Human Breathing

• The nasal cavity is moist so that as air flows past it warms up and it moistened - can diffuse more easily from the lungs to the blood
• pharynx - connects the nose and mouth to the larynx
• larynx - known as the voice box - contains the vocal cords
• trachea - allows air to pass into the lungs
• all the air pipes are lined with mucous secreting cells and tiny hairs cilia
• lungs - gaseous exchange - protected by the rib cage
• alveoli adapted for gas exchange - lots of them, large surface area and a rich blood supply
• breathing is under the control of the medulla oblongata in the brain which is determined by the CO2 levels in the blood
• inhalation - the diaphragm and intercostal muscles contract (active process - requires energy) - volume of lungs increases - the thoracic air pressure decreases
• exhalation - diaphragm and intercostal muscles both relax -the rib cage moves down and in, diaphragm moves up - volume of lungs decreases - the thoracic pressure increases - passive process
• asthma is a breathing disorder that results in the narrowing of the bronchioles which prevents air reaching the alveoli
• asthma symptoms - feeling lack of breathe
• asthma causes - can be triggered by certain allergens
• asthma prevention - allergen can be identified and staying clear of that particular allergen
• asthma treatment - steroids or inhalers