Lecture 14 Flashcards
What is the role of the respiratory system?
Conduct clean, warm and moist air in close proximity with the circulatory system’s blood for gas exchange
What does the respiratory system need to be efficient?
A surface for gas exchange, a path for air to flow to reach the gas exchange surface in optimal condition, the ability to draw breath in and out and production of sound and smell
What are the main components of the respiratory system?
Upper respiratory tract, lower respiratory tract, thoracic cavity, joins and respiratory muscles
What is the conducting zone?
From the nose to the bronchioles. Functions is to ensure air is warm, clean and moist
What is the respiratory zone?
From the bronchioles to alveoli. Function is gas exchange
What is the function of the nasal cavity?
Olfaction
What is the function of the oral cavity?
A passage for air and food
What is the general change in composition of epithelia as you move down the respiratory tract?
Becomes increasingly flattened. E.g. columnar -> squamose
What are the components of a mucosa tract?
Epithelium is attached via a basement membrane to a connective tissue lamina propria
Why does the epithelium change along the respiratory tract?
To reflect function
What is the conducting region composed of?
Respiratory epithelium
What is the oral cavity composed of?
Stratified squamose epithelia to create a barrier protecting against abrasions
What is the respiratory zone composed of?
Simple squamose epithelia for efficient gas exchange
What is the olfaction zone composed of?
Olfactory mucosa
What is a gland?
A group of mucus-secreting cells that combine. Can be found in the mucosal layer or submucosa layer
What is the submucosal layer?
Connective tissue that may contain glands
What is the name of respiratory epithelium?
Pseudostratified ciliated columnar epithelium with goblet cells
What does pseudostratified mean?
All cells are directly attached to the basement membrane giving simple epithelia however the allusion of stratified epithelia is created
What are the basal cells of the respiratory epithelium?
The regenerative stem cells which divide and replenish the above layers
What is a goblet cell?
Mucus producing cell which traps debris and moistens the air
What is the function of cilia?
They beat in tandem, moving mucus which may contain debris towards the pharynx to be swallowed and broken down by the stomach acid
What are the components of the URT?
Nose and nasal cavity, paranasal sinuses, pharynx
What is the function of the paranasal sinuses?
Resonating chambers for speech
How does olfaction occur?
Through sensory receptors for smell
What is the composition of the nose?
Soft and flexible cartilage, external nares, 2x nasal bones, vestibule lined with skin
What is the function of the nasal cartilage?
To maintain a patent airway
What is within the vestibule?
Sebaceous and sweat glands, hair follicles, vibrissae to filter inhaled air
What is the nasal septum
The midline separating the left side from the right side of the nose. Anterior is cartilage and posterior is bone
The internal nares open into the…?
Nasopharynx
What is the floor of the nasal cavity formed by?
Hard and soft palates
What are the conchae?
Three projections (superior, middle, inferior) which are covered in respiratory epithelium and swirl inspired air to make particles stick to the mucosa and allowing more time for warming and humidifying the air. Plus olfaction
Where are the conchae?
On the lateral walls
What is nasal epithelium composed of?
Mostly respiratory epithelium but also a specialised area on the roof of the nasal cavity, above the superior conchae with olfactory epithelium which contains olfactory nerve fibres, receptor cells, support cells and olfactory dendrites.
What is nasal mucosa?
Epithelium which sits on lamina propria with thin walled vascular plexus that help warm incoming air. When air temp drops, plexus dilates and more heat is transferred. Where nose bleeds generally originate.
What are the paranasal sinuses?
Cavities within the bones surrounding the nose which are lined with respiratory mucosa and drain into the pharynx
Where are the paranasal sinuses found?
Within the frontal, sphenoid, ethmoid and maxillary bones
What is the function of the paranasal sinuses?
To lighten the skull and increase the surface area to clean, warm and moisten the air. Also involved in sound resonance
What is the pharynx?
The throat
The pharynx is a…?
Muscular funnel-shaped tube shared by respiratory and digestive epithelium
What are the three regions of the pharynx?
The nasopharynx, the oropharynx and the laryngopharynx
What is the nasopharynx?
An air passage only! Posterior to the nasal cavity from the nares to the soft palate. Auditory tubes drain here from the middle ear to maintain pressure and the pharyngeal tonsils are on the posterior wall
What is the function of the soft palate and uvula?
To block the nasopharynx during swallowing to prevent food from entering the nasal cavity
What is the oropharynx?
An air and food passageway with stratified squamous epithelium to protect against abrasions. Posterior to the nasal cavity from the soft palate to the hyoid bone. Contains the palatine tonsils and lingual tonsils
What is the laryngopharynx?
An air and food passageway with stratified squamose epithelium. From the hyoid bone to the opening of the larynx/beginning of the oesophagus. Ends at the level where respiratory and digestive tracts diverge
