Respiratory Flashcards
What structures are included in the proximal conducting portion of the respiratory system?
nasal cavity, paranasal sinuses, nasopharyx and oropharynx, larynx
Where is the esophagus in relation to the conducting portion of respiratory system?
posterior
What kind of epithelium does the conducting portion of resp system have?
pseudostratified columnar with cilia (exceptions: olfactory area of nasal cavity oropharyx, parts of epiglottis and vocal cords)
What type of epithelium do the vocal cords have?
non-keratinized stratified columnar
What structures are included int the distal portion of the conduction respiratory system?
trachea, bronchi, bronchioles (last branch is the terminal bronchiole)
Structure of the trachea
hyaline cartilage (C-shaped partial ring) open posteriorly for expansion and contraction; trachealis (SM) in open part of the C
describe “typical” respiratory epithelium
pseudostratified columnar epithelium w/ cilia
describe more distal/smaller bronchi epithelium
gradual transition to simple columnar epithelium w/ cilia still apparent
describe bronchioles and more distal respiratory structure epithelium
epithelium changes simple low columnar –> cuboidal –> low cuboidal –> simple squamous (at level of gas exchange)
Types of cells in respiratory epithelium (5)
columnar cells w/ cilia “mucociliary escalator”, goblet cells, brush cells, neuroendocrine cells, basal stem cells
brush cells
in respiratory endothelium, have synaptic contact with afferent nerves
bronchus
trachea –> bronchi –> bronchioles; respiratory epithelium; cartilaginous plates maintain rigidity and prevent collapse
bronchiole
most proximal part of respiratory portion; transition ciliated simple columnar –> ciliated simple cuboidal; no cartilage, more SM and elastic fibers; no goblet cells but clara cells
clara cells
found in bronchioles; stem cells that divide and replace other ciliated cells; secrete GAGS (i.e. surfactin-type liquid that lowers surface tension and prevents bronchiole from collapsing on itself); may play detox role
draw a diagram of component transitions, characterizing frequency/type of epithelium, goblet cells, ciliated cells, glands, hyaline cartilage, SM, and elastic fibers from the trachea to alveoli
See slide 18 or 19
Asthma
state of persistent subacute inflammation; inflammatory cells –> mediators and cytokines –> constriction of SM in bronchioles, vascular congestion, edema, increase in mucus production, decrease in mucociliary transport
terminal bronchiole
last part of distal conducting portion of respiratory system; bifurcates into two respiratory bronchioles; alveoli may start budding off wall here
Components of respiratory portion
respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli
alveolar duct
respiratory bronchiole –> alveolar duct –> alveolar sac; lined entirely by alveoli
alveoli
where gaseous exchange occurs; blood-air barrier; fused basal lamina
alveolar septum
made up of a few types of cells: endothelial, type I and II alveolar, interstitial, alveolar macrophages; like walls of hotel room
macrophages in alveoli
macrophages exist within septum tissue and roaming macrophages (“dust cells”) that phagocytose debris
alveolar pores of Kohn
like open doors b/t hotel rooms; equalize pressure and allow collateral circulation of air b/f alveoli (in case air gets blocked ex. w/ mucus)
type I pneumocytes
covers 90% of surface area of alveolus; contains fenestrations (pores of Kohn)
type II pneumocytes
produce pulmonary surfactant, which lowers surface tension and prevents pulmonary collapse; has lamellar bodies; can replicate itself or differentiate into type I (responsible for alveolar epithelial renewal)
ratio of type I to type II pneumocytes
40% type I : 60% type II
alveolar sac
dead-end cluster of alveoli at end of alveolar ducts
lung segment
lung tissue that is serviced by a tertiary bronchus
pulmonary arteries
deliver deoxygenated blood to lungs; travel in close proximity to branches of bronchial tree
how does blood become oxygenated in lungs
circulates in capillaries between and alongside alveoli in order to become oxygenated b/f entering pulmonary vein
pulmonary veins
delivers oxygenated blood back to the heart; located b/t lung segments away from bronchial tree
autonomic nervous supply of resp system - parasympathetic
via vagus nerve; contracts SM –> bronchiole constriction
autonomic nervous supply of resp system - sympathetic
via cardiac nervs; relaxes smooth muscle –> bronchial dilation
what kind of drugs are used to treat asthma?
sympathomimetic
Which part of lung has significant lymphatic drainage?
visceral pleura lymph
Where does lymphatic drainage from the lung go?
hilar lymph nodes at root of the lung