unit 8 Flashcards
what are the conducting portions of the respiratory system?
nasal cavities
nasopharynx
larynx
trachea
primary bronchi to terminal bronchi
what are the respiratory portions of the respiratory system?
respiratory bronchioles
alveoli
what are the functions of the respiratory system?
air conduction
air filtration
gas exchange
carries stimuli for sense of smell
sound production
regulation of immune response to inhaled antigens
what are the nasal cavities?
bony and cartilaginous paired chambers
communicates anteriorly through the nares and posteriorly with nasopharynx through choanae
communicates with paranasal sinuses and nasolacrimal duct
epithelium of the vestibule of the nares
stratified squamous, keratinized or nonkeratinized & lamina propria
what do sebaceous glands do in the nares?
help entrap particles
what are vibrissae?
hairs in the vestibule of the nares
what happens posterior to the vestibule?
transition to pseudo stratified epithelium
sebaceous glands are absent
where is the olfactory region located?
at the dome of each nasal cavity
what are the specialized olfactory mucosa?
pseudostratified, olfactory receptor, supporting, basal, brush
what are olfactory receptor cells? what is special about them?
bipolar neurons that span the thickness of the epithelium
modified cilia that extend into overlying mucus
what are supporting cells? what is special about them?
columnar cells, more apical microvilli and abundant mitochondria
only adherens junctions are present
what do supporting cells do?
provide mechanical and metabolic support for olfactory receptor cells
secrete odorant binding proteins
what are basal cells? what is special about them?
stem cells which give rise to olfactory receptor cells and supporting cells
small, round cells, located close to basal lamina
what are brush cells? what is special about them?
columnar cell with microvilli on apical surface
bitter taste receptors present
basal surface is in contact with nerve fibers from CN III
what are brush cells involved in?
transduction of general and chemo sensation from the mucosa
what are Bowman’s (olfactory) glands?
tubuloalveolar serous gland
what do Bowman’s glands do?
deliver proteinaceous secretions to olfactory surface
serve as trap and solvent for odoriferous substances
what are the five cell types in the respiratory mucosa?
ciliated, goblet, brush, small granule, basal
what is lined by the respiratory mucosa?
bony trabeculae
what is in the respiratory mucosa?
pseudostratified ciliated columnar epithelium, basement membrane, lamina propria, extensive network of veins
what does lamina propria attach to in the nasal cavity?
periosteum and perichondrium of adjacent bone/cartilage
support in the larynx
provided by irregularly shaped plates of hyaline and elastic cartilage
what does the mucosa form in the larynx?
two folds, vestibular and vocal
space between is the ventricle
vestibular folds epithelium
pseudostratified ciliated columnar, contains seromucous glands within
vocal folds epithelium
nonkeratinized stratified squamous epithelium
muscular area near it
what is the vestibule of the larynx made of?
psuedostratified ciliated columnar epithelium (where epithelium transitions between the folds)
what are the four definable layers of the trachea and bronchi?
mucosa, submucosa, cartilaginous, adventitia
what is the epithelium of trachea and bronchi made of
PSCC, goblet cells, basal cells, small granule cells, brush cells
what is the lamina propria of the trachea and bronchi made of?
where is it located?
basement membrane and elastic fibers
deep to the basal lamina
what is the submucosa
dense CT with mucous and seromucous glands, rich blood and lymph supply
cartilaginous trachea and bronchi
C-shaped hyaline cartilage
keeps trachea from collapsing on self
adventitia
CT that binds the trachea to adjacent structures, with smooth muscle
what are small granule cells
aka enteroendocrine cells
occur singly and are sparsely dispersed
located near basement membrane
more cytoplasm than basal cells
what do small granule cells do?
secrete catecholamine, serotonin, calcitonin, gastrin releasing peptide
where is the basement membrane? what does it contain?
beneath tracheal epithelium
appears glassy or homogenous light-staining layer
contains densely packed collagenous fibers
what is lamina propria
dense CT, collagenous and elastic fibers
what does lamina propria contain?
lymphocytes, plasma cells, mast cells, eosinophils, fibroblasts
lymphatic tissue
extensive elastic fibers near boundary
what is the elastic membrane?
boundary between mucosa and submucosa
what is submucosa?
dense CT
contains diffuse lymphatic tissue and lymphatic nodules
large distributing vessels and lymphatics
what are the submucosal glands?
mucous and serous
ducts with simple cuboidal epithelium
most numerous on posterior aspect of trachea where hyaline cartilage is lacking
what does submucosa blend with?
perichondrium of cartilage layer
where is adventitia found? what does it contain?
peripheral to cartilages and trachealis muscle
contains large blood/lymphatics vessels, nerves
what does adventitia do?
binds trachea to adjacent structures in neck
what is involved in the muco-ciliary escalator?
goblet cells, submucosal glands, ciliary cells
what is the function of the muco-ciliary escalator?
goblet cells release gel and submucosal cells release a solution
there is a balance between the solution and gel
this allows the cilia to beat freely
what are complications of the muco-ciliary escalator?
kartagener’s syndrome (dynein) - immotile
excess serous secretion
excess mucus production
what are the five layers of the bronchi?
mucosa
muscularis mucosa (SM, long elastic fibers)
submucosa (glands/adipose)
cartilage (plates)
adventitia (moderately dense CT)
what is different about the mucosa of the bronchi?
height of the cells decreases, BM reduces, lamina propria reduces
what are distinguishing features of the bronchi layers?
irregular shaped cartilage plates that become smaller and less numerous
circular layer of SM that decreases as cartilage decreases and may appear discontinuous
bronchiole mucosa
simple, ciliated columnar to cuboidal
contains Clara cells
NO glands or goblet cells
what are Clara cells? what do they do?
dome shaped, serous material
secrete surface active agent that prevents lumen adhesion (secretory protein is CC16)
bronchiole adventitia
smooth muscle with no cartilaginous plates except maybe at branching points
respiratory bronchioles
transition zone
allow for both air conduction and gas exchange
respiratory bronchioles histology
ciliated cuboidal cells with alveolar out pockets
alveoli lined by capillaries
no goblet cells, few Clara cells, gradual loss of cilia
what are alveolar ducts
elongated airways that have almost no wall, only alveoli as their peripheral boundary
rings of smooth muscle
what are alveolar sacs?
spaces surrounded by clusters of alveoli
what are alveoli
terminal air spaces of the respiratory system surrounded by a network of capillaries
site of gas exchange
alveoli histology
simple squamous epithelium composed of pneumocytes which rest on a basal lamina
what is a type I pneumocyte
flat-squamous cell with a large SA for gas exchange
40% of the cells, 95% of alveolar surface
what are type I pneumocytes connected by
occluding junctions and desmosomes
what are type II pneumocytes
cuboidal shape, bulge into airspace
usually located in corners where alveoli meet
5% of surface, 60% of cells
what do type II pneumocytes do
contain lamellar bodies that produce surfactant
what do alveolar macrophages do
remove inhaled particulate fro air spaces
they may pass up the bronchial tree in the mucus to be disposed of
where are septal macrophages found
CT of inter alveolar septa
what do brush cells in the alveolar wall do
monitor air quality
what is the air blood barrier
cells and cell products that gases must diffuse across between alveolar and capillary compartments
what are the needs for gas exchange to occur
surfactant, type I pneumocyte, epithelium BM, CT, endothelium BM, endothelium cell, dust cell
