respiratory system- discussion, viva

Respiratory system:

1. Name the parts of respiratory system.
• Upper respiratory tract
• Nasal cavity
• Pharynx
• Larynx
• Lower respiratory tract
• Trachea
• Extrapulmonary bronchi or primary bronchi
• Intrapulmonary bronchi 
• Secondary bronchi or lobar bronchi
• Tertiary bronchi or segmental bronchi
• Bronchioles
• Terminal bronchioles
• Respiratory bronchioles
• Alveolar duct
• Alveolar sac
• Alveoli
2. Classify respiratory system on functional basis.
• Conducting portion- From trachea to terminal bronchiole
• Transition zone- respiratory bronchiole 
• Respiratory portion-  from alveolar duct to alveoli 
3. Name the functions of conducting, transition and respiratory portions.
• Conducting portion- conducts air to and from lungs, cleans and humidifies air
• Transition zone- conducts air and also exchange of gases
• Respiratory portion-  exchange of gases 
4. Name the cells in the respiratory passage.
• Tall columnar ciliated cells
• Basal cells
• Goblet cells
• Clara cells
• Brush cells (non-ciliated columnar cells)
• Small granule cells (Kulchitsky cells)
• Type 1 alveolar cells (type 1 pneumocytes)
• Type 2 alveolar cells (type 2 pneumocytes)
• Dust cells (alveolar macrophage cells)

Trachea:

1. Name the layers of trachea?
• From luminal surface to outwards
• Mucosa- 1. epithelial lining, 2. lamina propria
• Submucosa
• Fibromusculocartilagenous layer
• Adventitia
2. What is the epithelium lining the trachea?
• Pseudostratified ciliated columnar epithelium which has tall columnar ciliated cells and basal cells
3. Name the contents of lamina propria.
• Loose connective tissue
• Lymphocytes
• Blood vessels
• Seromucous glands, mainly mucous
4. Name the components of submucosa.
• Dense connective tissue
• Seromucous glands
5. Why the third layer is called fibromusculocartilagenous layer?
• The layer is made of 
• C-shaped hyaline cartilage which is deficient posteriorly.
• Smooth muscle bundle called trachealis muscle binds to two ends of hyaline cartilage
• Fibroelastic tissue mixed with smooth muscle
• Since this layer has all the three parts- cartilage, smooth muscle and fibroelastic tissue, it is called as fibromusculocartilagenous layer
6. Give the structure of hyaline cartilage.
• See the post on cartilage
7. What is adventitia made of?
• Connective tissue
• Blood vessels
• Nerves

Lung:

1. What are the components of lung?
• Intrapulmonary bronchi- secondary and tertiary bronchi
• Bronchioles- terminal and respiratory bronchioles
• Alveolar duct
• Alveolar sac
• Alveoli
2. What are the differences between trachea, extra pulmonary bronchus and intra pulmonary bronchus
• Refer the table below
3. What are the differences between bronchus and bronchiole?
• Refer the table below
4. Name the cells present in the walls of the alveoli.
• Type 1 alveolar cells (type 1 pneumocytes)
• Type 2 alveolar cells (type 2 pneumocytes)
• Dust cells (alveolar macrophage cells)
5. What are the functions of the cells in alveoli?
• Type 1 alveolar cells - squamous cells for exchange of gases
• Type 2 alveolar cells - cuboidal cells for secretion of surfactant
• Dust cells - macrophages for phagocytosis
6. What is blood-air barrier?
• Blood-air barrier are the layers present between blood in the capillary network and the air in the alveoli for the exchange of oxygen and carbon-dioxide.
7. Name the layers of blood-air barrier.
• Endothelial cells in the capillary
• Basal lamina of capillary
• Basal lamina of type 1 alveolar cells
• Type 1 alveolar cells

Differences between trachea and different parts of bronchial tree

Parts	Epithelium	Features of wall
Trachea	Pseudostratified ciliated columnar epithelium, goblet cells, basal cells	Lamina propria, submucosa with seromucous glands, fibromusculocartilagenous layer, adventitia
Bronchi	Pseudostratified ciliated columnar epithelium with goblet cells	Narrow thin lamina propria, layer of smooth muscle cells, submucosa with bronchial glands, irregular hyaline cartilage plates, adventitia
Bronchiole	Pseudostratified ciliated columnar to simple cuboidal epithelium from proximal to distal with occasional goblet cells, brush cells (nonciliated columnar), Kulchitsky cells (small granule cells), Clara cells	Mucosal folds, smooth muscle layer, adventitia. No cartilage and glands
Terminal bronchiole	Simple cuboidal epithelium, clara cells	Thin, incomplete layer of smooth muscle. No cartilage and glands
Respiratory bronchiole	Simple cuboidal epithelium, clara cells with scattered alveoli	Few smooth muscle fibers mostly around alveolar openings
Alveolar ducts, sacs	Simple cuboidal between many alveoli	Bands of smooth muscle around alveolar openings
Alveoli	Type 1 and type 2 alveolar cells (pneumocytes)	Only network of elastic and reticular fibers