32 Questions
What is the principal function of the respiratory system?
Air conduction, air filtration, and gas exchange
What is the function of the cartilaginous rings in the trachea?
They keep the lumen of the trachea open
What is the term for the smallest air spaces in the lungs?
Alveoli
What is the location of the main bronchi?
Within the lungs
What is the function of the nasal cavities?
To filter the air
What is the organ that contains a cartilaginous framework?
Larynx
What is the location of the lumen of the trachea?
In the mediastinum
What is the term for the tubes that branch from the main bronchi?
Bronchioles
What is the change observed in the bronchial wall where the cartilage rings are replaced?
By cartilage plates of irregular shape
What is the function of the smooth muscle layer in the bronchial wall?
To regulate the appropriate diameter of the airway
How many bronchopulmonary segments are there in the right lung?
10
What is the composition of the mucosa in the bronchial wall?
Pseudostratified epithelium with the same cellular composition as the trachea
What is the characteristic of the smooth muscle layer in smaller bronchi?
It becomes thinner and more discontinuous
What is the characteristic of the cartilage layer in smaller bronchi?
It becomes thinner and more discontinuous
What is the diameter of bronchioles?
Less than 1 mm
How many bronchial branches does the right bronchus divide into?
3
What is the primary function of the ciliated cells in the tracheal epithelium?
To provide a coordinated sweeping motion of the mucous coat toward the pharynx
What is the distinct feature of the cartilaginous layer of the trachea?
It is composed of C-shaped hyaline cartilages
What is the approximate number of C-shaped hyaline cartilages in the trachea in humans?
16-20
What is the primary function of the mucous cells in the tracheal epithelium?
To produce mucinogen
What is the characteristic of the right main bronchus compared to the left main bronchus?
It is wider and shorter
What is the layer of the trachea that binds it to adjacent structures?
Adventitia
What is the primary function of the respiratory bronchioles?
Both air conduction and gas exchange
What is the characteristic of the lamina propria in the mucosa layer of the trachea?
It is composed of elastic fiber-rich lamina propria
What is the main function of alveoli in the respiratory system?
To facilitate air conduction and gas exchange
What type of epithelium is present in the larger diameter bronchioles?
Ciliated, pseudostratified columnar epithelium
Which cell type is responsible for producing surfactant in the alveoli?
Type II alveolar cells
What is the main function of type II alveolar cells?
To produce surfactant and act as progenitor cells
What is the characteristic of the epithelium in the terminal bronchioles?
Simple ciliated columnar epithelium
What is the function of the alveolar septum?
To contain blood capillaries and facilitate gas exchange
What is the characteristic of type I alveolar cells?
They are extremely thin squamous cells that cannot proliferate
What is the function of cartilage plates in the bronchioles?
There are no cartilage plates in the bronchioles
Study Notes
The Respiratory System
- Consists of paired lungs and a series of air passages that lead to the lungs
- Performs three principal functions: air conduction, air filtration, and gas exchange (respiration)
- Gas exchange occurs in the alveoli
Conducting Portion
- Includes nasal cavities, larynx, trachea, and paired main bronchi
- Located outside and within the lungs
- Trachea is a flexible air tube that extends from the larynx to the thorax and divides into paired main bronchi in the mediastinum
- Paired main bronchi enter the root of the right or left lung
- Within the lungs, the main bronchi undergo extensive branching to give rise to bronchioles
The Respiratory Portion
- Includes respiratory bronchioles, alveolar ducts, and alveoli
- Where gas exchange occurs
Tracheal Wall Structure
- Composed of four definable layers:
- Mucosa: ciliated, pseudostratified epithelium and an elastic fiber-rich lamina propria
- Submucosa: slightly denser connective tissue than the lamina propria
- Cartilaginous layer: C-shaped hyaline cartilages that provide a supporting structure and prevent collapse of the tracheal lumen
- Adventitia: connective tissue that binds the trachea to adjacent structures
Tracheal Epithelium
- Composed of ciliated columnar cells and mucous (goblet) cells
- Ciliated cells are the most numerous and provide a coordinated sweeping motion of the mucous coat toward the pharynx
- Mucous cells are interspersed among the ciliated cells and produce mucinogen
Bronchi and Bronchioles
- Trachea divides into two main bronchi, which further divide into secondary bronchi
- Right bronchus is wider and shorter than the left
- Left lung is divided into two lobes, and the right lung is divided into three lobes
- Each main bronchus divides into secondary bronchi, which then branch into smaller bronchi
- Bronchioles are air-conducting ducts that measure 1 mm or less in diameter
- Terminal bronchioles give rise to respiratory bronchioles
Respiratory Bronchioles and Alveoli
- Respiratory bronchioles are involved in both air conduction and gas exchange
- Alveolar ducts are elongated airways that have almost no walls, only alveoli
- Alveoli are the terminal air spaces of the respiratory system and are the actual sites of gas exchange between air and blood
- Each alveolus is surrounded and separated from one another by a thin connective tissue layer that contains blood capillaries (alveolar septum)
- Alveolar epithelium is composed of type I and II alveolar cells
- Type I alveolar cells are extremely thin, squamous cells that are not capable of cell division
- Type II alveolar cells are cuboidal cells that are interspersed among the type I cells and are progenitor cells for type I alveolar cells
This quiz covers the anatomy and functions of the respiratory system, including the lungs and air passages, and their roles in air conduction, filtration, and gas exchange.
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