Respiratory Histology Flashcards
What is the conduction portion?
Carry air, and involved in air conditioning,, filtration, defence, sense of smell and sound production
What is the respiratory portion?
Where gas exchange takes place
What is the upper respiratory tract?
Nasal cavity, paranasal sinuses, nasopharynx and ends at larynx
What is the lower respiratory tract?
Trachea, bronchi, to terminal bronchioles
Describe the divisions of the conducting portion of the respiratory system
Trachea –> L and R main bronchi –> lobar bronchi –> segmental bronchi –> bronchioles –> terminal bronchioles
Describe the divisions of the respiratory portion of the respiratory system
Respiratory bronchioles –> alveolar ducts –> alveolar sacs –> alveoli
Describe the epithelia of the upper respiratory tract
Ciliated pseudostratified columnar epithelia with goblet cells
How does epithelia change with bronchial divisions?
As shrink in diameter –> gradual decrease in goblet cell number and transition to ciliated simple columnar and then to simple cuboidal epithelia
Describe the epithelia of the pharynx
Has stratified squamous epithelium (to resist abrasion)
Which cells contribute to the formation of mucus?
Submucosal mucous glands and goblet cells
What is the composition of the secretions in the respiratory tract?
Mucus contains mucin, water, ions, IgA and lysozyme
Describe the histology of the trachea
Epithelia: Ciliated pseudostratified
Lamina propria: lots of elastin and lymphoid tissue
Submucosa: mucous glands
Cartilage: C-shaped rings of hyaline cartilage outside submucosa
Describe the histology of the bronchi
Epithelia: ciliated pseudostratified (less goblet cells)
Lamina propria: greater elastic tissue
Muscularis mucosa: begins to form
Cartilage: in plates not rings
How does cartilage differ down the respiratory tract?
Starts off as C-shaped rings, then plates, then no cartilage at all
How does epithelia in primary bronchi differ to tertiary bronchi?
Primary bronchi = ciliated pseudostratified
Tertiary bronchi = simple columnar epithelia with few cartilage plates and mucous glands (in submucosa)
What are clara cells?
Secretory cells with unclear function
How do bronchioles differ from other structures in the conducting airway?
Has no cartilage or mucous glands
How are bronchioles kept open?
Radial traction of elastic fibres
Describe the histology of the bronchioles
Epithelia: ciliated columnar epithelium with few goblet cells (and few clara cells)
Muscularis mucosae: prominent to control air flow
Describe the histology of respiratory bronchioles
Epithelia: cuboidal ciliated epithelia and clara cells
Smooth muscle in walls (muscularis mucosae)
What is a pulmonary/respiratory acinus?
Functional unit of lung; all components involved in respiratory exchange
What cells do alveoli contain?
Type I and II pneumocytes and pulmonary macrophages
What are type I pneumocytes?
Simple squamous cells covering most of alveolar wall
What are type II pneumocytes?
Cuboidal cells which produce surfactant
