Respiratory System II Flashcards
how do the right and left pulmonary cavities flank the mediastinum?
laterally and anteriorly, extend superiorly above the costal cartilage of the first rib and inferiorly to the diaphragm
what is the pulmonary pleura?
a fibroserous membrane that surrounds each lung and lines the pulmonary cavities
what are the two layers of the pleura?
parietal and visceral pleura
what does the parietal pleura line?
the inner wall of the thoracic cavity, the superior surface of the diaphragm, and the mediastinum (named according to location)
what does the visceral pleura cover?
the surface of the lungs and extends into its fissures
what is the cervical pleura reinforced by?
by the suprapleural membrane– a fibrous extension of the endothoracic fascia and forms a cup-like dome over the apex of the lung (pleural cupula)
what is the pleural cavity?
the potential space between the visceral and parietal layers of pleura
what does the pleural cavity contain?
a thin layer of serous fluid to lubricate adjacent surfaces, facilitate movement of the lungs, and maintain surface tension
compare the lung and visceral pleura to the outer wall of the pleural cavity and its parietal pleura? what is the result?
The lung and visceral pleura are smaller than the outer wall of the pleural cavity and its parietal pleura
results in named recesses that accommodate the lungs during inspiration:
Costodiaphragmatic recess
Costomediastinal recess
what is the Costodiaphragmatic recess?
forms where the diaphragmatic pleura reflects from the perimeter of the diaphragm to meet the costal pleura on the thoracic wall
what is the Costomediastinal recess?
forms between the pericardial sac and the sternum, where the mediastinal pleura reflects to meet the costal pleura
what are the lines along which the parietal pleura changes direction as it passes from one wall of the pleural cavity to another called?
sternal, costal, and diaphragmatic
this forms the floor of the thoracic cavity?
the diaphragm
what is the most important muscle of inhalation?
the diaphragm
what is the effect of the diaphragm when it contracts?
it causes it to flatten and increase the volume of the thoracic cavity
what do the intercostal muscles prevent?
prevent the thoracic wall from collapsing under the negative pressure generated when the diaphragm contracts
what happens when the diaphragm and external intercostal muscles contract? what happens to the visceral and parietal pleura
the overall size of the thoracic cavity increases and the lungs are pulled outward
The visceral and parietal pleura are strongly adhered due to the surface tension created by the serous fluid between them
what happens to air flow during inhalation?
Air passively moves into the lungs as this time and gas exchange occurs
what are the accessory muscles of inhalation?
scalenes, pectoralis minor, and sternocleidomastoid and these only act during forced inhalation
when does exhalation occur?
when the diaphragm relaxes and elastic recoil of the lungs and surface tension as the thoracic cavity decrease in size while the diaphragm relaxes upward
what are the accessory muscles of exhalation?
abdominal muscles – only act when air movement out of the lungs is impeded
this is the proximal part of the tracheobronchial tree?
the trachea
where does the trachea descend?
through the superior mediastinum and lies anterior to the esophagus and posterior to the great vessels
how are the walls of the trachea supported?
by C-shaped rings of hyaline cartilage
where does the trachea bifurcate?
at the level of the transverse thoracic plane (T4-T5) into two main bronchi – marked by the carina
describe the right main bronchus?
shorter, wider, and more vertical than the left and is therefore more prone to obstruction by foreign objects
how is blood supplied to the trachea?
by descending branches of the inferior thyroid artery in the neck as well as bronchial arteries that arise from the descending aorta
where does the venous blood of the trachea drain?
to the inferior thyroid veins
what innervates the trachea?
pulmonary plexus
what are the organs of respiration?
their job is to bring inspired air into close relation with venous blood in the pulmonary capillaries
what are the surfaces of the lung?
costal, mediastinal, and diaphragmatic surfaces
describe the costal surfaces?
is large, smooth, and convex, and is related to the costal pleura
describe mediastinal surface?
is concave and includes the hilum which receives the root of the lung
describe the diaphragmatic surfaces?
is also concave (deeper on the right) and forms the base of the lung – the thin, sharp margin projects into the costodiaphragmatic recess
where does the apex of the lungs project?
projects into the neck above the first rib and is covered by cervical pleura
what does the root of the lung connect? where does it enter?
the lung to the mediastinum and contains the pulmonary vessels, nerves, and bronchi; Enters at the lung at the hilum – an indentation on the mediastinal surface
what is unique about the fissures of the lung?
lined by visceral pleura, divide each lung into lobes
Three on the right, two on the left
how are the lungs attached to the mediastinum?
by the roots of the lungs
what are the roots of the lung?
Bronchi, associated bronchial vessels, pulmonary arteries, pulmonary veins, pulmonary plexuses of nerves, and lymphatic vessels