Respiratory Flashcards
What are the functions of respiratory epithelium?
Filter, warm and moisten the air
What underlies the respiratory epithelium?
Connective tissue with abundant elastic fibers and both mucous and seromucous glands
What are the five types of cells in respiratory epithelium?
1- Ciliated psuedostratified columnar epithelial cells
2- Mucous goblet cells
3- Brush cells
4- Basal cells
5- Granule cells
What is the most abundant cell type in respiratory epithelium?
Ciliated psuedostratified columnar epithelial cells
What are basal bodies?
The base of cilia on the apical surface of cells
Where are mucous goblet cells the most abundant?
The larynx and trachea
What do mucous goblet cells secrete?
polysaccharide-rich mucous droplets
Do brush cells have microvilli or cilia?ry
they have microvilli
What do the microvilli on brush cells function as?
sensory receptors…..(afferent nerve endings can be found at the basal surface of brush cells)
What three cells types in respiratory epithelium extend from the basement membrane to the lumen?
1- Ciliated psuedostratified columnar epithelial cells
2- Mucous goblet cells
3- Brush cells
What is the function of the basal cells?
Generative cells that undergo mitosis and give rise to other cell types
What are granule cells?
They contain numerous dense granules and may be part of a neuroendocrine system that regulates mucous and serous secretory
What two cell types in respiratory endothelium sit on the basement membrane but DO NOT extend to the lumen?
Basal cells and granule cells
Explain the muco-ciliary elevator/
Inhaled particles become trapped in the mucous layer. The coordinated beating action of the cilia propels the mucous and trapped particles across the aqueous layer and towards the mouth and nose where it is swallowed or expectorated.
What type of cell secretes the mucous layer?
goblet cells and seromucous glands
Where does the mucous layer sit?
It floats on a more aqueous layer that surrounds the beating cilia
What is Katagener syndrome?
Genetic disorder where dynein is not functional or is absent. Results in chronic infections because inhaled microorganisms and particles cannot be effectively cleared from the respiratory tract.
Explain the change in epithelial cells deeper in the respiratory tree:
Ciliated psuedostratified columnar epithelium—> ciliated simple cuboidal —> squamous cells
Which are found deeper in the respiratory tract, gobletcells or cilia? Why?
Cilia…this is to prevent retrograde flow of mucous
What are the parts of the conducting portions of the respiratory tract?
Nasal cavity, paranasal sinus, pharynx, larynx, trachea, bronchi, bronchioles
What are the two main portions of the nasal cavity?
Vestibule and fossae (which is then composed of conchae and meatus)
What three factors characterize the vestible of the nasal cavity?
1- transition from keratinized to respiratory epithelium
2- sebaceous and sweat glands
3- vibrissae (nose hairs)
What are the conchae?
3 projections of bone covered with connective tissue and epithelium
What are swell bodies?
venous plexus in connective tissue of conchae that warm the air
What is the meatus of the nasal cavity?
the space between conchae for air passage that allows for turbulent air flow that warms and moistens air
Which meatus is not lined with respiratory epithelium?
Superior meatus
What are the three types of cells found in the olfactory epithelium?
Supporting cells, olfactory cells, basal cells
What is characteristic of supporting cells?
apical microvilli and apical nuclei
What is characteristic of olfactory cells?
bipolar neurons with a central nucleus
What is characteristic of basal cells?
small and round cells at the base of epithelium with basal nuclei
What do olfactory (Bowman’s) glands produce? Where are they found?
Proteinaceous serous secretions that clear cilia and facilitate access to new odors
They are found in the superior meatus
What line the paranasal sinuses?
Respiratory ciliated epithelium, goblet cells, and small glands
Are the paranasal sinuses connected to the nasal cavity?
Yes, through small passages
What types of epithelium are found in the pharynx?
Dorsally= respiratory epithelium Ventrally= stratified squamous epithelium
What are the two “cords” in the larynx?
False vocal cords and true vocal cords
What are the “upper” cords?
The false vocal cords
What type of epithelium lines the false vocal cords?
respiratory epithelium
What type of epithelium lines the true vocal cords?
stratified squamous epithelium
NON-KERATINIZED
What is the name of the smooth muscle in the true vocal cords?
The vocalis muscle (it alters sound)
What is the name of the ligament in the true vocal cords?
Vocal ligament (made of parallel elastic fibers)
Does the larynx have cartilage?
Yes, it has hyaline cartilage that has skeletal muscle that articulates the cartilage
What is the trachea lined with? What are some characteristics of the trachea?
respiratory epithelium, thick basement membrane, mixed glands and some elastic fibers, REGULAR rings of hyaline cartilage
Do bronchi have cartilage?
Yes, irregular rings or plates
What causes the wavy (folded) appearance of the mucosa of bronchi?
smooth muscle in irregular bands
What are bronchioles?
branches of small bronchi
Is there cartilage present in the bronchioles? Is there smooth muscle?
No cartilage. Smooth muscle is present (in varying amounts)
What cells line the regular bronchioles?
ciliated columnar epithelium, some goblet cells
Where does the majority o regulation of ventilation occur?
At the level of the regular bronchioles because the large cross section area, lack of cartilage, and presence of smooth muscle
Do terminal broncioles have cilia or goblet cells?
They have reduced cilia and do NOT have goblet cells?
What type of cells replace goblet cells in terminal bronchioles?
Clara cells
What is the function of clara cells?
They are tall cells that share the basement membrane with cuboidal epithelium and extend taller than surrounding epithelium.
They have dense granules in their apical cytoplasm containing protein that is secreted along with aqueous solution to moisten the epithelium
Is the mucosa of regular bronchioles wavy? What about the mucosa of terminal bronchioles?
Regulatory bronchioles= wavy
Terminal bronchioles= smooth (because less smooth muscle)
What is VERY characteristic of respiratory bronchioles?
outpocketings of alveoli in bronchiole walls to permit gas exhange
Are goblet cells or cilia preset in respiratory bronchioles?
No goblet cells, few cilia
What are alveolar ducts?
passageways completely lined with alveoli
Are goblet cells, clara cells, or cilia preset in alveolar ducts?
No
What type of epithelium line the alveolar ducts?
simple squamous epithelium
What allows for more regulation of ventilation in alveolar ducts?
smooth muscle knob-like projections of alveolar openings
What is the diffusion path for gases?
Surfactant
Epithelium
Fused basement membrane (basal lamina of epithelium and endothelium)
Endothelium
RBC membrane
What are the types of cells (and %) in the alveolar septum?
Type I epthelium (8%) Type II epithelium (16%) Capillary endothelial (30%) Interstitial (36%) Alveolar macrophages (10%)
Which type of cell forms the majority of lung lining?
Type I epithelium (it is squamous)
Which penumocytes participate in gas exhange?
Type I
Which penumocytes secrete surfactant?
Type II
Which pneumocytes divide to replace Type I and type II?
Type II
What do capillary endothelial cells look like?
very thin, cresent shaped nuclei
What are the interstital cells found in the alveolar septum?
fibroblasts, mast cells, and alveolar macrophages
What are “dust cells”?
alveolar macrophages…they accumulate debris and come from the bone marrow
What is another nae for alveolar pores?
Pores of Kohn
What is the function of alveolar pores?
Equalize aire pressure and promote collateral air circulation
Why is the acellular interstitium critical?
Critical for respiratory mechanics (passive exhalation)
What make up the acellular interstitium?
Collagen (type III)
Elastic fibers
Proteoglycans
What are the three broad categories of host defense?
Acid-base balance
Metabolic
Immunologic
How does the acid-base balance system work?
regulate the amount of carbon dioxide retained in the body which is a short term pH regulator
What are the humoral immunogenic host defense mechanisms?
IgA, IgE, Mast cells, BALT
What are BALTs?
Bronchially Associated Lymphoid Tissue….it is dense accumulations of lymphoid tissue
