histology

• Columnar epithelium is a type of epithelial tissue that consists of tall, column-shaped cells and is involved in absorption and secretion.
• The Nasal Cavity consists of two compartments: the Vestibule, which is the external, dilated portion, lined by stratified squamous-keratinized epithelium, and the Nasal Cavity, which is the internal surface, lined by respiratory epithelium.
• The Skin of the Nasal Cavity enters the nares, partway into the vestibule and contains sweat glands, sebaceous glands, and vibrissae.
• Vibrissae are used to filter particulates from inspired air.
• The Nasal Cavities lie within the skull as two chambers separated by the nasal septum.
• Nasal Conchae or Turbinates are three bony, shelf-like projections on the lateral walls of the nasal cavity, inferior and middle conchae are lined by respiratory epithelium, and the superior concha is lined by olfactory epithelium.
• The lecture also referred to "Clinical laboratory hematology" by McKenzie S.B., Landis-Piwowar K., and Williams J.L., published by Pearson, and "Bancroh's theory and practice of histological techniques" by Suvarna S.K., Layton C., and Bancroh J.D., published by Elsevier.
• The references for the lecture include "Histopathologic Techniques" by Bruce-Gregorios, J.H., published by JMC Press Inc., Quezon City, Philippines, "Laboratory hematology practice" by Kobke-Marchant K.D., published by Wiley-Blackwell/International Society for Laboratory Hematology, and "Junqueira's basic histology: text and atlas" by Mescher A.L. and Junqueira Luiz Carlos Uchôa, published by McGraw-Hill.
• The lecture on Histology and Histopathology was delivered by Dr. Peñafiel, Jr., MD in the Medical Biology Cluster of the Department of Biological Sciences, University of Santo Tomas.
• The lecture also referred to "Wheater's functional histology: a text and colour atlas" by Young B.O'Dowd G., and Woodford P., published by Churchill Livingston/Elsevier.
• The Laminaria Propria of the Nasal Cavity contains complex vasculature with loops of capillaries, near the epithelium, and flows opposite to the movement of the inspired air, releasing heat to warm the air.
• The pharynx is divided into three sections: Nasopharynx, Posterior to the nasal cavities and lined with respiratory epithelium; Oropharynx, the throat area and lined with stratified squamous epithelium; Laryngopharynx, the area of the larynx.
• Paranasal sinuses are bilateral cavities in the frontal, maxillary, ethmoid, and sphenoid bones of the skull that communicate with the nasal cavities through small openings and mucus produced there is moved into the nasal passages by the activity of the ciliated epithelial cells.
• The lamina propria of paranasal sinuses contains only a few small glands and is continuous with the underlying periosteum.
• The lining of paranasal sinuses is thinner and has fewer goblet cells than the nasal cavities.
• The lamina propria of the Nasopharynx contains some serous and mucous glands.
• Sound production in the Larynx is brought by the participation of skeletal muscles in the movement of these cartilages.
• Larynx is a short passageway for air between the pharynx and trachea with walls reinforced with hyaline cartilage, thyroid cartilage, cricoid cartilage, inferior arytenoid cartilage, smaller elastic cartilage, epiglottis, cuneiform, corniculate, and superior arytenoid cartilage, and is connected by ligaments.
• The Nasopharynx mucosa contains a large amount of lymphoid tissues forming the Waldeyer Ring.
• The Nasopharynx is lined with pseudostratified epithelium, with patches of stratified squamous epithelium as the person ages and for smokers.
• The olfactory glands produce a constant flow of fluid surrounding the olfactory cilia and facilitate the access of new odoriferous substances.
• Terminal bronchioles consist mainly of Clara Cells (Bronchiolar Exocrine Cells) which have non-ciliated, dome-shaped apical ends containing secretory granules.
• The lamina propria of terminal bronchioles contains elastic fibers and smooth muscles, forms the mucosa, and is innervated by the Autonomic Nervous System, eliciting muscular contraction in both the bronchi and bronchioles.
• Alveolar sacs are large clusters of alveoli that form the ends of alveolar ducts distally, have extremely thin lamina propria, contain elastic and reticular fibers, and encircle the alveolar openings, closely surrounding each alveolus.
• Bronchioles are important in clearing debris and mucus, moving upward along the bronchial tree and trachea.
• Alveolar ducts are tubes located on the distal ends of respiratory bronchioles, completely lined by the openings of alveoli, and lined by extremely attenuated squamous cells.
• The functions of Clara Cells include secretion of surfactant lipoproteins and mucin in the fluid layer on the epithelial surface, detoxification of inhaled xenobiotic compounds by enzymes of SER, secretion of antimicrobial peptides and cytokines, and other cell components such as Brush Cells and DNES Small Granule Cells.
• Alveoli in adults number approximately 200 million, have a total internal surface area of 75m², and are saclike evaginations, 200um in diameter, resembling a small rounded pouch open on one side, responsible for the spongy structure of the lungs.
• Each respiratory bronchioles divides into two or more respiratory bronchioles, connects with the alveoli, and its mucosa resembles the bronchioles but with openings to alveoli.
• The epithelium of respiratory bronchioles is a simple squamous epithelium with club cells.
• The Pleural Cavity is located between the parietal and visceral pleura, lined with mesothelial cells producing thin films of serous fluid, acting as a lubricant to facilitate smooth gliding of one surface over the other during respiration.
• General Visceral Afferent Fibers carry poorly localized pain sensations.
• The respiratory portion also enlarges, mainly as a result of expansion of the alveolar ducts.
• The Parietal Pleura is a membrane that lines the inner surface of the thoracic cavity.
• During inhalation, contraction of the external intercostal muscles elevates the ribs and contraction of the diaphragm lowers the bottom of the thoracic cavity, increasing its diameter and resulting in pulmonary expansion.
• The Pleural Membrane is a serous membrane that covers the outer surface of the lungs and inner walls of the thoracic cavity, composed of two layers: Parietal Pleura and Visceral Pleura.
• The Visceral Pleura is a membrane attached to the lung tissue, continuous at the hilum.
• The Pleural Cavity becomes permeable to water and fluids from plasma during inflammation and abnormal conditions.
• The bronchi and bronchioles increase in diameter and length during inhalation.
• The elastic fibers of the pulmonary parenchyma are stretched by this expansion during exhalation, the lungs retract passively because of muscle relaxation and the elastic fibers’ return to the unstretched condition.