1. Structure
1.1. Pathway of air
1.1.1. Trachea --> Bronchi --> Bronchioles --> Alveoli
1.2. Types of Cells
1.2.1. Goblet Cells
1.2.1.1. Produce Mucus to trap pathogens and dust particles
1.2.2. Ciliated Epithelial Cells
1.2.2.1. Keeps the airways clear by sweeping trapped debris out with cilia
1.2.3. Elastic Fibres
1.2.3.1. Allow airways to stretch and recoil
1.2.4. Smooth Muscle Cells
1.2.4.1. Contract and relax to allow for change in diameter of the airways
1.3. Cartilage
1.3.1. Gives support to walls of the airways from collapsing during pressure changes
1.3.1.1. C-shaped rings in the trachea
1.3.1.2. Irregular blocks in the bronchi and larger bronchioles
2. Alveoli
2.1. Structure
2.1.1. Single layer of flat squamous epithelium cells
2.2. Adaptations
2.2.1. Many alveoli
2.2.1.1. Provides a large surface area relative to the volume of the body for gases to diffuse
2.2.2. Moist
2.2.2.1. For gases to dissolve
2.2.3. Only one cell thick
2.2.3.1. Provides a very short diffusion pathway
2.2.4. Surrounded by blood capillary
2.2.4.1. Helps to maintain concentration gradients because the blood is always taking oxygen away from the alveoli and returning with carbon dioxide
2.2.5. Some cells secrete surfactant
2.2.5.1. To prevent alveoli from collapsing during expiration.
3. Smoking
3.1. Components of cigarettes
3.1.1. Nicotine
3.1.1.1. Colourless odourless chemical that is highly addictive
3.1.2. Carbon Monoxide
3.1.2.1. Colourless odourless gas that is highly toxic
3.1.3. Tar
3.1.3.1. Oily brown substance that is deposited in the filter of the smoked cigarette
3.2. Short term effects
3.2.1. Nicotine
3.2.1.1. Arteries and arterioles constrict causing a resistance to blood
3.2.1.2. Release of adrenaline increasing the heart rate
3.2.2. Carbon Monoxide
3.2.2.1. Combines with haemoglobin to form carboxyhaemoglobin depriving it of its oxygen carry capability
3.3. Diseases
3.3.1. COPD
3.3.1.1. Chronic Bronchitis
3.3.1.1.1. Tar causes overproduction of mucus and destroys cilia
3.3.1.1.2. Smokers Cough
3.3.1.2. Emphysema
3.3.1.2.1. Breakdown of the lung tissue due to irritation of years of smoking
3.3.1.2.2. Elastic tissue between walls of alveoli breakdown
3.3.1.3. Chronic Obstructive Pulmonary DIsease
3.3.1.3.1. Poor airflow in airways
3.3.1.3.2. A patient who has Emphysema, Chronic Bronchitis or both
3.3.2. Lung Cancer
3.3.2.1. Caused by carcinogens in tar
3.3.2.1.1. Symptoms include shortness of breath, persistent cough, chest pain, weight loss
3.3.2.2. Silent disease
3.3.2.2.1. Takes years before any noticeable symptoms are visible