16 Questions
What is the main function of the conducting portion of the respiratory tract?
To conduct air to the respiratory portion
What type of epithelium lines the olfactory area of the nasal cavity?
Olfactory epithelium
What is the main function of the nasal cavity's vestibule?
To direct the air we breathe towards the respiratory area
What is the main component of the submucosa layer of the trachea's wall?
Mucoserous tracheal glands
What is the function of the olfactory epithelium in the nasal cavity?
To respond to odors
What type of epithelium lines the nasopharynx?
Pseudo-stratified ciliated columnar epithelium
What is the main function of the respiratory portion of the respiratory tract?
To facilitate gaseous exchange
What type of cartilage is found in the wall of the trachea?
Hyaline cartilage
What is the difference in the number of lobes between the right and left lungs?
The right lung has one more lobe than the left lung
What type of epithelium lines the large bronchioles?
Simple columnar ciliated epithelium
What is a key difference between the mucosa of intrapulmonary bronchi and extrapulmonary bronchi?
Amount of folding present
What is the function of Clara cells in bronchioles?
To secrete surfactant
What is the composition of the muscle layer in bronchioles?
Circularly arranged smooth muscle fibers
What is absent in the submucosa of intrapulmonary bronchi?
Submucosa itself
What is the diameter of bronchioles?
Less than 1 mm
What type of epithelium lines the alveolar ducts?
Simple cuboidal epithelium
Study Notes
Respiratory System
- The respiratory tract consists of two major divisions: conducting portion and respiratory portion
- Conducting portion: conducts air to the respiratory portion and is characterized by rigid walls (mucosa-submucosa-cartilage layer & adventitia) that keep the airways open
- Respiratory portion: includes structures within the lung where gaseous exchange occurs
The Nasal Cavity
- Divided into three areas: vestibule, respiratory area, and olfactory area
- Vestibule: dilated anterior part lined by skin
- Respiratory area: lined by respiratory mucosa consisting of respiratory epithelium and underlying connective tissue (corium)
- Olfactory area: upper part of the nasal cavity, lined with olfactory mucosa consisting of olfactory epithelium and underlying connective tissue (corium)
The Olfactory Area
- Olfactory epithelium composed of olfactory bipolar nerve cells, supporting cells, and basal cells serving as stem cells for other cells
The Nasopharynx
- Connects the nasal cavity with the larynx
- Lined with pseudo-stratified ciliated columnar epithelium with goblet cells
The Larynx
- Connects the pharynx with the trachea and kept open by cartilages embedded in its wall
The Trachea
- Wall consists of:
- Mucosa: epithelium (respiratory epithelium), connective tissue (corium), and elastic membrane
- Submucosa: loose connective tissue containing mucoserous tracheal glands
- Cartilage and smooth muscle layer (supporting layer): formed of 16-20 C-shaped rings of hyaline cartilage connected posteriorly by trachealis smooth muscle
- Adventitia: formed of loose connective tissue
The Lungs
- Two lungs, right lung has three lobes, and left lung has two lobes
Intrapulmonary Bronchi
- Formed of:
- Mucosa: epithelium (pseudostratified columnar ciliated epithelium with few goblet cells), connective tissue (corium), and no elastic lamina
- Muscle layer: spirally arranged muscle fibers surrounding mucosa
- Adventitia: loose connective tissue containing plates of hyaline cartilage, mucoserous glands, and lymphatic nodules
Bronchioles
- Small airway tubes with a diameter less than 1 mm
- Wall consists of:
- Mucosa: epithelium (simple columnar ciliated epithelium with Clara cells in large bronchioles and simple cuboidal ciliated epithelium with Clara cells in small bronchioles) and lamina propria (connective tissue rich in elastic fibers)
- Muscle layer: well-developed circularly arranged smooth muscle fibers encircling the whole lumen
- Adventitia: connective tissue with no mucoserous glands, cartilaginous plates, or lymphatic nodules
Alveolar Ducts
- Lined with simple cuboidal epithelium
Learn about the two major divisions of the respiratory tract, including the conducting portion and respiratory portion, and their characteristics.
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