Lecture 11 Flashcards
What are the primary parts of the respiratory system structure? Which of these are in the upper respiratory tract?
Outside the lungs is the nose and nasal cavity, pharynx, larynx and trachea.
Inside the lungs are the main bronchi, the interpulmonary bronchi, bronchioles, terminal bronchioles and alveoli.
Of these the nose and nasal cavity (paranasal sinuses), pharynx and larynx are in the upper respiratory tract.
What is a mucosa
Mucosa: mucus membrane, typically open to the environment.
What are the external parts of the nose? Why is it made out of what it is?
The anterior nares (nostrils), paired nasal cartilages (lateral and alar) with septal cartilage down the midline. It is made out of cartilage to allow the nose to be flexible, ensuring unobstructed airway.
What does the nasal cavity consist of?
Midline (nasal septum) formed from hyaline cartilage anteriorly and bone posteriorly, there are internal nares (holes) at the posterior aspect. The roof of it is formed by the ethmoid and sphenoid bones, the floor is formed by hard (anteriorly) and soft (posteriorly) palates. Also contains turbinates/conchae on the lateral walls.
What are turbinates? What do they act to do?
Three mucosa covered projections (superior, middle and inferior) on the lateral walls of the nasal cavity. They are curved structures which swirl the inhaled air, deflecting heavier particles are deflected onto the mucosa (cleaning the incoming air). Also contains sensory nerve endings which can trigger the sneeze reflex.
What are the paranasal sinuses?
A ring of sinuses (cavities) which surround the nose (frontal, sphenoid, ethmoid and maxillary sinuses). These lighten the skull and also warm and moisten the air, they also allow for sound resonance (helping with voice. These can be blocked by infected muscus, creating partial vacuums within and leading to a sinus headache.
What is the pharynx? What regions does it have?
This is a funnel shaped passage which connects the nasal cavity to the larynx and oesophagus, it has three regions in order from highest to lowest these are, the nasopharynx, the oropharynx and the laryngopharynx.
What are the key points about the nasopharynx?
posterior to nasal cavity (extending from posterior nares to soft palate. It acts only as an air passage.
During swallows the soft palate and uvula will wing posteriorly and superiorly to cover this, preventing food from entering the nasal cavity. Auditory tubes (ears) drain from the middle ear into this layer. Mucosa on the posterior wall of the pharynx contains lymphoid tissue (known as the pharyngeal tonsils, or adenoids, these can become infected and restrict air flow).
What are the key points about the oropharynx?
Posterior to oral cavity (mouth), extends from soft palate to the epiglottis (flap of cartilage at the root of the tongue).
Both food and air pass through the oropharynx, the epithelium changes in this region therefore to a stratified, squamous epithelium, protecting the throat from increased friction and chemical trauma of food ingestion. It contains the palatine and lingual tonsils.
What are the key points about the laryngopharynx?
The region below the epiglottis, extends to the larynx, food has the right of way over air and breathing is paused for food.
What does the larynx do? What does it consist of?
Conducts air and protects the airway from collapse. Below the entrance to the oesophagus, cilia trap inhaled debris and propel it towards the pharynx.
Also plays a role in sound production.
It consists of nine cartilages which protect and maintain the open airway, it stretches from the hyoid bone to the oesophagus. The region of the larynx which air and food passes is lined with stratified squamous epithelium while the air only region is respiratory mucosa.
What is the epithelium of the nose like?
The vestibule (just above/inside the nostrils) is lined with skin which contains sebaceous glands (oil), sweat glands and hair follicles for protection. The hairs are known as vibrissae and act to filter particles from the inhaled air. The nasal cavity is lined with olfactory mucosa in the slit like opening at the roof of nasal cavity (contains smell receptors) and the rest is lined with respiratory mucosa).
What is respiratory mucosa?
Pseudostratified, ciliated, columnar epithelium, containing goblet cells.
Why do runny noses occur on cold days?
The movement of cilia in the nose creates slow moving current towards the pharynx (continually swallowing it), on cold days the cilia become to cool and stop beating, hence the nose dribbles.
