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
If the lung root is sectioned before (medial to) the branching of the primary bronchus and pulmonary artery, the general arrangement is?
Pulmonary artery: superiormost on the left (superior lobar bronchus may be superiormost on the right)
Superior and inferior pulmonary veins: anteriormost and inferiormost, respectively
Main bronchus: against and approximately in the middle of the posterior boundary, with the bronchial vessels coursing on its outer surface
what is the hilum of the lung?
a wedge-shaped area on the mediastinal surface of each lung through which the structures forming the root of the lung pass to enter or exit the lung
what are the characteristics of the lung? medially?
Medial to the hilum, the lung root is enclosed within the pleural sleeve – the area of continuity between the parietal and visceral pleura
what are the characteristics of the lung? inferiorly?
Inferior to the root this continuity of pleura forms the pulmonary ligament extending between the lung and the mediastinum
the right lung is higher on the right side?T/F?
true and also shorter and wider than the left
T/F, the anterior border of the right lung is relatively straight?
T
how do the fissures of the lung divide it?
Horizontal and oblique fissures divide the right lung into superior, middle, and inferior lobes
where does the root of the lung pass?
under the arch of the aorta, posterior to the right atrium, and under the arch of the azygos vein
what are the most poster structures within the root of the lung?
The right bronchus and its branches
where do the pulmonary artery and veins pass?
The pulmonary artery passes anterior to the bronchus, and the pulmonary veins lie anterior and inferior to the artery
what is the fissure that divides the left lung?
a single oblique fissure that divides it into superior and inferior lobes
what is the significance of the indentation along the anterior border of the superior lobe?
the cardiac notch – that accommodates the leftward projection of the apex of the heart
what is the lingual?
a thin tongue of tissue from the superior lobe
what does the lingula form?
the inferior border of the cardiac notch and moves into and out of the costomediastinal recess during respiration
how do the aortic arch and descending aorta pass the left lung?
The aortic arch crosses over the left bronchus, and the descending aorta passes behind the root of the lung
how is the superior structure for the root of the lung formed?
The left pulmonary artery arches over the left bronchus which allows the Pulmonary veins pass anterior and inferior to the bronchus
what does the tacheobronchial tree consist of?
the trachea and the bronchi in the mediastinum and the bronchial tree within the lungs
what are the components of the tacheobronchial tree?
conducting and respiratory components
what forms the conducting component of the tracheobronchial tree?
The trachea and its larger proximal branches
do the distal branches of the tracheobronchial tree have cartilaginous rings?
All but the most distal branches have cartilaginous rings or plates in their walls
what is the Lobar (secondary) bronchi branch?
this is a branch from the main bronchi and one lobar bronchus enters each lobe of the respective lung (three on the right, two on the left)
what does each lobar branch divide?
divides into several segmental (tertiary) bronchi that supply individual bronchopulmonary segments
what are the terminal bronchioles?
are the last branches of the conducting bronchioles and the final part of the conducting airway
what are the bronchopulmonary segments?
the largest subdivisions of a lung lobe
what is unique about each segment of the brochopulmonary segment?
Each segment is an anatomically and functionally independent respiratory unit, therefore they are surgically resectable
Usually 18-20 in number (10 right, 8-10 left)
What is the respiratory component of the tracheobronchial tree is made up of?
passages distal to the terminal bronchioles and is involved in air conduction as well as respiration (seen only histologically)
this is the part of the respiratory system where there are 20 to 25 generations of branching conducting bronchioles that eventually end as terminal bronchioles?
the tracheobronchial tree
what does each terminal bronchiole give rise too?
several generations of respiratory bronchioles – characterized by scattered, thin-walled outpocketings (alveoli) that extend from their lumens
what is the basic structural unit of gas exchange?
The pulmonary alveolus
the single celled walls of this structure give are designed for efficient gas exchange?
the alveoli
what are the two components to the circulation of the lungs?
Pulmonary circulation
Bronchial circulation
what is pulmonary circulation?
gas exchange within the lungs
what is bronchial circulation?
nutrition of the structures making up the root of the lungs, supporting tissues, and the visceral pleura
how many pulmonary arteries and pulmonary veins does each lung have?
Each lung has one pulmonary artery and two pulmonary veins
where do the pulmonary arteries arise from?
the pulmonary trunk at the sternal angle
what are the branches of the pulmonary trunk? what do these follow?
The pulmonary arteries, these transport deoxygenated blood to the capillary network surrounding the respiratory alveoli
branches of the pulmonary arteries follow branches of the bronchial tree
what are the pulmonary veins?
Each lung has superior and inferior pulmonary veins draining oxygen-rich blood to the left atrium
where do the pulmonary veins arise?
from the capillary beds surrounding the alveoli
what do the pulmonary veins form?
two pulmonary veins within each lung which traverse the hilum to carry oxygenated blood to the left atrium of the heart
what are the branches of the thoracic aorta?
Bronchial arteries that supply the bronchial tree, connective tissue of the lungs, and visceral pleura
how do the bronchial arteries travel?
along the posterior aspect of the main bronchi and eventually anastamose with distal branches of pulmonary arteries
how many branches go to the right and left lung?
one branch to the right and two to the left
Typically one branch to the right and two to the left lung
Right – may arise from the aorta or from a posterior intercostal artery or left superior bronchial artery
Left – typically arise from the thoracic aorta
where does the one branch to the right arise?
may arise from the aorta or from a posterior intercostal artery or left superior bronchial artery
where do the two branches to the left lung arise?
typically arise from the thoracic aorta
what do the bronchial veins drain?
drain only the proximal portion of the root of the lung and terminate in the azygos vein and accessory azygos vein or superior intercostal veins
where does the blood draining from the remaining lung structures go to?
drains into pulmonary veins to travel with oxygenated blood to the left atrium
what are the two types of lymphatic plexi?
the superficial lymphatic plexus and the deep lymphatic plexus
what is the superficial lymphatic plexus? drain?
deep to the visceral pleura, drains the pleura and lung tissue
Lymphatic vessels from this superficial plexus drain into the bronchopulmonary lymph nodes (hilar lymph nodes)
what is the deep lymphatic plexus? drain?
within the walls of the bronchi – drains structures associated with the root of the lung
The deep plexus drains initially into intrinsic pulmonary lymph nodes located along lobar bronchi and then into hilar lymph nodes
what do both superficial and deep plexuses drain into?
they drain into the superior and inferior tracheobronchial lymph nodes
where does the Lymph from the tracheobronchial lymph nodes pass?
to the right and left bronchomediastinal lymph trunks
where does the bronchomediastinal lymph trunks terminate?
Usually terminate on each side at the venous angles (junctions of internal jugular and subclavian veins) but may join the right lymphatic duct or the thoracic duct
what plexus innervates the lungs, bronchial tree, and visceral pleura? what nervous system controls this and describe the nerve networks?
the pulmonary plexus; These nerve networks contain parasympathetic, sympathetic, and visceral afferent fibers
describe the output of the parasympathetic fibers?
CN X that are bronchoconstrictors, vasodilators, and secretomotor to glands
what are the sympathetic fibers?
are bronchodilators, vasoconstrictors, and inhibit glandular secretions
what do the visceral afferent fibers carry?
information involved in cough reflexes, stretch reception, blood pressure, chemoreception, and nociception (response to harmful or potentially harmful stimuli)
what is the parietal pleura innervated by?
somatic nerves of the thoracic wall and is extremely sensitive to pain
with respect to the parietal pleura, what do the intercostal nerves innervate?
the costal surface and phrenic nerves innervate the mediastinal and diaphragmatic surfaces
with respect to the parietal pleura, irritation of parietal pleura are areas supplied by this nerve and referred to dermatomes _____ on the neck and shoulder?
phrenic nerve; C3-C5
