Respiratory Histology Flashcards
What structures make up the upper respiratory tract?
- Nasal cavity
- Paranasal sinuses
- Pharynx
- Larynx (proximal half)
What is the main function of the upper respiratory tract`?
To warm, humidify and filter air
What bone is in the nasal cavity?
Has shelves of bone called conchae, or turbinates
What is the function of conchae?
Increase the surface area of the nasal cavity, for rapid warming and humidification of air
What are paranasal sinuses?
Spaces in bones. Produce mucus that drains into the lateral walls of the nasal cavity
What is the function of the larynx?
- When open allows airways into the trachea
- Contains vocal cords that come together close the airways with movement from the epiglottis
- Vibration of these vocal cords produces sound
What is the epiglottis and what is its function?
A flap of tissue that sits beneath the tongue at the back of the throat. Closes over the windpipe while you eat to prevent food entering the airway
What does the conducting airway consist of?
Nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, terminal bronchioles
What is the function of the conducting airway?
To warm, humidify, and filter air
What type of respiratory epithelium does the conducting airway consist of?
Pseudostratified columnar ciliated epithelium with numerous goblet cells
What does the pseudostratified columnar epithelium contain?
- Has ciliated cells
- Goblet cells
- Basal cells (divide to form new cells)
- Basement membrane
- Not visible K cells- neuroendocrine cells
- Underlying lamina propria
What is mucociliary clearance?
Where the cilia beat in a unidirectional fashion to clear the mucus towards the pharynx, containing possible pathogens
-the mucus can then be coughed up or swallowed
What are the different layers of respiratory tract tissue?
- Respiratory mucosa
- Submucosa
- Muscularis/Cariligenous layer
- Adventitia
What does the respiratory mucosa consist of?
- Epithelium, underlying basment membrane and lmaina propria
- Goblet cells that gradually decrease distally
What does the respiratory submucosa consist of?
- Connective tissue containing seromucous glands
- Serous and mucous glands that gradually decrease distally
What does the respiratory muscularis/cartilaginous layer consist of?
- Cartlidge that disappears distally
- Smooth muscle- the amount depends on the region
Describe the bonchial tree
Trachea, bronchi, bronchioles, terminal bronchioles, respiratory broncioles, alveolar ducts, alveolar sacs, alveoli
Describe the histology of the trachea?
- Respiratory mucosa
- Submucosa
- Cartilaginous layer- consisting of 15-20 C-shaped cartlidges and cartlidge bridged posteriorly by smooth muscle and fibroelastin fibres (trachealis)
- Adventitia
What is the trachealis?
The trachelais muscle is a smooth muscle that bridges the free ends of the C shaped cartlidges at the posterior border of the trachea
-function is the constrict the trachea, allowing air to be expelled with more force e.g in coughing
How does the type of epithelium change from the terminal bronchioles to the respiratory bronchioles?
Terminal bronchioles are columar ciliated epithelia with very few goblet cells
Respiratory bronchioles are cuboidal epithelia with no goblet cells but contain clara cells
How does the epithelia change from the trachea to the terminal bronchioles ?
With each division: Less cartlidge Less goblet cells More smooth muscle Introduction of clara cells distally on terminal bronchioles
What are clara cells?
Secretes surfactant - a substance which reduces the surface tension of a surface
What does the lower respiratory system consist of?
Trachea
Bronchi
Bronchioles and alveoli (lungs)
What does the respiratory airway consist of?
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
Alveoli
