Tissues & Organs
Tissues & Organs
Trachea
1. Mucosa
Epithelium | pseudostratified ciliated columnar epithelium, thick basement membrane
Cellular Component | goblet cells, ciliated columnar cells, basal cells, brush cells, serous cells, DNES cells, neutrophils
Lamina Propria | loose, fibroelastic connective tissue, diffuse lymphatic tissue, lymph nodules
Glands | mucous and serous glands
Elastic Lamina | dense layer of elastic fibres
2. Submucosa
Connective Tissue | dense, irregular fibroelastic connective tissue
Glands | mucous and seromucous glands
Lymphoid elements
3. Adventitia
Connective tissue | fibroelastic connective tissue
Key ID | 10-12 horseshoe shaped hyaline cartilage C-rings connected to one another through trachealis muscle (smooth muscle) and fibroelastic connective tissue
Hyaline Cartilage
Respiratory Epithelium
Trachea & Esophagus
Mammal Trachea
Human Trachea
Trends observed as you move down the Bronchial Tree:
Decreased cartilage, glands, goblet cells, and height of epithelium
Perceived increase in smooth muscle cells, and elastic tissue
Bronchi
1. Mucosa
Epithelium | pseudostratified ciliated columnar epithelium
Cellular Component | goblet cells, ciliated columnar cells, basal cells, brush cells, serous cells, DNES cells, neutrophils
Lamina Propria | smooth muscle fibres, lymphoid tissue
Glands | more seromucous glands
SMC | two distinct SMC layers in opposite directions
2. Submucosa
Connective Tissue | dense, irregular fibroelastic connective tissue
Glands | seromucous glands
Lymphoid elements
3. Adventitia
Key ID | Cartilage C-rings replaced by irregular plates of hyaline cartilage surrounding lumen
Bronchi
Terminal Bronchioles
1. Mucosa
Epithelium | transition from ciliated simple columnar epithelium with goblet cells to simple cuboidal epithelium with club cells and no goblet cells in smaller bronchioles
Cellular Component | less goblet cells, club cells (Clara cells)
Lamina Propria | fibroelastic connective tissue surrounded by one or two smooth muscle cell layers
2. Submucosa
Connective Tissue | dense, irregular fibroelastic connective tissue
Glands | NO glands
3. Adventitia
Key ID | NO cartilage
Terminal & Respiratory Bronchioles
Terminal Bronchiole
Respiratory Bronchioles
1. Mucosa
Epithelium | transition from non-ciliated simple cuboidal epithelium to simple squamous epithelium in smaller bronchioles
Cellular Component | club cells (Clara cells)
Lamina Propria | fibroelastic connective tissue surrounded by one or two smooth muscle cell layers
2. Submucosa
Connective Tissue | dense, irregular fibroelastic connective tissue
Glands | NO glands
3. Adventitia
Key ID | NO cartilage
Walls | alveolus
Respiratory Bronchiole
Alveoli
Epithelium | Type I pneumocytes – squamous alveolar cells (simple squamous epithelium)
Type II pneumocytes – great alveolar cells, septal cells (cuboidal shaped cells)
Sphincter | single smooth muscle cell (SM knob) embedded in type III collagen
Cellular Component | macrophages (dust cells), fibroblasts, mast cells, lymphoid cells
Septum Connective Tissue | type III collagen and elastic fibres
Type I Pneumocytes
