Lecture 24: Respiratory System Flashcards
Functionally, the structures of the respiratory system can be subdivided into what three categories?
- Conductive system
- Transitional system
- Gas exchange system
The conductive system includes the
- Nasal cavity
- Pharynx
- Larynx
- Trachea
- Bronchi
The transitional system is composed of
Terminal bronchioles
The gas exchange system is composed of
- Respiratory bronchioles
- Alveoli
What system brings air to the respiratory portion?
The conducting system
What does the conducting system do to the incoming air?
Cleanses, moistens, and warms it
What regulates the temperature of the inhaled air?
Blood in the venous plexuses in the mucous membrane of the nasal cavity
What do the hair and secretions in the nasal cavity do?
Trap particulate matter
Transitional system
A transition zone between the conducting and gas exchange areas of the respiratory tree
Terminal bronchioles are lined by
- Club cells
- Non-ciliated secretory cells
- A few ciliated cells
Do healthy bronchioles have goblet cells?
Nope
Alveoli
Thin-walled structures enveloped by a rich network of pulmonary capillaries
Alveoli are lined by
Epithelial type 1 and type 2 pneumonocytes
Non-specific defense mechanisms of the respiratory system
- Mucous trapping
- Mucociliary clearance
- Phagocytosis
- Air turbulence
Specific defense mechanisms of the respiratory system
- Antibody production
- Antibody-mediated phagocytosis
- Cell-mediated immunity
Nasal cavity, pharynx, trachea, and bronchi are mostly lined by what epithelium?
Psuedostratified ciliated columnar with secretory goblet cells and submucosal serous cells
The respiratory portion of the nasal cavity is lined by what epithelium?
Psuedostratified columnar epithelium with goblet cells
The lamina propria of the nasal cavity contains what glands for olfaction?
Bowman’s glands: Tubulo-alveolar glands that are mainly serous, with lesser number of mucous and mixed glands
What supports the lamina propria in the nasal cavity?
Submucosa
Where are olfactory sensory cells located?
The olfactory epithelium in the nasal cavity
Three regions of each half of the bone supported cavity which is divided by the nasal cartilaginous septum
- Vestibular region
- Respiratory region
- Olfactory region
Vestibular region of the nasal cavity
- Initial, external part of the nasal cavity
- Has a cutaneous mucous membrane, haired skin, and glands
The vestibular region of the nasal cavity is lined by what kind of epithelium?
Stratified squamous keratinized epithelium
What is the largest part of the nasal cavity?
The respiratory region
The respiratory region of the nasal cavity is lined by what kind of epithelium?
Psuedostratified columnar ciliated epithelium with goblet cells
Mucociliary apparatus
- Combination of cells in the respiratory region of the nasal cavity
- Responsible for clearance
Conchae turbinates
- Projections from the lateral wall of the respiratory region of the nasal cavity
- Narrow the lumen of the nasal cavity and increase the area of contact of inhaled air with respiratory mucous membrane
- Regulates the quality and quantity of inhaled air
How does the mucociliary apparatus clean the upper respiratory passages?
- Goblet cells produce mucinogen granules
- Movement of cilia removes mucus with trapped inhaled particles
Goblet cell reactions to injury
- Hyperplasia (increased numbers)
- Metaplasia (change from ciliated stratified epithelium to squamous stratified epithelium)
Tips of the cilia of epithelial cells
- Have claws of dynein
- Beat in unison
Immotile cilia syndrome
Dynein claws are missing from cilia
Where is the olfactory region of the nasal cavity located?
The dorsal part
Is olfactory epithelium thicker or thinner that respiratory epithelium
Much thicker
Cells of the olfactory region of the nasal cavity
- Olfactory neurons
- Sustentacular cells
- Basal cells
Does the olfactory epithelium have goblet cells?
Nope
The lamina propria in the olfactory region contains what?
- Serous olfactory glands
- Non-myelinated axons of olfactory neurons that form nerve bundles Cr. N. 1
Where are swell bodies located?
Olfactory and respiratory regions of the nasal cavity
What is the vomeronasal organ used for?
Chemoreception and sexual behavior
The larynx includes
- Cartilage
- Vocal folds
- Skeletal muscle
Initial part of the larynx is lined by what epithelium?
Stratified squamous epithelium
After the vocal cords, the larynx is lined by what epithelium?
Psuedostratified ciliated columnar epithelium
The trachea is lined by what epithelium?
Ciliated psuedostratified columnar epithelium
What are not clearly demarcated in the trachea?
Lamina propria and submucosa
Where are serous glands seen in the trachea?
The lamina propria/submucosa
What completes the wall of the trachea?
A connective tissue adventitia
Brochus has plates of what kind of cartilage?
Hyaline
Bronchi are lined by what kind of epithelium?
Ciliated psuedostratified columnar epithelium
Mixed seromucous glands in the bronchus secrete
- Mucin
- Lactoferrin
- Lysozyme
Bronchi branch into
bronchioles
Bronchioles lack
cartilage and glands
Bronchioles are subdivided into
- Terminal bronchioles
- Respiratory bronchioles
Terminal bronchioles are lined by what?
Ciliated cuboidal cells with few to no goblet cells
Is a muscularis mucosae still present in terminal bronchioles?
Yup
Where are Club cells located?
They bulge at the surface of the terminal and respiratory bronchioles
Purpose of the club cells
- Source of surfactant-like substance which aids in maintaining patency of airway
- Metabolize airborne toxins, may have immune function
Function of the respiratory bronchiole
Conduction and gas exchange
Respiratory bronchioles are lined by what epithelium?
Ciliated cuboidal epithelium, which becomes flattened distally
Respiratory bronchioles have an incomplete
Muscularis mucosae
Respiratory bronchioles subdivide into
alveolar ducts
Alveolar ducts empty into
alveolar sac and alveoli
Walls of alveolar ducts are composed of ____ and lined with what kind of epithelium?
- Alveoli
- Simple squamous epithelial cells
The edge surrounding the opening of each alveoli of an alveolar duct contains
smooth muscle cells
What gives the lip of the alveolus a knob-like appearance on sections?
The presence of smooth muscle
Do alveolar sacs have smooth muscle?
Nope
Alveoli are lined by two distinct epithelial cells:
- Pneumocytes type 1
- Pneumocytes type 2
Pulmonary edema
Alveolar spaces are filled with proteinaceous fluid
Neighboring alveoli connect with each other via
Alveolar pores of Kohn
Purpose of the alveolar pores of Kohn
- Provides equalization of pressure and collateral ventilation if a bronchiole is obstructed
- Allow macrophage passage from one alveolus to another
Pneumocyte type 1 cells compose ___% of alveolar surface area
95
Pneumocyte type 1 cell structure
Extremely thin, have occluding junctions to prevent fluid passages
What is a desired function in pneumonocyte type 1 cells?
Gas permeability
Are pneumocyte type 1 cells mitotic?
Nope
Where are organelles located in pneumocyte type 1 cells?
Grouped around nucleus
Pneumocyte type 2 cells account of __% of the alveolar surface area?
5
Surfactant is produced by
Lamellar bodies of pneumocyte type 2 cells
Are pneumocyte type 2 cells mitotic?
- They can be.
- Produces both Type 1 and Type 2
Surfactant composition
Mono-molecular layer of phospholipoprotein
Functions of surfactant
Reduces surface tension, which reduces effort needed to inflate alveoli, which prevents alveolar collapse
What stimulates the production of surfactant in fetus just prior to parturition?
Cortisol
Hyaline membrane disease
Absence of surfactant in newborns
Blood-air barrier is composed of
- The vascular epithelium
- Basement membrane of the endothelial cell
- Basement membrane of the type 1 pneumocyte
- Cytoplasm of type 1 pneumocyte
Pulmonary macrophages
- Alveolar
- Intravascular
Are there lymph nodes in alveolar nodes?
Nope
Lungs are covered by the ____ pleural, which is composed of _____ ____ and lined by what epithelium?
- Visceral
- Connective tissue
- Simple squamous epithelium
Purpose of CT in the lungs
- Supports bronchial tree
- Separates the lung into lobules