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 ep

ithelium---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, no g.

-function: not very clear, may be

i. become into ciliated cell

ii.receive sensory stimuli-epitheliodendritic synapse

diffuse neuroendocrine cell:

-less, pyramidal

-EM: dense-core g.-small granule cell

neuroepithelial body: cell + NF

-Function: secret hormones to regulate contract of SM and secretion of gland

i. 5-hydroxytryptamine(serotonin)

ii. calcitonin

iii. enkephalin

* clear basement membrane

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

* branchi →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

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 cellsA layer of SM

i.   ciliated cell ii.  secreting cell: Clara cell EM:

dome-shaped apicalSERSecreting G: contains proteolytase and oxidase

function: dissolve the mucus biological thansformation undifferentiated 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 changingsimple 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:---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

EM:

secreting granules: Osmiophilic multilamellar body

-0.1-1.0 um

-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