LESSON 22 cortas Respiratory System

The nasal vestibule is lined by pigmented keratinized squamous epithelium in the rostral region, non-keratinized squamous epithelium in the middle part, and pseudostratified non-ciliated columnar epithelium in the caudal regions. The respiratory region is lined by a pseudostratified ciliated columnar epithelium. The olfactory region is lined by a pigmented olfactory epithelium.

The five types of epithelial cells are basal cells, ciliated epithelial cells, secretory cells (serous and mucous), brush cells, and non-ciliated cells. Basal cells can divide and differentiate into other epithelial cells. Ciliated epithelial cells have multiple cilia and microvilli, and a nucleus in the basal portion. Secretory cells produce and secrete specific substances, with serous cells containing neutral glycoproteins and mucous cells synthesizing and accumulating mucinogen. Brush cells have synapses with nerve cells and are considered sensory receptors. Non-ciliated cells metabolize toxic substances.

The lamina propria is a loose vascularized connective tissue with serous glands. In the caudal regions, there is a cavernous stratum with numerous tortuous venous sinuses. It eliminates odorous substances from the cilia of neurosensitive cells.

<p>The olfactory region contains three cell populations: basal cells, olfactory neurosensitive cells, and supportive cells. Olfactory neurosensitive cells are bipolar neurons with a dendritic bulb containing cilia and vesicles. Supportive cells are columnar cells with microvilli, a vesicular nucleus, and a well-developed Golgi complex.</p> Signup and view all the answers

<p>The olfactory mucosa is made up of loose connective tissue with numerous tubuloacinar seromucous glands (Bowman’s glands). The lamina propria eliminates odorous substances from the cilia of neurosensitive cells.</p> Signup and view all the answers

<p>The trachea is composed of a mucosa lined by a pseudostratified ciliated columnar epithelium, submucosa and lamina propria made up of vascularized connective tissue, hyaline cartilage, and muscularis (smooth muscle) or adventitia.</p> Signup and view all the answers

<p>Club cells are secretory cells that metabolize toxic substances, while neuroendocrine cells are pyramidal-shaped cells that release hormones.</p> Signup and view all the answers

<p>The trachea has incomplete cartilages made up of hyaline cartilage, which give the trachea a U or C shape, except in birds.</p> Signup and view all the answers

<p>The nasal vestibule is lined by pigmented keratinized squamous epithelium in the rostral region, non-keratinized squamous epithelium in the middle part, and pseudostratified non-ciliated columnar epithelium in the caudal regions.</p> Signup and view all the answers

<p>The respiratory region of the nasal cavity contains basal cells, ciliated epithelial cells, secretory cells (serous and mucous), brush cells, and non-ciliated cells. Basal cells can divide and differentiate into other epithelial cells. Ciliated epithelial cells have multiple cilia and microvilli. Secretory cells produce and secrete specific substances. Brush cells have synapses with nerve cells. Non-ciliated cells metabolize toxic substances.</p> Signup and view all the answers

<p>Olfactory neurosensitive cells are bipolar neurons with a dendritic bulb containing cilia and vesicles. Axons cross the lamina propria as unmyelinated nerve fibers and form the olfactory nerve.</p> Signup and view all the answers

<p>The lamina propria is a loose vascularized connective tissue with serous glands. In the caudal regions, there is a cavernous stratum with numerous tortuous venous sinuses. Tubulo-acinar seromucous glands produce lysozyme and enzymes to metabolize fat-soluble toxins.</p> Signup and view all the answers

<p>Respiratory bronchioles have a simple cuboidal epithelium with few cilia and Club cells, and sacculiform dilations (respiratory alveoli) that are lined by a simple squamous epithelium.</p> Signup and view all the answers

<p>Type I pneumocytes line 97% of the alveolar surface, diffusing respiratory gases through their cytoplasm. Type II pneumocytes line 3% of the alveolar surface, producing lung surfactant.</p> Signup and view all the answers

<p>Alveolar sacs have respiratory alveoli lined by a simple squamous epithelium with type I and type II pneumocytes.</p> Signup and view all the answers

<p>Pulmonary alveolar macrophages (PAMs) rest on type I pneumocytes and engulf particles of inspired air and toxins.</p> Signup and view all the answers

<p>The interalveolar septum is made up of highly vascularized thin connective tissue called the interstitium.</p> Signup and view all the answers

<p>The four concentric layers are mucosa, submucosa, cartilage/muscularis, and adventitia.</p> Signup and view all the answers

<p>Mucosa is lined by a pseudostratified ciliated columnar epithelium with Club or Clara cells and neuroendocrine cells, and a muscularis mucosae of smooth muscle fibers.</p> Signup and view all the answers

<p>Submucosa consists of connective tissue and tubuloacinar glands.</p> Signup and view all the answers

<p>Cartilaginous rings decrease in thickness and discontinuous cartilaginous sheets are formed, with smooth muscle increasing as cartilage decreases.</p> Signup and view all the answers

<p>Adventitia is connective tissue with blood vessels, lymphatics, nerves, and lymphoid follicles. It forms bronchi associated lymphoid tissue (BALT) in pigs.</p> Signup and view all the answers

<p>Bronchioles have a simple columnar or cuboidal epithelium consisting mainly of ciliated cells and Club cells, and a thin lamina propria and submucosa.</p> Signup and view all the answers

<p>The lung's functional unit is the pulmonary lobule, made up of respiratory bronchioles, alveolar ducts, alveolar sacs, and respiratory alveoli.</p> Signup and view all the answers