Chapter 15 Respiratory System

1. Components ---nose ---pharynx ---larynx ---trachea ---bronchi ---lung

2. Trachea and main bronchi three layers 1)      Mucosa: ---epithelium: pseudostratified ciliated columnar epithelium ---lamina propria: CT, contain LC, PC, MC, BV, LV

Pseudostratified ciliated columnar epi. ciliated cell: columnar, cilia goblet cell basal cell: -pyramidal, basally-located -undifferentiated cell→ciliated cell or goblet cell brush cell: -columnar, microvilli, -EM: RER -function: not very clear diffuse neuroendocrine cell: -less, pyramidal -function: secret hormones to regulate contract of SM and secretion of gland

Cilia on the surface of trachea Ciliated cell Goblet cell

2) Submucosa: LCT, with BV, LV and N tracheal gland: mixed diffuse LT and LN S Ig A = secretory component (secreted by epi. cell) + Ig A ( produced by plasma cell) 3) Adventitia: cartilage ring: 16-20 “C ” shaped circular ligament: elastic F SM- posterior part( membrane part): SM, elastic F, tracheal gland

3. Lung --paired organ, located in thoracic cavity

1) General structure: ---capsule: visceral layer of pleura- serous membrane-CT + mesothelium ---parenchyma: all branches of bronchi and alveoli( right 3, left 2) ---interstitia: CT, BV, LV, N

* bronchi →intrapulmonary bronchial tree( lobar bronchial tree, segmental bronchi and small bronchi) D < 1mm D < 0.5 mm →bronchioles →terminal bronchioles →respiratory bronchioles →alveolar duct →alveolar sac → alveoli * pulmonary lobule: one bronchioles and its all branches and all alveoli cone or pyramidal-shaped: apex pointed toward the hilum and basal(1.0 cm in D) faced the surface more CT between them

① from lobar bronchi to small bronchi 2) Conducting portion ① from lobar bronchi to small bronchi ---Regulation of simplification: (gradually) mucosa: -epi. : become thinner -goblet cell ↓ -lamina propria: thinner, SM ↑ submucosa: gland ↓ adventitia: cartilage→cartilage →decreasing ② bronchiole: D < 1mm ---continuous to change goblet cell, Gland, cartilage ↓ or disappear smooth muscle ↑,circular mucosa plica ↑ ③ terminal bronchiole: D < 0.5 mm ---goblet cell, gland, cartilage disappear ---SM: form a whole layer of circumferential SM ---Wall: simple columnar epi.: two types of cells A layer of SM

Simple columnar epi: i. ciliated cell ii. secreting cell: Clara cell EM: dome-shaped apical SER Secreting G: contains proteolytase and oxidase function: dissolve the mucus biological thansformation undifferentiated cell → ciliated cell Ciliated cell

3) respiratory portion ①     respiratory bronchiole ---similar to terminal bronchioles: simple ciliated columnar epi. smooth muscle ---place where connect with alveoli: gradual changing simple cuboidal epi. →simple squamous epi. less SM, elastic F ②  alveolar duct: 20-60 alveoli connect with it ---wall: hard to see- opening part between two alveoli simple cuboidal epi. or squamous epi. SM: single, EF- knob-liked structure ③   alveolar sac: ---many alveoli open to it ---no proper wall, no knob-liked structure ④   alveoli

④   alveoli: ---polygonal, with opening sac- 0.2mm in D, 300-400 million/per lung, total area: 70-80mm2 ---wall: epi. and basal lamina alveolar septum: CT with BV, EF

a.alveolur epi: ---type I alveolar cell: LM: flattened, 0.2um, N: round EM: plasmalemmal vesicles tight junction Function: constitute the blood-air barrier ---type II alveolar cell: scattered, 5-8/per alveoles LM: cuboidal or round, with round N paler- stained, foamy cytoplasm secreting granules: Osmiophilic multilamellar body -contains: phospholipid, glycosaminoglycan and protein microvilli, mito, lysosome, RER, Golgi Function: i. secreting surfactant ii. differentiated into type I alveolar cell

b. alveolar septum: CT EF Fibroblast, macrophage, plasma cell, mast cell LV, N capillary: endothelium + basement membrane * Blood-air barrier: the structure through which the gaseous exchange takes place ---0.2-0.5 um ---components: a layer of liquid type I alveolar cell and basement M CT capillary endothelial cell and BM

c. alveolar pore: 10-15 um ---equalize( balance) the air-pressure between alveoli ---lober pneumonia- bacteria or inflammatory spread through the pore

d. alveolar marcophage: monocytes- MPS ---dust cell: macrophage which phagocytose carbon or duct particles ---heart failure cell: when lung congested(edema), the alveolar marcophage phagocytose RBC, digest the hemoglobin into hemosiderin(pigment) and accumulated them within macrophage