Respiratory system

Respiratory system

Nasal cavity, pharynx & larynx. Trachea & bronchi. Lung.

一、trachea

mucosa submucosa adventitia trachea (HE) Mixed gland

EM: epithelium of trachea 1.Ciliated C 2.Brush C 3.Goblet C 5.Basal C 4. Small granule C

The wall of trachea 1. Mucosa=epithelium+lamina propria pseudostratiated ciliated columnar… Ciliated C, goblet C, brush C, basal C, small granular C. 2. Submucosa=CT+ mixed glands 3. Adventitia=16-20 ‘C’ shaped hayline cartilage rings.

二、lung bronchiole Gas exchange lung atmosphere & alveoli alveoli & blood (blood & tissue)

Lung Low power

lung parenchyma: bronchial trees & alveoli . Principal bronchi(Br)—lobular、segmental Br—smaller Br—bronchiole—terminal bronchiole—respiratory bronchiole—alveolar duct、alveolar sac—alveoli. Conduction portion : above terminal bronchioles. Respiratory portion :respiratory bronchiole to alveoli. Pulmonary lobule: bronchiole and it’s ramifications.

Epithelium Goblet C Glands Cartilage plate SMC Conduction portion－ lobular Br & small Br Epithelium Goblet C Glands Cartilage plate SMC

Simple ciliated columnar. Goblet C （－） Gland （－） Cartilage plate （－） Conduction portion－ bronchiole & terminal brochiole Simple ciliated columnar. Goblet C （－） Gland （－） Cartilage plate （－） SMC

Rules of structural variance in conducting portion Small Br bronchiole Terminal bronchiole Epi Pseudostratified Ciliated columnar Simple ciliated columnar Simple columnar** clara cell Goblet C + + +/- - Mixed gland Cartilage plate SMC + + ++

Respiratory bronchiole Respiratory portion－ Respiratory bronchiole The wall is interrupted Simple cuboidal Epi, clara C SMC

Alveolar duct & alveolar sac Respiratory portion－ Alveolar duct & alveolar sac Alveolar duct The wall, many alveoli SMC** Simple cuboidal, squamous Alveolar sac No SMC**

Respiratory portion－alveolus 肺泡管 Simple alveolar Epi.

(1) Respiratory portion ###constituents：respiratory bronchiole，alveolar duct，alveolar sac，alveolus。 1.Respiratory bronchiole The wall, few alveoli open into. Simple cuboidal Epi,SMC.

(2) Respiratory portion 2.Alveolar duct & alveolar sac The wall, many alveoli open into. Knobs in the wall of alveolar duct Knobs is sphincter-like SMC.

(3) Respiratory portion 3. alveolus: type I alveolar C type II alveolar C alveolar septum.

macrophage Type II alveolar C Elastic fiber

type I alveolar C

Type II alveolar C Osmiophilic Multilamellar bodies

blood-air barrier

Alveoli Type II cell Type I cell squamous, covered most surface of the alveoli . Type II cell LM: round or cuboidal, cell body protrude into the lumen. EM: osmiophilic multilamellar body, with abundant phospholipids. Functions: secret surfactant, reduce surface tension, stabilize alveoli.

Alveolar septum: continuous Cap., elastic fiber. macrophage dust C. @blood-air barrier includes: 1.mucus layer on surface of alveoli 2.type I alveolar C 3.BM of alveolar C 4.delicate layer of CT 5.continuous Cap. BM 6.continuous Cap. Endothelium.

Terminal bronchiole Respiratory bronchiole Alveolar duct Alveolar sac 1 Terminal bronchiole Respiratory bronchiole 2 Alveolar duct 3 4 Alveolar sac

Rules of structural variance in respiratory portion wall Epi. SMC Respiratory bronchiole Not integrated Alveoli open Simple columan Simple cuboidal thin Alveolar duct Many alveoli open into A few Alveolar sac of alveoli Alveolar Epi. no alveolus Irregular vesicular

Alveolar epithelial cell shape cytoplasm functions Type I squamous Phagocytotic vesicle Covered 95% of the surface of alveoli to benefit gas exchange. Type II round cuboidal Osmiophilic multilamellar body Secret surfactant to reduce surface tension and stabilize the alveoli. ** Type I cell can not regenerate. Type II cell can differentiate into Type I cell .

keypoints The basic structure of trachea. Histologic structure of conduction portion. Histologic structure of respiratory portion. Esp. the alveolar epithelium

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