Respiratory System Flashcards
respiratory system components
- conduits for air passage
- muscle and CT for movement of gases
- gas exchange tissues
respiratory system function
conduction of air
- conditioning of air
- gas exchange
- host defense
inspiration
- lung inflates and has neg pressure
- active at rest through contraction of external intercostals and diaphragm
expiration
- deflates lung and pressure becomes pos
- passive at rest through the elastic recoil properties of the connective tissue in the lungs and chest wall
air conditioning
- inspired air is filtered to prevent entry of pathogens or irritants
- inspired air is warmed and humidified to promote gas exchange and to prevent tissue damage due to cold air or desiccation
gas exchange
- highly specialized epithelia
- maximize SA
- minimize diffusion distance
respiratory epithelia
- conduction portion is pseudostratified columnar with cilia-extend to apical lumen
- gas exchange is simple squamous
respiratory epithelia 2
- ciliated psuedostratified columnar cells to apical lumen
- mucous goblet cells-to apical lumen
- brush cells-sensory receptors-to lumen-have micro-vili not cilia
- basal cells regenerate
- granule cells are neuroendocrine
mucociliary elevator
- coordinated beating of cilia toward exit
- particles trapped in mucous floating on aq layer
- cilia deeper in resp tract that goblet cells to prevent retrograde cells
kartagener syndrome
- dynein dysfunction
- no ciliary beating
- resp infections
conducting portion
- nasal cavity
- larynx
- trachea
- bronchi
- bronchioles-regular and terminal
nasal cavity-vestibule
- transition from keritinized to resp epithelium
- sebaceous and sweat glands
- vibrissae for filtration
nasal cavity-fossae
- chambers in skull separated by septum
- 3 conchae-bony projections covered with epithelium
- 3 meati-spaces between conchae
nasal meati and conchae
- dense venous plexus-warmth and humidity
- inferior and middle-ciliated pseudostratified columnar epithelium
- superior has olfactory epithelium
countercurrent exchange
- blood gives heat and goes toward cold
- air gains heat and goes to hot
- heat exchange the whole time
olfactory epithelium
- 10 sq cm of supperior conchae
- supporting cells
- olfactory cells
supporting cells of olfactory epi
microvilli not cilia, apical nuclei
olfactory cells
-bipolar neurons, basal nuclei
basal cells in olfactory epi
-basal cells, regenerative cells, basal layer
paranasal sinus
- chambers in bones of skull lined with respiratory epithelium
- connected to nasal cavity via small passages
larynx
- connects pharynx and trachea
- epiglottis prevents food entering trachea
- vocal cords permit phonation
- vestibular fold
- true vocal fold
vestibular fold
- false vocal cord
- respiratory epithelium
- serous glands in the lamina propria
- lie superior to vocal cords
- no dense ligaments or skeletal muscle
true vocal cords
- phonation
- vocal ligament-fibroelastic
- vocalis muscle-skeletal
- stratified squamous epithelium-abrasion resistance
laryngeal cartilage
- thyroid
- cricoid
- subject to calcification
trachea
- 10 cm tube connecting larynx and bonchi
- ciliated pseudostratified columnar epithelium
- goblet cells, mixed serous and mucous glands
- limited elastic fibers
- 16-20 incomplete rings of hyaline cartilage connected dorsally by smooth muscle and fibroelastic ligament
bronchi
- one primary bronchi per side
- 3 lobar bronchi in R 2 in L
- branches of lobar are small bronchi
- histologically similar to trachea but cartilage is irregular and smooth muscle in irregular bands
- postmortem constriction of smooth muscle induces folds
conducting bronchioles
- regular and terminal
- no cartilage
- epithelial transition to ciliated simple columnar/cuboidal
- increase in smooth muscle for ventilation control
- few goblet cells/glands
- clara cells take over secretory function
- regular are mostly columnar with folded intima
- terminal are cuboidal with no folding
respiratory portion
- respiratory bronchioles
- alveolar ducts, sacs, alveoli
respiratory bronchiole
- histologically identical to terminal bronchiole-some cilia remain on cuboidal epithelium
- outpockets of alveoli in bronchiolar walls permits gas exchange
alveolar ducts
- air passage completely lined with alveolar openings
- simple squamous epithelium
- no cilia or clara cells
- alveolar sacs are common space shared by multiple alveolar openings
alveolar cusps
- at common alveolar openings (sacs, ducts)
- there are knoblike projects containing innervated smooth muscle for regulation of pulmonary ventilation
alveolar septum
- 300 million alveoli
- 150 sq meters of gas exchange surface
- highly specialized epithelium
diffusion path for gas in
- surfactant
- epithelium-two membranes and cytoplasm
- epithelial basal lamina
- endothelial basal lamina (fused as one BM)
- endothelium (2 membranes and cytoplasm)
- RBC membrane
type II alveolar cells
- surfactant source
- regenerative
alveolar cells
- type II
- type I
- endothelial
- dust
- RBC
- fibroblasts, mast cells
type I alveolar cells
-8% by number, 97% by SA
alveolar macrophage
- dust cells
- found from capillary to alveolar space
- bone marrow in origin, differentiate on site
- critical to host defense against inspired pathogens or irritants
acellular alveolar features
- acellular interstitium
- pores of kohn
acellular interstitium
- type III collagen, elastic fibers, proteoglycans
- critical for pulmonary mechanics
pores of kohn
- equalize air pressure between alveoli
- promotes collateral air circulation
pulmonary circulation
- nutrient-systemic-brings oxygen and nutrients to lung tissue, found in submucosa
- functional, pulmonary-blood from pulm artery to be oxygenated, thin walled, low P, follows bronchial tree, branches to capillaries at sites of gas exchange
pulmonary host defense-acid base balance
-acid base balance- regulate CO2, short term pH regulator
metabolic defense
- pulmonary capillary endothelium
- inactivate bradykinin, serotonin, Ach
- convert angiotensin I to II
immunogenic defense
-cellular
-vibrissae, muco-ciliary elevator
-alveolar macrophages
humoral:
BALT-bronchus-associated lymphoid tissue
-immunoglobulins A and E
-monitor for specific antigens in the resp tree- mast cells reactive to allergens
pleura
- serous membrane which encapsulates entire lung
- fusion of parietal and visceral layers at hilus
- mesothelial layer
innervation
- both SNS and PNS
- regulation of bronchial dilation-ventilation
- poorly localized pain responses
