University:
Texas A&M University
Course:
BIOL 319 | Integrated Human Anatomy and Physiology I
Academic year:

2021
Views:

331

Pages:

54
Author:

Tyshawn Shaffer

Medical School Histology Basics Respiratory System Objectives The histologic characteristics of the components of conducting portion and respiratory portion of the respiratory system How these characteristics allow each component to contribute to the overall function of the respiratory system. Function of the Respiratory System All higher animals require a mechanism to: 1. Obtain O2 from the environment 2. and get rid of CO2 This “gas exchange” is the function of the respiratory system. Oxygen diffuses out and Carbon Dioxide diffuses into the air space of the alveolus. Lung alveolus and associate capillary Respiratory System Ventilation Mechanisms Elastic fibers in lung capsule Thoracic cage (boney cavity) Intercostal muscles (inspiration and expiration) Diaphragm (inspiration only) Elastic components of lungs (lungs to partialy deflate) Diaphragm Diaphragm 36721 Elastic fibers in an air duct Conducting portion Conducting Portion Cleans air Warms air Humidifies air Function Of Mucus in the Respiratory System Detoxifies gases Has protein that presents odor chemicals to receptors of olfactory cells Washes away current chemicals to allow one to smell the next chemical odor Traps dust and washes it away Contains IgA antibodies to guard against infection Goblet cell in respiratory epithelium Respiratory Portion - Site of Gases Exchange Respiratory bronchioles Alveolar ducts Alveolar sacs Alveoli Alveolus (Air) Capillary (Blood) Oxygen CO2 What does your nose do for you? Beyond its important role as the collector of olfactory information – such as whiffs of smoke that warn of impending danger or smells that whet the appetite – the nose acts as an air conditioner for the respiratory system. Everyday, it treats approximately 500 cubic feet of air, the amount enclosed in a small room .It filters dust, traps bacteria from the air, brings air to the temperature of the body and also adds moisture. And then, the nose has some lesser-known functions. Among them it gives your voice resonance, adding a richness of tone that would otherwise be lacking. Epithelium in the respiratory system Respiratory epithelium Olfactory epithelium Olfactory Air sacs Epithelium in the respiratory system Nose Skin junction Nasal cavity Conducting bronchiole Histo 36 Air sac Respiratory epithelium Olfactory Olfactory epithelium has no goblet cells. Conditioning Air By The Conducting Portion Nasal fossae – Superior conchae - olfactory epithelium long cilia, nervous cells – Middle conchae - respiratory epithelium – Inferior conchae - respiratory epithelium Swell bodies – large venous plexus that direct air (occludes air way) – Allergic reaction or inflammation restrict air flow counter current system warms air Histo 036 air Swell bodies air Animal Respiratory (Olfactory) mucosa and nasal septum Respiratory epithelium Highly vascular lamina propria Swell bodies Olfactory epithelium Bowman’s glands #7 Respiratory (Olfactory) mucosa and nasal septum Olfactory epithelium Nerve Highly vascular lamina propria Nerves Bowman’s glands 404 Elastic cartilage in epiglottis Hyaline cartilage provides flexible support in the respiratory system to hold the air way open. Hyaline cartilage larynx True vocal cords Tracheal cartilages The false vocal cords Vocal cord muscles Air space lumen Laryngeal ventricle Thyroid cartilage Cricoid cartilage Larynx Stratified squamous epithelium Respiratory epithelium Vocal cord muscles Thyroid cartilage Larynx (lower portion) Esophagus Cricoid cartilage Respiratory epithelium lining Tracheal cartilage Esophagus and trachea, monkey – Esophagus glands in trachea Trachea Thick hyaline cartilage bridged by smooth muscle bundle posteriorly Elastic fiber layer beneath the epithelium Submucosa with glands Trachea, whose lumen is lined with pseudostratified ciliated epithelium with goblet cells Trachea, monkey Thick hyaline cartilage Submucosa with glands Trachea, whose lumen is lined with pseudostratified ciliated epithelium with goblet cells 133 Trachea, monkey Pseudostratified ciliated epithelium with goblet cells Goblet cell Thick basement membrane Rich vascular supply to warm air Plasma cells to produce antibodies EM 8 trachea; 20630x 1. Mucous 2. Microvilli 3. Cilia 4. Goblet cell Ref code # 5, 16 Lung Bronchus The air-conducting tubes of the respiratory system can be thought of as a series of ducts which carry air to the sites of gaseous exchange - the alveoli Conducting bronchiole Respiratory bronchioles Alveolar duct Alveoli Alveolar sac Lung with bronchi Elastic artery Bronchus Bronchus Conducting bronchiole Bronchus Macrophages in Air Space of Alveoli Air space Alveolus Lung with bronchus Bronchus: 1) pseudostratified ciliated columnar epithelium with goblet-cells; 2) smooth muscle band between the lamina propria and the cartilage. The smooth muscle is not continuous around the bronchus as it spirals. 3) a change from cartilage rings to cartilage plates surrounding the tube; 4) glands in the submucosa. Bronchioles: 1) have a ciliated columnar epithelium; 2) do not have cartilage plates or glands; 3) have well organized muscle layers. Cells in the respiratory portion Histo 41 TERMINAL BRONCHIOLE CLARE CELLS Smooth muscle cells Smooth muscle Ciliated cells Respiratory BRONCHIOLE Elastic fibers Lung 42 42 Mesothelium and connective tissue of lung capsule Type I & Type II pneumocytes 42 41 Capillary endothelial cells and fibroblasts Alveolar macrophage Ref code # 6, 16 Blood Air Air Blood Lung (mast cells) Terminal bronchiole Mast cell Bronchus Conducting bronchiole Mesothelium Alveolar macrophage Respiratory bronchiole Alveolar duct Alveolar sac Type I pneumocyte Type II pneumocyte Alveoli 48 Mast cells Type II pneumocyte • Mast cells function in the localized release of many bioactive substances with roles in the local inflammatory response, innate immunity, and tissue repair. • Mast cell granules normally contain: heparin, histamine, serine proteases, eosinophil and neutrophil chemotactic factors, cytokines, etc. Type II pneumocyte Ref code # 12 Type I pneumocyte - gases exchange Type II pneumocyte – produce surfactant to reduce surface tension to enhance opening of alveoli and make breathing easier Type I pneumocyte 1. Type I pneumocyte 2. Type II pneumocyte Type II pneumocyte (EM 18c). 1. Nucleus 2. Surfactant bodies Type II pneumocytes 36722 Surfactant bodies in Type II cells Respiratory Physiology Surfactant functions in reducing surface tension, reduces work of breathing, and helps keep alveoli open and may have a bactericidal effect. Hyaline membrane disease - premature infants cannot get or make sufficient surfactant. Bronchoalveolar fluid - cleared by ciliary action toward oral cavity (contain lysosome, collagenase, glucuronidase, and antibodies). Macrophages - contain hemosiderin, produce lytic enzymes in bronchoalveolar fluid. Normal Asthma Respiratory Physiology Con’t Emphysema destruction of alveolar wall Means too much air in the lungs. Natural Defenses of Our Respiratory System Large particles get trapped by nose hairs. Smaller particles are trapped in mucus that lines our respiratory system. The mucous keeps harmful particles out of the lungs. Coughing forcibly expels foreign particles trapped in our lungs and airways. Sneezing removes bacteria trapped in mucus from our nasal passages. Sneezes travel at about 100 miles per hour and remove 100,000 bacteria). Respiratory System Ref code # 15 • Conduction o Maintenance of an open lumen o Ability to accommodate expansion and contraction, o Warming, moisturizing and filtering of the inspired air • Respiration o Rapid exchange of atmospheric gases o Alveolar wall cells secrete surfactant • Structure o Skeletal components (cartilage, etc.) o Vascularization o Glands in lamina propria - In summary Questions on the Respiratory System The conducting portion of the respiratory system modifies the air in the following way(s): a. warms b. cleans c. dries d. a and b e. a, b, and c Which of the following are involved in both inspiration and expiration? Contraction of a. intercostal skeletal muscle between the ribs b. diaphragm c. smooth muscle d. a and b e. a, b, and c Variation in the epithelium lining the respiratory system facilitates varied functions. Which epithelium-function does not match? a. simple squamous - alveolar ducts b. goblet cells - humidifies air c. stratified squamous - false vocal cords d. ciliated cells - move dust-laden mucus e. hair follicle - filtration of air The Respiratory System: Conducting portion Respiratory portion Defense Mechanism (con’t) Specific Elaborate immunological processes occur in lymphoid tissue (T & B lymphocytes) Tumor of the lung • More often in males • Related in cigarette smoking Routes of Environmental Exposure Small pieces of lungs from a non-smoker and from a smoker “Conditioning Air” by the Conducting Portion Specialized respiratory epithelium Numerous mucous and serous gland • Traps particulate and gaseous impurities • Prevents alveolar lining from desiccation Rich superficial vascular network in lamina propria - warms blood in a counter current system (blood flows against inspired air)

Respiratory System Study Guide

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