Respiratory system week 3 Flashcards
Components of the conducting zone of respiratory tract (RT)
nose, pharynx, larynx, trachea, bronchi, bronchioles and terminal bronchioles
Components of respiratory zone of RT
respiratory bronchioles, alveolar ducts, alveolar sacs and the alveoli
Components of the upper RT
nasal cavity through the start of larynx
Components of the lower RT
larynx through to the lungs also contains the whole respiratory zone
functions of nasal passage (4)
- warms and humidifies air
- removal and retention of pathogens/particulate matter (anything bigger than 5-10 nm
- olfaction
- trap and drain paranasal sinuses and lacrimal ducts
What are turbinates?
bone shelf projections, force air into a regular steady flow over mucosal surfaces
What are the components of the mucosa?
- Lamina propria- complex capillary loop system to heat inspired air
- Seromucus glands release water to humidify air and trap air impurities
- Lots of IgA produced by plasma B cells
What are the two types of epithelium in the nasal passage?
- Respiratory epithelium(ciliated pseudostratified columnar) found on inferior and middle turbinates and rest of conducting portion of system
- Olfactory epithelium (specialized pseudostratified) and covers the superior turbinate and roof of nasal cavity.
Components of olfactory epithelium
1. olfactory neruons
ciliated bipolar olfactory neurons with membrane chemoreceptors(axons from CN I)
Components of olfactory epithelium
2. supporting cells
pseudostratified columnar cells that support the olfactory cells
Components of olfactory epithelium
3. basal cells
the stem cells that replace every 2-3 months
Components of olfactory epithelium
4. Brush cells
columnar cells with microvilli. Afferent conncection to CN V (trigeminal)
Components of olfactory epithelium
5. lamina propria contains Bowman’s glands
olfactory glands-produce liquid to facilitate odor detection
The larynx
- passage of air between pharynx and trachea
- rigid wall for protection
- cartilage movements participate in sound production during phonation
- Serves as gate for GI and RT via epiglottis
Histology of larynx
- lingual surface has stratified squamous epithelium
- transition to respiratory epithelium that covers vestibular folds
- vocal cords are covered with stratified squamous epithelium
Trachea
larynx to carina
16-20 C-shaped hyaline cartilage rings
100-120 mm long and 25 mm in diameter
C-rings are joined by smooth muscle called trachealis
Layers of the Trachea 3
- respiratory epithelium(mucosa)
- Lamina propria(tunica fibromusculocartilaginea)
mixed seromucus glands that humidify air - Tunica adventitia
terminal bar components
tight junctions
zonula adherenes
desmosomes
3 cell types in the mucosa of trachea
- mucous goblet cell
- Basal cell-progenitor cells
- Ciliated columnar cell-push stuff up and out
supporting structures of the trachea
C shape hyaline cartilage and trachealis smooth muscle
As you descend the lower RT what alterations occur?
- epithelium height and complexity decreases
- cartilage rings become irregular plates and then go away at the level of the bronchioles
- Trachealis muscle is replaced with bundles of smooth muscle (SM) that spiral airways
- Amount of elastic fibers and SM proportionally increases. Goblet cells and glands decrease
3 layers of bronchi
- mucosa (RE gives to simple ciliated columnar as you go down
- lamina propria (SM, elastic tissue, C-rings give to plates at level of secondary bronchi)
- Adventitia (CT)
Bronchioles
- ciliated simple cuboidal epithelium with some goblet cells
- NO cartilage
Terminal bronchioles
- end of conduction
- Some simple cuboidal ciliated cells
- club cells
- no cartilage, some SM but not much
What are club cells in the terminal bronchioles?
club shaped, non ciliated, secretory granules, secret surfactant and antimicrobial peptides, progenitor cell population
pathway from terminal bronchiole to alveoli
TB->respiratory bronchiole->alveolar duct->alveolar sac
->alveoli
Alveoli
Structural and functional unit of lung
specialized for gas exchange
300 mil/lung
made of simple squamous epithelium
Alveoli structure
- thin sacs separated by inter-alveolar septa
- connected by alveolar pores aka pores of Kohn
- these distribute air evenly
- prevent total loss of ventilation
- aid in spread of of bacteria and neoplasms.
Alveolar cell types
type I
type I physically make up the very thin membrane for gas exchange
make up most of alveolar surface
joined by tight junctions
Alveolar cell types
type II
type II larger cuboidal cells that make surfactant and serve as progenitor cells for tissue renewal
Alveolar cell types
Dust cell
these are the Macs of the alveoli
