respiratory development Flashcards
what occurs during week 4:
the lower respiratory organs begin to develop (trachea, pharynx, larynx, and lungs) with the emergence of the layngotracheal groove
week 4
-laryngotracheal groove
starts as an indentation at the midline on a week 4 embryo, caudal to the pharyngeal pouches, responsible for the growth and development of lower respiratory organs
end of week 4
-what happens to the laryngotracheal groove
-evaginates to form laryngotracheal diverticulum: outpouching that forms a respiratory bud
end of week 4:
-respiratory bud
evaginates further from the caudal end of the laryngotracheal diverticulum. gives rise to primary bronchial buds
end of week 4
-what occurs when the primary bronchial buds grow further
yield the secondary and tertiary buds which are growing laterally into the pericardioperitoneal canals (future pleural cavities), grows into the coelom.
end of week 5:
the bronchial buds give rise to the bronchi, while the connection of the bronchial buds to the trachea enlarge to form the main bronchus
-bronchial tree is established
-left and right asymmetry is present
week 7:
-branching is completed
-segmental bronchi are present but not mature, the segmental bronchi primordia with its mesenchyme will form the basis for the bronchopulmonary segment
week 7
the mesenchyme:
gives rise to the cartilage capillaries, bronchial smooth muscle, CT, pulmonary CT
week 7
lungs
grow and take on a layer of visceral pleura derived from splanchnic mesoderm, does not feel pain
week 7:
pleural cavities:
expand into the body wall mesenchyme and take on a layer of parietal pleural derived from somatic mesoderm: does feel pain
embryonic period week 4-7
3 branchings are completed
- laryngotracheal diverticulum forms (growth in cranial/caudal direction)
- primary bronchial buds are formed: (growth in lateral direction); trachea and larynx form out into the coelom
- primary bronchi begin to differ: left and right side differences are beginning; 3 lobes on right and 2 on left
Pseudoglandular period week 5-17:
-the fourth branching emerges: tertiary bronchi
-14 additional branchings will yield the true bronchial tree and terminal bronchioles: bronchial tree is completed
-all major respiratory dev has begun with the exception of gas exchange
-terminal sacs have not yet dev, cant survive.
canalicular period: week 16-25
-terminal bronchioles continue to mature and divide into two or more respiratory bronchioles
-the surrounding tissue becomes highly vascularized, necessary for eventual gas exchange and completion is essential for surivival
-terminal sacs have begun to develop at the ends of respiratory brionchiles
what are two key components for gas exahnge
epithelium needs to be thin and enough capillaries surrounding
terminal sac period: week 24-late fetal period week 36
-terminal sacs continue to develop
-epthelial ling gets thinner
-the communication between epithelial and endothelial tissue at this stage is the precursor to blood-air barriers in mature lungs
-vascularization continues
-capillaries and lymphatic vessels multiply
alveolar period: week 36-8 years
-terminal sacs continue to multiply
-epithelium continues to thin and gas exchange occurs more
-the capillary network increases
-lung ultimately matures
pleurisy
-injury to the pleural
-the parietal pleura can be sensitive to pain because of its intercostal and phrenic nerve innervation (somatic mesoderm)
-rubbing of the pleural layers can cause roughed patches
-pain is referred to the thoracic and abdominal body walls and or the root of the neck and shoulder, lack of serous fluid
pulmonary collapse
a collapsed lung happens when too much air enters the pleural cavity
-the surface tension that adheres the visceral to parietal pleura is eliminated and the elasticity of the lung causes the lung to shrink within its own pleural cavity
thoracocentesis
procedure that involves the insertion of a hypodermic needle through a intercostal space into the pleural cavity for aspiration of pathologic material
-needle is inserted superior to the rib, high enough to avoid collateral damage costodiaphragmatic recess; ribs 9-11
lung cancer
higher in cigarette smokers, erode cilia. can quit and try to let the lungs improve
-treatment: removal of a long, rare due to metastasis
-other factors: genetic predisposition, interstitial lung disease and env pollution
auscultation of lungs
-must include root of the neck
-anteriorly, laterally, posterior, and near apex (above first rib)
pneuomothorax
entry of air into the pleural cavity as a result of a penetrated wound or fractured ribs
hydrothorax
accumulation of a suficient amount of fluid in the pleural cavity may result from a pleural effusion
hemothorax
accumulation of blood, freq resulting from an injury toa major intercostal vessel rather than a lung laceration
chylothorax
accumulation of lymph from a thoracic duct, major emergency
