Lea Lecture Lungs Flashcards
the lung is not in the pleural cavity it is….
surrounded by the pleural cavity
according to Dr. Lea
does anything penetrate the pleural cavity?
no it only contains a small amount of lubricating fluid
what is sibson’s fascia?
suprapleural membrane at the apex (thickened portion of the endothoracic fascia)
what is the upper respiratory tract
- Nose/nasal cavities/paranasal sinuses
- Pharynx
- Larynx
what is the lower respiratory tract
- Trachea
- Bronchi
- Lungs
what do the pulmonary cavities contain?
lungs
pleura
pleural cavity
what is the tracheobronchial tree
multiple levels of airway branching from trachea to alveoli (18-22 divisions)
where does the trachea start and where does it run in the superior mediastinum
starts at CV6 and runs through the midline of the superior mediastinum
when does the trachea bifurcate into right and left primary main bronchi
at the transverse thoracic plane (T4-T5)
what is the trachea composed of?
C-shaped hyaline cartilage bars
filled in posteriorly with longitudinal smooth muscle called trachealis (one of the only smooth muscle we name in the body)
what is the carina
last cartilage ring located at bifurcation of trachea; projects into lumen; identifiable on broncoscopy and on chest x-ray.
what is the vascular supply to the trachea
bronchial and inferior thyroid vessels
what is the lymphatic supply to the trachea
paratracheal lymph nodes
what is the innervation of the trachea
recurrent laryngeal branches of vagus nerves
what can cause the carina to become distorted?
Certain pathologies (bronchial carcinomas),due to spread of metastatic cancer cells into tracheobronchial (carinal) lymph nodes.
why do foreign objects typically lodge in the right bronchus
Right bronchus is wider, shorter, and more vertically oriented than the left bronchus
what do the primary bronchi give rise to and what is the difference in the right and left sides?
give rise to secondary (lobar) bronchi;
3 on the right (b/c there are 3 lobes on the right)
2 on the left (2 lobes on the left)
what do secondary bronchi give rise to?
further branch into tertiary (segmental) bronchi;
10 bronchopulmonary segments on the right
8 segments on the left
supply bronchopulmonary segments which are the smallest individually functional unit of the lung
what do tertiary branches give rise to?
branch 18 - 20 times;
bronchioles give rise to alveolar ducts;
alveolar ducts give rise to alveoli (thin-walled structures which compose the parenchyma of the lungs and are visualized using microscopy
what are the two pleural layers
what are they composed of?
what is their function?
what do they secrete?
parietal and visceral
- Composed of simple squamous epithelial cells + thin layer of loose connective tissue.
- Provide smooth surface for the lungs to move on during respiration.
- Secrete serosal fluid (a watery secretion derived from the blood supply) which fills the pleural cavity and provides lubrication.
what is the visceral pleura
- Intimately adherent to all external surfaces of the lungs (including fissures).
- Continuous with parietal pleura at the hilum of the lung.
what does the parietal pleura line
internal surface of thoracic wall
what are the surfaces of the parietal pleura
a. Costal
b. Diaphragmatic
c. Mediastinal – lines mediastinal surfaces; continuous with the visceral pleural at the root of the lung;
d. Cervical – extends superiorly into the root of the neck reaching its apex slightly superior to the neck of the first rib; reinforced by the suprapleural membrane (which is the thickened portion of the endothoracic fascia)
what forms the pulmonary ligament
what is the function of the pulmonary ligament
mediastinal surface of the parietal pleura and the visceral pleura
this inferior extension of pleura assists in maintaining position of lung in thoracic cavity
what is the vertebral line of reflection
costal pleura becomes continuous with mediastinal pleura posteriorly.
what is the costal line of reflection
costal pleura becomes continuous with diaphragmatic pleura inferiorly.
what is the sternal line of reflection
costal pleura becomes continuous with mediastinal pleura anteriorly
why is the extension of the cervical pleura (part of parietal pleura) into the root of the neck clinically important
may be punctured as a result of wounds in this region.
what happens if the pleura membranes become inflamed due to disease (pleuritis or pleurisy)?
they become rough and no longer slide easily over one another.
why is pleuritis painful?
because the parietal pleura receives extensive sensory innervation from intercostal and phrenic nerves. Thus, pain is referred to the area of the thoracic wall or to the point of the shoulder via the phrenic nerve(C3,4,5). The visceral pleura sensory nerves travel with autonomic fibers of the bronchial vessels.
what is the clinical significance of the left sternal reflection that passes inferiorly in medial plane to the level of the 4th costal cartilage and then turns laterally and inferiorly to the level of the 6th costal cartilage?
it creates a cardiac notch that allows a small part of the pericardium to be in direct contact with the anterior thoracic wall (bare area of the heart)
*** important for pericardiocentesis
what is the inferior level of the parietal pleura and the visceral pleura at the midclavicular line
visceral–> 6th rib
parietal–> 8th rib
what is the inferior level of the parietal pleura and the visceral pleura at the midaxillary line
visceral–> 8th rib
parietal –> 10th rib
what is the inferior level of the parietal pleura and the visceral pleura at the scapular line
visceral –> 10th rib
parietal –> 12th rib
what is a pleural recess?
Areas of pleural cavity which the lungs do not completely occupy during quiet respiration;
Two layers of parietal pleura come into contact with each other.
at 2 and 4 they are pretty much together
what is the costomediastinal pleural recess
where mediastinal pleura contacts costal pleura anteriorly
what is the costodiaphragmatic pleural recess
clinical significance?
where costal pleura contacts diaphragmatic pleura (around periphery of diaphragm).
The costodiaphragmatic recess can inadvertently be damaged during procedures or injuries in the abdomen.
what is pneumothorax
Pneumothorax results from puncture of the visceral or parietal pleura (from a broken rib, ice pick, emphysema etc)
This allows air to enter the pleural cavity and this potential space becomes a real space. When the pleural cavity is compromised, the natural elasticity of lung causes it to collapse.
Air (pneumothorax), blood (hemothorax), or fluid (hydrothorax; chylothorax) may accumulate in pleural recesses and must be aspirated to allow the lungs to reinflate once the pleura heals.
what is tension pneumothorax
It is caused by a loss of integrity of the visceral or parietal pleura resulting in air entering the pleural space, however the air is unable to exit.
Thus, a one-way valve is created. With each breath more air accumulates in the pleural space and intrathoracic pressure becomes high.
The increased pressure will cause a shift in mediastinal contents to the contralateral side. This compromizes venous return through the superior and inferior venae cavae.
what are the signs of tension pneumothorax?
distended neck veins
muffled heart sounds
hypotension due to low cardiac output
called Beck’s triad***
what if Dr. Lea attacked zach with an ice pick laterally?
skin-> superficial fascia–> external intercostal –> internal intercostal–> innermost intercostal–> endothoracic fascia–> parietal pleural–> pleural cavity–> visceral pleura–> lung
OUCH
A 25 y/o male presents to the ED with a ice pick stab wound to the left thoracic wall at the level of the 9th intercostal space near the MAL (mid axillary line). The patient displays dyspnea, cyanosis, and lack of breath sounds on the left. The knife most likely damaged which of the following structures?
costodiaphragmatic recess
what are the surface projections of the left and right lung s
there is something specific about the left lungs surface projection
Right Lung
- Apex – extends to level of neck of first rib.
- At midclavicular line, lung projects inferiorly to rib 6.
- At midaxillary line, lung projects inferiorly to rib 8.
- At scapular line, lung projects inferiorly to rib 10.
Left Lung
a. Apex – extends to level of neck of first rib.
b. At midsternal line, lung projects inferiorly to rib 4, then turns inferolaterally to 6th rib at MCL. This sharp lateral turn creates the cardiac notch.
c. At midaxillary line, lung projects inferiorly to rib 8.
d. At scapular line, lung projects inferiorly to rib 10.
what is the apex?
the cupula
top most part of lung
what are the surfaces of the lungs
costal
mediastinal
diaphragmatic
what is the hilum
the area where all structures enter and leave the lung
located on the mediastinal surface of the lung
how many fissures and lobes does the right lung have
- 2 fissures (oblique and horizontal) thus,
2. 3 lobes (superior, middle, inferior)
how many fissures and lobes does the left lung have
- 1 fissure (oblique) thus,
- 2 lobes (superior, inferior)
- Cardiac notch and Lingula
where do the oblique fissures start and where do they course
- The oblique fissures (of right and left lungs) begin posteriorly at the level of the 4th rib. They pass anteroinferiorly, crossing the 4th and 5th intercostal spaces, to the 6th rib and costal cartilage anteriorly.
what is the landmark for the horizontal fissure of the right lung
follows the course of the 4th rib
what are the 6 structures that enter the root of the lung
- Pulmonary artery
- Pulmonary veins (superior and inferior)
- Primary bronchi (right superior lobar bronchus may branch within root of lung)
- Bronchial arteries and veins (typically 1 on right and 2 on left)
- Pulmonary plexus of nerves
- Lymphatic vessels and lymph nodes
what are the bronchopulmonary segments ?
what is it supplied by (air and blood)
how are they separated
what runs between the segments?
- Smallest functional unit of the lung.
- Area supplied by 1 tertiary bronchus and associated branch of pulmonary artery.
- Separated from adjacent segments by connective tissue septa.
- Pulmonary veins run between bronchopulmonary segments (i.e. intersegmentally)
where do disease of the lung typically localize and why is this clinically relevant
typically localize to a bronchopulmonary segment
these segments can be surgically resected without altering function of other segments
pneumonectomy
remove one lung
lobectomy
remove one lobe
segmentectomy
remove a bronchopulmonary segment
what does the pulmonary circulation consist of?
pulmonary arteries
pulmonary veins
what do the pulmonary arteries carry?
where do they originate
what do they branch and course with
what do they supply
- Carry poorly-oxygenated blood from right ventricle to lungs.
- Originate from the pulmonary trunk (artery) at the sternal angle.
- Branch and course with the bronchial airways.
- Supply distal portions of the tracheobronchial tree (small bronchioles and alveoli) and visceral pleura.
what do the pulmonary veins carry
where do they originate
superior and inferior veins
- Return oxygenated blood to the left atrium.
- Originate from capillary beds around alveoli and course intersegmentally. (within the intersegmental connective tissue.)
what is a pulmonary embolism and what does it do
Pulmonary embolism results when a blood clot (usually from the lower extremities) enters a pulmonary artery or one of its branches and blocks blood flow to a portion of the lung.
This is a life-threatening condition due to decreases in blood oxygenation and obstruction of pulmonary blood flow.
Large emboli (blocking the main pulmonary artery) result in acute respiratory distress and often lead to death in a matter of seconds to minutes.
Smaller emboli result in pulmonary infarction.
where do the bronchial arteries originate
how many on the right vs. left
where does the right often originate?
what do the bronchial arteries supply?
- Originate from thoracic aorta.
- Typically two on the left and one on the right; the right often originates from 3rd right posterior intercostal artery.
- Courses with the bronchial tree.
- Supply trachea and bronchii.
where do the bronchial veins terminate?
azygos veins
course with the bronchial arteries
where are the pulmonary nodes
within substance of lung; along bronchial tree.
where are the bronchopulmonary nodes
at hilum of lung
where are the tracheobraonchial nodes
at the tracheal bifurcation
what does the superficial lymphatic system drain
what is the path
a. Drains visceral pleura and most of lung parenchyma.
b. Drain to bronchopulmonary nodes → superior and inferior tracheobronchial nodes → bronchomediastinal trunk.
what does the bronchomediastinal trunk drain to on the left and on the right?
right–> right lymphatic duct
left–> thoracic duct
what does the deep pulmonary lympathic system drain?
what is the path
a. Drains larger bronchioles and bronchi.
b. Drain to pulmonary nodes → bronchopulmonary nodes → tracheobronchial nodes → bronchomediastinal trunk
where does lymph from the left inferior lobe drain?
to the right tracheobronchial nodes
what does sympathetic input do to bronchial smooth muscle?
dilation
vasoconstriction
inhibit gland secretion
what does parasympathetic input do to bronchial smooth muscle
bronchoconstriction
vasodilation
gland secretion
what are the main sympathetic supply to the lungs
thoracic cardiopulmonary splanchnic nerves
Postganglionic nerve cell processes form cardiac branches which are called cardiopulmonary splanchnic nerves. (c.f. Most other “splanchnic’’ nerves are preganglionic.)
where do preganglionic nerve cell bodies of sympathetic innervation to the lungs sit?
T2-T6 segments of the spinal cord, processes enter sympathetic chain
where are the postganglionic nerve cell bodies of sympathetic innervation to the lungs
located in upper thoracic and cervical
portions of the sympathetic chain ganglia.
what is the afferent output of the nerves of lungs
acute pain
where do the preganglionic nerve cell bodies of the parasympathetic innervaiton to the lungs sit?
in the brain stem, processes travel with the VAGUS nerve.
b. In the thorax, the vagus gives off thoracic cardiac parasympathetic branches.
where are postganglionic nerve cell bodies of the parasympathetic innervation
in the wall of the airways ***
NOTE: innervation of the parietal pleura is via nerves supplying the thoracic wall including the intercostal and phrenic…. thus pain is referred where?
to the area of the thoracic wall supplied by the intercostal nerve or to the root of the neck/shoulder via phrenic nerve
what are the afferents of the visceral pleura
afferents piggybacking sympathetics (about T2-T5)
what is the cough reflex (bronchial sensation)
via afferent fibers of vagus
A 7 y/o male with a history of asthma attacks presents with difficulty breathing and obvious wheezing sounds with each breath. What is the most likely mechanism mediating this patient’s symptoms?
Increased parasympathetic stimulation to tracheobronchial tree
what is tension pneumothorax
air in thoracic cavity with mediastinal shift leading to decreased venous return ergo decreased cardiac output (symptoms include distended neck veins, hypotension, muffled heart tones Beck’s triad)
what is hemothorax
blood in thoracic cavity
empyema
pus in thoracic cavity
chylothorax
chyle(lymphatic fluid) in thoracic cavity
what is horner’s syndrome
Ptosis- upper lip droops
Myosis- constricted pupils
Anhidrosis- loss of sweating on one side of the face
what is a pancoast tumor
Pancoast (tumor) syndrome results from a malignant neoplasm of the superior lobe of the lung with destructive lesions of the thoracic inlet and involvement of the brachial plexus and cervical sympathetic ganglion (stellate ganglion).
Symptoms include:
Severe pain in the shoulder region radiating toward the axilla and scapula
Pain along the ulnar aspect of the muscles of the hand
3) Atrophy of hand and arm muscles
4) Horner’s syndrome= “ptosis, miosis and anhidrosis”
what is virchow’s node
abnormally enlargedlymph node(s) in the leftsupraclavicular fossa. They get
their supply fromlymph vessels in the breast, thorax and abdominal cavity.
(Virchow’s node is also sometimes called “the seat of the devil” given its ominous association with malignant disease.)
usually having to do with breast cancer
