Histology Sheet 18 + 19 PDF

18+19 Mohammad Al-khaliyl and Nadine Dababseh Razan Al.khaizaran and Noor Hamadneh & Jeyad Alkhzouz Ghada Abu el Ghanam  Respiratory System ‫) هي من الحج قوقل‬G( ‫السالم عليكم خلينا نتفق انو الصور التوضيحية الي عليها هذا الرمز‬...

18+19 Mohammad Al-khaliyl and Nadine Dababseh Razan Al.khaizaran and Noor Hamadneh & Jeyad Alkhzouz Ghada Abu el Ghanam  Respiratory System ‫) هي من الحج قوقل‬G( ‫السالم عليكم خلينا نتفق انو الصور التوضيحية الي عليها هذا الرمز‬ ‫الكالم ألي مكتوب باللون السكني مطلوب قراءة فقط‬ We will divide it structurally & functionally into two subcategories: Structurally based on location: 1- The upper respiratory system: nose, nasal cavity, pharynx, and associated structures. 2- The lower respiratory system: larynx, trachea, bronchi, and lungs. Functionally based on gas exchange ability: 1- The conducting zone: series of interconnecting cavities and tubes both outside and within lungs; nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, to the terminal bronchioles; their function is to filter, warm, and moisten air and conduct it into the lungs. Conductive zone Paranasal Terminal Nose Pharynx Larynx Trachea Bronchi bronchioles bronchioles sinuses 2- The respiratory zone: consists of tubes and tissues inside the lungs where gas exchange occurs. start from the respiratory bronchioles, alveolar duct, alveolar sacs, and alveoli are the main sites of gas exchange between air and blood. Respirator y zone Respirator y Alveolar Alveoli bronchiole duct s Respiratory Cells Respiratory epithelium = pseudo stratified columnar cells with goblet cells. Cell types: 1- Ciliated columnar cells: most abundant, each one has 250-300 cilia on its apical surface, the function of cilia is to move the mucus production of goblet cells tward the nose, so the regions where there is no cilia there is no goblet cells. 2- Goblet cells: numerous and predominate in some areas, contain much glycoproteins. 3- Brush cells: much less numerous, columnar, a small apical surface bears sparse, blunt microvilli --chemosensory receptor--connected with afferent nerve endings on their basal surfaces. 4- Small granule cells (kulchitsky cells): difficult to distinguish, contains dense core granules, part of the Diffuse NeuroEndocrine System (DNES), it is rare like brush cells, only about 3% of the cells. Both kulchitsky & brush cells are neuroendocrine cells have afferent nerve endings on their basal surface, and the way to distinguish them is either by immunostaining or by staining the related nerve endings. 5- Basal cells: are mitotically active stem and progenitor cells, that give rise to other epithelial cells. They are the reason of pseudo stratified appearance. Components of the Respiratory System The nose and the nasal cavity Specialized organ at the entrance of the respiratory system. It Consists of an external nose and an internal portion inside the skull called the nasal cavity. The external nose consists of a supporting framework of bone and hyaline cartilage covered with muscle and skin and lined by a mucous membrane. The cartilaginous framework of the external nose consists of several pieces of hyaline cartilage (septal nasal, lateral nasal, alar cartilages) connected to each other and to certain skull bones. Air should get filtered, heated, and humidified before reaching the lungs. When air enters the nostrils, it passes first through the vestibule, which is first lined by keratinized stratified squamous epithelium, then it loses its keratinized nature and transitions into pseudostratified columnar epithelium., it also contains coarse hairs that filter large dust particles, and sebaceous and sweat glands. The nasal cavity is a large space in the anterior aspect of the skull that lies inferior to the nasal bone and superior to the oral cavity. Nasal septum: is a vertical partition that divides the nasal cavity into right and left sides. Anteriorly, the nasal cavity merges with the external nose, and posteriorly it communicates with the pharynx through two openings called the internal nares or choanae.  Ducts from the paranasal sinuses and the nasolacrimal ducts (drain tears) open into the nasal cavity. The nasal cavity boundaries start from the External naris of the external nose to the beginning of the pharynx posteriorly at the Internal naris. Nasal septum Nasal conchae The significance of the opening of the auditory tube to the middle ear is equalize the pressure. The nasal conchae covered with respiratory epithelium; they increase the surface area of the nasal cavity. The nasal cavity is majorly covered by respiratory lining that covers the respiratory region. It has sebaceous and seromucous glands The glands in the underlying lamina propria also aid with the lubrication of the nasal cavity. The roof of the nasal cavity and superior conchae are covered with olfactory epithelium connected with the olfactory nerve responsible for smell sensation. Paranasal sinuses Paranasal sinuses: are bilateral cavities in the frontal, G maxillary, ethmoid, and sphenoid bones of the skull. Lined with thinner respiratory epithelium that have fewer goblet cells. The lamina propria have also a few small glands and its directly continous with underlying periostium. The mucus produced there is moved into the nasal passages by the ciliated epithelial cells.  Pharynx Starts from internal nares and extends about 13cm till it reaches cricoid cartilage at the larynx. It lies posterior to the nasal and the oral cavities, superior to the larynx, directly anterior to cervical vertebrae. The nasopharynx covered with respiratory epithelium, extends to the soft palate (an- arch shaped muscular part that forms the posterior portion of the roof of the mouth), when we eat or drink the soft palate contract separating the nasopharynx from the oropharynx. – while swallowing Also the epiglottis will move downward, paving the way for the food to the esophagus avoiding the laryngeal inlet-. The oropharynx: - Lies posterior to the oral cavity extends from the soft palate inferiorly to the level of the hyoid bone. - Common passageway for air, food, and drink. - Lined with nonkeratinized stratified squamous epithelium. - Two pairs of tonsils, the palatine and lingual tonsils, are found in the oropharynx. The laryngopharynx: - Begins at the level of the hyoid bone. - A respiratory and digestive pathway. - Lined by nonkeratinized stratified squamous epithelium.  Larynx It connects the laryngopharynx with the trachea. Lies anterior to the esophagus at the level of C4-C6 vertebrae: It’s composed of nine pieces of cartilage: - Two hyalines: Thyroid cartilage anteriorly, & Cricoid cartilage posteriorly. - Seven elastic: the Epiglottis, and 3 pairs Arytenoid, Cuneiform, & Corniculate cartilages (all pairs are elastic C) these tiny pairs are involved with the movement of the vocal cords. Hyaline cartilage gets calcificated slowly as we go older, while elastic cartilage allow flexibility in movement that’s why epiglottis is made from elastic cartilage. The thyroid cartilage (Adam’s apple) forms the anterior wall of the larynx and give it a triangular shape. It is usually larger & more prominent in males. Voice vibrations are produced by the vocal cords in the larynx. G The epiglottis is a large, leaf-shaped piece of elastic cartilage that is covered with epithelium. It’s attached to the anterior rim of thyroid cartilage. It’s anterior surface along with the vocal cords are covered by stratified squamous nonkeratinized epithelium, while the posterior wall of it and the rest of the trachea are covered by respiratory epithelium. The rest of the larynx is covered by ciliated pseudostratified columnar with goblet cells.  ‫النص يتحدث عن ثالث حاالت طبية تؤثر على الحنجرة و األوتار الصوتية‪:‬‬ ‫‪.١‬التهاب الحنجرة‪ :‬يحدث بسبب عدوى فيروسية ويسبب بحة في الصوت أو‬ ‫‪.‬فقدان الصوت‪.‬‬ ‫‪.٢‬الخشونة‪ :‬تصيب األطفال الصغار وتسبب بحة في الصوت وسعاال ا قويا‪.‬‬ ‫‪.٣‬عقيدات المغني‪ :‬هي نتوءات حميدة تظهر على األوتار الصوتية وتؤثر على‬ ‫الصوت‪.‬‬ ‫جميع هذه الحاالت تتسبب في مشاكل في الصوت بسبب تورم أو تغير في شكل‬ ‫‪.‬األوتار الصوتية أو األجزاء المحيطة بها‪.‬‬ ‫الربو هو مرض يسبب التهابات مزمنة في مجاري الهواء الصغيرة داخل‬ ‫الرئتين (القصيبات)‪.‬هذا االلتهاب يؤدي إلى انقباضات مفاجئة في العضالت‬ ‫المحيطة بهذه المجاري‪ ،‬مما يجعلها تضيق ويصعب على الشخص التنفس‪.‬‬ ‫يُطلق على هذه االنقباضات "تشنجات القصيبات"‪.‬‬ ‫السبب وراء هذه التشنجات هو تفاعل مناعي يحدث عندما تلتقي خاليا معينة‬ ‫في الجسم بمستضدات (مواد غريبة مثل الغبار أو حبوب اللقاح) تؤدي إلى‬ ‫‪.‬رد فعل تحسسي‪.‬‬ ‫خالل نوبة الربو‪ ،‬يُستخدم األدرينالين وأدوية مشابهة للمساعدة في استرخاء‬ ‫‪.‬العضالت المحيطة بالقصيبات‪ ،‬مما يزيد من قطرها ويسهل عملية التنفس‪.‬‬ ‫‪Trachea‬‬ ‫‪ A tubular passageway for air.‬‬ ‫‪ 12 cm long and 2.5 cm in diameter.‬‬ ‫‪ Located anterior to the esophagus.‬‬ ‫‪ Extends from the end of the larynx to the superior border of T5 before it divides to‬‬ ‫‪right and left primary bronchi.‬‬ ‫‪ It is composed of 16-20 hyaline cartilage (C-shaped rings) providing semirigid‬‬ ‫‪support keeping the air way open and allowing the posterior esophagus to expand a‬‬ ‫‪little while swallowing.‬‬ ⚫ Layers of tracheal wall: 1. Mucosa: (epithelium + lamina propria) - Consists of an epithelial layer of ciliated pseudostratified columnar epithelium with goblet cells. - An underlying layer of lamina propria: loose connective tissue contains elastic / reticular and seromucous glands. 2. Submucosa: - Consist of areolar connective tissue that contains seromucous glands and their ducts. 3. Hyaline cartilage: - 16-20 C-shaped, horizontal rings of hyaline (connected by dense connective tissue). -Spanned by fibromuscular membrane: transverse smooth muscle fibers (trachealis muscle) and elastic connective tissue attached to perichondrium. 4. Adventitia: (outermost layer) - Consists of Areolar loose connective tissue that joins the trachea to surrounding tissues.  Division of Bronchi The bronchi will give rise to 8-9 generations of divisions (gen 2-10), The first generation is the division of trachea will give two main bronchus (or primary bronchus), one for each lung (it is O shaped) The 2nd gen of division the main bronchi will give 3 lobar bronchi (secondary bronchi) to the right lung and 2 to the left lung, secondary bronchi will give rise to segmental bronchi generations starting from the tertiary (segmental) bronchi till we reach the 10th generation at the terminal bronchus where cartilage disappear after it, then we have bronchioles generations (11-16) that will end at the terminal bronchiole, this stage also considered as the end of the conductive zone, then the respiratory bronchioles begin with at generations (17-19) that are connected with the alveolar ducts gens (20-22), that will finally connect to Alveolar sac gen (23). ➤ The wall of the alveolar sac is made from alveoli (bubble like structure), the respiratory bronchioles possess some alveoli. ➤ A medical benefit of that, the lung is created in this branched and organized way is that in pathological conditions like cancer we do specific excision of certain segments or certain lobes or even one of the lungs with the least amount of damage. ➤ Club cells (or Clara cells) columnar, nonciliated cells interspersed among the epithelial of the terminal bronchioles, their function is to produce surfactant. ➤ Surfactant: lipid derived molecule that spread at the alveolar surface to decrease the surface tension facilitating the dilation of the alveoli during inhalation. o Another other source of surfactant at the level of alveoli are Alveolar Type II cells (also called pneumocytes). o In Premature births, the baby’s lung may have not produced surfactant, so they may die if not treated properly, because their lung will be collapsed. The Lungs Anatomy of the lungs: (read only but understand very well) The lungs are paired, the left and right lung. The right lung is slightly larger and has three lobes each lobe divided by a fissure (upper, middle, and lower), while the left lung has only two lobes (upper and lower). This asymmetry occurs because the heart takes space from the left lung (which is tilted to the left side of the chest). Each lobe has its own bronchus (the right lobe has superior, middle and inferior bronchi). Each lung is enclosed and protected by a double layered serous membrane called the pleural membrane. Parietal pleura lines the wall of the thoracic cavity and the visceral pleura covers the lungs Pleural cavity is a small space between the visceral and parietal pleurae contains pleural fluid that reduces friction.  Bronchi They are two large air passages that branch from the trachea, which connects the upper respiratory system to the lungs. Anatomy: Right bronchus: This bronchus is wider, shorter, and more vertical than the left (Because of its orientation, it is more likely for objects to enter the right bronchus). Left bronchus: The left bronchus is longer, narrower, and more horizontally oriented than the right. Again this asymmetry is due to the position of the heart, which pushes against the left lung, leaving less space. Mucosa: The mucosa consists of a pseudostratified ciliated columnar epithelium (includes goblet cells) and a basement membrane. The function of the cilia and mucus is trapping and clearing foreign particles and pathogens. Submucosa: This layer is under the mucosa, the submucosa contains connective tissue, blood vessels, and lymphatic vessels. It also contains glands (mucous and serous) Cartilage: The bronchi contain hyaline cartilage in C-shaped rings in primary and secondary bronchi, and cartilage plates (in smaller bronchi). Cartilage helps maintain the airway’s structure and prevents the bronchi from collapsing during exhalation. Smooth muscles: The lamina propria contains crisscrossing bundles of spirally arranged smooth muscle, elastic fibers and numerous lymphocytes. As we move distally less cartilage will be present, its replaced by smooth muscles, and MALT can be seen (most distally there is NO MALT and little smooth muscle) Adventitia (Outermost layer): The outermost layer consists of connective tissue that helps bind the bronchi to surrounding structures.  Bronchioles: Anatomy: Bronchioles are the smallest airways in the lungs and do NOT contain cartilage in their walls. This allows them to be more flexible and responsive. In the larger bronchioles the epithelium is ciliated pseudostratified columnar but this decreases in height and complexity to become ciliated simple columnar or simple cuboidal epithelium in the smallest terminal bronchioles. There are 2 types of bronchioles: Terminal Bronchioles: The conducting bronchioles divide into terminal bronchioles and then futher divides into 2-3 respiratory bronchioles, which are the last part of the airways, they do NOT participate in gas exchange. The lamnia propria contains elastic fibers and smooth muscles Muscular contraction in the bronchi and the bronchioles is controlled primarily by nerves of the autonomic nervous system They are made up of non-ciliated cuboidal epithelium and have dome shaped ends. It contains club (clara) cells and secretory cells that secrete surfactant (lipoproteins and mucins), detoxification of inhaled xenobiotic compounds, and secretion of antimicrobial peptides. They also contain brush cells and DNES. Respiratory Bronchioles: After the terminal bronchioles, the airways transition into respiratory bronchioles, which contain a few alveoli in their walls and are involved in gas exchange. Respiratory bronchioles lead to alveolar ducts and alveolar sacs, where the primary gas exchange occurs. The epithelium consists of club cells, with simple squamous cells at the alveolar openings. Alveolar ducts: Epithelium: The walls of the alveolar ducts are lined by a simple squamous epithelium, which is very thin to facilitate the diffusion of gases between the alveoli and the blood in the surrounding capillaries. This epithelium is similar to the epithelium of the alveoli themselves. The ends of the alveolar sacs the lamina propria are extremely thin, consisting of a web of elastic, reticular fibers, and network of capillaries.  Alveolar sacs and alveoli Alveolar Walls: The walls of each alveolus are extremely thin, consisting of a single layer of epithelial cells. These thin walls are essential for allowing the diffusion of oxygen from the alveolus into the capillaries, and carbon dioxide from the blood into the alveolus to be exhaled. Types of Cells in the Alveolar Wall: 1. Type I Alveolar Cells (type I pneumocytes): o These are flat, squamous cells that cover about 90-95% of the surface area of the alveolar walls. Type I cells are responsible for the structural support of the alveolus and allow for the diffusion of gases across their membranes. (these cells are thin, and organelles are grouped around the nucleus).  2. Type II Alveolar Cells (type II pneumocytes): o These cells are rounded, cuboidal and have microvilli and are found interspersed between Type I cells and bound to them with tight junctions and desmosomes. (the cells nuclei are rounded and may have nucleoli, and their cytoplasm is lightly stained with many vesicles) o They have 2 major functions: ▪ Surfactant production: Type II cells secrete pulmonary surfactant, a substance that reduces the surface tension in the alveoli, preventing the alveolar walls from sticking together and collapsing, especially during exhalation. ▪ Proliferation: Type II cells can divide and differentiate into Type I cells when needed 3. Alveolar Macrophages (dust cells): o Macrophages are specialized immune cells that reside within the alveolar spaces. They act as the first line of defense by engulfing and digesting pathogens, particles, and dust that may enter the lungs with inhaled air. These cells are essential for maintaining lung health. (they are slightly darker due to their content of dust and carbon from air and iron from erythrocytes) 4. Capillaries: The alveolar walls are surrounded by a dense network of capillaries, where gas exchange occurs. Respiratory membrane 1. Alveolar Epithelium (Alveolar Cells type 1 or 2) 2. Epithelial Basement Membrane 3. Capillary Basement Membrane 4. Capillary Endothelium ‫‪1) B‬‬ ‫‪2) C‬‬ ‫‪3) A‬‬ ‫‪4) D‬‬ ‫‪5) B‬‬ ‫‪6) B‬‬ ‫‪7) E‬‬ ‫‪8) C‬‬ ‫‪9) E‬‬ ‫‪10) A‬‬ ‫تمت كتابة هذا الشيت صدقة جارية عن روح والدة زميلنا عمرو رائد من دفعة تيجان‬ ‫دعواتكم لها بالرحمة والمغفرة‬ ‫‪Thank you‬‬