Download - Histology of trachea and lung
HISTOLOGY OF TRACHEA AND LUNG
Dr.ushakannan,Asst.professor.
RESPIRATORY SYSTEM Conducting Part-
responsible for passage of air and conditioning of the inspired air. Examples:nasal cavities,pharynx, trachea, bronchi and their intrapulmonary continuations.
Respiratory Part-involved with the exchange of oxygen and carbondioxide between blood and inspires air.Includes the lungs
Trachea
Left and Right lobar bronchus Lungs.
Lobar Bronchi. . Lobes(Right 3 and Left 2.).
Segmental bronchi Broncho-pulmonary segments(10+10)
Bronchioles Terminal bronchioles. Respiratory Bronchioles. Alveolar ducts Alveolar sacs
Alveoli.
RESPIRATORY SYSTEM HISTOLOGY
Trachea Bronchus -Primary bronchus -Secondary bronchus -Tertiary bronchus Bronchiole Lung
Trachea
Mucosa -Epithelium -Lamina propria Sub mucosa Cartilage &muscle
layer Adventitia
RESPIRATORY EPITHELIUM
Trachea Mucosa Epithelium -Pseudo stratified ciliated
columnar/ Respiratory epithelium
Cells-Ciliated columnar cells - Goblet cells -Brush cells - Basal cells -Granule (kulchitsky)
cellsSecretory cells -Clara
cells( bronchiolar cells) surfactant.
Lamina propria - Elastic fibre, Lymphocyte, Mast cells, Blood vessels
Trachea Sub mucosa- Loose connective tissue Tracheal glands-Mixed
(serous &mucus) glands Blood vessels and ducts Cartilage &smooth muscle
layer- ”C” Shaped hyaline cartilage
having perichondrium and chondrocytes
Ends of cartilage connected by smooth muscles
Adventitia-fibro elastic tissue
TRACHEA (T.S. LOW POWER)
CELLS SEEN IN THE RESPIRATORY PASSAGES Goblet cells Non-ciliated serous cells Basal cells Cells of Clara Brush cells Argyrophil Cells similar to diffuse
endocrine cells of gut Lymphocytes
HISTOLOGY OF LUNG
BRONCHUS Principal bronchus -same as trachea Secondary /Lobar bronchus -Irregular hyaline cartilage -Pseudo stratified ciliated
columnar Tertiary /Segmental
bronchus -Columnar epithelium -Patches of cartilage
Segmental or tertiary bronchus: The number of Goblet cells reduced.
(epithelium) The number of Glands reduced.
(submucosa) The cartilage is present in the irregular
plates.
BRONCHIOLE Terminal bronchiole -Columnar epithelium -No cartilage
- smooth muscle + -Clara cells (dome shaped)
present
-Cuboidal epithelium -No mucous gland Respiratory bronchiole
RESPIRATORY BRONCHIOLE
Cuboidal epithelium.
No mucus gland.
Lined by simple ciliated or columnar epithelium.
Smooth muscles form ring underneath the epithelium in between two adjacent alveoli.
Alveolar duct-Alveolar sac. Alveolar duct lined by simple squamous
epithelium. Increase the surface area of gaseous
exchange. Surrounded by network of capillaries.
Inter alveolar septum- Is the wall present in between the two
adjacent alveoli. Consists of epithelial cells of each alveolus on
both sides. Connective tissues contain
capillaries,collagen,elastic fibres,fibroblasts and macrophages(dust cells).
Alveoli are thin walled outpouchings , lined by a single layer of cells.
Two types: Pneumocyte 1 and2 cells. Also called pneumocyte or alveolar cells.
Type 1 Pneumocyte are squamous cells ,adjacent cells are joined together by tight junctions.
Function: Gaseous exchange. Type 11 Pneumocytes: Cuboidal cells,scattered among type 1 cells. Secrete Pulmonary surfactant which lowers the surface
tension and prevents alveoli from collapsig. Alveolar macrophages or Dust cells – Remove debris.
Bronchus and Bronchiole
DIFFERENCES BETWEEN BRONCHI AND BRONCHIOLES
Bronchus Glands are present. Presence of cartilage. Goblet cells are
present. Spiraliy arranged
smooth muscle layer. Mucosa folded lined
by ciliated pseudostratified columnar cells.
Bronchioles No glands No cartilage No goblet cells Thick smooth muscle
layer Mucosa highly folded
lined by simple columnar or cuboidal cells with Presence of Clara cells
Many elastic fibres
Trachea (T.S. Low Power)