Table of contents :

• respiratory apparatus

Organogenesis : laryngotracheal groove : a furrow at the caudal end of the floor of the embryonic pharynx that develops into the respiratory tract
Cell types : simple cylindric epithelium (aimed to create the so-named "mucociliary elevator") except than over vocal cords
• mucociliary apparatus : on the inner surface of the respiratory tract, a layer of columnar epithelial cells covered by a thin mucous layer and many projecting cilia that beat in a rhythmic manner to bring about mucociliary clearance
• ciliated cell
• unciliated secretory cells
• goblet, beaker, caliciform, chalice or muciparous cells : a unicellular mucous gland found in the epithelium of URT. Droplets of mucigen collect in the upper part of the cell and distend it, while the basal end remains slender, and the cell assumes the shape of a goblet.
• Clara's cells : unciliated cells found in the epithelium of the respiratory and terminal bronchioles. They produce little mucus to prevent obstruction of bronchioles during bronchospasm of small airways and undergo goblet metaplasia in small airway disease
• basal or reserve cells (precursor cells) : cells of the basal or germinal layer of the bronchial epithelium.
• pulmonary neuroendocrine cells (PNECs)
• Kultchitsky cells (APUD cells whose number decreases with age)
• conduction system (mass flow ventilation) warm air from room temperature to 35°C (patient with tracheostomy develop squamous metaplasia of the URT), humidifies air (P_H2O 3.7 => 47 mmHg), filters air (particles with Ø > 1 mm are entrapped into mucus and swallowed). Even if airway diameter reduces moving downward, R_tot decreases as resistances are placed in parallel.
• upper respiratory tract (URT) / upper airways
• nose (rhinology) (see also diseases of the nose)
• bony skeleton :
• nasal bones
• maxillary bones
• external nose / nasus externus : the part of the nose that protrudes on the face; made up of an osteocartilaginous framework, covered externally by muscles and skin and lined internally by mucous membrane; it has two apertures that open into the nasal cavity and is separated into 2 halves by the nasal septum.
• nasal cartilages / cartilagines nasi
• (upper) lateral cartilage of nose / cartilago nasi lateralis / quadrilateral cartilage / triangular cartilage of nose
• greater alar cartilage / cartilago alaris major / inferior cartilage of nose / lower or inferior (lateral) nasal cartilage / tip cartilage
• crus mediale cartilaginis alaris majoris / internal crus of greater alar cartilage / medial crus of greater alar cartilage : the part of the greater alar cartilage, loosely attached to its fellow of the opposite side, and helping to form the mobile septum of the nose
• crus laterale cartilaginis alaris majoris / lateral crus of greater alar cartilage : the part of the greater alar cartilage that curves laterally around the naris and helps maintain its contour
• accessory or sesamoid cartilages of nose / cartilagines nasales accessoriae
• lesser alar cartilage / cartilagines alares minores / sesamoid cartilage
• Jacobson's subvomerine or vomeronasal cartilage / cartilago vomeronasalis [Jacobsoni] : either of the two narrow, longitudinal strips of cartilage, one lying on either side of the anterior portion of the lower margin of the septal cartilage
• nasal septum :
• (quadrangular) cartilage of nasal septum / cartilago septi nasi / septal cartilage of nose
• perpendicular lamina of ethmoid
• vomer
• organum vomeronasale / Jacobson's vomeronasal organ : a short rudimentary canal just above the vomeronasal cartilage, opening in the side of the nasal septum and passing from there blindly upward and backward
• nose shape
• leptorrhine : having a nasal index below 48
• platyrrhine : having a broad nose; having a nasal index exceeding 53
• catarrhine : characterized by nostrils that are close together and directed downward
• vestibulum nasale or nasi / vestibule of nose / nasal vestibule : the anterior part of the nasal cavity situated just inferior to the nares and limited posteriorly by the limen nasi. It is lined with stratified squamous epithelium and contains hairs (vibrissae) and sebaceous glands
• nasal cavity
• tunica mucosa nasi / Schneider's or schneiderian membrane : the mucous membrane lining the nasal cavity
• pars olfactoria cavitatis nasi / olfactory region : the superior part of the nasal cavity, the mucosa of which contains most of the receptors for the sense of smell.
• glandulae olfactoriae / Bowman's olfactory glands : small mucous glands in the olfactory mucosa. They secrete :
• odorant-binding protein 2A
• odorant-binding protein 2B
• pars respiratoria cavitatis nasi / respiratory region : the part of the nasal cavity inferior to the olfactory region, lined by multilayered cylindric epithelium..
• limen nasi / nasal valve : the ridge at the junction of the lateral nasal cartilage and the lateral crus of the greater alar cartilage, marking the boundary between the vestibule of the nose and the nasal cavity proper, above locus Valsalvae
• agger nasi / nasoturbinal concha / ridge of nose : a ridgelike elevation midway between the anterior extremity of the middle nasal concha and the inner surface of the dorsum of the nose
• turbinates / turbinals / nasal conchae / conchae nasales
• supreme turbinate / concha nasalis suprema
• superior turbinate / concha nasalis superior
• middle turbinate / concha nasalis media
• inferior turbinate / concha nasalis inferior
• sphenoid turbinate / concha sphenoidalis
• meati of nose : the spaces between conchae
• tegmen : the narrow cavity above the superior nasal concha, into which the sphenoid sinus opens
• meatus nasi superior / superior meatus of nose : the narrow cavity below the superior nasal concha, with which the posterior ethmoidal cells communicate
• meatus nasi medius / middle meatus of nose : the space beneath the middle nasal concha, with which the anterior and intermediate ethmoidal cells and frontal and maxillary sinuses communicate
• atrium meatus medii / atrium of middle meatus : a depression in front of the middle nasal meatus, between the agger nasi and the middle nasal concha
• meatus nasi inferior / inferior meatus of nose : the space beneath the inferior nasal concha, into which the nasolacrimal duct opens

The primary functions of the nose are :
• filtration is accomplished by the vibrissae in the anterior nares and by mucus. Most of the mucous glands are in the nasal mucosa. The mucous blanket is moved by cilia toward the nasopharynx at the rate of five mm per minute. Although amazingly resistent to heat, cold, fumes, dust, and chemicals, the cilia are most vulnerable to drying from inspired dry air, such as central heating or 100% O₂.
• warming
• humidification
• sense of smell
• origin and recipient of numerous reflex areas
Air flow during inspiration is directed over the turbinates to the roof of the nasal cavity and then into the nasopharynx. The air is warmed by heat transfer from the mucous membranes. During expiration, the air makes a loop before exiting the nose anteriorly, allowing for retention of the moisture in the air. The air flow volume is regulated by the changing size of the turbinates and the resistance of the 2 narices is nearly in phase opposition, but the whole nose resistance is constant.
• sinus paranasales / paranasal sinuses : the monolayered cylindric epithelium-lined air cavities in the cranial bones which communicate with the nasal cavity
• cellulae ethmoidales / ethmoidal cells / sinus ethmoidales : collective name for a type of paranasal sinus occurring in groups within the ethmoid bone and communicating with the ethmoidal infundibulum and bulla and the superior and highest meatuses. They are often subdivided into cellulae named according to the location of their openings into the nasal meatus :
• cellulae ethmoidales anteriores / anterior ethmoidal cells / sinus ethmoidales anteriores : ethmoidal air cells that open into the middle nasal meatus; they are often grouped with adjacent middle and posterior ethmoidal cells and called simply ethmoidal cells or sinuses
• cellulae ethmoidales mediae / middle ethmoidal cells / sinus ethmoidales medii : ethmoidal air cells that open into the middle nasal meatus; they are often grouped with adjacent anterior and posterior ethmoidal sinuses and called simply ethmoidal cells
• cellulae ethmoidales posteriores / posterior ethmoidal cells / sinus ethmoidales posteriores : ethmoidal air cells that open into the superior nasal meatus; they are often grouped with adjacent middle and anterior ethmoidal sinuses and called simply ethmoidal cells
• sinus frontalis / frontal sinus : one of the paired irregular shaped paranasal sinuses located in the frontal bone deep to the superciliary arch, separated from its fellow of the opposite side by a bony septum; it communicates by way of the nasofrontal duct with the middle meatus of the nasal cavity on the same side.
• sinus maxillaris / maxillary sinus / antrum of Highmore : one of the paired paranasal sinuses, located in the body of the maxilla on either side and communicating with the middle meatus of the nasal cavity on the same side
• sinus sphenoidalis / sphenoidal sinus : one of the paired paranasal sinuses, located in the anterior part of the body of the sphenoid bone and communicating with the superior meatus of the nasal cavity on the same side; it is separated from its fellow on the opposite side by a septum.
The primary functions of the paranasal sinuses are :
• voice resonation
• enlightning of skull bones
• protection of skull base
Innervation :
• olfactory nerve (I)
• sphenopalatine nerve (induces neurovegetative congestion)
• choana / posterior nasal apertures / posterior nares : the paired openings between the nasal cavity and the nasopharynx
• primary choana : the opening of the embryonic olfactory sac into the mouth.
• secondary choana : the definitive choana after the formation of the palate
• rhinopharynx / nasopharynx / epipharynx
• Eustachian tube is approximately 37 mm long and connects the middle ear with the nasopharynx. The lateral or tympanic third of the tube is bony, the medial or pharyngeal portion is cartilaginous. The course of the tube is forward, downward, and inward from the ear, opening into the nasopharynx about 15 mm lower than the tympanic opening in adults. It lies just posterior to the inferior nasal turbinate. The cartilaginous and bony portions meet at an obtuse angle in the narrowest portion of the tube. The osseous tympanic orifice is open, but the cartilaginous tube is a closed, slit-like cavity. It must be opened by acts of swallowing or yawning that contract the tensor and levator veli palatini muscles or by direct air pressure.
• oropharynx
• aditus laryngis : the aperture by which the pharynx communicates with the larynx; called also aperture of larynx
• larynx (laryngology) (see also diseases of the larynx) : the musculocartilaginous structure, lined with mucous membrane, connected to the superior part of the trachea and to the pharynx inferior to the tongue and the hyoid bone; the essential sphincter guarding the entrance into the trachea and functioning secondarily as the organ of voice in some animals. It is formed by 9 cartilages (epiglottis, thyroid, cricoid, 2 aryepiglottic, 2 cuneiform, and 2 corniculates) connected by ligaments and 8 muscles (2 each of cricothyroid, thyroarytenoid, posterior cricoarytenoid, lateral cricoarytenoid)
• supraglottis : the area of the pharynx above the glottis as far as the epiglottis.
• epilarynx / vestibulum laryngis / vestibule of larynx : the portion of the laryngeal cavity above the vestibular folds
• suprahyoid epiglottis : the lidlike cartilaginous structure overhanging the entrance to the larynx and serving to prevent food from entering the larynx and trachea while swallowing thanks to contraction of aryepiglottic muscle, lined by multilayered squamous cell epithelium
• cartilago triticea / triticeal cartilage / corpusculum triticeum / corpus triticeum : a small cartilage in the thyrohyoid ligament
• aryepiglottic fold
• Morgagni's cuneiform cartilages / Wrisberg's cartilages / cartilago cuneiformis
• staff of Wrisberg : a slight mounding up of the mucosa over Wrisberg's cartilage (cartilago cuneiformis) in the larynx
• Santorini's corniculate cartilages
• infrahyoid epiglottis
• false vocal cords / false vocal folds / vestibular folds / plicae vestibulares / plicae ventriculares : a fold of mucous membrane covering muscle in the larynx, separating the ventricle from the vestibule
• ligamentum vestibulare / vestibular ligament / ligamentum ventriculare and ventricular ligament : the membrane that extends from the thyroid cartilage in front to the anterolateral surface of the arytenoid cartilage behind; it lies within the vestibular fold, above the vocal ligament
• false glottis / rima vestibuli :  fissure of vestibule: the space between the right and left vestibular folds of the larynx
• ventriculus laryngis Morgagnii / ventricle of larynx : a lateral evagination of mucous membrane between the vocal and vestibular folds, reaching nearly to the angle of the thyroid cartilage, whose upper part contains laryngeal tonsil within tunica propria.
• glottis : the vocal apparatus of the larynx
• true vocal cords / plicae vocales / vocal folds / chordae vocales / labia vocales : a fold of mucous membrane (multilayered squamous cel epithelium) covering the vocalis muscle in the larynx, forming the inferior boundary of the ventricle
• pars cartilaginea : vocal process of arytenoid cartilages
• pars membranacea / vocal ligament / ligamentum vocale : the elastic tissue membrane that extends from the thyroid cartilage in front to the vocal process of the arytenoid cartilage behind; it lies within the vocal fold, below the vestibular ligament
Cell types : vocal fold stellate cells (VFSC) constantly synthesize extracellular matrices
• true glottis / rima glottidis : opening between the true vocal cords
• pars intercartilaginea rimae glottidis / intercartilaginous glottis / glottis respiratorius / respiratory glottis / interarytenoid space : the part of the rima glottidis between the arytenoid cartilages, which remains open even during maximal true vocal cords adduction
• pars intermembranacea rimae glottidis / glottis vocalis : the part of the rima glottidis between the vocal folds
• laryngeal commissures :  the region of junction (anterior or posterior) of the 2 sides of the larynx.
• Reinke's space : a potential space between the vocal ligament and the overlying mucosa; inflammation results in Reinke's edema.
• laryngeal glands / glandulae laryngeae : the mucous glands in the mucosa of the larynx
• anterior laryngeal glands : mucous glands in the anterior part of the larynx.
• middle laryngeal glands : mucous glands located in the arytenoepiglottic fold.
• posterior laryngeal glands / arytenoid glands : mucous glands in the posterior part of the larynx, near the aryepiglottic fold and the arytenoid cartilages
• infraglottis / subglottis / cavitas infraglottica / infraglottic cavity : the most inferior part of the laryngeal cavity, extending from the rima glottidis above to the cavity of the trachea below
Sensitive innervation : internal ramus of superior laryngeal nerve (perforates thyrohyoid membrane together with superior laryngeal artery and vein)

Movements of the larynx		skeletal muscles	nerve supply
as a whole	elevations close layngeal orifice	thyrohyoid (hyoid fixed);  stylopharingeal ;  palatopharingeal	C1 nerve ventral ramus ;  glossopharyngeal ;  pharyngeal plexus
	depression opens laryngeal orifice	sternothyroid	ansa cervicalis
of the vocal cords	tension	cricothyroid ;  vocalis (pars medialis of thyroarytenoid)	external ramus of superior laryngeal nerve ;  inferior (recurrent) laryngeal nerve
	slackening all part	vocalis (pars medialis of thyroarytenoid)	inferior (recurrent) laryngeal nerve
	abduction / dilatation	posterior cricoarytenoid	inferior (recurrent) laryngeal nerve
	adduction / costriction	lateral cricoarytenoid ;  oblique arytenoid ;  transverse arytenoid ;  pars lateralis of thyroarytenoid	inferior (recurrent) laryngeal nerve

Characteristics of the primary larynx sound :
• pitch (fundamental frequency) depends on grade of adduction of vocal cords in larynx
• amplitude / intensity (kinetic energy : 0 (soft) -120 (loud) dB) depends on bronchopulmonary apparatus
• timbre (dynamic profile, spectral composition) depends on shape of articulation and resonance cavities
Phonation : adducted vocal cords produce sound which is modified by ventricle, vestibule, palate, cheeks, tongue, teeth, and lips to form speech or singing tones.
Voice quality = vocal tract configuration + laryngeal anatomy + learned component

• lower respiratory tract (LRT) / lower airways
• trachea / windpipe : the tube with posterior cartilaginous and membranous sheaths descending from the larynx and branching into the right and left main bronchi. It is kept patent by a series of about twenty transverse horseshoe-shaped cartilages (15-20 cm) which facilitate inspiration but obstacle expiration
• bronchi : any of the larger air passages of the lungs, having an outer fibrous coat with irregularly placed partial circumferential plates of hyaline cartilage (so that the whole circumference is involved at different levels), an interlacing network of smooth muscle, mucous glands behind epithelium, and columnar ciliated epithelium (monopodic division : each of the 23 divisions is named generation) => lobar bronchi / bronchi lobares (3 cytotypes ; 1 generation (total : 5))
• right primary bronchus / bronchus principalis dexter (1.5-2 cm long)
• right superior lobe bronchus / epiarterial bronchus
• intermediate bronchus (3 cm long)
• left middle lobe bronchus
• left inferior lobe bronchus
• left primary bronchus / bronchus principalis sinister (5 cm, longer due to presence of aortic arc)
• left superior lobe bronchus
• upper division bronchus
• lingular bronchus
• superior lingular bronchus / bronchus lingularis superior
• inferior lingular bronchus / bronchus lingularis inferior
• left inferior lobe bronchus
=> segmental bronchi / bronchi segmentales (3 cytotypes ; 1 generation (total : 19)
• bronchus lobaris superior dexter / right superior lobar bronchus
• bronchus segmentalis apicalis [B I] / apical segmental bronchus
• bronchus segmentalis posterior [B II] / posterior segmental bronchus
• bronchus segmentalis anterior [B III] / anterior segmental bronchus
• bronchus lobaris medius / middle lobar bronchus
• bronchus segmentalis lateralis [B IV] / lateral segmental bronchus
• bronchus segmentalis medialis [B V] / medial segmental bronchus
• bronchus lobaris inferior dexter / right inferior lobe bronchus
• bronchus segmentalis superior [B VI] / superior segmental bronchus
• bronchus segmentalis basalis medialis [B VII] (bronchus cardiacus) / medial basal segmental bronchus (cardiac bronchus)
• bronchus segmentalis basalis anterior [B VIII] / anterior basal segmental bronchus
• bronchus segmentalis basalis lateralis [B IX] / lateral basal segmental bronchus
• bronchus segmentalis basalis posterior [B X] / posterior basal segmental bronchus
• bronchus lobaris superior sinister / left superior lobar bronchus
• bronchus segmentalis apicoposterior [B I+II] / apicoposterior segmental bronchus
• bronchus segmentalis anterior [B III] / anterior segmental bronchus
• bronchus lingularis superior [B IV] / superior lingular bronchus
• bronchus lingularis inferior [B V] / inferior lingular bronchus
• bronchus lobaris inferior sinister / left inferior lobar bronchus
• bronchus segmentalis superior [B VI] / superior segmental bronchus
• bronchus segmentalis basalis medialis [B VII] (bronchus cardiacus) / medial basal segmental bronchus (cardiac bronchus)
• bronchus segmentalis basalis anterior [B VIII] / anterior basal segmental bronchus
• bronchus segmentalis basalis lateralis [B IX] / lateral basal segmental bronchus
• bronchus segmentalis basalis posterior [B X] / posterior basal segmental bronchus
The anterior basal and medial basal segmental bronchi of the left inferior lobe are often described collectively as the anteromedial basal segmental bronchus.
=> lobular / subsegmental bronchi or bronchioles (no cartilage (=> first portion obliterable by smooth muscle contraction), no mucous glands but mucus within lumen; each one drains 3-5 terminal bronchioles; 3 cytotypes ; 15 generations)
=> (terminal) bronchioles (Ø < 2 mm; 3 cytotypes ; 1 generation; 1-8 millions) =>
• exchange system (respiration) : lungs (pneumonology) are made of acini (Ø = 7 mm), including...
• respiratory bronchioles (each one drains more alveolar ducts; cubic epithelium : 3 generations)
• => ductuli alveolares / alveolar ducts or ductules : small passages connecting the respiratory bronchioles and the alveolar sacs

(cubic epithelium with 1 only cytotype)
• => alveolar sacs / atria (pavimentous epithelium)
• alveolar-capillary, alveolocapillary, blood-air or blood-gas barrier or membrane : a thin tissue barrier between pulmonary alveoli and adjacent capillaries, the site of gas exchange between alveolar air and capillary blood
At all levels of exchange system pulmonary alveoli / air sacs / air cell (300-600 millions; Ø = 200 mm) appear, consisting of squamous epithelium made up of alveolar epithelial cells / pneumocytes / pneumonocytes :
• type I pneumocyte / small or foliaceus or squamous alveolar epithelial type I cell (ATI) : flattened cells distinguished by their greatly attenuated cytoplasm and paucity of organelles
• type II pneumocyte / granular pneumonocytes / cubic or great or large alveolar epithelial type II cell (ATII) / septal cells : pleomorphic cells of the pulmonary alveolar epithelium that secrete surfactant and are distinguished by abundant cytoplasm containing numerous multilamellar bodies / cytosomes (any of the osmiophilic, lipid-rich, layered bodies). mAbs PE-10 and 439-9B both recognize molecules mainly expressed by type II alveolar cells
• corpora amylacea
Human epithelial airway cells constitutively produce molecules involved in initiating epithelial proliferation and differentiation : the growth factor heregulin / neuregulin 1, and its receptors; erbB2, erbB3 and erbB4. Under normal conditions airway epithelium has a low rate of cell division, but the physical segregation of receptor and ligand regulates EGF-R activation and epithelial proliferation. Heregulin-a is present exclusively in the apical membrane and the overlying airway surface liquid, physically separated heregulin-a from the basolateral membrane where erbB2, 3 and 4 reside. When epithelial integrity is disrupted heregulin-a activated erbB2 in cells at the edge of the wound, promoting cell proliferation to repair the epithelial layer.
Alveolar or interalveolar septum : one of the thin septa that separate adjacent pulmonary alveoli, containing connective tissue constituents of the respiratory tissue and the capillary network of the blood supply of the lung. They consist of 2 basal laminae separated by the alveolar or pulmonary interstitium, which in turn consists of :
• collagen fibers
• elastic fibers
• cells :
• fibroblasts
• white blood cells (7%)
• alveolar macrophages (AM) / dust cells (93%) : myeloid dendritic cells type 1 (mDC1) and myeloid dendritic cells type 2 (mDC2) express mRNA transcripts for TLR1, TLR2, TLR3, TLR4, TLR6 and TLR8. Flow-cytometric analysis demonstrated high TLR2 protein expression for mDC1 and moderate TLR4 expression for mDC2. mDC1 and mDC2 release proinflammatory cytokines (TNF-a,  IL-1b, IL-6 and IL-8) in response to TLR2 and TLR4 ligands. TLR3 ligands induce cytokine release in mDC1, but not in mDC2. Plasmacytoid DC (pDC) express TLR7 and TLR9 and release proinflammatory cytokines in response to imiquimod and IFN-a in response to CpG oligonucleotides. mDC1 are strong inducers of T cell proliferation, while pDC hardly induce any T cell proliferation. mDC2 have an intermediate T cell stimulatory capacity^ref.
• lymphocytes (7%)
• T lymphocytes (90%)
• B lymphocytes (10%)
• granulocytes (< 1%)
It is subclassified into :
• peribronchovascular or central interstitium
• intralobular interstitium (joining peribronchovascular and subpleural interstitium)
• subpleural or peripheral interstitium (below visceral pleura)

The alveolar interstitium occurs also below pleura, while lobules are separated just by a few connective tissue.
Bronchioli have no cartilage !
Lobules (Miller) have Ø = 2-3 cm each (hence obliterations are detected with chest X-ray)
• classical or secondary lobule of lung : terminal bronchioli + acini (respiratory bronchiole + alveolar ducts + alveolar sacs)
• terminal respiratory unit / primary lobule of lung / pulmonary acinus / transitional and respiratory zone : the part of the lung distal to a single terminal bronchiole; it is the anatomical and functional unit of the lung and consists of a respiratory bronchiole, 2 or more alveolar ducts + alveolar sacs
Kohn pores connect alveoli.

The first breath is generated by :
• chemical stimuli :
• increased P_CO2 and decreased pH senses directly by respiratory centres
• decreased P_O2 sensed by chemoceptors in aorta and carotids
• pressure stimuli : increased systemic arterial blood pressure after opening of umbilical cord, sensed by baroceptors in aorta and carotids
• sensorial stimuli (thermal, pain, and tactile)
Regulation :
• central or nervous breath regulation (since pregnancy week 24-26)
• development of alveolar surface and vascular network (since pregnancy week 28)
• alveolus stabilizing factors :
• surface active agent (surfactant) / anti-atelectatic factor produced by type II pneumocytes reduces superficial tension and maintain alveoli opened. It consists of :
• phospholipids (80.7%)
• dipalmitoylphosphatidylcholine
• surfactant proteins (5.4%)
• SP-A
• SP-B
• SP-C
• SP-D
• cholesterol (5.6%)
• free fatty acids (1.6%)
• glycerids (0.6%)
It begins to be produced in the fetus at about 24 to 28 weeks of pregnancy. Surfactant is found in amniotic fluid between 28 and 32 weeks. By about 35 weeks gestation, most babies have developed adequate amounts of surfactant. Without surfactants, according to Laplace's equation (P_transmural = 2t/r), all air would move into larger alveoli and finally into a single air boil. At birth alveolar fluids are removed from alveoli by chest squeezing in the birth canal (absent in caesarean delivery) (33%) and catecholamine incretion induced by birth stress (66%).
• tissue tension : fiber scaffold of lung
• axial fibres (centrifugal)
• peripheral fibres (centripetal)
• alveolar septal fibres join axial and peripheral fibres
• vascular distension pressure
Anatomy : each lung weighs 300-400 g.
• right lung
• upper lobe
• apical segment
• anterior segment
• posterior segment
• intermediate lobe
• medial segment
• lateral segment
• lower lobe
• Nelson's upper segment
• lateral basal segment
• anterior basal segment
• left lung
• upper lobe
• posterior segment
• apical segment
• anterior segment
• upper segment
• lower segment
• lower lobe
• Nelson's upper segment
• anterior basal segment
• lateral basal segment
• (medial basal segment)
• (posterior basal segment)
Upper lobes are better auscultated from the anterior chest wall, while lower lobes are better ausculted from the back.
Nelson's lobe is the most targeted by infections affecting patients lying in bed.
Segments are respiratory but not circulatory units !
• groove for aorta / aortic sulcus : a longitudinal groove on the median surface of the left lung corresponding to the thoracic aorta
• Barety's space / right hilar or peritracheal space : occupied by lymph nodes frequently metastatized in lung cancer^ref
• pleura : the serous membrane investing the lungs and lining the thoracic cavity, completely enclosing a potential space known as the pleural cavity. There are two pleurae, right and left, entirely distinct from each other. The pleura is moistened with a serous secretion which facilitates the movements of the lungs in the chest
• serous cell
• cervical pleura / cupula pleurae or pleuralis : the domelike roof of the pleural cavity on either side, extending up through the superior aperture of the thorax.
• pleura mediastinalis / mediastinal pleura : the part of the parietal pleura that covers the lateral face of the mediastinum and the structures within it.
• pleura pericardiaca / pericardiac pleura : the portion of the mediastinal pleura covering the pericardium and firmly attached to it.
• pleura parietalis / parietal pleura : the portion of the pleura lining the walls of the thoracic cavity.
• pleura costalis / costal pleura : the part of the parietal pleura lining the rib cage.
• pleura diaphragmatica / diaphragmatic pleura : the part of the parietal pleura covering the diaphragm.
• pleura pulmonalis or visceralis / pulmonary or visceral pleura : the portion of the pleura investing the lungs and lining their fissures, completely separating the different lobes
• villi pleurales / pleural villi : the shaggy appendages on the surface of the pleura near the costomediastinal sinus
The parietal pleura is vascularized by intercostal arteries, while the visceral pleura is vascularized by bronchial arteries. Due to difference in vascular pressure, 600-800 mL of pleural fluid are produced each day by the parietal pleura and absorbed by lymphatic blood vessels in the visceral pleura : only 5 mL are normally present between the 2 layers.
• ligaments :
• ligamentum pulmonale / pulmonary ligament : a vertical pleural fold associated with the lung, extending from the hilus down to the base on the medial surface of the lung; on the left it forms the posterior boundary of the impressio cardiaca.
• pressures (compared to atmospheric pressure)
• pleural, intrapleural or intrathoracic pressure (P_pl) = - 4 cmH₂O (peak = - 7.5 cmH₂O when V = FRC + TV). It is negative thanks to :
• lymphatic draining
• active transport of salts from mesothelium into capillary intersitium, followed by osmosis
• chest wall growth rate is greater than lung growth rate, hence a isothermal expansion of pleural fluid occurs according to Boyle-Mariotte law.
It is measured ...
• in vivo by measuring endoesophageal pressure
• ex vivo by using an aspirating pump
• intralveolar pressure (P_alv) = - 1 cmH₂O during inspiration, + 1 cmH₂O during expiration. Small alveoli don't empty into larger ones as they have a greater superficial tension => t_small / r_small = t_great / r_great.
• transpulmonary pressure or lung retraction pressure or lung static pressure (P_st(l)) = P_alv - P_pl = + 4 cmH₂O (peak = + 7.5 cmH₂O when V = FRC)
• work of breathing (WOB)
• compliance (elastic work) ~ current V
• work against R_tissues ~ V ^. v ^. h
• work against flow resistances ~ V ^. v ^. R
By increasing n (and hence v), E_{elastic recoil} doesn't increase and hence you have to recruit expiratory muscles.
• compliances (C)
• lung compliance C_lung = dV / dP_{transpulmonary} = dV / d(P_alv - P_pl) = 200 mL / cmH₂O
• lung/chest wall system compliance C_lung/chest = dV / d(P_{transpulmonary} - P_{chest expansion}) = dV / d[(P_alv - P_pl) - (P_atm - P_pl)] = dV / d(P_alv - P_atm) = 110 mL / cmH₂O
• ventilation / breathing / pneusis / respiration : the process of exchange of air between the lungs and the environment, including inspiration and expiration
• alveolar ventilation : a fraction of the pulmonary ventilation, being the amount of air that reaches the alveoli and is available for gas exchange with the blood.
• pulmonary ventilation : a measure of the rate of ventilation, referring to the total exchange of air between the lungs and the ambient air, usually in liters per minute.
• spontaneous ventilation : term used to denote breathing accomplished naturally, without any artificial aids, as opposed to mechanical ventilation and other forms of artificial respiration. It is based on respiratory movements
• inspiration (P_alv < P_atm) : airway resistance (R_aw) is due for the major part to mid-diameter bronchioli ; it is lower during inspiration as lung dilatation is transmitted to terminal airways and higher when pulmonary volumes are reduced
• principal inspiratory muscles
• external intercostal muscles
• parasternal muscles
• diaphragm
• posterior cricoarytenoideal muscle
• genioglossus muscle
• accessory inspiratory muscles
• sternocleidomastoid muscles
• scalenus muscles
• expiration (P_alv > P_atm) : it requires a greater effort as constriction occurs only forward, in the URT.
• normal breathing : passive
• forced expiration : expiratory muscles
• internal intercostal muscles
• abdominal muscles (rectus of the abdomen, external oblique, internal oblique, and transverse muscles)
• diaphragmatic respiration : that which is mainly performed by the diaphragm
• abdominal respiration : respiration maintained by contribution of the diaphragm and respiratory muscles, as normally seen in females
• costal or thoracic respiration : respiration performed by the intercostal and other thoracic muscles, as normally seen in males
• pulmonary function tests (PFT) : any of numerous tests that measure aspects of the respiratory system in order to assess functional state and presence or nature of any disease process. Factors evaluated include lung mechanics (capacities, flow rates, and volumes), gas exchange, pulmonary blood flow, blood gases, and pH of blood.
• normal value if 80%-120% of mean predicted nomogram value (based on the patient's sex, age, and height (and BMI ?), and laboratory practices)
• mild reduction if 79 < x > 70% (79 < x < 65%)
• moderate reduction if 69 < x < 55% (64 < x < 50%)
• severe reduction if 54 < x < 45% (49 < x < 35%)
• very severe reduction if x < 45% (< 35%)
• respiratory volumes (V)
• tidal volume (TV) = 0.5 L (up to 2,300 mL in tachypnea) = 10–15 mL / kg of ideal body weight
• inspiratory reserve volume (IRV) = 3.0 L
• espiratory reserve volume (ERV) = 1.1 L
• residual volume (RV) = 1.2 L, including conduction airways. It can be calculated with ...
• respiration of an inert, nondiffusing gas (usually He) diluition method : at the end of the n-th mask expiration (~ 7', consumed O₂ is added and expired CO₂ is adsorbed on active coal) ...
• [He]_airways = [He]_spirometer and He_beginning = He_end (He doesn't diffuse) =>
• [He]_{spirometer before first inspiration} ^. V_spirometer = [He]_spirometer ^. (V_spirometer + FRC)
• FRC = [([He]_{spirometer before first inspiration} - [He]_spirometer) / [He]_spirometer ] ^. V_spirometer
• RV_He = FRC - ERV
• N₂ washout method : forced inspiration of 100% O₂ => total volume of slowly exhaled air is collected separately and the concentration of exhaled nitrogen is obtained for each breath. Test normally lasts for  7' or until [N₂]_{expired air} is 1-2.5%.

FRC = volume of N₂ expired /  N₂%_{previously inspired air} = (total volume collected ^. measured N₂%_{expired air}) / 0.8
• single-breath nitrogen washout test : the patient inhales a vital capacity's volume of pure oxygen and then slowly exhales. It is used to determine closing volume, ie the point during slow exhaled VC maneuver at which small airways begin to collapse (10% of VC in youngs, 40% at age 60). At exhalation, the curve can be analyzed for uniformity of ventilation and determination of anatomic dead space and closing volume
• phase 1 : N₂% = 0 (gas from upper airways)
• phase 2 : steep increase in N₂% (gas from mostly airways & alveolar regions)
• phase 3 : slow increase in N₂% (gas from mostly alveolar regions)
• phase 4 : closing volume (gas from apices only is exhaled : N₂ is highest in apices)
• whole-body plethysmography (the most accurate method in patients with obstructive lung diseases) : when measured by whole-body plethysmography, resting end-expiratory volume is known as the intrathoracic gas volume (ITGV) and will include the volume of gas contained in noncommunicating spaces such as blebs or bullae that the FRC measured by gas dilution techniques will not measure. In addition to this advantage, body plethysmography allows multiple determinations of lung volumes to be made rapidly.

As the patients pants against an obstruction for 20-40 breaths/min, the volume in the thorax increases and the pressure in thorac is decreased.
P_{box, initial} ^. V_{box, initial} = P_{box, final} ^. V_{box, final}
P_{thorax, initial} ^. FRC = P_{thorax, final} ^. V_{thorax final}
P_{thorax, initial} ^. FRC = P_{thorax, final} ^. (FRC + V_{box, final} - V_{box, initial})
FRC = P_{thorax, final} ^. (V_{box, final} - V_{box, initial}) / (P_{thorax, initial} - P_{thorax, final})
FRC = [P_{thorax, final} ^. V_{box, initial} (P_{box, initial} - P_{box, final})] / [P_{box, final}^. (P_{thorax, initial} - P_{thorax, final})]
• respiratory capacities (C) are sums of respiratory volumes
• total lung capacity (TLC) = TLC_He = VC + RV_He = 5.8 L. It is decreased in individuals with restrictive lung diseases.
• normal value if 70%-120% of mean predicted nomogram value (based on the patient's sex, age, and height (and BMI ?), and laboratory practices)
• mild reduction if 70 < x > 60%)
• moderately severe reduction if 60 < x < 50%
• severe reduction if 54 < x < 45%
• very severe reduction if x < 34%
• Motley index / RV-to-TLC ratio = RV / TLC = 0.2
• vital capacity (VC) = TV + IRV + ERV = IC + ERV = 4.6 L = the volume of gas that can be expelled from the lungs from a position of full inspiration, with no limit to the duration of expiration = maximum exchangeable volume in vivo
• forced vital capacity (FVC) : VC measured when the patient is exhaling with maximum speed and effort. This is a cheapest test. As forcing causes earlier airway closure, FVC is < VC
• forced inspiratory vital capacity (FIVC)
• inspiratory capacity (IC) = TV + IRV = 3.5 L = the volume of gas that can be taken into the lungs on a full inspiration, starting from the FRC
• functional residual capacity (FRC) = RV + ERV = 2.3 L = the volume of gas remaining at the end of a normal quiet exhalation, when P_atm = P_{intrapulmonary}. It is unaffected in subjects with obstructive lung diseases, while is decreased in individuals with restrictive lung diseases.
• closing capacity : the volume of gas in the lungs at the time the airways close during respiration; the closing volume added to the RV, usually expressed as a %TLC.

• flow rates (V^.) = volume / time are measured (average of > 3 measurations) with
• pneumotachograph (open output)
• bell spirometer with nose clip (closed output)
• volume-time loop
• flow-volume loop
• the upper portion of the curve reflects the expiratory portion of the forced vital capacity (FVC) maneuver and is also referred to as the maximal expiratory flow-volume (MEFV) curve
• the lower portion of the curve reflects the inspiratory portion of the forced vital capacity (FVC) maneuver
• flow-pressure loop
• normal values in pulmonary emphysema
• decreased values in chronic bronchitis
• pressure-volume loop
• lung retraction pressure at 90% of TLC (P_st(l)90) : it is decreased in pulmonary emphysema
• lung retraction pressure at 100% of TLC (P_st(l)100) : it is decreased in pulmonary emphysema
• forced inspiratory volume in the first second (FIV₁ / FIV_1.0)
• FIV₁ / FIVC
• forced expiratory volume in the first 0.5 seconds (FEV_0.5)
• forced expiratory volume in the first second (FEV₁ / FEV_1.0) = 0.8 L or 80%-120% of mean predicted nomogram value (based on the patient's sex, age, and height (and BMI ?), and laboratory practices). It decreases in patients with ...
• obstructive lung diseases, whose reversibility is assessed with inhaled bronchodilators
• restrictive lung diseases
• mild reduction if 70-80 < x > 60%
• moderately severe reduction if 60 < x < 50%
• severe reduction if 54 < x < 45%
• very severe reduction if x < 34%
• forced expiratory volume in the first 3 seconds (FEV₃ / FEV_3.0)
• FEV₁:FEV_0.5 ratio
• Tiffeneau-Pinelli index = FEV₁ / VC. It decreases in subjects with obstructive lung diseases, while is unaffected in individuals with restrictive lung diseases.
• FEV₁ / FVC (a.k.a. FEV₁%) is a cheapest equivalent of Tiffeneau index commonly used in laboratory practice : it is affected later and has less sensitivity (more false negatives) and specificity (more false positives) in restrictive lung diseases. Normal values :
• > 70%
• 80%-120% of mean predicted value (based on the patient's sex, age, and height)
• mean predicted value (based on the patient's sex, age, and height) - 1.64 s_{from the population study on which the reference equation is based}.
• FEV₁ / VC is more sensible but also more expensive to determine as it requires 2 assays (forced expiration to calculate FEV₁ and normal expiration to calculate VC)
• maximal inspiratory flow (MIF) / forced inspiratory flow (FIF) at ...
• at 100% of the FVC / peak inspiratory flow (PIF) / peak inspiratory flow rate (PIFR) = 400 L / min
• at 50% of the FVC (FIF₅₀)
• maximal expiratory flow (MEF) / forced expiratory flow (FEF)  ...
• first 200 mL up to 1200 mL (FEF_200-1200 / FEF_0.2-1.2). Looks at quality of airflow in the larger airways
• at 100% of the FVC (FEF_max / MEF_max) / peak expiratory flow (PEF) / peak expiratory flow rate (PEFR)
• at 75% of the FVC (FEF₇₅ / MEF₇₅)
• at 50% of the FVC (FEF₅₀ / MEF₅₀) / maximal mid-expiratory flow (MMEF)
• between 75% and 25% of the FVC (FEF_25-75). It is the angular coefficient of the rect joining the points of 25% and 75% of the FVC in the volume-time loop. Looks at the quality of airflow from the smaller airways. During the last 25% of exhalation (from 75% to 100% of expiratory flow), flow rate is effort independent. Good index of small airways disease seen in asthma and emphysema
• between 85% and 75% of the FVC (FEF_75-85)
• mid-maximal flow rate ratio (MMFRR) = FEF₅₀ / FIF₅₀ or MEF₅₀ / MIF₅₀.
• pulmonary ventilation : a measure of the rate of ventilation, referring to the total exchange of air between the lungs and the ambient air, usually in liters per minute.
• minute or total ventilation / minute volume (V^.) = n^. TV = the total volume of gas in liters expelled from the lungs per minute
• maximal voluntary ventilation (MVV) / maximal breathing capacity (MBC) : the greatest volume of gas that can be breathed per minute by voluntary effort
• alveolar ventilation (V^._A) = n^. (V_A) = 4,200 mL / minute.
• respiratory rate (RR / n) = 12 breaths / minute (up to 30 in tachypnea)
• alveolar volume (V_A)  = TV - DV_anat
• anatomical dead volume (DV_anat) = TV - V_{ventilated airway volume} = 350 mL. It can be calculated by measuring the plateau of [N₂] / [CO₂]_{expirated air} after inspiration of pure O₂.
• physiological dead volume (DV_phys) = TV - V_{ventilated and perfused airway volume} = 150 mL. It can be calculated by measuring [CO₂]_{expirated air} after inspiration of pure O₂.
• pulmonary blood circulations
• functional blood circulation
• truncus pulmonalis / pulmonary artery or trunk / arteria pulmonalis : the vessel arising from the conus arteriosus of the right ventricle, extending upward obliquely to divide into the right and left pulmonary arteries beneath the arch of the aorta, and conveying unaerated blood toward the lungs
• sinus trunci pulmonalis / sinus of pulmonary trunk : a slight dilatation between the wall of the pulmonary trunk and each of the semilunar cusps of the pulmonary trunk valve.
• arteria pulmonalis dextra / right pulmonary artery : origin, pulmonary trunk; branches, of superior lobe: apical, anterior ascending and descending, posterior ascending and descending, of medial lobe: medial and lateral, of inferior lobe: anterior basal, lateral basal, medial basal; posterior basal; distribution, right lung.
• arteriae lobares superiores pulmonis dextri / superior lobar arteries of right lung : the branches of the right pulmonary artery that carry blood to the superior lobe of the right lung, consisting of the apical, anterior , and posterior segmental arteries
• arteria segmentalis anterior pulmonis dextri / anterior segmental artery of right lung : one of the branches of the right pulmonary artery to the superior lobe of the right lung, supplying its anterior segment; it gives rise to ascending and descending branches
• arteria segmentalis apicalis pulmonis dextri / apical segmental artery of right lung : one of the branches to the superior lobe, supplying its apical segment
• arteria segmentalis posterior pulmonis dextri / posterior segmental artery of right lung : one of the branches of the right pulmonary artery to the superior lobe of the right lung, supplying its posterior segment; it gives rise to ascending and descending branches.
• arteria lobaris media pulmonis dextri / middle lobar artery of right lung : the branch of the right pulmonary artery that carries blood to the middle lobe of the right lung, giving rise to the lateral and medial lobar arteries
• arteria segmentalis lateralis pulmonis dextri / lateral segmental artery of right lung : one of the two branches to the middle lobe, supplying its lateral segment.
• arteria segmentalis medialis pulmonis dextri / medial segmental artery of right lung : one of the two branches to the middle lobe, supplying its medial segment.
• arteriae lobares inferiores pulmonis dextri / inferior lobar arteries of right lung : the branches of the right pulmonary artery that supply the inferior lobe of the right lung, consisting of the superior, anterior basal , lateral basal, medial basal, and posterior basal segmental arteries
• arteria segmentalis basalis anterior pulmonis dextri / anterior basal segmental artery of right lung : one of the branches to the inferior lobe, supplying the anterior basal segment.
• arteria segmentalis basalis lateralis pulmonis dextri / lateral basal segmental artery of right lung : one of the branches to the inferior lobe, supplying the lateral basal segment.
• arteria segmentalis basalis medialis pulmonis dextri / medial basal segmental artery of right lung : one of the branches to the inferior lobe, supplying the medial basal segment.
• arteria segmentalis basalis posterior pulmonis dextri / posterior basal segmental artery of right lung : one of the branches to the inferior lobe, supplying the posterior basal segment.
• arteria segmentalis superior pulmonis dextri / superior segmental artery of right lung : one of the branches of the right pulmonary artery to the inferior lobe, supplying its superior segment.
• arteria pulmonalis sinistra / left pulmonary artery : origin, pulmonary trunk; branches, of superior lobe: apical, ascending and descending, posterior, lingular (inferior and superior), of inferior lobe: superior, anterior basal, lateral basal, medial basal, posterior basal; distribution, left lung.
• arteriae lobares superiores pulmonis sinistri / superior lobar arteries of left lung : the branches of the left pulmonary artery that carry blood to the superior lobe of the left lung, consisting of the apical, anterior, and posterior segmental arteries
• arteria segmentalis apicalis pulmonis sinistri / apical segmental artery of left lung : one of the branches to the superior lobe, supplying its apical segment.
• arteria segmentalis anterior pulmonis sinistri / anterior segmental artery of left lung : one of the branches of the left pulmonary artery to the superior lobe of the left lung, supplying its anterior segment; it gives rise to ascending and descending branches.
• arteria lingularis inferior / inferior lingular artery / inferior lingular segmental artery : a branch of the left pulmonary artery to the superior lobe, supplying the inferior lingular segment
• arteria lingularis superior / superior lingular artery / superior lingular segmental artery : a branch of the left pulmonary artery to the superior lobe, supplying the superior lingular segment
• arteria segmentalis posterior pulmonis sinistri / posterior segmental artery of left lung : one of the branches of the left pulmonary artery to the superior lobe of the left lung, supplying its posterior segment; it gives rise to ascending and descending branches.
• arteriae lobares inferiores pulmonis sinistri / inferior lobar arteries of left lung : the branches of the left pulmonary artery that supply the inferior lobe of the left lung, consisting of the superior, anterior basal , lateral basal, medial basal, and posterior basal segmental arteries
• arteria segmentalis basalis anterior pulmonis sinistri / anterior basal segmental artery of left lung : one of the branches to the inferior lobe, supplying its anterior basal segment.
• arteria segmentalis basalis lateralis pulmonis sinistri / lateral basal segmental artery of left lung : one of the branches to the inferior lobe, supplying its lateral basal segment.
• arteria segmentalis basalis medialis pulmonis sinistri / medial basal segmental artery of left lung : one of the branches to the inferior lobe, supplying its medial basal segment.
• arteria segmentalis basalis posterior pulmonis sinistri / posterior basal segmental artery of left lung : one of the branches to the inferior lobe, supplying its posterior basal segment.
• arteria segmentalis superior pulmonis sinistri / superior segmental artery of left lung : one of the branches of the left pulmonary artery to the inferior lobe, supplying its superior segment.
• pulmonary arterioles travel around bronchi
• venae pulmonales / pulmonary veins : the 4 veins, right and left superior and right and left inferior, that return aerated blood from the lungs to the left atrium of the heart
• vena pulmonalis dextra inferior / right inferior pulmonary vein / vena pulmonalis inferior dextra : the vein that returns blood from the lower lobe of the right lung (from the superior [apical] branch and from the common, superior, and inferior basal veins) to the left atrium of the heart
• vena superior lobi inferioris pulmonis dextri / superior vein of inferior lobe of right lung / ramus superior venae pulmonalis dextrae inferioris / superior segmental vein of right lung : a venous branch that drains the superior segment of the inferior lobe of the right lung and empties into the right inferior pulmonary vein
• vena pulmonalis dextra superior / right superior pulmonary vein / vena pulmonalis superior dextra : the vein that returns blood from the upper and middle lobes of the right lung (from the superior [apical], anterior, and posterior branches and the middle lobar branch) to the left atrium of the heart
• vena lobi medii pulmonis dextri / middle lobar vein of right lung / ramus lobi medii venae pulmonalis dextrae superior : a branch that drains the middle lobe of the right lung, emptying into the right superior pulmonary vein and formed by the union of lateral and medial parts
• vena anterior lobi superioris pulmonis dextri / anterior vein of superior lobe of right lung / ramus anterior venae pulmonalis dextrae superioris / anterior segmental vein of right lung : a branch that drains the anterior segment of the right upper lobe and empties into the right superior pulmonary vein
• vena apicalis lobi superioris pulmonis dextri / apical artery of superior lobe of right lung / ramus apicalis venae pulmonalis dextrae superioris / apical segmental vein of right lung : a branch that drains the apical segment of the right upper lobe
• vena posterior lobi superioris pulmonis dextri / posterior branch of right superior pulmonary vein / ramus posterior venae pulmonalis dextrae superioris / posterior segmental vein of right lung : a branch that drains the posterior segment of the right upper lobe
• vena pulmonalis sinistra inferior / left inferior pulmonary vein / vena pulmonalis inferior sinistra : the vein that returns blood from the lower lobe of the left lung (from the superior apical branch and the common basal vein) to the left atrium of the heart
• vena superior lobi inferioris pulmonis sinistri / superior vein of inferior lobe of left lung / ramus superior venae pulmonalis sinistrae inferioris / superior segmental vein of left lung : a venous branch that drains the superior segment of the inferior lobe of the left lung and empties into the left inferior pulmonary vein
• vena pulmonalis sinistra superior / left superior pulmonary vein / vena pulmonalis superior sinistra : the vein that returns blood from the upper lobe of the left lung (from the apicoposterior, anterior, and lingular branches) to the left atrium of the heart
• vena lingularis / lingular vein / ramus lingularis venae pulmonalis sinistrae superioris : a venous branch that drains the lingular segments of the superior lobe of the left lung, emptying into the left superior pulmonary vein and formed by the union of superior and inferior parts
• vena apicoposterior lobi superioris pulmonis sinistri / apicoposterior vein of superior lobe of left lung / ramus apicoposterior venae pulmonalis dextrae superioris / apicoposterior segmental vein : a venous branch that drains the apicoposterior segment of the left lung and empties into the left superior pulmonary vein
• vena anterior lobi superioris pulmonis sinistri / ramus anterior venae pulmonalis sinistrae superioris / anterior segmental vein of left lung : 1. anterior branch of left superior pulmonary vein: a venous branch that drains the anterior segment of the left lung and empties into the left superior pulmonary vein. Called also anterior segmental vein of left lung.  2. anterior vein of superior lobe of left lung: a branch that drains the anterior segment of the left upper lobe and empties into the left superior pulmonary vein
• vena basalis communis / common basal vein : either of 2 veins, one draining the lower lobe of each lung and draining into the corresponding inferior pulmonary vein; both are formed by the union of superior and inferior basal veins
• vena basalis superior / superior basal vein : either of 2 veins, each draining the apical segment of an inferior lobe of the corresponding lung and draining into a common basal vein
• vena basalis inferior / inferior basal vein : either of 2 veins, each draining the inferior segments of an inferior lobe of the corresponding lung and draining into a common basal vein
• vena basalis anterior / anterior basal vein / ramus basalis anterior venae basalis communis : a venous branch draining the anterior basal segment of either lung and emptying into the common basal vein
The basal membranes of alveolus and endothelium are usually fused allowing gas diffusion in a 0.2 mm-wide space.
West zones :
• I : P_{endocapillary} always < P_alv => lung parenchyma is never perfused
• II : P_{endocapillary} > P_alv only during systole (corresponding to lung apex when staying upright)
• III : P_{endocapillary} always > P_alv => lung parenchyma is always perfused (corresponding to lung base when staying upright and to whole lung when lying in bed)

• nutritional blood circulation
• bronchial arteries arise from thoracic aorta
• venae bronchiales / bronchial veins : vessels that travel in interstitium and drain blood from the larger subdivisions of the bronchi; on the left they drain into the azygos vein and on the right they drain into the hemiazygos vein or superior intercostal vein
=> pulmonary capillaries have mixed-type blood. The double circulation system also reduces risk of pulmonary infarction.
• pulmonary artery pressure
• at the beginning
• pulmonary artery systolic pressure (PASP) = 15÷30 mmHg
• pulmonary artery diastolic pressure (PADP) = 5÷15 mmHg
• pulmonary capillary wedge pressure (PCWP) / pulmonary artery occlusion pressure (PAOP) = 5-12 mmHg
• at the end ~ left atrium pressure
• mean pulmonary arterial pressure (MPAP) = 10÷20 mmHg
• pulmonary vascular resistance (PVR) = 80 ^. (MPAP - PWAP) / CO = 250 dine/sec/cm^-5
• pulmonary vascular resistance index (PVRI) = PVR / BSA
When staying upright both pulmonary perfusion and ventilation increase from apex to base (V^. is better at apex only in inspiration following forced expiration, when base alveoli are still collapsed), but V^./Q rate is higher at apex and lower at base. The V^./Q mismatch is annihilated at the level of the 3^rd rib.
• diffusing or diffusion capacities of the lung (D / DL / D_L) / transfer factor of the lung (TL) : the ability of the alveolocapillary membrane to transfer gas: a reflection of the thinness and area of the alveolocapillary membrane. It is the amount of gas transferred per minute from the alveolar gas to the pulmonary capillary blood divided by the mean pressure gradient of the gas between the alveolar gas and the capillary blood; unit, mL/min/torr (or mm Hg)
• DL_O2 = 21 mL / (min ^. mmHg)
• DL_CO2 = 400 mL / (min ^. mmHg)
• DL_CO / D_LCO / TL_CO = 17 mL / (min ^. mmHg). In the single breath technique (DL_CO-SB) it is measured by forced expiration to RV => forced inspiration of a mix containing 10% He, 0.3% CO, 21% O₂, and 68.7% N₂ ==10" at VC breath size==> forced expiration into a sample bag after an initial discard of 0.5-0.75 L to account for DV. [CO]_{spirometer before first inspiration} ^. V_spirometer = [CO]_spirometer ^. (V_spirometer + FRC)

As Hb has very high avidity for CO, DL_CO / TL_CO is a measurement of the ease of transfer for CO molecules from alveolar gas to the Hb of the RBCs in the pulmonary circulation. It is reduced in lung interstitial diseases and pulmonary emphysema. The value depends on diffusion and perfusion, while other parameters can be adjusted :
• Hb-adjusted DL_CO (DL_COc)
• DL_COc_{males > 15 years}  = measured DL_CO ([10.22 + Hb g/dL]/[1.7 Hb])
• DL_COc_{males <15 years and women} = measured DL_CO ([9.38 + Hb g/dL]/[1.7 Hb])
• carboxyhemoglobin-adjusted DL_CO (DL_COc) = measured DL_CO (1 + [%CO Hb/100])
• Krogh diffusion / transfer coefficient, factor or constant (K_CO) = DL_CO / V_A
• assessment of respiratory muscle strength
• maximum inspiratory pressures (MIP) < - 80 cmH₂O
• maximum expiratory pressures (MEP) > 50 cmH₂O
• negative inspiratory force (NIF)
• 40 millimeter test (for athletic efficiency) : the subject sits with nasal respiration occluded with a clamp, and by expiring through a mouthpiece, sustains a column of mercury at the height of 40 mm as long as he can. The pulse rate is taken meanwhile, every 5 seconds. In a satisfactory test the pulse rate is unaltered for a minute or more
• CO₂ response curve : patients are connected to a rebreathing circuit and given a mixture of 93% O₂ while CO₂% is gradually increased up to 7%. Changes in minute ventilation determined by the peripheral chemoreceptors are measured as CO₂ concentration is increased : decreased response to CO₂ is seen in COPD patients with severe airway obstruction.
• mediastinum : the mass of tissues and organs separating the 2 pleural sacs, between the sternum anteriorly and the vertebral column posteriorly and from the thoracic inlet superiorly to the diaphragm inferiorly. It contains the heart and pericardium, the bases of the great vessels, the trachea and bronchi, esophagus, thymus, lymph nodes, thoracic duct, phrenic nerves and vagus nerves, and other structures and tissues. The mediastinum is divided into a superior region and an inferior region that comprises anterior, middle, and posterior parts.
• mediastinum superius / superior mediastinum / superior mediastinal cavity : the division of the mediastinum extending from the pericardium to the root of the neck, and containing the esophagus and the trachea posteriorly, the mediastinum or its remains anteriorly, and the great vessels related to the heart and pericardium, the thoracic duct, and the vagus nerves in between
• mediastinum inferius / inferior mediastinum : the 3 inferior portions of the mediastinum, comprising the
• mediastinum anterius / anterior mediastinum / anterior mediastinal cavity : the division of the mediastinum bounded posteriorly by the pericardium, anteriorly by the sternum, and on each side by the pleura. It contains loose areolar tissue and lymphatic vessels
• mediastinum medium / middle mediastinum / middle mediastinal cavity : the division of the mediastinum containing the heart enclosed in its pericardium, the ascending aorta, the superior vena cava, the bifurcation of the trachea into bronchi, the pulmonary arteries and veins, the phrenic nerves, a large portion of the roots of the lungs, and the arch of the azygos vein
• mediastinum posterius / posterior mediastinum / posterior mediastinal cavity : the division of the mediastinum bounded posteriorly by the vertebral column, anteriorly by the pericardium, and on each side by the pleurae. It contains the descending aorta, parts of the greater and lesser azygos and superior intercostal veins, the thoracic duct, the esophagus, the vagus nerves, and the greater splanchnic nerves

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