Untitled Flashcards Set

Actin

Thin filament involved in muscle contraction that slides over myosin.

Myosin

Thick filament involved in muscle contraction that pulls actin.

Sarcomere

The functional unit of a muscle fiber, composed of myosin and actin filaments.

Slow-Twitch Fibers

Muscle fibers primarily used in aerobic activities, containing high levels of myoglobin.

Fast-Twitch Fibers

Muscle fibers used in anaerobic activities, producing energy without oxygen.

Calcium Ions (Ca²⁺)

Molecules released from the sarcoplasmic reticulum that trigger muscle contraction.

ATP

A molecule that provides energy for myosin to bind to actin during muscle contraction.

Tetanus

A state of continuous muscle contraction without relaxation due to frequent stimuli.

Antagonistic Muscles

Muscle pairs that work in opposition, such as biceps and triceps.

Inhalation

The process of air entering the lungs, initiated by the contraction of the diaphragm and intercostal muscles.

Exhalation

The process of air leaving the lungs, caused by the relaxation of the diaphragm and intercostal muscles.

Alveoli

Tiny air sacs in the lungs where gas exchange occurs.

Bronchi

The primary passageways that carry air into the lungs.

Gas Exchange

A passive process where oxygen and carbon dioxide diffuse across the alveolar membrane.

Tidal Volume

The amount of air inhaled or exhaled in a normal breath.

Surfactant

A fluid in the alveoli that reduces surface tension, preventing their collapse.

External Respiration

Gas exchange occurring between alveoli and blood.

Internal Respiration

Gas exchange occurring between blood and body tissues.