Respiratory system Flashcards
respiratory system divided in 2 diff ways
- upper and lower resp tract
upper: frontal+ sphenoidal sinus, nasal cavity, and pharynx
lower: larynx, trachea, bronchi and lungs - conducting and respiratory portion
conducting: nasal cavity, nasopharynx, larynx, pharynx, trachea and bronchi (main, lobar, segmental), bronchiole and terminal bronchiole
-resp epithelium
- cells: ciliated columnar (abundant)/columnar w goblet cells; basal cells, brush cells (microvilli); dendritic cells; intraepithelial lymphocytes; granular cells (neuroendocrine/kulchnisky)
-contacts basement membrane
- some areas where goblet cells predominate
- lamina propria: loose CT+elastic fibres, abundant in cells (fibroblast, macrophages, mast+ plasma cells), seromucous cells, MALT-mucosa assoc lymphoid tissue)
F: clean+modify air; provide uninterrupted supply through cartilage, smooth m and elastic+collagen fibres= rigidity, flexibility and extensibility
respiratory portion
where gas exchange (resp bronchioli, alveolar ducts (2-11), sacs (5-6) and alvoli (300mil)
-
Nasal cavity
divided in external vestibule and internal cavity
- vestibule: sweat and sabecous glands, vibrassae (hair cells), where keratinized-> non keratined sq epi-> resp epi(inf+middle concha)
*in cavity: mucosa in nasal cavity lined by lamina propria (capillaries carry blood opp to air- warm and air is humidified by water secreted by glands. mucous traps the impurities; IgA)
inf +middle concha = resp epithelia, thick basement membrane 5 main cell types (ciliated columnar, basal, brush- sparse microvilli+ chemosensory receptors similar to gustatory by signal transduction+ synaptic afferent fibres, goblet (mucin glycoproteins) , granular cells-dense granules 100-300um, 3%, DNES= kulchinsky )
superior: special olfactory epi, thick columnar epi w 3 major cells
- OLFACTORY neurons: bipolar n, receptors, apical has dendritic ends w basal bodies (long nonmotile cilia w chemoreceptors: respond to odour by AP along axon at LP->cribriform plate-> olfactory n-> bulb)
- SUPPORTING cells: columnar w broad apex and narrow bottom, microvilli bound to adj olfactory cells surrounded by fluid, abundant ion channels, junctional complexes
- BASAL cells: small spherical and cone like, near basal lamin. Stem cells
lamina p of olfactory epi: *BOWNAN’S GLANDS: secrete mucous surrounds odoriferous substances
paranasal sinus
bilateral cavities on frontal, sphenoid, ethmoidal and maxillary bone. lined w thinner resp epithelia.
LP (continues periosteum, few smaller glands)
epiglottis
flattened structure project from larynx so food doesn’t go down
- upper surface: LINGUAL
STRAT SQ EPIi-non keratinized;
- lower surface: LARYNGEAL
resp epi, ELASTIC cartilage, SEROMUCOUS glands, lymph nodes
nasopharynx
Part of pharynx (that and oropharynx- strat sq epi)
- resp epi, where nasal cavity leads to, medial pharyngeal tonsil+ bilateral opening of auditory tube connected to middle ear cavity
larynx
F: passage of aIr between pharynx and trachea
rigid reinforced by *HYALINE (thyroid, cricothyroid, inferior arytenoid cartilage) and ELASTIC cartilage (epiglottis, cuneiform, corniculate, superior arytenoid cartilage )
LARYNGEAL VESTIBULE- resp epith, seromucous glands, LP has LARYNGEAL TONSIL w lymphatic FOLLICLES
vestibule mucosa projects into lumen bilaterally w 2 pairs of folds separated y ventricle=space : VESTIBULAR fold (resp epi, sm glands, lymphoid nodules) and VOCAL fold (vocal lig (dense reg bundle of elastic CT) and vocal muscle, STRAT SQ epi NO GLANDS.
F: phonation: adduction vocal folds, intervening lumenal space narrows=rima glottidis, air expelled caused adducted vocal folds vibrate and sound produced by lips, tongue and pharynx
- pitch is modified by tension local folds, width of rima glottidis, volume of air expelled. ventricular fold, ventricle and upper resp tract contribues to phonation
- larynx men> female why voice deeper
trachea
1) tunica mucosa-resp epi+goblet+ LP
2) elastic fiber layer
3) tunica submucosa- loose CT, seromucous glands
4) hyaline cartilage- 16-20 rings to reinforce wall +keep tracheal lumen open
5) tunica adventitia
*hyaline plates open dorsally OESOPHAGUS +bridged by trachealis muscle + fibroelastic issue : elastic property allow distension when food pass through oesophagus it bulges into rtacheal lumen (which is relaxed)
coughing: tracheal m strongly contracts in cough reflex which narrows the lumen and increases velocity of expelled air to remove material
trachea- 2 bronchi- R3 L2 lobar bronchi - segmental bronchi- bronchopulmonary segment - bronchiole
segment is needed for surgery; makes up 10-12% of each lung; has own blood supply+CT capsule
bronchi
> 1mm
1) tunica mucosa-resp epi+ goblet+ LP (elastic fibers, loose CT, lymphocytes, l.n, MALT
2) tunica muscularis- smooth muscle crisis cross and spirally arranged w elastic fibers in LP
3) tunica submucosa- loose CT, seromucous glands+duct open to lumen of bronchi
4) hyaline cartilage- rings encircle lumen; as diameter decreases, rings replates by plates hyaline cart
5) tunica adventitia-loose CT
MALT and smooth m increases as the diameter decreases
seromucous glands decreases as diameter decreases
bronchiole
around 5mm
1) tunica mucosa- brush cells (columnar, less numerous, sparse microvilli, chemosensory receptors DNES small granule cells, mucous +ciliated cells
primary: RESP epi+ GOBLET+ LP
terminal- SIMPLE COLUMNAR CILIATED epi or simple CUBOIDAL epi+ CLARA cells
respiratory - simple CUBOIDAL epi+CLARA cells. Has opening for alveoli (SIMPLE SQ),
2) tunica muscularis- circular smooth muscle bundles
*no cartilage or glands
3) tunica adventitia-loose CT
clara cells=exocrine bronchiolar cells: non-ciliary, dome-shaped apical ends secretory granules F: detoxification (of inhaled xenophobic- foreign subst), stem cells, secrete surfactant (lipoproteins+ mucins), secrete antimicrobial peptides +cytokines
decrease diameter: decrease ciliated cells+ increase clara cells
alveolar duct
sac
alveolus
duct: lines opening alveolar, simple sq epi
thin LP, w strand smooth m surrounding opening;
matrix elastic fibres+ collagen to support duct+alveoli
sac: cluster of alveoli at end of duct; thin LP, elastic (prevent excess distension) +reticular fibres (to prevent collapse of fibres) to encircle opening; also has capillaries (o2 exchange occurs)
alveolus: sac like invagination 200um d and 75m^2. 200 million
responsible for spongy texture
interalveolar septum
how 02 travels
cappillary endothelia
tissue between adj alveoli: fibroblast, sparse ECM, ELASTIC+RETICULAR has MACROPHAGE, richest network of capillary in body
- pulmonary anast also supported by fibres above =primary structural support
- BLOOD AIR BARRIER = all layers 0.1-1.5 um
1) 2 or 3 thin cell lining of alveolus type i cells
2) fusion of basal lamina w endothelial cells of capillary
3) thin endothelial cells of capillary - alveolar pores 10-15um, penetrate septa and connect diff alveolar for COLLATERAL CIRCULATION (if bronchiole is obstructed) + to equalise air pressure in alveoli
- O2 from alveoli -> diffuse to blood-air barrier-> capillary hb
CO2 gets in through carbonic acid which is liberated by carbonic anhydrase - capillary endothelia
NOT FENESTRATED+ CONTINUES
organelles cluster around nucleus the walls around are thinner and (helps w o2 exchange) has pinocytotic vesicles
alveoli cells
duct cells
type i- gas exchange, 95%, walls are thin 25nm, pinocytes for turnover surfactant+removal of particles. has DESMOSOMES+TIGHT junction (prevent leakage of fluid)
type II- 5%, surfactant producing, simple CUBOIDAL cells that bind to type I through tight junctions+desmosomes. rests on BASAL LAMINA. mitotic division for regeneration+ differentiate to type I (clara cells also help)
has LAMELLAR BODIES: membrane-bound granules 1-2um-d; closely staked parallel membrane lamellae
- used as MARKERS
- lipids, phospholipids and proteins forms film of inner alveoli surface = surfactant
- prevents alveolar COLLAPSE at exhalation and inflation w less inspiratory force by applying film over lower surface tension at air-epithelia interface
critical components of surfactant
- DPPC- dipalmitoyphosphatidylcholine
- cholesterol
- 4 surfactant proteins
SP-A- hydrolytic glycoproteins
SP-D- innate proteins
SP C+B- mature DPPC +orient film in alveolus
dust cells
alveolar macrophages (need help to identify)
- million monocyte migrate to lung and mature to macrophage and phagocytose rbc that lost from damaged cappillaries +Airborn matter
- macrophage is darker than type II (due to content of C, dust and Fe
- after phagocytosis -> bronchiole -> mucocilliary app->removed in pharynx
exit lungs via lymphatic fluid
stays in septa CT for years
bronchoalveolar fluid
alveolar fluid removed by cilia joins w bronchi mucous= bronchoalveolar fluid = bacteriostatic w lysosome + clara cells and type II and dust cells
vasculature
nerves
pulmonary a+v= thin bc pressure low
forms dense capillary network
pulmonary a-> arteriole-> capillary-> venule-> pulmonary v
lymphatic vessels originate in CT of bronchioles -> bronchi-> pulmonary vessels-> l.n in hilum
- deep network parallels a superficial network and that drains the visceral pleura
Nerves GVA (parasymp) to serous membrane
nerves in CT +surrounds larger elements of bronchial tree and exist lungs in hilum
pleural membranes
mesothelium- simple sq epi = serous membrane
parietal layer-thoracic cavity surface
visceral layer- lung surface continues w lung parenchyma
fluid between them produced by mesothelial cells
pleural effusion when blood leaks in cavity and mix w fluid
- cause inflammation
