WEEK 1: HISTOLOGY OF THE RESPIRATORY SYSTEM Flashcards
What are the two subdivisions of the respiratory system?
conducting portions
respiratory portions
Name all parts that make up the conducting system
nasal cavity, nasopharynx, larynx, trachea, primary bronchi, secondary (lobar) bronchi, tertiary (segmental) bronchi, and terminal bronchioles
What is the function of the conducting system?
clean, warm and moisten air prior to reaching respiratory portion
Name the 3 histological regions of the nasal cavity .
vestibule,
respiratory and
olfactory regions
Describe the VESTIBULE?
*Lined with skin and has short, stiff hairs named VIBRISSAE that prevent large dust particles to enter.
*Keratinized stratified squamous epithelia (but changes within the vestibule to nonkeratinized)
*Dermis houses numerous sebaceous glands
What is the epithelium found on the respiratory region of the nasal cavity called?
pseudostratified ciliated columnar epithelium (respiratory epithelium)
List all cells which are found on the respiratory region of the nasal cavity.
*Ciliated columnar cells: most common, each cell has about 300 cilia
*Goblet cells: secret mucous
*Brush cells: have short microvilli, nerve fibers, sensory function
*Basal cells: are rounded stem cells that located near basal lamina and show mitotic figures
*Small granule cells (kulchitsky cells) - Are a diffuse neuroendocrine cells (DNEs) similar to enterochromaffin cells that are scattered throughout the epithelium and secrete bronchoactive hormones
*Subepithelial CT (lamina propria) – areolar connective tissue; is richly vascularized, containing large arterial plexuses and venous sinuses, many seromucous glands and lymphoid elements
What is lamina propria?
LP is a thin layer of loose connective tissue, or dense irregular connective tissue, which lies beneath the epithelium.
What is the mucosa made up of?
Epithelium and the lamina propria
Describe the 3 types of cells found in the olfactory region
*Olfactory cells - olfactory cells are bipolar neurons whose apical aspect (dendrite) is modified to form a bulb known as olfactory vesicle
-Each olfactory cell also has an axon which extends from the basal end of the cell to the olfactory bulb of the brain. The many axons from olfactory receptors pass through the medial portion of the ethmoid bone, the cribriform plate.
*Sustentacular (support cells) - has a striated border composed of microvilli, and secretory granules
they provide physical support, nourishment
*Basal cells - are short basophilic cells; their apical aspects do not reach the epithelial surface they proliferate and replace both two other cells
Describe the lamina propria of the olfactory region
Serous secreting Bowman’s glands
a rich vascular plexus and many
axons arising from olfactory cells of the olfactory epithelium)
The paranasal sinuses and the nasopharynx have a pseudostratified ciliated columnar epithelium. There is also the presence of lymphoid tissue from the Pharyngeal tonsil on lamina propria of nasopharynx.
Describe the epithelium of the epiglottis and lamina propria.
*It is lined by non-keratinized stratified squamous epithelium on lingual (oral) surface
*Pseudostratified ciliated columnar epithelium lined the laryngeal side
*Serous and mucous glands located in lamina propria
Describe epithelium of the larynx
-lined by respiratory epithelium.
-Larynx has two folds consist of superior and inferior.
*Superior vestibular folds lined by respiratory epithelium
*Inferior vocal folds lined by stratified squamous non-keratinized epithelium.
-Laryngeal cartilages (hyaline and elastic) are located in lamina propria
Describe the trachea
*The trachea is lined by ciliated, pseudostratified columnar epithelium.
*Incomplete rings of hyaline cartilage encircle the trachea.
*this epithelium consists of both short and tall cells, all resting on the basement membrane.
*Most of the tall (columnar) cells are ciliated, a specialization that allows dust and mucous to be swept upward and eliminated.
