Respiratory System Part 1 Flashcards
Embryologically, respiratory tract originates as outgrowth of the
GI tract
Respiratory system derived from — —
laryngotracheal groove
Develops along — — — — ~ 4th week of development
ventral midline of posterior pharynx
Later develops into — —, an outgrowth of —
respiratory diverticulum
esophagus
Grows into & interacts with surrounding
mesoderm
1’ functions include (3)
air conduction, filtration, & gas exchange
2’ functions include (2)
olfaction (sense of smell) in nasal cavity
& phonation (vocalization—speech) from larynx (voicebox)
Respiration divided into (2)
mechanical respiration & cellular
respiration
Mechanicalrespiration associated with lungs—functions
in
gas exchange (O2 & CO2)
O2 carried to tissues for
cellular respiration (oxidative metabolism => ATP, energy)
Diaphragm
thin, dome-shaped muscle, separates thoracic cavity from abdominal cavity in mammals
With inspiration
intercostal Mm contract, raise ribs; simultaneously, diaphragm contracts (lowers) => increases intrathoracic volume => negative pressure in thorax => inspiration
With expiration
intercostal Mm relax, lower ribs; diaphragm relaxes (raises) => decrease intrathoracic volume => increase intrathoracic pressure => expiration
Pleural cavities lined by
simple, squamous to cuboidal mesothelium
mesothelium overlays thin layer of connective tissue containing
elastic fibers
These two layers collectively referred to as
pleura
Pleura lining thoracic wall is
parietal pleura
parietal pleura is continuous with outer surface of lung as
visceral pleura
Two layers (visceral & parietal) separated by space — — containing — –
pleural space
pleural fluid
pleural fluid acts as — to
lubricant, decrease friction
Pleural space normally contains
partial vacuum resulting in
negative
intrathoracic pressure
pleural space assists with
inspiration
Breach of pleural space results in
pneumothorax
positive intrathoracic pressure, difficulty
breathing & collapsed lung
pneumothorax
Remains unilateral due to
mediastinum
mediastinum
loose connective
tissue layer, separating L & R
hemithoraces
Air enters upper respiratory
tract at
nostrils
nostrils
external
nares
what do external nares open into?
vestibule
Vestibule contains —, help
filter & trap particulate
matter
hairs
hairs are also known as — and incorrectly
called
sinus hairs, vibrissae
Vibrissae are
“sinus
hairs”, meaning the hair
follicle is surrounded by a
blood-filled sinus
Vibrissae
Large sensory hairs, aka
“whiskers” in dogs, cats,
rodents
Air then enters
nasal
cavity
nasal
cavity contains
thin,
scroll-shaped bones,
nasal turbinates/
conchae
nasal cavity is lined with
moist, pseudostratified, ciliated, columnar epithelium
covered by mucus
Nasal cavity also contains
olfactory receptors (bipolar
neurons) for sense of smell;
synapse with olfactory N (CN
I)
Olfactory epithelium also
contains small #’s of
brush
cells
brush
cells
columnar cells with
apical microvilli
Generalized sensory cells of
olfactory & respiratory
epithelia
brush cells
Air then travels into
2
paranasal sinuses &
nasopharynx(series of
interconnected spaces)