Transcript Cells in alveoli

Respiratory System:
- nasal cavity
- Primary Bronchi, bronchioles & alveoli
- Cells in alveoli
Organization of the respiratory
system
• Functions, movement of air (breathing); exchange
oxygen for carbon dioxide
• Conducting portion and respiratory portion
• Conducting: epithelium, cartilage, smooth muscle,
bones
– Nasal and oral cavities, nasopharynx, pharynx, larynx,
tracea, primary bonchi, secondary bronchi, brondhiles,
terminal bronchioles.
Conducting portion
• warm air, filter out bacteria, prevent
dehydration, immune against infection
• Olfactory epithelium
Nasal Cavity
• Respiratory epithelium and keratinizing stratifed
squamous epithelium
• Pseudostratified ciliated epithelium also in the
trachea and bronchioles (respiratory ep)
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Ciliated columnar cells – secretory IgA transcytosis
Goblet cells
Basal cells
Brush cells with tall microvilli
DNES cells (diffuse neuroendocrine system)
Olfactory epithelium
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OSNs
SCs
BC
Bowman’s glands
Glomeruli (1000 – 1500) around 10,000
odors
Trachea
• Mucosa – respiratory epithelium
– Lamina propria, loose fibroelastic tissue, lymph
elements, elastic lamina
• Submucosa – dense fibro-elastic, mucous
and seromucous glands, lymphoid elements,
BV
• Adventitia – C rings, fibroelastic CT,
anchors to various structures
Primary Bronchi
- histological structure same as trachea
Intrapulmonary bronchi
- adventitia has irregular plates of cartilage
- elastic fibers
- between lamina propria and submucosa
- smooth muscle
- form opposing spirals around bronchi
- lamina propria with seromucous glands
Bronchioles
- ciliated simple columnar, few goblet cells
--> simple cuboidal, no goblet cells, yes Clara cells
Clara cells
- produce surfactant
- contain cytochrome P450 enzymes
- proliferate and can differentiate to epithelial cells
Lamina Propria
- no glands
- surrounded by a loose network of helically
oriented smooth muscle cells
**no cartilage**
Terminal bronchioles
- epithelium is cuboidal ciliated with Clara cells
- one or two layers of smooth muscle
Respiratory bronchioles
- similar to terminal bronchioles
- wall has alveolar outpouchings
Alveolar Ducts
- linear arrangements of alveoli
Alveolar sacs
- cluster of alveoli
Alveoli - primary structural and functional unit of the
respiratory system
- allow for gas exchange between air and blood
Cells in alveoli:
Type I pneumocytes
- simple squamous epithelium
- occluding junctions
- basal lamina
Type II pneumocytes
- cuboidal cells
- form occluding junctions with type I pneumocytes
- contain lamellar bodies with pulmonary surfactant
that is secreted by exocytosis
Alveolar macrophages - phagocytose dust and bacteria
Continuous capillaries:
- endothelial cells without fenestrae
- fasciae occludentes
Blood-Gas Barrier
- surfactant and type I pneumocytes
- fused basal laminae
- endothelial cells
Digestive System - Oral Cavity
Tongue - epidermis, taste cells, glands, muscles
Lingual papillae:
- filiform - no taste buds
- fungiform - dorsal taste buds
- foliate - taste buds in neonates, lateral furrows
- circumvallate - look like a submerged donut
- taste buds on sides
Taste buds - taste pore
- nerve fibers form synaptic junctions with
type I, type II, type III cells
- type IV are basal cells
Glands of the tongue - von Ebner’s glands
- serous glands
- ducts at the base of
circumvallate and folate papillae