Respiratory System PDF

Respiratory System B e t h a n D a v i e s -J o n e s b .w. d a v i e s -j o n e s @ b a n g o r. a c . u k Learning Outcomes • Describe and identify distinctive structural features of the components of the conductive and respiratory passages. • Define and give the location of MALT in the res...

Respiratory System B e t h a n D a v i e s -J o n e s b .w. d a v i e s -j o n e s @ b a n g o r. a c . u k Learning Outcomes • Describe and identify distinctive structural features of the components of the conductive and respiratory passages. • Define and give the location of MALT in the respiratory organs. • List the sampling methods used. • Discuss the investigative methods/techniques used in respiratory pathology Facts and Functions • The right lung is slightly larger than the left. • The nose filters air through four distinct stages. • The alveolar epithelium covers a surface area of approximately 100 m 2 and contains over 700 million individual alveoli. • What are the major functions of the respiratory system? Serous Membranes • Serosa/mesothelium • Lines closed body cavities • Borders cavities containing small amount of fluid • Parietal membrane lines the pleural cavity. • Visceral pleura covers the lungs. Simple squamous epithelium Basal lamina Loose connective tissue Mucous Membranes • Also referred to as the mucosa. • Lines cavities that connect to the outside of the body: • Gastrointestinal tract • Respiratory tract • Urinary bladder • Uterus Basal lamina Various kinds of epithelia Anatomic Divisions STRUCTURAL FUNCTIONAL Conducting Zone: Nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles and terminal bronchioles Respiratory zone: Respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli Nasal Cavity • The nasal cavities are paired chambers separated by bony and cartilaginous septum. • The chambers are divided into three regions: • Vestibule • Respiratory region • Olfactory region • The nasal and sinus submucosa is highly vascular and contains both mucous and serous glands. Hard palate Septum Vestibule of the Nasal Cavity • Forms a part of the external nose and communicates with the external environment. • Stratified squamous epithelium. • Contains vibrissae (stiff hairs) and sebaceous glands. Respiratory Epithelium • Most of the nasal and paranasal sinus cavities are lined by a pseudostratified columnar epithelium bearing numerous cilia and goblet cells. • This mucosa is seen throughout most of the conducting part of the respiratory tract. Cells of the Respiratory Epithelium Cilia Goblet cells Basal cells Epithelium Lamina propria Sero -mucous glands Basement membrane • Ciliated epithelial cells • Goblet cells • Brush cells • Kulchitsky cells • Basal cells Respiratory Region (Conchae) • Conchae divide each nasal cavity into separate air chambers. • They increase the surface area and cause turbulence in air flow. • By increasing surface area, the conchae increases the efficiency with which the inspired air is warmed and filtered. Hard palate Septum Olfactory Mucosa • Located in the roof of the nasal cavity, and extends a short way down the septum and lateral wall. • Pseudostratified columnar epithelium. • Surface area of approximately10 cm 2 in humans. Olfactory vesicle Pathologies of the Nasal Passages Category Conditions Inflammatory Rhinitis; Nasal polyps. Infective Sinusitis. Benign Tumours Papilloma; Haemangioma; Angiofibroma. Malignant Tumours Squamous cell carcinoma; Transitional cell carcinoma; Adenocarcinoma; Plasmacytoma ; Olfactory neuroblastoma . Note: Tumours of the nasal passages and sinuses are uncommon Pharynx • Connects the nasal and oral cavities to the larynx and oesophagus. • Passageway for air and food. • Divided regionally into the nasopharynx, oropharynx and laryngopharynx. • Mucosa -associated lymphoid tissue (MALT) forms the Waldeyer’s ring in the nasopharynx. Trachea Oesophagus Larynx • The laryngeal region comprises of the epiglottis, true and false vocal cords. • Prevent inspired air entering the oesophagus. • Prevent ingested food and fluid entering the trachea. • Permit the production of complex sounds. Anterior surface Posterior surface Respiratory epithelium Sero -mucous glands Non -keratinised stratified squamous epithelium Cartilage Transition zone Perichondrium Epiglottis What is the function of stratified squamous epithelium? Provide protection to underlying tissue Why does the epiglottis need protection? Abrasions from movement and food Vocal Cords • The true vocal cords are responsible fro the production of sound. • The false vocal cords, saccules and ventricles modify the nature of the sound produced by the vibrating true cords. • The constant rush of air and vibration of these cords induces an epithelial reaction early in life transforms the epithelium from respiratory mucosa into non - keratinized stratified squamous epithelium. Microanatomy of the vocal cords Non -keratinised stratified squamous epithelium Pseudo stratified respiratory epithelium Sero -mucous glands Vocalis muscle True vocal cord False vocal cord Ventricle Pathologies of the Pharynx / Larynx Category Conditions Inflammation Pharyngitis (sore throat) Laryngitis; Epiglottitis; Tonsillitis. Infective (see above) Benign Tumours Polyps; Squamous papilloma. Malignant Tumours Squamous cell carcinoma. • Squamous cell carcinoma of the larynx is strongly associated with cigarette smoking. • Laryngeal cancer often presents with persistent hoarseness of voice. Trachea • Formed for four layers and is lined with respiratory mucosa. • Braced with 15 -20 C -shaped hyaline cartilage rings. • Bifurcates into two main bronchi, which further subdivide. Cystic Fibrosis • Inherited metabolic disease caused by a genetic mutation in the CFTR protein. • Cells are unable to move chloride, sodium ions and water around effectively. • Lungs and digestive system can become clogged with thick, sticky mucus. • Susceptible to lung infections (often with Staphylococcus aureus , Pseudomonas aeruginosa and Aspergillus). Bronchus, bronchi, and bronchioles • Right main bronchus and the left main bronchus branch from the trachea • The main bronchus enter the lungs at the hilum with the pulmonary arteries • The conducting zone of the respiratory tract stops at the terminal bronchiole • Alveoli are the terminal air spaces and are the sites of gas exchange Right Left Trachea Main bronchus Lobar bronchus Segmental bronchus Bronchiole Terminal bronchiole Respiratory bronchioles Alveolar duct Alveolar sacs Alveoli Bronchial tree Structure of the respiratory epithelium Main - Stem Bronchus Cartilage Pseudostratified columnar epithelium (respiratory epithelium) Sero -mucous glands Perichondrium Smooth muscle Chondrocyte Alveolar sack Ciliated simple columnar epithelium Smooth muscle Alveolar ducts Bronchiole Non -ciliated simple cuboidal epithelium Anthracite Terminal Bronchiole Alveoli Macrophage RBC Simple Squamous epithelium (Type 1 pneumocyte ) Type II pneumocyte Pneumocytes TYPE I • Comprise 40% of the alveolar lining cells, lining 95% of the surface of the alveoli. • Thin simple squamous cells. • Not capable of cell division. TYPE II • Secretory cells. • Stem cells for Type 1 pneumocytes. • Account for 60% of the alveolar lining cells, however they only cover 5% of the alveolar air surface (cuboidal in shape). • Rich in a mixture of phospholipids, neutral lipids and proteins. • Bear microvilli on their surface. Disorders of the Bronchi & Lungs Category Conditions Inflammatory Bronchitis; Bronchiolitis. Infective Pneumonia; Tuberculosis, Aspergillosis. Vascular disease Embolism; Arterial hypertension; Oedema; Haemorrhage. Autoimmune Wegener's granulomatosis; Goodpasture’s syndrome. Obstructive disease Bronchitis; Bronchiectasis; Asthma; Emphysema; COPD; Cystic fibrosis. Restrictive disease Pneumoconiosis; Pulmonary fibrosis; Druga and toxins; Ionising radiation; Sarcoidosis; ARDS; BOOP; Collagen vascular disorders (e.g. SLE); Hypersensitivity pneumonitis (e.g. farmer’s lung); Asbestosis. Malignant Tumours Bronchogenic carcinoma (Squamous cell carcinoma; Adenocarcinoma; Small cell carcinoma; Large cell carcinoma); Neuroendocrine tumours; Metastatic lung tumours. Disorders of the Pleura Category Conditions Associations Pleural effusion Inflammatory Inflammation of the adjacent lung (e.g. pneumonia, lung abscess, TB, collagen vascular disease, pulmonary infarction). Non -inflammatory Cardiac failure; Renal failure; Liver failur ,; Chest trauma; Ruptured aortic aneurysm; Obstruction of the lymphatics by tumour. Benign Tumours Solitary fibrous tumour Malignant Tumours Mesothelioma; Metastatic tumours Asbestosis (Restrictive lung disease). Reasons for a Biopsy • To evaluate an abnormality seen on chest X -ray or CT scan • To investigate the cause of unexplained fluid collection in the lung • Diagnose certain lung conditions such as such as sarcoidosis or pulmonary fibrosis. • To determine if a mass is malignant or benign • To stage malignant tumours • In rare cases, a lung biopsy may be done for severe pneumonia, especially if the diagnosis is not clear Procedure overview • A biopsy may be performed using either a closed or an open method. • Closed methods are performed through the skin or through the nasal cavity with an endoscope. • An open biopsy is performed in the operating room under general anaesthesia. Closed Methods Laryngoscopy Bronchoscopy Needle biopsy Thoracoscopic biopsy (VATS) Laryngoscopy/ Broncoscopy • A thin, flexible, fibre -optic tube with a light and a camera lens at the end is passed through the nose and to the site of interest. • Instruments can be passed through tubes to remove any blockages, polyps or take a biopsy sample. What can we use to decalcify specimens? Acid de -calcifiers : • Nitric Acid • Hydrochloric Acid • Formic Acid Chelating agents: ◦ Ethylenediaminetetraacetic acid (EDTA) ◦ Trisodium citrate Needle/Core/True Cut Biopsy During the procedure, the tissue or mass is located via ultrasound/CT scan, and a Temno /true -cut biopsy needle is guided to the area. This technique can be used for various tissue biopsies such as liver, lymph nodes, muscle, breast, prostate and kidney biopsy. Thoracoscopy Biopsy (VATS) • Three incisions are made through the chest wall into the chest cavity. • Various biopsy tools can be inserted to obtain lung tissue for examination. • Therapeutic procedures, such as the removal of a nodule or other tissue lesion may be performed. Investigative methods/techniques Category Methods/Techniques Benign H&E Inflammatory H&E; Toluidine Blue; possibly IHC to stain inflammatory cells. Autoimmune Renal Biopsy; serum sample for ANCA ( MPO /PR3) and GBM Infective H&E Gram Stain; ZN stain; PAS or Grocott’s Methanamine Silver Obstructive disease H&E; Van Gieson ; Stains for infective agents (see above) Restrictive disease H&E ; Masson Trichrome; PAS (for basement membranes) Malignant Tumours Lung: H&E; Toluidine Blue; IHC e.g. TTf -1, ALK, P63, CK5/6, CD56, MNF116; Molecular tests e.g. EGFR mutations; Mesothelium: H&E, IHC for Mesothelioma e.g. Calretinin, TTF1, WT1, BerEP4, CEA, CD15, CAM5.2; Perl’s Prussian Blue for Asbestos bodies. Toluidine Blue • This basic dye selectively stains acidic tissue components via the phenomenon of ‘metachromasia ’. • Nuclei are stained dark blue, but mast cell granules and polysaccharides will stain violet • Used when there is a need to evaluate patients with pathological conditions that involve mast cells. • Mast cells would be present in allergic inflammatory diseases. Van Gieson • A combination of two acidic dyes to stain collagen red and muscle yellow. Elastic fibers will stain a blue/black colour . • Used to identify the presence or absence of elastic fibers in tissues. • May be used to demonstrate loss of elastic tissue in the lung in patients with emphysema, and thinning and loss of elastic fibers in blood vessels of patients with arteriosclerosis or arteritis. Masson Trichrome • Three dyes are employed to stain muscle, collagen fibres, fibrin, and erythrocytes. • The selective differential staining of connective tissues is achieved due to the molecular size of the dye and the tissue density. • Provides helpful information about the degree of fibrosis, or scarring, in a tissue. • Aid the diagnosis of restrictive lung diseases such as sarcoidosis, pulmonary fibrosis and collagen vascular disease. Asbestosis • Long term inflammation and scarring of the lungs due to asbestos. • Symptoms may include shortness of breath, cough, wheezing, and chest pain. • Complications may include lung cancer, mesothelioma and pulmonary heart disease. • Asbestos use has been banned in a number of countries in an effort to prevent disease. Perl’s Prussian Blue • For the demonstration of iron/haemosiderin. • Used to diagnose haemosiderosis (iron storage disease) but is also used to demonstrate asbestos bodies (dumbbell appearance). • Iron can also be found in chronic passive congestion of the lung due to left ventricular failure.