Lecture 7: Respiratory Histology Flashcards
What two portions can our respiratory system be divided into?
- Conducting portion
- Respiratory portion
Describe the conducting portion of the respiratory sytem
The conduction portion of the respiratory system is includes our:
nasal cavity, paranasal sinuses, nasopharynx, trachea, [primary, secondary and tertiary bronchi], bronchioles and terminal bronchioles.
Role: It collects and warms the air and sends it to our respiratory portion.
Descibe the respiratory portion of the respiratory system.
The respiratory portion of our respiratory system includes:
Respiratory bronchioles, alveolar ducts and alveolar sacs.
Role: Gas exhange
Describe the respiratory epithelium
-Pseudostratified columnar ciliated epithelium with an extensive lamina propia (a rich vascular network)
Located in the airways of the respiratory system.
What are the cells of the respiratory epithelium? (3)
- Ciliated columar epithelial cells
- Goblet cells-> secrete granules to produce a mucous layer, which collects substances.
- Stem cells (non-ciliated basal cells)
What are goblet cells? Describe them.
Goblet cells are modified columnar epithelial cells.
Mucigen granules, located in the cytoplasm, are released via exocytosis and combine with water to form mucus.
The stem of the golblet cell has a basal nucleus and many organnels
The nasal cavities are divided by what?
Nasal septum
What are the three regions of the nasal cavity?
- Nasal vestibule
- Respiratory region
- Olfactory region
What is the function of the nasal cavity?
Adjusts temperature and humidity of inspired air.
The [turbinate bones] enhances this process by increasing the SA.
Nasal vestibule
Cell type?
Located?
- Keratinized stratified squamous epithelium
- Located just inside the nostril and is lined by skin.
Respiratory region
Cell type?
Location?
- Pseurostratified columnar ciliated epithelium
- Located posterior to the nasal vestibule.
- Inferior 2/3 of the nasal cavity and lined with respiratory muscosa
Olfactory region
Cell type?
Location?
Fx?
-Pseudostratified columnar ciliated epithelium
EXCEPT; it is way thicker than the respiratory epithelium and does NOT have goblet cells.
-Located at the apex (superior 1/3 portion of the nasal cavity) and lined with olfactory mucosa
- Has receptors for smell and has our olfactory glands, that has serous secretiosns that dissolve odorant molecules.
What are the cell types in the olfactory mucosa?
1. Olfactory receptor cells
2. Basal cells
3. Brush cells
4. Supporting/sustentacular cells
Describe olfactory receptor cells.
- Have one dendrite process
- Non-motile cilia with odorant receptors
- When a ligand binds to the receptors, it sends the signal to the [olfactory bulb]
What are basal cells?
Stem cells for olfactory receptors and supporting cells
What are brush cells?
Ciliated columnar epithelial cells
What are supporting/sustentacular cells?
Give mechanical and metabolic support to the olfactory receptor cells.
How are the cells of the olfactory epithelium arranged?
Superficial–> deep
- Supporting/sustentacular cells and the mucuous layer
- Olfactory neurons
- Basal cells (deep in the basement membrane).
Below the basal cells, in the basement membrane, is the lamina propria.
As we go from the conducting portion–> respiratory portion of the respiratory system, how does the respiratory epithelium change in size?
It becomes thinner.
As we go from the conducting portion–> respiratory portion of the respiratory system, how does the amount of goblet cells change?
Equal amounts until our main bronchus, then decreases, ending at our bronchioles.
Thus, trachea has more than main bronchus.
Main bronchus has more than lobar bronchus.
Lobar bronchus has more than the segmental
As we go from the conducting portion–> respiratory portion of the respiratory system, how does the amount of ciliated cells, glands and hyaline cartilage change?
Ciliated cells- Equal amount from trachea- segmental bronchus, then decreases, with them ending at the respiratory bronchioles.
Glands- Equal amounts from trachea- segmental bronchus, then decreases and end at the the segmental bronchus.
Hyaline cartilage- decreases and ends at the segmental bronchus.
As we go from the conducting portion–> respiratory portion of the respiratory system, how does the amount of smooth muscle and elastic fibers change?
Smooth muscle- equal amounts until the segmental bronchus, then decreases and ends at the alveaolar duct.
Elastic fibers- Equal amounts until the respiratory bronchioles, then decreases until alveoli.