleural Pressure

The pressure in the pleural cavity, always negative.

Boyle’s Law

The principle stating that as the volume of a gas increases, pressure decreases.

Inspiration

The process of taking air into the lungs.

Expiration

The process of expelling air from the lungs.

Tidal Volume (TV)

The amount of air inhaled or exhaled during normal breathing.

Vital Capacity (VC)

The total amount of air that can be exhaled after maximal inhalation.

Total Lung Capacity (TLC)

The total volume of air the lungs can hold.

Minute Ventilation

The total volume of air breathed in one minute.

Partial Pressure

The pressure exerted by a single type of gas in a mixture.

External Respiration

The exchange of gases between the alveoli and blood.

Internal Respiration

The exchange of gases between blood and tissues.

CO₂ Transport

The ways carbon dioxide is carried in the blood.

Hypoventilation

Inadequate ventilation leading to increased carbon dioxide levels.

Hyperventilation

Excessive ventilation leading to decreased carbon dioxide levels.

Asthma

A respiratory condition characterized by inflammation and difficulty in breathing.

COPD

Chronic obstructive pulmonary disease including chronic bronchitis and emphysema.

Lung Cancer

Cancer that originates in the lungs, commonly associated with smoking.