1. Respitarory system
Practice, 2010

2. general structure of respiratory system
respiratory epithelium (5 cell types)
microscopic structure of respiratory portion (alveols, alveolar epithelium, pneumocytes – 2 types)
blood-gas barrier, structure
developmental stages of lungs (clinical significance)

3. Structure upper airways lower airways Nasal cavity Paranasal sinuses
Nasopharynx
lower airways
Larynx
Trachea
Bronchial tree
Respiratory portion 3

4. D3 - trachea
structure is analogue to general structure of respiratory pathways:
tunica mucosa
respiratory epithelium
thick basement membrane
lamina propria
tunica fibro-musculo-cartilaginea (seromucous glands, lymphoid folicles)
hyaline cartilage, C –shape, smooth muscle and elastic fibres in dorsal part )
tunica adventitia

5. Respiratory epithelium
pseudostratified, ciliated
5 types of cells:
ciliated
goblet
brush
DNES (cells of diffuse neuroendocrine system)
stem, basal

6. D1 – epiglottis , HE - plate from elastic cartilage
- tunica mucosa - covers both surfaces (lingual and laryngeal)
- epithelium - 2 types: pseudostratified
stratified, non-keratinized
lamina propria mucosae – frequent sero-mucous glands

7. D2 – larynx, HE responsible for phonation
tunica mucosa- prominents in two pairs of folds:
upper folds (vestibular folds) - seromucous glands
lower folds (vocal folds) - stratified epithelium, elastic fibres (vocal ligament), striated muscle (intrinsic)
hyaline cartilage (thyroid, cricoid, arytenoids)
elastic cartilages (corniculate, cuneiform, superior aspect of arytenoids)

8. Bronchial tree dichotomic branching
primary bronchi (left and right), extrapulmonary
secondary bronchi (bronchi lobares)
tertiary bronchi (bronchi segmentales) intrapulmonary
bronchioles
terminal bronchioles - terminate conducting portion
respiratory bronchioles - starting respiratory portion
trends following the progressive decrease in size of airways:
cartilage, glands, goblet cells, height of epithelium
elastic fibres, smooth muscle 8

10. D4-bronchus intrapulmonalis
intrapulmonal bronchi:
C-shape cartilage replaced by fragments (round region)
smooth muscle in 2 distinct layers spiraling in opposite direction
elastic fibres
bronchioles , diameter less than 1mm:
0 cartilage , 0 glands, epithelium still standard, DNES in groups
terminal bronchioles, less than 0,5mm, terminal portion of airways, epithelium simple, goblet cells replaced by secretory Clara cells

12. D5- lungs, HE
pulmonary lobes divide into bronchopulmonary segments and lung acini
intrapulmonary bronchi, bronchioles
honeycomb structure – alveolar sacs and alveoli
in respiratory portion of lungs – wall is attenuated – where gas can be exchanged
epithelium simple cuboideal and simple squamous
Clara cells (in bronchioles) secretory, surfactant-like material, can divide, degrade toxins in inhaled air (cytochrome P-450 in SER)

15. Lungs, blood-gas barrier
alveoli, small outpocketing, 200um in diameter
total number 300mil., total surface area for gas exchange 140m2
alveolar pores, spaces 8-60um in alveolar wall, equilibrate air pressure within the segments
interalveolar septum, the region between ajacent alveoles, containing:loose connective tissue:reticular and elastic fibres, extensive capillary bed from continues capillaries
the thinnest region of interalveolar septum form
blood-gas barrier

16. Lungs, alveolar epithelium
type I pneumocytes, 95%, s.c. alveolar, squamous, attenuated, width 80nm, occluding junction prevent seepage of tissue, extracellular fluid into alveoles
type II pneumocytes, produce surfactant, the secretory product stored in the form of lamellar bodies
surfactant decreases surface tension, preventing collapse of the alveoles
type II pneumocytes can divide to type I

17. D6 – fetal lungs histogenesis of the lungs – 4 developmental stages:
I. pseudoglandular th week
II. canalicular 17th-24th week, development of primitive alveoles and vascularisation. Respiration and survival is possible, but with intensive care. Non maturity is however severe , often resulting to outdying of such prematurity. Respiratory distress syndrom from non sufficient amount of surfactant (can be increased by corticoid therapy)
III. terminal sacs 24th week up to the birth, considerable increase of terminal sacs with sufficiently formed blood-air barrier. Surfactant production.
26th-28th week, corresponding fetal weight of1000g,sufficient surfactant amount and capillary bed enable surviving without intervention.
IV. alveolar , from the birth until 8th year