histology respiratory system Flashcards
resp.system. anatomical division og functional division
1) upper resp. passage:
nasal cav, paranasal sinuses, nasal+oral
part of pharynx
2) lower resp passage:
laryngeal p. of pharynx, trachea og bronchi
og lungs
1) conducting portion:
nasal cav, trachea, bronchi, bronchioles, terminal bronchioles
2) respiratory portion:
resp. bronchioles, alveolar ducts, alveolar sacs, alveoli
development of resp.system
at 4th week m outgrowth of endoderm on ventral side of foregut—->
respiratory divertculum
A) endoderm origin: epithelial lining of resp. passage og glands
B) mesoderm origin (mesenchyme): CT, cartilage, smooth muscle, blood vessels og pleura
Newborn respiratory distress syndrome
gerist í premature infants (before 28 weeks of pregnancy)
due to:
lung immaturity, mest type 2 alveolar cells–>
lack of surfactant formation
-the alveoli develop worse after repeated breaths when they stop developing and eventually they collapse
-histology:
necrosis of alveolar cells, collapsed alveoli, (atelectasis)
layers of hyaline membrane and interstitial edema
prevention: (before delivery)
-administration of substances that accelerate maturation alveolar cells (glucocorticoids)
therapy: administration of exogenous surfactant by intratracheal instillation
larynx macroscopic
laryngeal skeleton:
-6 cartilages
-3 of them unpaired (epiglottis, thyroid cartilage and cricoid cartilage)
-3 paired (arytenoid, corniculate og cuneiform)
-epiglottis, corniculate og cuneiform elastic cartilages, hin eru hyaline cartilages
-thyroid cartilage protrudes forward in men —>
ground for adams apple
-striated skeletal laryngeal muscle—>
their role is to control the cartilage movement + regulate tension of vocal folds
larynx, microscopic view
laryngeal cavity divided into 2 pairs of mucosal folds (plicae) into 3 sections
1) vestibulum laryngis (supraglottic part, milli vocal og vestibular folds)
2) ventriculum laryngis (ventricle/sinus. Below vestibule)
3) infraglottic cavity
*Glottis (voice apparatus): consists of true vocal folds and the opening milli the vocal cords called the rima glottidis.
–>Makes the voice, closes airway og vocal cord
Larynx microscopic
2 paired mucosal folds:
A) upper (plicae vestibularis):
-false vocal cords, w pseudostratified ciliated epithelium + goblet cells (resp. epithelium)
-Lamina propria: sparse collagen ligament under epithelium
-Reinke space: m seromucus glands + l.tissue
(laryngeal tonsil - MALT)
B) lower (plicae vocales) - true vocal cords,
lined w stratified sq. non-keratinized epith
-lined w vocal lig
-composed of elastic + collagen fibers
-under the ligg is vocalis m (p. of thyroarytenoid)
Trachea
air passes from larynx to bronchi
-um 13cm length, 1.8 cm width
-reinforced w 15-20 C-hyal.cartilage shaped rings. (opened at back, conn w CT wall, joining the cartilage ends, paries membranaeous)
-C6-T4/5
-ending in bifurcation—> carina (cartilage ring, divides bronchi into 2 bronchi)
-paries membranaeous: collagen, elastic fibers + smooth muscle (trachealis)
-all structures form supporting apparatus –>
tunica fibro-musculo-cartilaginea
Trachea - microscopic view 4 layers
1) mucosa (tunica mucosa) - lined w pseudostratified columnar epith + cilia + goblet cells (f. utan bifurcation)
-lamina propria m seromucus glands, reaching up to the submucosa + l.tissue
2) submucosa (tela submucosa)
-Loose CT, Seromucus glands
3) hyal. cartilage/paries membraneous, trachealis muscle
4) Tunica adventitia:
-loose ct, conn. trachea w surr. structures + providing for breathing movement
Lung (pulmo)
each lung stored in its own pleura.
right lung bigger and heavier.
-right lung (superior, inferior og medius lobes dexter)
-left lung (superior and inferior sinister)
—> bronchial tree:
br. of airway from bronchi–>alveoli
(by dichotomous branching)
bronchial tree
-extrapulmonary airways:
up to the upper p. of primary bronchi
-intrapulmonary airways:
up to the alveoli
Pulmonary acinus:
ventilated by 1 terminal bronchiole, consisting of resp.bronchioles and alveoli
Pulmonary lobe:
formed by 8 acins (functional unit of lung tissue)
Bronchus
1) Tunica mucosa:
lined w resp epithelium, lamina propria rich in elastic fibers + l.cytes + mast cells
2) smooth muscle layer
3) hyaline cartilage (formed by irregular cartilage plates/islands)
4) CT or interstitium:
-surr. bronchi
-m blood+l.vessels
-l.follicles (bronchial-associated-l-tissue) og nerves
-creates CT septa
-seromucus, bronchial glands (milli smooth muscle cells og cartilage) –> creates mucins (mucus layer on epith. surf) og AB(IgA)
-Neuroendocrine cells (DNES) among epith.cells, located individually or in groups
Bronchiolus
1) tunica mucosa:
-simple columnar epith w or w.out cilia
-goblet cells gradually diminish
-in the terminal bronchioli the epith decreases to simple cuboidal
-also secretory clara cells
2) smooth muscle layer
3) CT interstitium
Bronchiolus
1) tunica mucosa:
-simple columnar epith w or w.out cilia
-goblet cells gradually diminish
-in the terminal bronchioli the epith decreases to simple cuboidal
-also secretory clara cells
2) smooth muscle layer
3) CT or interstitium:
-without glands and cartilage
-Clara cells (club cells) in terminal and resp.bronchioles (columnar cells w secr. granules in apical p)
they produce 3 proteins: surfactant proteins and clara proteins (they inhibit inf.response og facilitate phagocytosis )
Clinical correlation
Bronchial asthma:
chronical infl lower resp. disease
-repeated attacks of reversible expiratory dyspnoea due to bronchial obstruction (bronchospasm)
-cause is genetical predispostion to infl of mucosa, initiated by non-spec og specific triggers (allergies, infections, physical and chemical factors)
-histologia:
rearrangement of resp mucosa–>
goblet cell hyperplasia, muscle basement membrane thickening og infiltration of eosinophiles
therapy:
medication controlling asthma. Td inhalation og systemic glucocortisteroids
resp bronchioli og alveoli
resp bronchioli lined w simple cuboidal epith (including clara cells)
-their course interrupted by alveoli
-alveoli: basic funct. unit of resp system
(gas exchange). Air filled polygonal spaces in the lung parenchyma
(total in both lungs 300 millions)
-alveoli sep. by walls
—->interalveolar septa
