respiratory development

Question 1

what occurs during week 4:

Answer 1

the lower respiratory organs begin to develop (trachea, pharynx, larynx, and lungs) with the emergence of the layngotracheal groove

Question 2

week 4
-laryngotracheal groove

Answer 2

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

Question 3

end of week 4
-what happens to the laryngotracheal groove

Answer 3

-evaginates to form laryngotracheal diverticulum: outpouching that forms a respiratory bud

Question 4

end of week 4:
-respiratory bud

Answer 4

evaginates further from the caudal end of the laryngotracheal diverticulum. gives rise to primary bronchial buds

Question 5

end of week 4
-what occurs when the primary bronchial buds grow further

Answer 5

yield the secondary and tertiary buds which are growing laterally into the pericardioperitoneal canals (future pleural cavities), grows into the coelom.

Question 6

end of week 5:

Answer 6

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

Question 7

week 7:

Answer 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

Question 8

week 7
the mesenchyme:

Answer 8

gives rise to the cartilage capillaries, bronchial smooth muscle, CT, pulmonary CT

Question 9

week 7
lungs

Answer 9

grow and take on a layer of visceral pleura derived from splanchnic mesoderm, does not feel pain

Question 10

week 7:
pleural cavities:

Answer 10

expand into the body wall mesenchyme and take on a layer of parietal pleural derived from somatic mesoderm: does feel pain

Question 11

embryonic period week 4-7
3 branchings are completed

Answer 11

1. laryngotracheal diverticulum forms (growth in cranial/caudal direction)
2. primary bronchial buds are formed: (growth in lateral direction); trachea and larynx form out into the coelom
3. primary bronchi begin to differ: left and right side differences are beginning; 3 lobes on right and 2 on left

Question 12

Pseudoglandular period week 5-17:

Answer 12

-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.

Question 13

canalicular period: week 16-25

Answer 13

-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

Question 14

what are two key components for gas exahnge

Answer 14

epithelium needs to be thin and enough capillaries surrounding

Question 15

terminal sac period: week 24-late fetal period week 36

Answer 15

-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

Question 16

alveolar period: week 36-8 years

Answer 16

-terminal sacs continue to multiply
-epithelium continues to thin and gas exchange occurs more
-the capillary network increases
-lung ultimately matures

Question 17

pleurisy

Answer 17

-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

Question 18

pulmonary collapse

Answer 18

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

Question 19

thoracocentesis

Answer 19

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

Question 20

lung cancer

Answer 20

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

Question 21

auscultation of lungs

Answer 21

-must include root of the neck
-anteriorly, laterally, posterior, and near apex (above first rib)

Question 22

pneuomothorax

Answer 22

entry of air into the pleural cavity as a result of a penetrated wound or fractured ribs

Question 23

hydrothorax

Answer 23

accumulation of a suficient amount of fluid in the pleural cavity may result from a pleural effusion

Question 24

hemothorax

Answer 24

accumulation of blood, freq resulting from an injury toa major intercostal vessel rather than a lung laceration

Question 25

chylothorax

Answer 25

accumulation of lymph from a thoracic duct, major emergency