GCSE Physical Education – Respiratory System: Structure and Functions (Notes - Page 1)

Vocabulary flashcards covering the structure and function of the respiratory system as described in the notes. Terms include components of inhaled/exhaled air, processes of breathing, major anatomical structures, diffusion and gas exchange, and respiration types.

Oxygen

A gas that makes up about 21% of inhaled air and about 16% of exhaled air.

Carbon Dioxide

A gas that makes up about 0.04% of inhaled air and about 4% of exhaled air.

Nitrogen

A gas that makes up about 79% of both inhaled and exhaled air.

Inhaled air

Air entering the respiratory system; contains roughly 21% oxygen, 0.04% carbon dioxide, and 79% nitrogen.

Exhaled air

Air leaving the respiratory system; contains roughly 16% oxygen, 4% carbon dioxide, and 79% nitrogen.

Inspiration

Breathing in; the diaphragm and intercostal muscles contract, the chest cavity enlarges, and air moves into the lungs.

Expiration

Breathing out; the diaphragm and intercostal muscles relax, the chest cavity decreases, and air leaves the lungs.

Diaphragm

A dome-shaped muscle that contracts to move down during inspiration and relaxes to its dome shape during expiration.

Intercostal muscles

Muscles between the ribs that contract during inspiration and relax during expiration to move the rib cage.

Tidal Volume

The amount of air inhaled and exhaled per breath; resting value about 500 ml.

Resting tidal volume

The tidal volume at rest; approximately 500 ml per breath.

Breathing Rate

The number of breaths taken per minute.

Minute Volume

The total amount of air inhaled and exhaled per minute; measured in litres.

Alveoli

Tiny air sacs with thin, moist walls where diffusion occurs; surrounded by capillaries to shorten diffusion distance.

Capillaries

One-cell-thick blood vessels surrounding the alveoli to reduce diffusion distance.

Diffusion

Movement of oxygen and carbon dioxide from high to low concentration across membranes (alveolar and capillary walls).

Gas exchange

The exchange of oxygen into the blood and carbon dioxide into the lungs at the alveoli.

Oxygen diffusion

Oxygen moves from the alveoli into the capillaries.

Carbon dioxide diffusion

Carbon dioxide moves from the capillaries into the alveoli to be exhaled.

Aerobic respiration

Respiration that uses oxygen; at a steady exercise level, glucose + oxygen → carbon dioxide + water.

Anaerobic respiration

Respiration that occurs when oxygen supply is insufficient; glucose → lactic acid.

Glucose

A simple sugar used as fuel in respiration (reactant in both aerobic and anaerobic processes).

Lactic acid

A product of anaerobic respiration.

Nasal Passage

Air enters the respiratory system through the nasal passages.

Trachea

The windpipe; conducts air from the larynx to the bronchi.

Bronchi

Two main airways that branch from the trachea to each lung.

Bronchioles

Smaller airways within the lungs that lead to the alveoli.

Lung

Organ containing the alveoli where gas exchange occurs.

Pathway of Air

Route air follows: nasal passage → trachea → bronchi → bronchioles → alveoli.