Histology of the respiratory system Flashcards
What are the parts of the respiratory tract?
Conducting part
Respiratory part
What is meant by the conducting part of the respiratory tract?
Air passes through here
but no gas exchange occurs
What are the actual conducting parts of the respiratory tract?
Nasal cavity
Pharynx
Larynx
Trachea
Bronchi
Terminal bronchioles
What is meant by the respiratory part of the respiratory tract?
Where gas exchange takes place
What are the actual respiratory parts of the respiratory tract?
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
Alveoli
What covers the surface of the nasal cavity?
Mucosa
What are the different types of mucosa in the nasal cavity?
Nasal mucosa
Olfactory mucosa
Where are the nasal and olfactory mucosa located in the nasal cavity?
Olfactory mucosa is located in the superior posterior region of the nasal cavity
Nasal mucosa is located everywhere else
What type of epithelium lines the nasal mucosa?
Pseudostratified ciliated epithelium
Goblet cells
What is the function of goblet cells in the nasal mucosa?
Produce mucus
What is the function of mucus in the nasal cavity?
Trap particles, bacteria etc.
What is the function of the cilia in the nasal mucosa?
Beat
waft mucus containing particles, bacteria etc. down to oropharynx to be swallowed
What does the lamina propria of the nasal mucosa contain?
Serous glands, mucous glands
Lots of blood vessels
What is the function of the mucous glands in the nasal mucosa?
Secrete mucus
What is the function of the serous glands in the nasal mucosa?
Secrete watery substance
What is the function of the watery substance secreted by the serous glands in the nasal mucosa?
Humidify the inspired air
What is the function of the rich blood supply of the nasal mucosa?
Warms the inspired air
How does the olfactory mucosa compare to the nasal mucosa?
Contains olfactory neurons
What is the function of the olfactory neurons?
Special sensory - smell
What is the wall of the trachea made up of?
Mucosa
Submucosa
Hyaline cartilage
Adventitia
What type of epithelium lines the mucosa of the trachea?
Pseudostratified ciliated epithelium
Goblet cells in between
What is significant about the basement membrane of the epithelium of the trachea?
Thick
What does the submucosa of the trachea contain?
Seromucous glands
Trachealis muscle
What is the function of the seromucous glands in the submucosa of the trachea?
Secrete watery-mucus substance
What is the function of the hyaline cartilage in the trachea?
Prevent collapse of the trachea during inspiration
What shape is the hyaline cartilage of the trachea?
C shaped rings
How does the trachealis muscle relate the C-shaped rings of hyaline cartilage?
Trachealis muscle joins the free ends of the C-shaped rings
What is the function of the smooth muscle outside of the lamina propria in the primary bronchi?
Contracts to give bronchoconstriction
Relaxes to give bronchodilation
How do the walls of the primary bronchi compare to the wall of the trachea?
Primary bronchi have layer of smooth muscle outside of lamina propria
In primary bronchi, the hyaline cartilage forms a complete circle, not C-shaped
How do the walls of the secondary and tertiary bronchi compare to the walls of the primary bronchi?
In secondary and tertiary bronchi, the hyaline cartilage forms a crescent shape, not a complete circle
How do the walls of terminal bronchioles compare to the walls of secondary and tertiary bronchi?
Terminal bronchiole has simple ciliated columnar epithelium, Clare cells, no goblet cells
Terminal bronchiole has no seromucous glands in its submucosa
Terminal bronchiole has no cartilage
How do the walls of respiratory bronchioles compare to the walls of terminal bronchioles?
Respiratory bronchioles have simple cuboidal epithelium
What is the function of Clara cells?
Produce surfactant
Why are there no seromucous glands and goblet cells in the terminal bronchioles?
Bronchioles have narrow lumen
mucus would narrow the lumen, close the lumen
If the walls of terminal bronchioles have no cartilage, how are they held open during inspiration?
By the pull of the surrounding alveoli
What is an alveolar sac?
Air space which many alveoli open into
What is an alveolar duct?
Airway which many alveoli open into
What are the walls of alveoli made up of?
Simple squamous epithelial cells
Macrophages
Pulmonary capillaries
Elastic and reticular fibres
What are the types of simple squamous epithelial cells lining alveoli? Which is more common?
Type 1 pneumocytes - more common
Type 2 pneumocytes
What is the function of type 1 pneumocytes in the alveoli?
Gas exchange
What is the function of type 2 pneumocytes in the alveoli?
Produce and secrete surfactant
What lies between the pneumocytes and the pulmonary capillaries?
Basement membrane of both the endothelium of the pulmonary capillaries and of the pneumocytes fused together as one
How are the type 2 pneumocytes differentiated from the type 1 pneumocytes?
Type 2 pneumocytes contain lamellar bodies
What are lamellar bodies of type 2 pneumocytes?
Vesicles containing surfactant
What happens to the lamellar bodies of type 2 pneumocytes?
Exocytosed
What is the function of the macrophages of the alveoli?
To phagocyose particles or bacteria in the alveoli
How does the lumen of the respiratory tract change as you go down the tract?
Decreases in diameter
How does the thickness of the walls of the respiratory tract change as you go down the tract?
Decrease in thickness