AQA PHED 1 PE RESPIRATORY SYSTEM

Structure of the respiratory system.

• NASAL CAVITY
• PHARYNX
• LARYNX
• TRACHEA
• BRONCHII
• BRONCHIOLES
• ALVEOLI
• LUNG

THE MECHANICS OF BREATHING.

INSPIRATION (REST)

• External intercostal muscles contract, causing the chest to move outwards and upwards.
• Diaphram contracts, causing it to flatten.
• The thorcacic cavity increases in size 
• The pressure withing the lungs decrease.

INSPIRATION (EXERCISE)

• Breathing rate and depth increases
• Inspiration is aided by: sternocleidomastoid, pectoralis minor and scalenes.

EXPIRATION (REST)

• External intercostal muscle relaxes, causing the chest to move inwards and downwards
• The diaphram also relaxes, causing it to return to its dome shape
• The thoracic cavity decreases in size
• The lung pressure is now increased.

EXPIRATION (EXERCISE)

• Aided by the intercostal muscles contracting, causing the ribs to move inwards and downwards quicker.
• Also aided by the abdominal muscles.

LUNG VOLUMES AND CAPACITY.

• TIDAL VOLUME: The volume of air that can be inspired and…