Respiratory System Flashcards
respiratory portion
respiratory bronchioles aveolar ducts aveolar scas alveoli Exchange of gases bet air and blood Maximize surface area
conducting airways
nasal cavities paranasal sinuses pharynx larynx trachea bronchi
structure of conducting portion
1) Mucosa - epithelium
2) Lamina propria - underlying CT = loose fibro-elastic CT, may contain lymph
3) Submucosa - fibro-elastic CT
4) Support elements - bone/cartilage/smooth mm
5) Adventitia - CT merging w/ surrounding tissues (when not resting on bone)
Respiratory epithelium
pseudostratified columnar
ciliated cells
goblet cells
Olfactory epithelium
pseudostratified columnar olfactory receptor cells basal cells (lacks goblet cells) thicker than resp epithelium
Bronchiolar epithelium
simple cuboidal -> columnar
Clara cells
Alveolar epithelium
simple epithelium
Type I cells (squamous)
Type II cells (rounded to cuboidal)
Nasal epithelium
minimally keratinized simple squamous epithelium
Respiratory epithelial cell types
5 cell types:
- columnar ciliated cells
- goblet
- brush
- small granule
columnar ciliated cells
type of resp epi
regular motile cilia move mucus
goblet cells
type of resp epi
make and secrete mucus
features; rER, golgi, apical secretory vesicles
Mucus = hydrated mix of glycoproteins and proteoglycans
brush cells
columnar cells with short blunt microvilli
general sensation
innervated by CN V
small granule cells
Bronchial cell of Kulchitsky
diffuse neuroendocrine sys (DNES)
- amine precursor uptake & decarboxylation
Stain w/ silver salts
extrapulmonary bronchi
c-shaped rings of cartilage
same structure as trachea just smaller
smooth mm restricted to cartilage-free border at first
ciliated pseudostrat columnar epi w/goblet cells
intrapulmonary bronchi
complete but broken ring of cartilage
surrounded by lung parenchyma
trachea
Mucosa - cil pseudostrat col epi w/ thick basement membrane (ciliated, goblet, and basal cells)
1) Lamina propria - loose fibro-elastic CT, also contains lymphoid aggregations
2) boundary w/ Submucosa marked by elastic lamina
Submucosa - mixed seromucous glands, blood vessels, larger lymph, ANS ganglia
Cartilaginous/ Smooth mm layer/Fibro-elastic CT
Adventitia - lots of fat, nerve cells, and blood vessels
Primary bronchi divide into
lobar (secondary) bronchi
tertiary (segmental) bronchi
lobar (secondary) bronchi divide into
tertiary (segmental) bronchi
bronchopulmonary segment
supplied by a tertiary bronchus
largest subdivision of a lobe
separated by CT septa
surgically resectable portion - has own conduction system and vascular supply
bronchial mucosa
similar to trachea but smaller lamina propria
spirals of smooth mm (muscularis mucosae) replace elastic fiber layer of trachea - sep mucosa from submucosa
Submucousa - serous and mucous glands become fewer the farther down, ANS ganglia, br of bronchial artery & vein, lymph
Adventia - irregular plates of cartilage
bronchial glands
seromucous
bronchioles
smallest conducting passages lack cartilage lack glands goblet cells only in larger bronchioles smooth mm major component of wall attach to surrounding tissue via elastic fibers
Clara Cells
Bronchiolar (clara) cells inc as # of ciliated cells decrease dome-shaped apical end projects into lumen secrete some protein comp of surfactant degrade toxins stem cells for bronchiolar epithelium
terminal bronchioles
ciliated cuboidal epithelium clara cells NO goblet cells in healthy lungs last part purely conducting must see a resp bronchiole branching from it to say it is truly terminal
respiratory bronchiols
junction between conducting & exchange portion
cuboidal epithelium interrupted by alveoli
clara cell dominate
br 3-8 times, ea br ends in an alveolar duct
alveolar duct
linear arrangement of alveoli
interalveolar septa
smooth mm and collegen III regulate opening into ea alveolus lining the duct
alveolar sac
small clusters of alveoli that open from a common space
alveolus
small outpouching w/ thin-walls that permid gas exchange
alveolar pores - allow airflow between adjacent alveoli keeping pressures equalized
alveolar wall (septum)
thin epi and CT layers
CT - delicate reticular & elastic fibers in Interstitial tissue bet alveoli
Capillary endothelium - simple squa, non-fenestrated type
Alveolar type I and II cells at air surface (epithelial cells)
alveolar type I cells
squamous pulmonary epithelial cell small alveolar cell pneumocyte type 1 cover 95% of alveolar surface provide intact surface of min thickness permeable to gases
alveolar type II
cuboidal
located at septal junctions
numerous as type 1 but only cover 2-5% of alveolar surface
lamellar bodies release pulmonary surfactant (via exocytosis)
pulmonary surfactant
release by lamellar bodies of type II alveolar cells
decreases surface tension and prevents collapse of alveoli
brush cells
found infrequently in alveolar epithelium
thought to be sensory receptor cells
alveolar pores (pores of Kohn)
permit airflow bet adjacent alveoli, keeping pressures equalized
imp in obstructive disease prevents normal passage of air to some alveoli
also used by macrophhages, pathogens etc
alveolar macrophage
alveolar phagocyte/dust cell derived from monocytes enter lung via bloodstream in CT and on alveolar surface phagocytose RBCs - yellow
alveolar wall (inter-alveolar septum)
Thin region - basal lamina of cap and alveolar epi merge - minimal blood-air interface
Thick region - epi retain own basal lamina, CT also contains some elastic and reticular fibers
elastic fibers important for collapse of alveolus during exhalation
major site of fluid accum in pulmonary edema
bronchial arterial system
systemic circ, br of aorta
supplies oxy blood to tissues of airway walls and pleura
extend as fara as terminal bronchioles then anastomose w/ pulmonary arteries
bronchial veins
only drain the CT of the hilar region of the lungs (hilar = hilum = root)
lung pleura
two layers:
Visceral - covers lung
Parietal - covers chest wall and diaphragm
meet at hilar root
Pleural mesothelium rest on thin layer of collagen and elastic CT, cuboidal -> columnar
parietal pleural lymphatics
major exit rout of liquid from the pleural space
- stomas -> collecting lymphatics -> infracostal lymphatics -> parasternal and periaortic nodes -> thoracic duct -> systemic venous system
innvervation of pleura
visceral portion not innervated
pain is from parietal pleura
