Histology of Respiratory System Flashcards
What is the conduction portion
Air passages that lead to sites of respiration within the lung where gas exchange takes place
What structures are part of the conduction system
Nasal cavities Nasopharynx Larynx Trachea Primary bronchi
What is the respiratory portion
Where gas exchange occurs
What structures make up the respiratory portion
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
Alveoli
Components included in the conducting system
Epithelium Lamina propria Mucous and serous glands Cartilage Smooth muscle Adventitia
What epithelium does respiratory mucosa contain
ciliated pseudostratified columnar epithelium
What five cells does the respiratory region of the nasal cavity consist of
Ciliated cells Goblet cells Brush cells Small granule cells Basal cells
What are ciliated cells
Tall columnar cells with cilia that project into the mucus covering the epithelial surface
What do goblet cells do
Synthesise and secrete mucus
What are brush cells
General name for cells in the respiratory tract that bear short, blunt microvilli
What are small granule cells
Resemble basal cells but contain secretory granules; endocrine cells of DNES
What are Basal cells
lie on basement membrane; stem cells from which other cells arise
What is the lamina propria attached to in the respiratory region of nasal cavity
Periosteum and perichondrium of adjacent bone/cartilage
What is the olfactory region of nasal cavity lined with
Specialised olfactory mucosa
What epithelium does the olfactory region of nasal cavity have
pseudostratified epithelium
What cells do olfactory region of nasal cavity
Olfactory receptor cells
Supporting cells
Basal cells
Brush cells
What are olfactory receptor cells
bipolar olfactory neurons that span the thickness of the epithelium
supporting cells
columnar cells that provide mechanical and metabolic support to ORC
What is larynx formed by
Plates of both hyaline and elastic cartilage
What two folds are formed from mucosa of the larynx
Upper folds - vestibular folds
Lower folds - vocal folds
Difference between vestibular folds and vocal folds
Vestibular is immobile whereas vocal folds are mobile and play a role in phonation
What is the luminal surface of the vocal cords covered with
Stratified squamous epithlium
What is the remainder of larynx covered in
Ciliated pseudostratified columnar epithelium
$ layers of the trachea
Mucosa
Submucosa
Cartilaginous layer
Adventitia
What is the mucosa composed of
Composed of a ciliated pseudostratified epithelium and an elastic, fibre rich lamina propria
What is the Submucosa composed of
Composed of a slightly denser connective tissue than the LP
What is the cartilaginous layer
Composed of C-shaped hyaline cartilage
What is the Adventitia composed of
Composed of connective tissue that binds trachea to adjacent structures
What cells does the tracheal epithelium contain
Ciliated columnar cells Mucous cells (goblet cells) Basal cells Brush cells Small granule cells
What is the identifying feature of the tracheal epithelium
Thick basement membrane
What structural changes occurs when bronchi enters lungs
Cartilage rings replaced by irregular shaped cartilage plates
Plates arranged linearly around the entire circumference of the bronchial wall
Plates become smaller and less numerous as the bronchi decrease in size
addition of smooth muscle to wall of bronchi
What layers can you find in bronchial wall
Mucosa Muscularis Submucosa Cartilage layer Adventitia
What epithelium do large bronchioles have
Ciliated pseudostratified/simple columnar epithelium
What epithelium do small bronchioles have
Simple cuboidal epithelium
What are club cells
non-ciliated, rounded/dome-shaped
What is the first part of the bronchiole tree that allows gas exchange
Respiratory bronchioles
What epithelium are respiratory bronchioles lined with
Cuboidal epithelium
ciliated and club cells both present in the epithelium
How many alveoli is present in each adult lung
150-250 million alveoli
What are alveolar sacs
spaces surrounded by clusters of alveoli
what is the tissue between adjacent alveolar air spaces called
interalveolar septum or septal wall
What does the alveolus contain
Type I alveolar cells
Type II alveolar cells
Macrophages
occasional brush cell
What are type I alveolar cells
Extremely thin squamous cells
Unable to divide
Account for 40% of alveolar lining cells; line around 95% of the alveolar surface
What are type II alveolar cells
Cuboidal cells interspaced among type I cells
line only 5% of the alveolar surface
Account for 60% of alveolar lining
Act as progenitor cells for type I cells
Function of macrophages in alveolus
Work in the air space of the alveolus
Remove debris and particles that have escaped mucus and cilia
