GAF FPP, Wk12, Lect3, Respiratory Anatomy and Physiology 23-24.pptx

Respiratory Anatomy and Physiology Week 12 | Lecture 3 Foundations for Physiotherapy Practice University of Hertfordshire | FPP | 2023-24 1 Learning Outcomes Following this session and appropriate independent study you should be able to: ‐ Discuss what we need for respiration to occur. ‐ Descri...

Respiratory Anatomy and Physiology Week 12 | Lecture 3 Foundations for Physiotherapy Practice University of Hertfordshire | FPP | 2023-24 1 Learning Outcomes Following this session and appropriate independent study you should be able to: ‐ Discuss what we need for respiration to occur. ‐ Describe the structure of the respiratory system. ‐ Describe the function of the alveolus. ‐ Describe the control of respiration. University of Hertfordshire | FPP | 2023-24 2 Major respiratory organs University of Hertfordshire | FPP | 2023-24 3 Definitions of the respiratory system Upper respiratory tract (URT) o Nasal and oral passages o Pharynx o Larynx o Lower respiratory tract (LRT) o From below the larynx to the alveoli (some texts include the larynx) o Conducting zone o All the airways that transport gases to and from the atmosphere to the gas exchange regions (mouth/nose down to and including terminal bronchioles) o Respiratory zone o The area of the lungs that contain respiratory membrane, i.e. respiratory bronchioles, alveolar ducts and alveoli University of Hertfordshire | FPP | 2023-24 4 Upper Respiratory Tract • Structure • Function • Nasal Cavity o Nasal Cavity o Cilia o Mucus membrane o Blood capillaries o Pharynx (throat) o Passage between nasal cavities and larynx o Tonsils • Pharynx o Larynx o Epiglottis o Vocal folds • Larynx University of Hertfordshire | FPP | 2023-24 5 Respiratory tract structure Martini - The Respiratory Epithelium of the Nasal Cavity and Conducting System. 6 Normal Swallow http://strokengine.ca Note the pharyngeal phase of swallow University of Hertfordshire | FPP | 2023-24 7 University of Hertfordshire | FPP | 2023-24 8 http://what-when-how.com/wp-content/uploads/2012/04/tmp26117_thumb.jpg University of Hertfordshire | FPP | 2023-24 9 Cross Section of Trachea + Oesophagus Posterior Mucosa Submucosa Oesophagus Trachealis muscle mucous gland in submucosa Lumen of trachea Hyaline cartilage Adventitia Anterior University of Hertfordshire | FPP | 2023-24 10 Marieb Figure 22.6a Structure of the conducting zone walls • Epithelium • This is the lining of the tubes – changes according to function as you go down the bronchial tree • Mucus cells and cilia vary in concentration • Smooth muscle • Gets relatively greater as you go down • Cartilage • Dense connective tissue • Gets relatively less and less organised in rings, the further down you go • Non-existent in bronchioles University of Hertfordshire | FPP | 2023-24 11 Functions of the conducting zone • Passage of gases to and from the atmosphere to the alveoli • Warming • Humidification • Filtration and cleaning • By the time the air reaches the alveoli it is at 37oC and fully saturated with water vapour University of Hertfordshire | FPP | 2023-24 12 Terminology Trachea • Divides into two primary bronchi at the carina • Left and Right Main Bronchus, which then divide into: • Lobar bronchi (secondary bronchi) • Right upper lobe, right middle lobe, right lower lobe bronchus • Left upper lobe, left lower lobe bronchus which further divide into: • Segmental bronchi (tertiary bronchi) • Leading to a segment of the lobe • Further bronchiolar divisions • 20–23 orders of branching • Bronchioles (less than 1 mm diameter) • Terminal ( the last division of bronchioles without alveoli attached) and respiratory bronchioles • Cartilage decreases & smooth muscle increases (support, permit changes in resistance to air flow) University of Hertfordshire | FPP | 2023-24 13 Conducting Zone Passages Marieb & Hoehn Fig 22.7 University of Hertfordshire | FPP | 2023-24 14 Respiratory Tract Diameter Diameter (mm) & cartilage % smooth muscle 20-25 12-16 Conducting zone 1-12 0.5-1 < 0.5 Respiratory zone < 0.5 0.3 University of Hertfordshire | FPP | 2023-24 15 Fig. 16.3 Stanfield The Respiratory Zone • The respiratory bronchioles which terminate in alveolar ducts that attach to the alveoli (not the terminal bronchioles as these do not have alveoli) • A cluster of alveoli is called an alveolar sac University of Hertfordshire | FPP | 2023-24 16 Function of the alveoli • • • Predominantly gaseous exchange • Oxygen into the blood • Carbon dioxide out Defence mechanisms of the body • Alveolar macrophages • These phagocytose any very small particles and micro-organisms that haven’t been removed by the mucociliary escalator Lung Inflation • surfactant University of Hertfordshire | FPP | 2023-24 17 Respiration Respiration Pulmonary ventilation External respiration Transport of respiratory gases Internal respiration University of Hertfordshire | FPP | 2023-24 18 Pulmonary Ventilation (breathing) Intrapulmonary pressure  pressure in the alveoli Intrapleural pressure  pressure in the pleural cavity Marieb & Hoehn Fig 22.12 University of Hertfordshire | FPP | 2023-24 19 Inspiration – quiet breathing o Diaphragm & intercostal muscles contract o Decreases the intrathoracic pressure and increases the intrathoracic volume o Intrapleural pressure decreases and intrapleural volume increases o Intrapulmonary pressure decreases and intrapulmonary volume increases o Air rushes into the lungs A breath in! University of Hertfordshire | FPP | 2023-24 20 Expiration – quiet breathing oPassive process oInspiratory muscles relax oLungs recoil oIntra-thoracic, intrapleural and intrapulmonary volumes decrease oIntra-thoracic, intrapleural and intrapulmonary pressure increases oGases flow out of the lungs A breath out! University of Hertfordshire | FPP | 2023-24 21 Respiration overview – External respiration – Transport of respiratory gases – Internal respiration O 2 CO 2 Oxygenated blood Deoxygenated blood O 2 CO 2 CO 2 CO 2 CO 2 O 2 O 2 O 2 Fig. 16.1 Stanfield University of Hertfordshire | FPP | 2023-24 22 Internal Respiration (cellular level) Oxygenated blood Deoxygenated blood University of Hertfordshire | FPP | 2023-24 23 Fig. 16.1 Stanfield Control of respiration Neural control • Medullary respiratory centres Responsible for the rhythm • Pontine respiratory centre Modify the activity of the medulla Both of these centres receive inputs from higher centres of control and from the periphery University of Hertfordshire | FPP | 2023-24 24 Control of respiration Neural control Medullary response centres Two groups of neurons, one drives inspiration the other inhibits this group to allow expiration. Inspiratory group of neurons send signals to: • diaphragm via the phrenic nerve • external intercostal muscle via the intercostal nerve University of Hertfordshire | FPP | 2023-24 25 Control of respiration Factors influencing rate and depth of breathing Chemical Factors • Arterial CO2 – central chemoreceptors rising CO2 results in increase in rate & depth of breathing • Arterial O2 – peripheral chemoreceptors only becomes a major stimulus if levels drop very low • Arterial pH – peripheral chemoreceptors • Higher Brain Centres • strong emotions and pain acting via the hypothalamus • voluntary control via the cerebral cortex • reflex activity in response to irritants or inflation University of Hertfordshire | FPP | 2023-24 26 Neural control of breathing University of Hertfordshire | FPP | 2023-24 27 Any questions? University of Hertfordshire | FPP | 2023-24 28 Thank you for your attention. University of Hertfordshire | FPP | 2023-24 29 References Marieb, E. N. and Hoehn, K. (2013). Human anatomy and physiology. (9th ed.). Pearson.San Francisco: London. Martini, F. H. (2006). Fundamentals of anatomy and physiology. (7th ed.). San Francisco: Pearson Benjamin Cummings. Stanfield, C. L. & Germann, W. J. (2008). Principles of human physiology. (3rd ed.). San Francisco: Pearson Benjamin Cummings. Thibodeau, G. A. & Patton, K. T. (2007). Anatomy and physiology. (6th ed.). St Louis, Missouri: Mosby Elsevier. University of Hertfordshire | FPP | 2023-24 30