Epiglottis
- A thin flap of tissue covering the trachea (windpipe) when a person swallows. It prevents food and drink from entering the airways leading to the lungs.
Cartilage
- A strong and elastic connective tissue found in places of the body like the nose.
- The flexibility of nose allows humans to easily breathe in and out throughout the nasal cavity. Also, cartilage is found in the bronchioles as C-shaped cartilage rings.
- In the secondary bronchi and tertiary bronchi the cartilage is more widely spaced and smoother muscle and elastin protein is in the walls.
- The bronchioles structure contain no cartilage allowing them to be more flexible.
Muscles of Respiration
- “intercostal muscles” lay between the ribs and help the diaphragm to expand and compress the lungs.
- In exhalation, the internal intercostal muscles compress the thoracic cavity and depress the ribs forcing the air out of the lungs.
- During inhalation, the external intercostal muscles cause air to rush into the lungs by expanding the volume of the thoracic cavity and elevating the ribs.