Respiratory System I PDF Lecture Notes

Anatomy &Physiology for Health Science I Block 3 |Lecture 12 Respiratory System I Dr Ali Drigo [email protected] Department of Anatom ical Sciences School of Medicine, St. George’s University  Lecture Objectives 1. List the organs o...

Anatomy &Physiology for Health Science I Block 3 |Lecture 12 Respiratory System I Dr Ali Drigo [email protected] Department of Anatom ical Sciences School of Medicine, St. George’s University  Lecture Objectives 1. List the organs of the respiratory system. a) Identify the vestibular and vocal folds a) Differentiate between the upper and lower respiratory system. b) Identify and describe the actions of the muscles of the larynx b) Differentiate between the conducting and respiratory zones of c) Describe how they interact to produce phonation. the respiratory system. 6. Describe the gross anatomy and function of the trachea. 2. Describe the gross anatomy and functions of the nose. Outline the branching of the bronchial tree and respiratory 7. a) Describe the nasal cavity. zone and describe the anatomical changes that happen as b) Describe the components of the nasal septum. this branching occurs. c) Identify and describe the function of the nasal conchae and choanae. 8. Briefly describe respiratory epithelium and the changes of epithelium within the entire respiratory system. d) Describe the paranasal sinuses and their drainage. 3. Describe the gross anatomy and function of the pharynx. 10. Describe the structure of alveolar sacs and individual 4. Describe the gross anatomy and function of the larynx. alveoli. a) List the cartilages of the larynx. a) List the cells of alveoli and their function. b) Identify the epiglottis, the glottis and rima glottis. 5. Describes the structures involved in voice production. Introduction to the Respiratory system Respiration Exchange of gases — at the respiratory membrane Regulate blood pH balance (homeostasis) Other Special senses (Smell) Condition + filter of inspired air Phonation (larynx) Excretion (water, heat)  Organs of the respiratory system Figure 19.1 Histology: A Text and Atlas, 8ed © 2020 Wolters Kluwer Structural division of the respiratory system Upper Respiratory System Nose Nasal Cavity Pharynx Associated structures Lower Respiratory System Larynx Trachea Bronchi Lungs Functional division of the respiratory system Conducting Zone/ Portion Respiratory Zone/ Portion Filter, warm, moisten + deliver Main site of gas exchange air to the lungs between air and blood Nose & Nasal cavity Respiratory bronchioles Pharynx (throat) Alveolar ducts Larynx (voice box) Alveolar sacs Trachea (windpipe) Alveoli Bronchi Bronchioles Terminal bronchioles Figure 23.8b Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons Upper Respiratory Tract Nose, Nasal cavity, Pharynx, and associated structures. Lined by: Olfactory epithelium Respiratory epithelium (pseudo‐ stratified ciliated columnar with goblet cells) [RE] Stratified squamous nonkeratinized epithelium [SSE] The walls have modifications which serve to condition the air.  Nose External nose Structure Visible portion Framework: bone, hyaline cartilage — Keep nasal cavity patent Covering: skin, muscle, mucous membrane Nostrils (external nares) open into the nasal vestibule Functions 1. Warm, moisten, filter air 2. Detect olfactory stimuli 3. Modify speech vibrations Figure 23.3a Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons  Nasal Cavity Internal Nose Between nasal bone + hard palate Lined by muscle and mucous membrane Drains Paranasal sinuses and nasolacrimal ducts o Moistens air Anterior: Nasal vestibule — Cavity just inside the nostrils (external nares) — Surrounded by cartilage; Lined by skin — Coarse hairs – filter out large dust particles Posterior: Choanae — Communicates with pharynx: Choanae (internal nares) Superior: Olfactory region (smaller) Inferior: Respiratory region (larger) Medial: Nasal Septum Lateral: Ethmoid, maxillae, lacrimal, palatine, inferior nasal conchae bones (Turbinates) Figure 23.3b Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons  Nasal Cavity Superior: Olfactory region (smaller) Roof – Ethmoid bone Surrounded by bone Lined by Olfactory epithelium ―Olfactory sensory neurons ―Supporting epithelial cells ―Basal epithelial cells ―Cilia; no goblet cells FYI IMAGE Figure 19.3 Histology: A Text and Atlas, 8ed © 2020 Wolters Kluwer  Nasal Cavity Inferior: Respiratory region (larger) Floor – palatine and maxillae bones (hard palate) Lined by respiratory; Pseudostratified ciliated columnar epithelium with goblet cells. ―Goblet cells: secrete mucous o Moistens air o Traps dust particles ―Ciliated columnar cells o Move mucus and trapped dust particles toward pharynx ―Underlying mucosa o Capillaries warm air Table 4.1 Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons Nasal Septum Vertical partition Separates the cavity into left + right Anteriorly: hyaline cartilage Posteriorly: vomer, ethmoid, maxillae, palatine bones Visible shelf- like projections called conchae (turbinates). Figure 7.11 Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons  Review: Paranasal Sinuses Structure Cavities within certain skull bones Frontal, Sphenoid, Ethmoid, Maxillae Lined by mucus membranes Continuous with lining of nasal cavity Secretions drain into nasal cavity Functions Increase surface area of nasal mucosa Help moisten and clean air Resonance chambers – enhance phonation Figure 7.9e; 7.13a, b, & c Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons  Nasal Conchae/ Turbinates Paired, scroll-shaped projections Extend from lateral wall into nasal cavity Lined by mucous membranes Superior conchae — Projection from Ethmoid bone — Olfactory receptors terminate in mucosa — Increases surface area for smell Middle conchae — Projection from Ethmoid bone Inferior conchae — Separate facial bone Figure 7.9a; 23.3a Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons  Nasal Conchae/ Turbinates Subdivide nasal cavity into air passageways – meatuses Superior meatus Middle meatus Inferior meatus Functions Increase vascular and mucosal surface area Cause air to swirl Inhalation: — Humidify (warm + moisten) air — Filter/cleanse air (trap dust particles) Exhalation: — Trap water droplets to prevent dehydration Sense of smell — ONLY Superior Nasal Conchae Figure 23.3d Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons  Hyoid Bone Axial skeleton U-shaped Articulates with ligaments and muscles Attachment sites for several muscles Tongue Neck Pharynx Figure 7.15a Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons Pharynx Funnel-like muscular tube Extends from Choanae to cricoid cartilage (larynx) Measures about 13cm (5 inches) Subdivided into 3 regions Nasopharynx Oropharynx Laryngopharynx Lined by stratified squamous nonkeratinized epithelium Two layers of skeletal muscle: Inner longitudinal/outer circular Relax – patent/ Contract - swallowing Function Passageway for air/ food particles Resonance during phonation Protection - presence of tonsils  Pharynx Nasopharynx Posterior nasal cavity to tip of uvula (soft palate) Posterior wall – Pharyngeal tonsil (adenoid) Five openings: 2 from internal nares (choanae) 2 from pharyngotympanic (Eustachian) tubes 1 from oropharynx Receives air, dust laden mucus from nasal cavity Equalize air pressure (tympanic cavity and atmosphere) Respiratory epithelium Oropharynx Tip of uvula to upper part of epiglottis The palatine and lingual tonsils. 1 opening from mouth Common passageway for air, food and drink Stratified squamous nonkeratinized epithelium Laryngopharynx Hyoid bone to the lower border of cricoid cartilage Two openings: Esophagus posteriorly Larynx anteriorly Performs both digestive and respiratory function Respiratory + Stratified squamous non keratinized epithelium Figure 23.3b Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons Lower Respiratory tract Larynx, Trachea, Bronchi, Lungs, and alveoli. Lined by Respiratory epithelium Contains structures that function in conduction and gas exchange  Larynx Also known as the voice box Midline, anterior neck Connects laryngopharynx to trachea Anterior to esophagus From C4 to C6 vertebrae Composed Cartilages (9) Cavity Vocal folds (2) Muscles Figure 23.2a Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons Fig 8.215 © 2020 Elsevier Ltd. Drake et al: Gray’s Anatomy for Students, 4ed www.studentconsult.com  Laryngeal cartilages Three (3) Paired Arytenoid Cartilage Arytenoid, Corniculate, Cuneiform Most important of paired cartilages Three (3) Unpaired Wide range of mobility Thyroid, Cricoid and Epiglottic Involved in phonation Figure 23.5a,b,b Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons Influences change in position/tension of vocal folds  Laryngeal Cavity & Folds Cavity Opening of larynx to inferior border of cricoid cartilage Two portions Laryngeal Vestibule (LV) Rima vestibuli — Above Vestibular folds [SSE] Infraglottic cavity (IC) — Below vocal folds [RE] Vocal Folds Paired mucous membrane folds Vestibular folds (false vocal cords) Vocal folds (true vocal cords) Rima glottidis Rima glottidis Space between the true vocal folds Glottis True Vocal folds with mucous membrane + Rima glottidis Figure 23.5c,d Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons Vocal Folds: Effort Closure Vestibular folds False vocal cords Superior pair of folds Space between: rima vestibuli NOT involved with Phonation When held together: — Hold breath against thoracic cavity pressure — E.g., heavy lifting Fig 8.225d © 2020 Elsevier Ltd. Drake et al: Gray’s Anatomy for Students, 4ed www.studentconsult.com  Vocal Folds: Phonation Vocal folds Main structures for voice production Vocal ligament – elastic ligament Phonation Vocal ligaments stretch between laryngeal cartilages Activity of intrinsic muscles of larynx — Vary tension in vocal folds — Vary size of rima glottidis Air forced through larynx ⭢ vibration of folds ⭢ produce sound — Tension: Pitch — Pressure: Volume Recognizable speech, individual quality: Resonance: pharynx, mouth, nasal cavity, paranasal sinuses Pronunciation (Muscles): pharynx, face, tongue, lips; teeth Fig 8.225c © 2020 Elsevier Ltd. Drake et al: Gray’s Anatomy for Students, 4ed www.studentconsult.com Vocal Folds: Movement Intrinsic muscles Contract ⭢ pull on arytenoid cartilage Posterior cricoarytenoid muscle Abduction of vocal folds Open rima glottidis Lateral cricoarytenoid muscle Adduction of vocal folds Close rima glottidis Other Intrinsic muscles Elongate (tighten) on folds Shorten (relax) vocal folds Figure 23.6 Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons, Fig 8.223 © 2020 Elsevier Ltd. Drake et al: Gray’s Anatomy for Students, 4ed www.studentconsult.com Trachea Also known as windpipe Cylindrical tube, 12cm (5 inches) long Anterior to the esophagus Larynx to the 5th thoracic vertebrae Carina Bifurcation of trachea Sensitive mucosa – cough reflex Wall has 4 layers: Mucosa Submucosa Cartilage Adventitia Passageway for air from the upper to the lower respiratory tract Figure 19.5 Histology: A Text and Atlas, 8ed © 2020 Wolters Kluwer  Trachea Mucosa Respiratory epithelium Lamina propria (elastic + reticular fibers) Submucosa Figure 23.7a Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons Glands and loose connective tissue Hyaline Cartilage Anteriorly: 16-20 C-shaped rings — Prevents collapse of the trachea Posteriorly: Membranous wall — Trachealis muscle (posterior) — Elastic connective tissue o Allows for diameter change of the trachea Adventitia Areolar connective tissue  Bronchi Primary (Main) bronchi Right Primary (Main) Bronchi — Right lung — Shorter and more vertical than left Left Primary (Main) Bronchi Left Main Bronchus — Left lung Wall identical to trachea Secondary (Lobar) bronchi Supply the lobes of the lungs Right Lobar Right – 3/ Left – 2 Bronchus Resp. epithelium w/ plates of cartilage Tertiary (Segmental) bronchi Supply bronchopulmonary segments Resp. epithelium w/ plates of cartilage Left Segmental Bronchus Figure 23.8 Principles of Anatomy and Physiology, 15ed © 2016 John Wiley & Sons  Bronchioles From branching of Segmental bronchi Epithelium varies Ciliated simple columnar Exocrine Clara cells Larger: w/ goblet cells Smaller: w/o goblet cells — No cartilage — Replaced by Smooth muscle Terminal bronchioles End of the conducting zone Supply lung lobules Nonciliated simple columnar Figure 23.8b Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons Bronchioles Respiratory bronchioles Microscopic branches Beginning of Respiratory Zone Have pulmonary alveoli Simple cuboidal to squamous Eventually divide into alveolar ducts Alveolar ducts More alveoli outpouchings Simple squamous epithelium Figure 23.8b Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons Alveolar sacs & Alveoli Alveolar saccules/sacs Terminal dilation of alveolar duct Cluster of grapes ~100 sacs at end of each duct ―Each saccule: ~20-30 outpouchings ―Pulmonary alveoli (single grape) Alveoli Air‐filled sacs Site of actual gas exchange Give the lung its spongy characteristic Alveoli Interalveolar Septum The lung tissue made up of many alveoli. Interalveolar septum: Wall between alveoli Simple squamous epithelium Alveolar epithelial cells Type I Pneumocytes — (95% of cells) Type II Pneumocytes Alveolar macrophages (Dust cells) Figure 23.12d Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons Alveolar Cells Type I Pneumocytes Type II Pneumocytes (Septal cells) Squamous (flat cells) Cuboidal cells w/ microvilli Most numerous Fewer in number Line ~95% of alveolar surface area Found between type I cells Nearly continuous lining Secretes pulmonary alveolar fluid Part of the blood‐gas barrier with surfactant (respiratory membrane) Mixture: phospholipids + lipoproteins Main site of gaseous exchange Reduce surface tension Regenerates itself as well as the type I cells (stem cells) Alveolar Cells Alveolar macrophages phagocytose fine dust particles, debris Figure 23.12c Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons  Bronchial Tree Changes Lumen: 🢙diameter Mucosa 🢙in cell height, layer height 🢙in goblet cells 🢙in cilia Appearance of new cells (e.g., macrophages) Cartilage C-Rings ⭢ Incomplete rings ⭢ Plates ⭢ etc. Smooth Muscle ⭡as cartilages ↓ Figure 19.23 Histology: A Text and Atlas, 8ed © 2020 Wolters Kluwer Epithelium of Respiratory Tract Refer to Table in Textbook Table 23.1 Principles of Anatomy and Physiology, 16ed © 2021 John Wiley & Sons References Tortora, G., and Nielsen, M.T.(2021). Principles of Anatomy and Physiology, 16th ed. John Wiley & Sons, Inc. USA Drake, R., Vogl, A., and Mitchell, A. (2015). Gray’s Anatomy for Students, 3rd ed. Philadelphia: Churchill Livingstone. Ross, M.H., and Pawlina, W.(2020). Histology: A Text and Atlas: With Correlated Cell and Molecular Biology, 8th ed. Wolters Kluwer Health