Respiratory System PDF

Respiratory system  Lecture Objectives Describe the histological structure? Its relation to function and some clinical problems? Structure of: 1.Trachea. 2.Bronchus. 3.Lungs (adult and foetal). The respiratory system is subdivided into 2 portions: 1-Conduction Portion: Conveys air fro...

Respiratory system  Lecture Objectives Describe the histological structure? Its relation to function and some clinical problems? Structure of: 1.Trachea. 2.Bronchus. 3.Lungs (adult and foetal). The respiratory system is subdivided into 2 portions: 1-Conduction Portion: Conveys air from the external milieu to the lung It is concerned with conduction, warming, Namogitisation moistening and filtration of air. 2-Respiratory Portion: Located within the lungs It is concerned with gaseous exchange )Exchange of oxygen for carbon dioxide.( It includes: msn.TW 1. Respiratory bronchioles. 2. Alveolar ducts. 3. Alveolar sacs. 4. Alveoli.  Eption Olfactory Region in the nasal cavity A-Olfactory epithelium (Neuroepithelium): 1-Olfactory cells o ✓ Are fusiform bipolar neurons. F ✓ The cell body : De ndrites extend from the upper surface , end above the surface of supporting cells in expansion called olfactory vesicle. From this vesicles 6-8 non motile olfactory cilia radiate and lie parallel to the surface a.cc e pithelium. Axon: axon penetrate basal lamina and join other axons to form non Fattain myelinated olfactory nerve. 2-Supporting epithelium (Sustentacular) cells: Are tall columnar cells ,Nucleus: oval, pale. The upper surface gives apical Jabetween microvilli. Support olfactory cells. theolfactorycells 3-Basal cells: Are small conical cells not reach lumen with dark rounded nucleus. Differentiate into supporting cells or olfactory cells. g LAMINA PROPRIA (corium): under the olfactory epithelium there is fibroelastic C.T. Contains: Numerous lymphoid elements. Axons of olfactory cells. Bowman’s glands w hich are muco-serous gland and lined by columnar and pyramidal cells that secret watery substances moisten and fresher olfactory mucosa. 0 c bipolar neurons waterTertian Nasopharynx teredo Lined by respiratory epithelium. Simplecolumnar ciliated The lamina propria is composed of vascularized CT contains lymphoid elements mmmm (pharyngeal tonsil). Larynx Between the pharynx and the trachea. The wall is reinforced by several cartilages: - Hyaline CARTILAGE in thyroid and cricoid and inferior aspect of arytenoids. -ELASTIC CARTILAGE In epiglottis , corniculate , cuneiform and superior of arytenoids. The larynx is lined by pseudostratified ciliated columnar epithelium. psetustratifiefiliated The superior surface of the epiglottis and vocal column folds are covered by stratified squamous nonkeratinized epithelium. 1111 244 9sammes not neratinizes  Submucosa 38,03 Trachea I -MUCOSA: 1-Epithelium: pseudo stratified ciliated columnar with goblet cells. 2-basal lamina: loose, fibroelastic C.T. (lymphoid nodules, Glands; mucous and seromucous) tormesefioaaa.ca II-Submucosa: C.T. with blood vessels, lymphatic, nerves and mixed tubuloaveolar gland. is mm III-Fibromusculo cartilages. I - cartilagenous coat: 16-20 C-shape hyaline IV –Adventia: formed of dense CT. rich in elastic fibers. THE BRONCHI 1-Extrapulmonary Bronchi: as trachea. 2-Intrapulmonary Bronchi: are formed of: 1-Mucosa: a-Epithelium is respiratory epithelium , few number of goblet cells. Basal b-Lamina propria: C.T. with elastic fibers, mast cells, fibroblasts and lymphatic nodules. 2-Muscle: smooth muscle, spirally arranged. 3-Fibrocartilagenous plates: of hyaline cartilage ,mixed glands and lymphatic nodules in C.T. 4-Adventitia:C.T. with blood vessels, lymphatics and nerves.  Being alveoli PRETERMINAL AND TERMINAL BRONCHIOLES e NO cartilage, no glands no goblet cells, no lymphatic nodules, I-Mucosa: competes a-Epithelium: Simple columnar ciliated. Clara cells 0 L ( columnar non ciliated cells). They secrete alveolar surfactant and glucose-amine that protect bronchioles I and help in secretion of surfactant. b-Corium: C.T. with more elastic fibers and No lymphocytes. 0 It II-Muscle: spirally arranged smooth muscle. III-Adventitia: fibroelastic C.T, surround the muscle layer. No cartilage. COPD Emphysema is a chronic lung disease characterized by enlargement of the air space distal to the bronchioles, in with destruction of the interalveolar wall. Emphysema usually develops gradually and results in respiratory insufficiency. The major cause of emphysema is cigarette smoking. ALVEOLI - T he functional unit of respiratory tract. - Connected to respiratory bronchioles, alveolar ducts, and alveolar sacs, separated by inter-alveolar septum. 1-Pneumocyte type I (squamous or small alveolar cells): Numerous (95%), flat cells with flat nucleus. Function: gas exchange. WE 2-Pneumocyte type II (granular or great alveolar cells): mm Less numerous(5%), cubical cells. The nucleus is central rounded. The cytoplasm contains lamellar boides (cytosomes) containing, phospholipids, glycosaminoglycan. Function: secrete pulmonary surfactant (decreases surface Type 1 tension to prevent alveolar collapse). flatcells TP 2 3-Alveolar macrophages: Large, irregular with pseudopodia and microvilli. They may be either : 1-Dust cells: Phagocytose dust particles. CabiHybtopgerent.fr 2- Heart failure cells: phagocytose erythrocytes in heart failure and contain haemosidrin granules. gasexchange producingsurfactant  Blood Air Barrier T.EEIEEiiii -It is the wall through which exchange of gases takes place, and is formed of: 1. Cytoplasm of type I pneumocytes (simple squamous epithelium).. 2. Basement membrane of type I pneumocytes. 3. Basement membrane of the surrounding blood capillaries. 4. Cytoplasm of endothelial cells of blood capillaries. ❖ Asthma is thought to be mainly from increased small airway resistance due to bronchiolar smooth muscle contraction. ❖ The increase in bronchiole diameter in response to stimulation of the sympathetic nervous system explains why epinephrine αblockers and other sympathomimetic drugs are frequently used to relax smooth muscle during asthma attacks. Characteristics of fetal lung: ✓Has a clear lobulation similar to glands. Itf ✓Has collapsed alveoli are oftipe2premicites development lined with simple cuboidal epithelium instead of mm simple squamous. ✓Its bronchi are partially collapsed with hyaline cartilage in their walls. ✓Its pulmonary blood vessels are congested with blood.