Bronchus 1. Mucosa ciliated column cell, goblet cell, basal cell, stem cell, small granule cell(neurosecretory granules) 2. Submucosal glands- serous and mucus 3. Wall -smooth muscle, contractile elastic fibers, provide flexibility cartilage plate, for support BronchioleΦ<1mm Mucosa ciliated epithelial cell Clara cell (non-ciliated secretary cell) ★ 2. Wall smooth muscle no gland no cartilage4 Bronchiole Φ < 1mm 1. Mucosa — ciliated epithelial cell — Clara cell (non-ciliated secretary cell) 2. Wall — smooth muscle — no gland — no cartilage Bronchus 1. Mucosa ciliated column cell，goblet cell, basal cell, stem cell, small granule cell (neurosecretory granules) 2. Submucosal glands — serous and mucus 3. Wall — smooth muscle, contractile — elastic fibers, provide flexibility — cartilage plate, for support