Endeavour College of Natural Health endeavour.edu.au

BIOH122 Human Biological Science 2 Session 10 Respiratory System 1 Anatomy & Physiology Bioscience Department Endeavour College of Natural Health endeavour.edu.au

Session plan o Functions of the respiratory system o Respiratory System Anatomy: Nose Pharynx Larynx Vocal Cords Trachea Bronchi Lungs o Blood Supply to the Lungs Endeavour College of Natural Health endeavour.edu.au 3

Functions of the Respiratory System Endeavour College of Natural Health endeavour.edu.au 4

The Respiratory System o The respiratory system: contributes to homeostasis Provides for gas exchange intake of O2 and elimination of CO2 Helps adjust the ph of body fluids o Respiration: the exchange of gases between the atmosphere, blood, and cells. o Three basic steps: Ventilation (breathing) External (pulmonary) respiration Internal (tissue) respiration Endeavour College of Natural Health endeavour.edu.au 5

The Respiratory System o Functions of the respiratory system Gas exchange: intake of O 2 2 for delivery to body cells and removal of CO 2 2 produced by body cells Helps regulate blood ph Contains receptors for sense of smell Filters inspired air Produces vocal sounds (phonation) Excretes small amounts of water and heat Endeavour College of Natural Health endeavour.edu.au 6

Respiratory System Anatomy Endeavour College of Natural Health endeavour.edu.au 7

The Respiratory System Endeavour College of Natural Health endeavour.edu.au 8

Respiratory System Anatomy Structural divisions: o The upper respiratory system: consist of Nose Nasal cavity Pharynx (throat), and associated structures. o The lower respiratory system: consists of Larynx (voice box) Trachea (windpipe) Bronchi (airways) Lungs Endeavour College of Natural Health endeavour.edu.au 9

Respiratory System Anatomy Functional divisions: o The conducting zone: consists of a series of interconnecting cavities and tubes both outside and within the lungs. the nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles o Function: to filter, warm, and moisten air and conduct it into the lungs. o The respiratory zone: consists of tubes and tissues within the lungs the respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli o Function: the main sites of gas exchange between air and blood. Endeavour College of Natural Health endeavour.edu.au 10

Nose o The nose: A specialized organ at the entrance of the respiratory system o Two parts: External nose: External portion Nasal cavity: Internal portion Endeavour College of Natural Health endeavour.edu.au 11

Nasal cavity o The nasal cavity: A large space in the anterior aspect of the skull that lies inferior to the nasal bone and superior to the oral cavity. o Duct openings: Duct from the paranasal sinuses (which drain mucus) and the nasolacrimal ducts (which drain tears) open in nasal cavity. o Regions: Superior olfactory region: smaller, olfactory function Inferior respiratory region: larger, respiratory function lined with the respiratory epithelium-pseudostratified ciliated columnar epithelium with numerous goblet cells. Endeavour College of Natural Health endeavour.edu.au 12

Nasal cavity Endeavour College of Natural Health endeavour.edu.au 13

Airway Epithelium o Ciliated pseudostratified columnar epithelium with goblet cells produce a moving mass of mucus. Endeavour College of Natural Health endeavour.edu.au 14

Functions of the Nasal Structures o Ciliated pseudostratified columnar with goblet cells: Lines the nasal cavity Warms air due to high vascularity Mucous moistens air and traps dust Cilia move mucous towards pharynx o Olfactory epithelium: Detecting olfactory stimuli o Paranasal sinuses: Modifying speech vibrations as they pass through the large, hollow resonating chambers. Resonance refers to prolonging, amplifying, or modifying a sound by vibration. Endeavour College of Natural Health endeavour.edu.au 15

Pharynx Endeavour College of Natural Health endeavour.edu.au 16

Pharynx o Structure: a funnel-shaped tube about 13 cm (5 in.) long that starts at the internal nares and extends to the level of the cricoid cartilage, the most inferior cartilage of the o Functions: Passageway for food and air Resonating chamber for speech production Tonsils (lymphatic tissue) in the walls protects entryway into body o Distinct regions: nasopharynx, oropharynx and laryngopharynx Endeavour College of Natural Health endeavour.edu.au 17

Pharynx Endeavour College of Natural Health endeavour.edu.au 18

Larynx o The larynx (voice box): A passageway that connects the laryngopharynx with the trachea. o Structure: Contains nine pieces of cartilage: Three single cartilages: thyroid cartilage, epiglottis, and cricoid cartilage Three paired cartilages: arytenoid, cuneiform, and corniculate cartilages o Function: Voice production o Vocal folds (true vocal cords): produce sound. o Taunt vocal folds produce high pitches, and relaxed vocal folds produce low pitches. Endeavour College of Natural Health endeavour.edu.au 19

Larynx Endeavour College of Natural Health endeavour.edu.au 20

Trachea o The trachea (windpipe): o Location: anterior to the oesophagus, extends from the larynx to the primary bronchi level of T5 o Size: 12 cm long and 2.5 cm diameter o Layers of the tracheal wall: Mucosa Submucosa Hyaline cartilage Adventitia Endeavour College of Natural Health endeavour.edu.au 21

Trachea o Mucosa: consists of pseudostratified ciliated columnar epithelium Protects from dust and foreign particles. o Submucosa: Consists of areolar connective tissue that contains seromucous glands and their ducts. o Hyaline cartilage:16 to 20 incomplete C shaped cartilage rings Provide a semirigid support to maintain patency so that the tracheal wall does not collapse inward (especially during inhalation) and obstruct the air passageway. o The Adventitia: consists of areolar connective tissue joins the trachea to surrounding tissues. Endeavour College of Natural Health endeavour.edu.au 22

Trachea and Bronchial Tree o The bronchial tree begins at the trachea and ends at the terminal bronchioles. o Full extent of airways is visible starting at the larynx and trachea Endeavour College of Natural Health endeavour.edu.au 23

Bronchi o Primary bronchi: the trachea divides into a right primary bronchus and a left primary bronchus supply each lung The right primary bronchus is more vertical, shorter, and wider than the left. an aspirated object is more likely to enter and lodge in the right primary bronchus than the left o Carina: An internal ridge formed by a posterior and inferior projection of the last tracheal cartilage, at the point where the trachea divides into right and left primary bronchi Significance: One of the most sensitive areas of the entire larynx and trachea for triggering a cough reflex. Endeavour College of Natural Health endeavour.edu.au 24

Bronchi o Secondary bronchi: Supply each lobe of the lungs (3 right + 2 left) o Tertiary bronchi: Supply each bronchopulmonary segment (10 in each lung) Divide into bronchioles which in turn branch repeatedly, divide into smaller tubes called terminal bronchioles Endeavour College of Natural Health endeavour.edu.au 25

Bronchial Tree Structural changes as the branching becomes more extensive: o The mucous membrane: Gradually changes from pseudostratified ciliated to cuboidal nonciliated o Rings of cartilage: Gradually replaced by rings of smooth muscle and then connective tissue Endeavour College of Natural Health endeavour.edu.au 26

Bronchial Tree o Sympathetic nervous system: stimulates adrenal glands to release epinephrine that relaxes smooth muscle. dilates airways and improves lung ventilation o Parasympathetic nervous system: cause contraction of bronchiolar smooth muscle constricts of distal bronchiole o Mediators of allergic reactions such as histamine: Released during asthma attacks or allergic reactions constrict distal bronchiole smooth muscle o Nebulization therapy = inhale mist with chemicals that relax muscles and reduce thickness of mucous Endeavour College of Natural Health endeavour.edu.au 27

Pleural Membranes and Pleural Cavity o Pleural membrane: A double-layered serous membrane that enclose and protect each lung Visceral pleura covers lungs Parietal pleura lines thoracic cavity o Pleural cavity: A potential space between the visceral and parietal pleurae Contains a pleural fluid secreted by the membranes. Reduces friction between the membranes, allowing them to slide easily over one another during breathing. Endeavour College of Natural Health endeavour.edu.au 28

Pleural Membranes and Pleural Cavity Endeavour College of Natural Health endeavour.edu.au 29

Lungs o Shape: Paired cone shaped organs o Location: in the thoracic cavity; extend from the diaphragm to just slightly superior to the clavicles and lie against the ribs anteriorly and posteriorly. o Enclosed and protected by the pleural membrane. Endeavour College of Natural Health endeavour.edu.au 30

Gross Anatomy of Lungs o Base, apex (cupula), costal surface, cardiac notch o Lobes: The right lung: three lobes separated by two fissures- Oblique and horizontal fissure The left lung: two lobes separated by one fissure- Oblique fissure Endeavour College of Natural Health endeavour.edu.au 32

Mediastinal Surface of Lungs o Blood vessels and airways enter lungs at hilus o Forms root of lungs o Covered with pleura (parietal becomes visceral) Endeavour College of Natural Health endeavour.edu.au 33

Microscopic Anatomy of Lungs o Bronchopulmonary segment: The segment of lung tissue that each tertiary bronchus supplies o Lobules: Small compartments of bronchopulmonary segment Wrapped in elastic connective tissue Each contains an arteriole, a venule, and a branch from a terminal bronchiole Endeavour College of Natural Health endeavour.edu.au 34

Microscopic Anatomy of Lungs o Respiratory bronchioles: microscopic sub branches from terminal bronchioles o Alveolar ducts: Respiratory bronchioles in turn subdivide into several (2 11) alveolar ducts, o Alveoli: A cup-shaped outpouching around the circumference of the alveolar ducts (150 million/lung) o Alveolar sacs: Two or more alveoli that share a common opening Endeavour College of Natural Health endeavour.edu.au 35

Cells Types of the Alveoli o Type I alveolar cells: Form a continuous lining of the alveolar wall. Site for gas exchange. Are the most prevalent alveolar cells o Type II alveolar cells (septal cells): Found between type I alveolar cells Secrete alveolar fluid containing surfactant Surfactant lowers the surface tension of alveolar fluid, preventing the collapse of alveoli with each expiration Endeavour College of Natural Health endeavour.edu.au 36

Other cells types of the Alveoli o Alveolar dust cells Wandering macrophages that remove debris o Fibroblasts: Produce reticular and elastic fibers Endeavour College of Natural Health endeavour.edu.au 37

Alveolar-Capillary Membrane o Alveolar-capillary membrane/ Respiratory membrane: Formed by alveolar and capillary walls where the alveoli are in close proximity to the capillaries 0.5 micron thick Site for exchange of gases Endeavour College of Natural Health endeavour.edu.au 38

Blood Supply to the Lungs o Arterial supply: Pulmonary arteries: carry deoxygenated blood from the right heart to the lungs for oxygenation Bronchial arteries: branch from the aorta and deliver oxygenated blood to the lungs primarily perfusing the muscular walls of the bronchi and bronchioles o Venous drainage: Four pulmonary veins: Drain into the left atrium o Ventilation perfusion coupling: Vasoconstriction in response to hypoxia diverts pulmonary blood from poorly ventilated areas of the lungs to well-ventilated regions for more efficient gas exchange. Endeavour College of Natural Health endeavour.edu.au 39

Readings and Resources o Tortora, GJ & Derrickson, B 2014. Principles of Anatomy and Physiology, 14th edn, Wiley. o Harris, P, Nagy, S & Vardaxis, N 2010, Mosby s Dictionary of Medicine, Nursing and Health Professions, 2nd edn, Mosby Elsevier. o Guyton, AC & Hall, JE 2011, Textbook of Medical Physiology, 12th edn, Saunders Elsevier. o Marieb, EN & Hoehn, K 2010, Human Anatomy and Physiology, 8th edn, Benjamin Cummings Pearson. o Moore, KL, Dalley, AF & Agur, AMR 2010, Clinically Orientated Anatomy, 6th edn, Lippincott, Williams & Wilkins. Endeavour College of Natural Health endeavour.edu.au 40

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