Section 2 g) Key Words

Alveoli: Tiny air-sacs in the lungs surrounded by capillaries in which gas exchange takes place.

Breathing: The process of inhaling and exhaling air so the body can perform gas exchange.

Bronchioles: The many small tubes held open by rings of cartilage inside the lungs.

Bronchus: The two medium sized tubes that connect the lungs to the windpipe.

Capillaries: The smallest type of blood vessel.

Cilia: A small, hair-like structure found on ciliated cells. Used to move mucus.

Ciliated epithelial cells: Cells found in the trachea, brochus and bronchioles that move mucus around and prevent pathogens and infection from reaching the lungs.

Diaphragm: The large muscle found beneath the lungs (when you have the hiccups, your diaphragm is spasming) that contracts and relaxes to change the volume of the chest and makes breathing possible.

Expiration: Expelling air from the lungs.

Gas exchange: The process by which carbon dioxide is excreted and oxygen is taken in.

Goblet cells: Mucus-producing cells found amongst ciliated cells.

Guard cells: Cells found in the lower epidermis of the leaf, they become turgid to open the stomata and flaccid to close them.

Haemoglobin: A red, iron-based protein that bonds with oxygen (forming oxyhaemoglobin) to transport it around the body for respiration in cells.

Hydrogen carbonate indicator: A sensitive indicator that can show very slight changes in carbon dioxide levels in the surroundings. It starts off red/orange, and when exposed to high concentrations of CO2 it becomes yellow, while when exposed to low concentrations, it becomes purple.

Inspiration: Taking air into the lungs.

Intercostal muscles: Muscles found inbetween the ribs that relax and contract to change the volume of the chest and allow breathing to take place.

Photosynthesis: The process by which plants produce glucose and oxygen from carbon dioxide and water, with the help of sunlight.

Pleural membrane: The membrane found between the lungs and the ribcage. Contains pleural cavity fluid which allows the lungs to move easily, while keeping them in place.

Respiration: The process by which energy is released from glucose.

Spirometer: A machine that measures the air capacity of the lungs.

Stomata: The holes found in the bottom of the leaf that allow gas to flow in and out.

Trachea/windpipe: A large tube held open by large rings of cartilage, allows the passage of air from the mouth into the bronchus, bronchioles and lungs.

Ventilation: The process of breathing.