Lungs and Mediastinum Flashcards
what is the mediastinum?
central compartment of the thoracic cavity
contains thoracic viscera outside of the lungs
bordered laterally by lungs and pleural cavities
what is the mediastinum bordered by anteriorly
sternum
what is the mediastinum bordered by inferiorly
diaphragm
what is the mediastinum bordered by posteriorly?
thoracic vertebral column
what are the two divisions of the mediastinum
superior and inferior
what seperates the superior mediastinum from the inferior mediastinum
every around and above the manubrium belongs to the superir mediastinum, everything below the manuberium of the sternum belongs to the inferior mediastinum
what viscera belongs to the superior mediastinum?
superior portions of the esophagus and the trachea
What vessels belong to the mediastinum?
arch of the aorta and branches, SVC, and bracgiocephalic veins
what are the divisions of the inferior mediastinum
anterior mediastinum, middle mediastinum, and the posterior mediastinum
where is the anterior mediastinum?
between the sternum and the pericardium (heart)
what gland does the anterior mediastinum contain?
thymus gland
what does the middle mediastinum contain?
heart and roots and great vessels
where is the posterior mediastinum located?
between heart (pericardium) and vertebral column
what does the posterior mediastinum contain
thoracic aorta, inferior esophagus, azygous system (axygoys, homozygous, accessory. homozygous)
what is the thymus gland
lymphoid organ - important site of white blood cell *T cell) maturation and hormone production
where is the thymus gland located?
in the chest, btw lungs and behind sternum
what structures make up the conducting portion of the respiratory system?
nasal cavity, pharynx, larynx, trachea, primary brochi, secondary bronchi, tertiary bronchi, bronchioles, terminal bronchioles
what does the trachea split into the carina?
the right and left primary bronchus
how many lobar/secondary bronchi does the right primary bronchus branch into
3
how many lobar/secondary bronchi does the left primary bronchus branch into
2
what comes affter the lobar bronchi?
the tertiary/segmetnal bronchi
how many tertiary/segmental bronchi are in each lung
9-10
what does each tertiary/segmental bronchi supply?
bronchopulmonary tract/bronchioles and terminal bronchioles
how many lobes does the right lung have?
3
how many lobes does the left lung have?
2
what is a distinguishing factor of the left lung?
cardiac notch
what does the oblique fissure seperate in the left lung
superior and inferior lobe
what does the horixonal fissure seperate in the right lung
the superior and the middle lobe
what does the oblque fissure seperate in the right lung?
the middle and the inferior lobe
what is the hilium of the lung?
depressed surface at the center of the medial surface of the lung - lies anteriorly to the 5th and 7th thoracic vertebrae, it is the point where various structures (mainly vessels) enter and exit lung
in the hilium, which vessel is most superior
pulmonary artery
in the lung which structure is most medial
pulmonary vein
in the lung which structure is most inferior
pulmonary vein
what is the parietal pleura?
pleura that covers the inner surface of the thoracic wall and extends over the diaphragm and mediastinum
what is the visceral pleura?
pleura that covers the outer surfaces of the lungs - and extends the fissures between lobes
what does the potential space between the visceral and parietal pleura contain?
pleural fluid
what does pleural fluid do?
lubricates pleural surface to reduce friction during lung inflation and deflation
what does the respiratory portion include?
respiratory bronchioles, alverolar ducts, aveoli + alverolar sacs
what is the role of the respiratory portion of the respiratory system
gas exchange
what does the alveolar duct end in?
alveolar sac
what are alveolar sacs made up of
alveoli
what happens at alveoli
main site of gas exchange
what gives lungs their spongy appearance
alveoli
what makes alveoli so good at gas exchange? (2 things)
- extensive capilary network surrounds each alveolus
- elastic fibers surround alveoli which facilitates stretch and recoil during gas exchange
what do pulmonary veins do?
carry oxygenated blood to the left atrium
what enters and exits via the hilium?
pulmonary arteries and veins (and bronchus)
what do bronchial arteries do?
carry oxygenated blood to the lungs and bronchi
what do bronchial veins do?
carry deoxygenated blood from lungs and bronchi (blood drains into th azygous system)
what does sympathetic innervation do to the airway?
bronchodialation
what does parasympathetic innervation do to the airway
bronchoconstriction
what does the phrenic nerve do?
innervate the diaphragm
how are pressure and volume related in the lungs?
they are inversely related - as lung volume increases, lung pressure decreases so air is drawn into the lungs.
as lung volume decreases, pressure in the lungs increases relative to atmospheric pressure - air is drawn out of the lungs
what is the primary muscle of inspiration
diaphragm
what are the secondary muscles of inspiration
external intercostal muscles (elevate ribs)
what are the primary muscles of expiration?
diaphragm
what are the secondary muscles of expiration
internal intercostal muscle (depresses ribs)
what happens to the alveoli during expiration
elastic recoil
where does gas exchange btw lungs and blood take place?
alveolar and capilary walls
how does CO2 leave the body?
CO2 diffuses across the respiratory membrane into the alveolus and is then expelled by respiration
