Upper Respiratory Tract Flashcards
What are the main structure making up the upper respiratory tract?
Structure of the upper respiratory tract include: paranasal sinuses, oral cavity, pharynx and the Larynx (Larynx becomes trachea at the lower border of the Cricoid cartilage).
Describe the external structure of the nose
External nose is formed from a bony framework surrounded by a cartilaginous model. Within the nose is nasal hair which traps foreign particles preventing them from entering and damaging the respiratory tract. The nostrils are called nares.
Describe the basic internal structure of the nasal cavity
Nasal cavity has a roof, floor, 2 lateral walls and a septum (medial wall). The septum is made from a cartilaginous portion and a bone portion. 3 bony projection create Conchae or turbinates (superior, middle and inferior) that are on the lateral walls of the nasal cavity. These are covered in the mucosa of the respiratory tract. These chochae create spaces underneath called the superior, middle and inferior meatuses. Their role is to slow airflow and increase surface area over which the air is in contact with the mucosa. This allows the nasal cavity to modify the air before it continues down the trachea.
How does the nasal cavity modify the air you breath in, what kind of cells are present and what relation does the nasal cavity have to the eye?
The respiratory mucosa filters, humidifies and warms this air as a result there is a great blood supply for warming. The epithelial cells are pseudostratified ciliated epithelium. Also goblet cells creating mucus to trap other smaller particles not caught by the nasal hairs. Drainage of the eye takes place through the nasolacrimal ducts.
What are the paranasal sinuses?
Paranasal sinuses are air filled spaces in bones near the nose. There are 4 pairs of these sinuses called the frontal, ethmoidal, maxillary and sphenoidal. Covered in respiratory mucosa with secreted mucus. They help humidify and warm inspired air. Drain into the nasal cavity via openings called ostia in all 3 meatuses. Infection of the nasal cavity can spread to the sinuses – sinusitis.
How does the Eustachian tube differ between children and adults?
Eustachian tube between middle ear and back of nose. Shorter and more horizontal in children so slightly easier for bacteria to travel into the middle ear.
Describe the pharynx
Runs from the base of the skull to the inferior border of the cricoid cartilage (C6). The pharynx directs air from the nasal cavity into the larynx (away from oesophagus). It contains three regions, nasal pharynx, oropharynx and the laryngopharynx.
What is the clinical significance of the oropharynx?
Oropharynx transmits both air and food, if in an unconscious state won’t be able to direct food away from the larynx – may choke.
Describe the larynx
Muscular tube with a lot of cartilage. Such as the thyroid cartilage. Function is to protect the air passages especially during swallowing, maintains patent airway and for sound production. Separation of larynx from the oesophagus is done by the cartilaginous epiglottis but also the glottis which consists of the vocal cords.
Describe the structure and function of the vocal cords
Vocal cord abducts and adduct during respiration, coughing and swallowing to guard the air passages, Movement are created by intrinsic muscles of the larynx. Space between the vocal cords is called the Rima Glottidis.
How do the vocal cords produce noise and what innervates them?
To create noise, the vocal cords come together and leave a small gap for air. Vocal cords innervated by the recurrent laryngeal nerve which are both looped around the aorta and so a hoarse voice can be a sign of some other morbidity.
