THE RESPIRATORY SYSTEM The complex of organs and tissue which are necessary to exchange blood carbon dioxide (CO2) with air oxygen (O2) is called the respiratory system. It consists of structures, which function as ducts, and which together are called the Conductive Portion of the respiratory system structures which form the Respiratory Portion of the respiratory system, in which the exchange of CO2 and O2 is occurring and Nasal Cavity The Nasal cavity is divided into three structurally and functionally different parts. The Vestibules (the first ~1.5 cm of the conductive portion following the nostrils) are lined with a keratinised stratified squamous epithelium. Hairs, which filter large particulate matter out of the airstream, and sebaceous glands are also present. At the transition from the vestibule to the respiratory region of the nasal cavity the epithelium becomes first stratified squamous and then pseudostratified columnar and ciliated. Mucus producing goblet cells are present in the epithelium. The olfactory epithelium Formed by Olfactory Cells, Sustentacular Cells and basal cells. Basal cells can be identified by their location. Sustentacular cells are preferentially located in the superficial cell. Cilia are not visible and goblet cells are absent from the olfactory epithelium. Cilia do not move, because they Lack Dynein Arms which are necessary for cilial motility. The cell membrane covering the surface of the cilia contains olfactory receptors which Lightly stained rounded areas in the lamina propria represent bundles of Olfactory Axons in the lamina propria. Small mucous glands, Olfactory Glands Or Bowman's Glands, Nasal Cavity, Olfactory Region, rat - Alcian blue & van Gieson Respiratory region of the nasal cavity - H&E, van Gieson The surface of the lateral parts of the nasal cavity is thrown into folds by bony projections called Conchae. These folds increase the surface area of the nasal cavity and create turbulence in the stream of passing air, both of which facilitate the conditioning (warming, cooling and filtration) of the air. Mucous and serous glands in the connective tissue underlying the epithelium, the lamina propria, supplement the secretion of the goblet cells. Superficial Blood Vessels Nasal Cavity Pharynx The pharynx connects the nasal cavity with the larynx. The pharynx is either lined with respiratory epithelium (nasopharynx) or with a stratified squamous epithelium (oropharynx), which also covers the surfaces of the oral cavity and the oesophagus. Lymphocytes frequently accumulate beneath the epithelium of the pharynx. Accumulations of lymphoid tissues surrounding the openings of the digestive and respiratory passages form the Tonsils. Pseudostratified Columnar Epithelium Composed of one Layer of Cells All cells of this type of epithelium are in contact with the basement membrane, but not all of them reach the surface of the epithelium. Nuclei of the epithelial cells are typically located in the widest part of the cell. Consequently, the nuclei of cells which do or do not reach the surface of the epithelium are often located at different heights within the epithelium and give the epithelium a stratified appearance. The epithelium will look stratified but it is not - hence its name "pseudostratified". Pseudostratified columnar epithelia are found in the Respiratory System Pseudostratified columnar epithelium Larynx The vocal folds of the larynx control airflow and allow the production of sound. The vocal folds are lined by stratified squamous epithelium and contain the muscle (striated, skeletal) and ligaments needed to control the tension of the vocal folds. The larynx is supported by a set of U/C shaped cartilages. The number of goblet cells is variable and depends on physical or chemical irritation of the epithelium which increase goblet cell number. Prolonged intense irritation of the epithelium may lead to its transformation to a stratified squamous epithelium (squamous metaplasia). Cartilage Platelets Tertiary Bronchiole Alveolar Cells Alveolar type I cells (small alveolar cells or type I pneumocytes) are extremely flattened (the cell may be as thin as 0.05 m) and form the bulk (95%) of the surface of the alveolar walls. Alveolar type II cells (large alveolar cells or type II pneumocytes) are irregularly (sometimes cuboidal) shaped. They form small bulges on the alveolar walls. Type II alveolar cells contain large number of granules called cytosomes (or multilamellar bodies), which consist of Precursors To Pulmonary Surfactant (the mixture of phospholipids which keep surface tension in the alveoli low). There are less type II cells than type I cells. But since Type I are smaller in size we see more type I in one focus of the section. Organ? 40X 1 3 2 Organ? 400X 4 Tissue from Trachea slides 2-3 Slide # 2: Trachea (40X) 1. Lumen of the trachea 2. Epithelium of the Trachea 3. Submucosa 4. Seromucous Gland 5. Hyaline Cartilage 6. Adventitia Slide # 3: Trachea (400X) 1. Lumen 2. Pseudostratified Ciliated Columnar Epithelium (Cilia not seen) 3. Lamina Propria 4. Submucosa Organ? 40X Organ? 100X Organ? 400X Tissue from Tertiary Bronchi slides 5- 7 Slide # 5: Tertiary Bronchi with Lung tissue (40X) 1. Lumen 2. Epithelium of the Tertiary Bronchi 3. Lamina Propria 4. Seromucous Gland 5. Hyaline Cartilage 6. Smooth Muscle 7. Blood Vessel 8. Lung Tissue Tissue from Tertiary Bronchi slides 5- 7 Slide # 6: Tertiary Bronchi with Lung tissue (40X) 1. Lumen 2. Epithelium of the Tertiary Bronchi 3. Lamina Propria 4. Seromucous Gland 5. Hyaline Cartilage 6. Smooth Muscle 7. Submucosa 8. Lung Tissue Tissue from Tertiary Bronchi slides 5- 7 Slide # 7: Tertiary Bronchi with Lung tissue (400X) 1. Lumen 2. Pseudostratified Ciliated Columnar Epithelium 3. Lamina Propria 4. Seromucous Gland 5. Hyaline Cartilage 6. Smooth Muscle 7. Submucosa Organ? 40X Organ? 100X Organ? 400X 1 2 3 Tissue from Lung slides Slide # 11: Lung (40X) 1. Visceral pleura 2. Respiratory bronchiole 3. Alveolar duct 4. Alveolar sac 5. Alveolus Slide # 12: Trachea (100X) 1. Visceral pleura 2. Respiratory bronchiole 3. Alveolar duct 4. Alveolar sac 5. Alveolus Tissue from Lung slides Slide # 13: Lung (40X) 1. Alveolar sac 2. Alveolus 3. Blood Vessel Cystic Fibrosis and the Lungs Cystic Fibrosis One of the most common autosomal- recessive diseases. First seen in newborn babies as: Persistant diarrhea Frequent Pneumonia Chronic coughing Salty skin Poor Growth Cystic Fibrosis Autosomal recessive Genetic disorder Mutation in CFTR (cystic fibrosis transmembrane conductance regulator) gene Product of this gene makes chloride ion channel Inherited disease of secretory glands (which make mucous and sweat) Cystic Fibrosis Pathophysiology Mutation in the CFTR gene The protein created by this gene is anchored to the outer membrane of cells in the sweat glands, lungs, pancreas, and other affected organs The protein spans this membrane and acts as A Channel Connecting The Inner Part Of The Cell (Cytoplasm) To The Surrounding Fluid Cystic Fibrosis Pathophysiology This channel is primarily responsible for Controlling The Movement Of Chloride From Inside To Outside Of The Cell; however, in the sweat ducts it facilitates the movement of chloride from the sweat into the cytoplasm When the CFTR protein does not work, Chloride Is Trapped Inside The Cells In The Airway And Outside In The Skin Cystic Fibrosis Mucus Becomes Thick And Sticky Mucus Builds Up In Lungs And Blocks Airways Buildup Of Mucus Makes It Easy For Bacteria To Grow This Leads To Repeated, Serious Lung Infections. Over Time, These Infections Can Severely Damage Lungs Healthy and CF Lung Cystic Fibrosis (GIT) The thick, sticky mucus also can Block Tubes, or ducts in pancreas As a result, the digestive enzymes that pancreas makes can't reach small intestine Intestines can't fully absorb fats and proteins This can cause vitamin deficiency and malnutrition It also can cause bulky stools, intestinal gas, a swollen belly from severe constipation, and pain or discomfort Cystic Fibrosis (SKIN) Also causes sweat to become very salty As a result body loses large amounts of salt during sweating This can upset the balance of minerals in blood CF and the Lungs The lungs when affected by CF have very thick mucous. Unlike other parts of the body that it is unknown why the missing CFTR gene effects the lungs so greatly. The mucous that builds up is able to hold bacteria so large amounts of bacteria begin to grow in the lungs. Genetic information about CF The (CFTR) gene responsible for Cystic Fibrosis (CFTR) was determined to be at the location to be 7q31.2. The gene that is encoded is 1480 proteins long with the mutation causing CF coming at the 508 th amino acid location with the loss of phenylalanine How the lungs work The lungs work after receiving air by: The air enters the nose or mouth where it is filtered, warmed, and moistened. The air then travels down the throat and enters the trachea. The air proceeds down the trachea, which branches into the left and right bronchi. These two main stem bronchi continue to branch into smaller bronchi and they eventually branch into bronchioles. How the lungs work continued After the air reaches the bronchioles: The bronchioles end in sacs known as alveoli. They act as balloons that inflate when breathing in. Gas exchange occurs at the alveoli. The concentration of oxygen is greater in the alveoli during inspiration then in the capillaries so the oxygen will diffuse across the alveolar walls and enter the blood plasma and carbon dioxide undergoes the opposite process. Definitions Emphysema - abnormal permanent enlargement of the airspace distal to the terminal bronchioles, accompanied by destruction of their walls and without obvious fibrosis. Chronic Bronchitis - presence of chronic productive cough for 3 months in each of 2 successive years COPD - disease state characterized by airflow limitation that is not fully reversible. DEFINITION COPD is characterised by airflow obstruction. air flow obstruction is usually progressive It is not fully reversible does not change markedly over several months. The disease is pre-dominantly caused by smoking. CAUSES OF COPD SMOKING: 90 % of cases,are caused by smoking 15% are susceptible. Lung function decline is 3 times faster If smoking stops, at one year FEV1 decline is age related (Morgan & Britton 2003) ALPHA 1 ANTITRIPSIN DEFICIENCY:GENETIC Found in only 1% of cases. OCCUPATIONAL EXPOSURE TO RESPIRATORY POLLUTANTS: Chemicals, dust, atmospheric pollutants, inherited tendency CHRONIC BRONCHITIS Continuous inflammation of the cells lining the bronchi Mucous hypersecretion Destruction of the cilia, impairing mucous clearance leading to increased risk of infection Diagnosed by the production of sputum and cough on most days for three months in two consecutive years EMPHYSEMA Destructive of the alveoli and terminal bronchioles Loss of elasticity of smaller airways Loss of patency of bronchioles