Respiratory Tract Flashcards
What forms can epithelium come in?
Simple (single layered)
Stratified (multiple layers)
Squamous (scale like)
Cuboidal (cube like)
Columnar (Column like)
Pseudostratified (simple appearing to look stratified)
List the upper and lower components of the respiratory system (conducting portion)
Upper:
Nasal cavity
Pharynx
Larynx
Lower:
Trachea
Bronchi
Bronchioles
Terminal bronchioles
List the three components of the respiratory portion of the respiratory tract
Respiratory bronchioles
Alveolar ducts
Alveolar sacs and alveoli
Outline the function of the lungs
Olfaction (environmenal smelling)
Phonation (vocal folds)
Conduction and conditioning of air (warmth, air transport and clearance)
Gaseous exchange
Endocrine (hormones)
Immune functions (macrophages, lymphoid tissue)
Outline features of the nasal cavity
Vestibule
Respiratory region
Olfactory region
What is the vestibule?
- A cartilage framework
- Stratified squamous epithelium
- Short firm hairs
- Sweat and sebaceous glands
What is the respiratory region?
- Respiratory epithelium
- Lamina propria
- Has turbinates to increase SA of resp. mucosa
What is the olfactory region?
- Roof of nasal cavity
- Lined by pseudostratified columnar epithelium, 4 cell types
What illnesses affect the nasal cavity?
Allergic reactions or vital infections
Can lead to Rhinitis/coryza (inflammation of nasal mucous membrane - capillaries near surface become engorded, restricts breathing)
What glands are located at the nasal olfactory region?
Serous olfactory (Bowman’s) glands
Produce a serous fluid, bathes cilia and serves as a solvent to dissolve odor molecules so olfactory cells can detect them
What cell types are in the olfactory epithelium?
Olfactory receptor cells
Supportive
Brush cells
Basal cells
What cells are in the nasal respiratory epithelium?
Ciliated columnar cells
Mucus cells
Brush cells
Small granule
Basal cells
Outline the ciliated columnar cell type
- Columnar, extend to surface
- 250 cilia
- Sweeping motion to expel particles trapped in mucus
Outline the mucus cell type
- Short, blunt microvilli
- Secretes mucin granules to form a protective barrier
- Increased in smokers/chronic inflammation
Outline the brush cell type
- Columnar, extend to the apical surface
- Short microvilli
- Synapse with afferent nerves gives sensory function
- Sensory receptors allow transduction of sensation
Outline the small granule cell type
- Most numerous at bifurcation of primary bronchi
- Basal granules
- AKA Kulchitsky
- Primary cells affected in small cell carcinoma of the lung
Outline the basal cell type
- Near basement membrane
- Stem cells
- Regenerate all other cell types
Outline Kartagener syndrome
- Immotile cilia syndrome
- Genetic disorder (autosomal recessive)
- Mutation in gene coding for ciliary proteins
- Results un situs inversus, recurrent sinus, pulmonary infections, sterility
Outline the larynx
- Tubular region
- Skeletal framework contains plates of hyaline cartilage
- Functions include sir conduction, phonation (speech sounds)
Outline the trachea
Contains:
- Mucosa (Resp. epith, elastic fibres, Lamina propria)
- Submucosa (seromucous glands, loose connect. tissue)
- Cartilaginous layer (c-shaped hyaline, fibroelastic membrane, trachealis muscle)
- Adventitia (connective tissue)
Outline the bronchi
-:Primary bronchi: structurally like trachea
- Segmental bronchi supply a bronchopulmonary segment
- Bronchi can be primary/secondary/tertiary, or extrapulmonary/intrapulmonary (surrounded by lung tissue)
What features do the bronchi have?
Mucosa (Resp. epith)
Muscular layer (smooth muscle, regulate airway diameter)
Submucosa (seromucus glands)
Cartilage layer (plates in intrapul, rings in extrapul)
Adventitia (connective tissue)
What type of cartilage is found in extrapulmonary and intrapulmonary bronchi?
Intrapulmonary: cartilage plates
Extrapulmonary: cartilage rings
What does squamous metaplasia mean?
Noncancerous (benign) changes in squamous cells in epithelium.
E.g., smoking looses ciliated cells. Bronchitis. Squamous cell carcinoma.
Outline the bronchioles
- 1mm diameter or less
- Regular (larger), terminal, respiratory types
Larger: epithelium:
- ciliated, pseudostratified columnar transitioning into simple ciliated columnar, goblet cells
Smaller: epithelium:
- Simple cuboidal with secretory club and ciliated cells, NO goblet cells, smooth muscle instead of cartilage
- Bronchial asthma = inflammatory airway disease
Outline type I and II pneumocytes
Type I:
- Squamous cells line 95% of alveolar surface
- Incapable of mitosis
- Surface covered by surfactant
Type II:
- Cuboidal cells, secrete surfactant
- Found at septal junctions/cells
- Only cover 5% of alveolar surface
How is alveolar surfucant managed
Regulated by cortisol, insulin, thyroxin, prolactin
What does interalveolar septum contain?
Collagen fibres
Elastic fibres (for pulmonary recoil)
Continuous capillaries
Permanent and transient cells
It is the site of the air-blood barrier
Pneumonia is spread by their alveolar pores
Give three examples of clinical conditions
Smoking induced metaplasia
Chronic obstructive pulmonary disease
Cystic fibrosis
