Respiratory System PDF - Anatomy & Physiology

Because learning changes everything.® Chapter 15 Respiratory System Lecture Outline Seeley’s ESSENTIALS OF ANATOMY & PHYSIOLOGY Eleventh Edition Cinnamon VanPutte Jennifer Regan Andrew Russo Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the pr...

Because learning changes everything.® Chapter 15 Respiratory System Lecture Outline Seeley’s ESSENTIALS OF ANATOMY & PHYSIOLOGY Eleventh Edition Cinnamon VanPutte Jennifer Regan Andrew Russo Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.  Anatomy of the Respiratory System The respiratory system consists of the structures used to acquire O2 and remove CO2 from the blood. All cells in the body require O2 to synthesize the chemical energy molecule, ATP. CO2 is a by-product of ATP production and must be removed from the blood. Increased levels of CO2 will lower the pH of the blood. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 2  Anatomy of the Respiratory System External nose - encloses the chamber for air inspiration. Nasal cavity - a cleaning, warming, and humidifying chamber for inspired air. Pharynx - commonly called the throat, it serves as a shared passageway for food and air. Larynx - the voice box. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 3  Anatomy of the Respiratory System Trachea - commonly known as the windpipe. An air-cleaning tube to funnel inspired air to each lung. Bronchi - tubes that direct air into the lungs. Lungs - labyrinths of air tubes and a complex network of air sacs, called alveoli, and capillaries. Each air sac is the site of gas exchange between the air and the blood. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 4  Respiratory System Figure 15.1 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 5  Functions of the Respiratory System Upper respiratory tract - structures from the nose to the larynx Lower respiratory tract - structures from the trachea through the alveoli in the lungs Conducting zone - structures from the nose to the air tubes within the lungs used strictly for ventilation Respiratory zone - small air tubes in the lungs and the alveoli where gas exchange occurs Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 6  Functions of the Respiratory System. Ventilation - breathing, the movement of air into and out of the lungs. External Respiration - the exchange of O2 and CO2 between the air in the lungs and the blood. Gas Transport - O2 and CO2 travel in the blood to and from cells. Internal Respiration - the exchange of O2 and CO2 between the blood and the tissues Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 7  Additional Functions of the Respiratory System Regulation of blood pH - respiratory system can alter blood pH by changing blood CO2 levels Production of chemical mediators - lungs produce an enzyme called angiotensin-converting enzyme (ACE), which regulates blood pressure Voice production - air moving past the vocal folds makes sound and speech possible Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 8  Other Respiratory System Functions Olfaction - sensation of smell occurs when airborne molecules are drawn into the nasal cavity Protection - system provides protection against some microorganisms by preventing them from entering the body and removing them from respiratory surfaces Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 9  Upper Respiratory Tract External nose Nasal cavity Pharynx Larynx Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 10  Nose External nose: composed of mainly of hyaline cartilage Nasal cavity: extends from nares (nostrils) to the choana which are the openings to pharynx hard palate is its roof nasal septum divides it in half Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 11  Nose Paranasal sinuses: air filled spaces within bone open into nasal cavity lined with mucous Conchae: bony projections on each side of nasal cavity increase surface area of nasal cavity help in cleaning, humidifying, warming of air Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 12  Nose Nasolacrimal ducts: carry tears from eyes open into nasal cavity Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 13  Functions of the Nasal Cavity Serves as a passageway for air - remains open even when the mouth is full of food Cleans the air - lined with hairs, which trap some of the large particles of dust in the air Humidifies and warms the air - moisture is added to the air as it passes through the nasal cavity Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 14  Functions of the Nasal Cavity Contains the olfactory epithelium - sensory organ for smell, is located in the most superior part of the nasal cavity. Helps determine voice sound - nasal cavity and paranasal sinuses are resonating chambers for speech. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 15  Pharynx Pharynx: a common passageway for the respiratory and digestive systems Nasopharynx: takes in air Oropharynx: extends from uvula to epiglottis takes in food, drink, and air Laryngopharynx: extends from epiglottis to esophagus food and drink pass through Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 16  Pharynx Uvula: “little grape” extension of soft palate Pharyngeal tonsil: aids in defending against infections Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 17  Nasal Cavity and Pharynx Figure 15.2a Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 18  Larynx Located in the anterior throat and extends from the base of the tongue to the trachea Consists of 9 cartilages Thyroid cartilage: largest piece of cartilage called Adam’s apple Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 19  Larynx Epiglottis: piece of cartilage flap that prevents swallowed materials from entering larynx Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 20  Anatomy of the Larynx Figure 15.3 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 21  Larynx Vestibular folds: false vocal cords Vocal Folds: source of voice production air moves past them, they vibrate, and sound is produced force of air determine loudness tension determines pitch Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 22 Vestibular and Vocal Folds (b) ©CNRI/Science Source Figure 15.4 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 23  Lower Respiratory Tract Trachea Bronchi Tracheobronchial Tree in Lungs Alveoli Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 24 Respiratory System Figure 15.1 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 25  Trachea Windpipe Consists of 16 to 20 C-shaped pieces of cartilage called tracheal rings Lined with ciliated pseudostratified columnar epithelium Smoking kills cilia Coughing dislodges materials from trachea Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 26 Anatomy of the Trachea and Lungs Figure 15.5 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 27  Bronchi Divides into right and left main (primary) bronchi in the lungs at the carina Lined with cilia Contain C-shaped pieces of cartilage Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 28  Tracheobronchial Tree Structures become smaller and more numerous from primary bronchi to alveoli. 1. Primary bronchi 2. Lobar (secondary) bronchi 3. Segmental (tertiary) bronchi 4. Bronchioles 5. Terminal bronchioles 6. Respiratory bronchioles 7. Alveolar ducts Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 29  Tracheobronchial Tree Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 30  Changes in Air Passageway Diameter Bronchodilation -smooth muscle relaxes, making the bronchiole diameter larger. Bronchoconstriction - smooth muscle contracts, making the bronchiole diameter smaller. Asthma attack - contraction of terminal bronchioles leads to reduced air flow CURE INHALATION : ALBUTEROL Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 31  Alveoli -sites of external respiration small air-filled sacs where air and blood come into close contact where gas exchange occurs surrounded by capillaries 300 million in lungs Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 32  Alveoli -From the terminal bronchioles to the alveoli, there are multiple levels of branching Respiratory bronchioles have a few attached alveoli Alveolar ducts arise from the respiratory bronchioles and open into alveoli SERVE AS DOORWAY Alveolar sacs are chambers connected to two or more alveoli at the end Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 33  Bronchioles and Alveoli Figure 15.6 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 34  Respiratory Membrane In lungs where gas exchange between air and blood occurs Formed by walls of alveoli and capillaries Alveolar ducts and respiratory bronchioles also contribute Very thin for diffusion of gases Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 35  Layers of Respiratory Membrane Thin layer of fluid from alveolus Alveolar epithelium (simple squamous) Basement membrane of alveolar epithelium Thin interstitial space Basement membrane of capillary endothelium Capillary endothelium (simple squamous) Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 36 Alveolus and the Respiratory Membrane Figure 15.7 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 37  Thoracic Wall and Muscles of Respiration The thoracic wall consists of: thoracic vertebrae ribs costal cartilages sternum associated muscles Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 38  Thoracic Wall and Muscles of Respiration Thoracic cavity - the space enclosed by the thoracic wall and the diaphragm Diaphragm - a sheet of skeletal muscle separating the thoracic cavity from the abdominal cavity The diaphragm and skeletal muscles of the thoracic wall change thoracic volume during ventilation Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 39  Lungs Primary organ of respiration Cone shaped The base rests on the diaphragm The apex extends above the clavicle Right lung has 3 lobes Left lung has 2 lobes Contains many air passageways (divisions) Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 40 Lungs, Lung Lobes, and Bronchi Figure 15.9 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 41  Blood Flow to Lungs Oxygenated blood has passed through the lungs and picked up O2 Deoxygenated blood has passed through the tissues and released some of its O2. Pulmonary arteries carry deoxygenated blood to pulmonary capillaries. Blood becomes oxygenated and returns to the heart through pulmonary veins. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 42 Lymphatic Supply to the Lungs Superficial lymphatic vessels: deep to the connective tissue that surrounds each lung drain lymph from the superficial lung tissue and the visceral pleura. Deep lymphatic vessels: follow the bronchi drain lymph from the bronchi and associated connective tissues Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 43  Pleural Membranes and Cavities Pleural cavity: space around each lung Pleura: double-layered membrane around lungs Parietal pleura: membrane that lines thoracic cavity Visceral pleura: membrane that covers lung’s surface Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 44 Pleural Cavities and Membranes Figure 15.10 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 45  Ventilation Ventilation (breathing): the process of moving air in and out of the lungs Two aspects to ventilation: actions of the muscles of respiration air pressure gradients Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 46 Muscles of Respiration Increase Volume decrease pressure Muscles of inspiration: increase the volume of the thoracic cavity. diaphragm external intercostals pectoralis minor scalene muscles Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 47  Muscles of Respiration Decrease volume increase pressure Muscles of expiration: decrease thoracic volume by depressing the ribs and sternum. internal intercostals transverse thoracis abdominal muscles Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 48  Quiet versus Labored Breathing Quiet breathing - expiration is a passive process due to elastic tissue in the thorax wall and the lungs. Also called eupnea Labored inspiration - more air moves into the lungs because all of the inspiratory muscles are active. Labored expiration - more air moves out of the lungs due to the forceful contraction of the internal intercostals and the abdominal muscles. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 49  Pressure Changes and Air Flow When the volume of a container increases the air pressure decreases. When the volume of a container decreases air pressure increases. Air flows from areas of high to low pressure. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 50  Inspiration Diaphragm descends and rib cage expands Thoracic cavity volume increases, pressure decreases Atmospheric pressure is greater than alveolar pressure Air moves into alveoli (lungs) Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 51  Expiration Diaphragm relaxes and rib cage recoils Thoracic cavity volume decreases, pressure increases Alveolar pressure is greater than atmospheric pressure Air moves out of lungs Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 52  Effect of the Muscles of Respiration on Thoracic Volume Figure 15.8 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 53  Pulmonary Volumes Spirometer: device that measures pulmonary volumes Tidal volume (TV): volume of air inspired and expired during quiet breathing Inspiratory reserve volume (IRV): volume of air that can be inspired forcefully after a normal inspiration Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 54  Pulmonary Volumes Expiratory reserve volume (ERV): volume of air that can be expired forcefully after a normal expiration Residual volume (RV): volume of air remaining in lungs after a maximal expiration (can’t be measured with spirometer) Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 55  Pulmonary Capacities Inspiratory capacity (IC): the amount of air a person can inspire maximally after a normal expiration IC = TV + IRV Vital capacity (VC): maximum amount of air a person can expire after a maximal inspiration VC = IRV + ERV + TV Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 56  Pulmonary Capacities Functional residual capacity (FRC): the amount of air remaining in the lungs at the end of a normal expiration FRC = ERV + RV Total lung capacity (TLC): TLC = IRV + ERV + TV + RV Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 57  Respiratory Volumes and Respiratory Capacities Figure 15.11 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 58  Alveolar Ventilation Alveolar ventilation is the measure of the volume of air available for gas exchange per minute. Only a portion of each breath reaches the alveoli for gas exchange. The remaining area where no gas exchange occurs is called the dead space. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 59  Alveolar Ventilation Anatomical dead space areas include all the structures of the upper respiratory tract, and structures of the lower respiratory tract to the terminal bronchioles. Physiological dead space is the combination of the anatomical dead space and the volume of any alveoli with lower than normal gas exchange. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 60 Alveolar Pressure Changes During Inspiration and Expiration Figure 15.12 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 61  Factors Affecting Ventilation Gender Age Body Size Physical Fitness Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 62  Partial Pressure pressure exerted by a specific gas in a mixture of gases total atmospheric pressure of all gases at sea level is 760 mm Hg atmosphere is 21% O2 partial pressure for O2 is 160 mm Hg upper case letter P represents partial pressure of a certain gas (Po2) Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 63  Lung Recoil tendency for an expanded lung to decrease in size occurs during quiet expiration due to elastic fibers and thin film of fluid lining alveoli Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 64  Surfactant mixture of lipoproteins produced by secretory cells of the alveoli fluid layer on the surface lining the alveoli reduces surface tension keeps lungs from collapsing Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 65  Pleural Pressure Pleural pressure is: pressure in the pleural cavity less than alveolar pressure keeps the alveoli from collapsing Pneumothorax if the thoracic wall or lung is pierced the lungs collapse Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 66  Pneumothorax Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 67 Diffusion Through the Respiratory Membrane Three factors influence the rate of gas diffusion through the respiratory membrane: partial pressure gradients for O2 and CO2 thickness of the respiratory membrane surface area of the respiratory membrane Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 68  Partial Pressure Gradients Gas diffuses from a higher partial pressure on one side of the respiratory membrane to a lower partial pressure on the other side. If the partial pressure gradient of a gas is higher in the alveolus, it will diffuse across the respiratory membrane into the blood. If the partial pressure of a gas is higher in the blood, it will diffuse across the respiratory membrane into the alveolus. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 69  Gas Exchange Figure 15.13 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 70  Gas Exchange in the Lungs Blood returning from tissues and entering alveoli in the lungs has a lower partial pressure of O2 and a higher partial pressure of CO2 than the air in the alveoli. O2 diffuses from the alveoli into pulmonary capillaries (blood). CO2 diffuses from capillaries into the alveoli. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 71 Gas Exchange in the Lungs Figure 15.15a Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 72  Gas Exchange in the Tissues Blood traveling from the lungs and through capillaries in the tissues has a higher partial pressure of O2 and a lower partial pressure of CO2 than the interstitial fluid. Oxygen diffuses from capillaries into interstitial fluid. CO2 diffuses from the interstitial fluid into the blood in the capillaries. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 73 Gas Exchange in the Tissues Figure 15.15b Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 74  Respiratory Membrane Thickness Increased thickness decreases rate of diffusion of gases Pulmonary edema decreases diffusion Rate of gas exchange is decreased O2 exchange is affected before CO2 because CO2 diffuse more easily than O2 Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 75  Respiratory Membrane Surface Area Total surface area is about 70 square meters May be decreased due to removal of lung tissue, destruction from cancer, emphysema, tuberculosis Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 76  O2 and CO2 Transport in the Blood Once O2 and CO2 enter the blood they interact with components that increase their solubility. Both O2 and CO2 are transported by the protein, hemoglobin. CO2 is also transported in other ways. CO2 can have a dangerous impact on the blood pH. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 77  Hemoglobin Hemoglobin is a complex protein occupying about the one-third of the total volume of the cytoplasm of red blood cells. Hemoglobin consists of four subunits, each containing one iron-based heme group which binds O2. CO2 can bind to the protein portion of hemoglobin. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 78  Oxygen Transport in Blood O2 diffuses through the respiratory membrane into the blood and is transported to all the cells of the body. 98.5% is transported reversibly bound to hemoglobin within red blood cells 1.5% is dissolved in the plasma Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 79  Carbon Dioxide Transport and Blood pH CO2 diffuses from cells into capillaries CO2 enters blood and is transported in three ways: 7% is dissolved in blood plasma 93% enters red blood cells where 23% is bound to hemoglobin 70% is transported as bicarbonate ions Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 80  Carbon Dioxide Transport and Blood pH CO2 reacts with water to form carbonic acid CO2 + H2O ↔ H2CO3 Carbonic acid dissociates into a hydrogen ion and a bicarbonate ion H2CO3 ↔ H+ + HCO3- Carbonic anhydrase (RBC) increases rate of CO2 reacting with water As CO2 levels increase, blood pH decreases Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 81  Regulation of Ventilation Respiratory rate is regulated to maintain gas concentrations in the blood within normal limits. Body is particularly sensitive to changes in CO2 levels and blood pH. Neurons in the medulla oblongata control the rate of ventilation through stimulation of the muscles of respiration. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 82  Regulation of Ventilation Medullary respiratory center in the medulla oblongata consists of: Dorsal respiratory group (DRG) - most active during inspiration Ventral respiratory group (VRG) - active during inspiration and expiration VRG contains the pre-Bötzinger complex which is believed to establish the basic rhythm of respiration Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 83  Regulation of Ventilation Pontine respiratory group is a collection of neurons in the pons that helps regulate respiration rate. Precise function is unknown Some neurons are active during inspiration, some during expiration, and others during both inspiration and expiration Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 84 Respiratory Structures in the Brainstem Figure 15.16 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 85  Generation of Rhythmic Ventilation s 1. Starting inspiration - medullary respiratory center establishes the basic rhythm of ventilation. Receives stimulation from receptors for blood gas levels, blood temperature, movements of muscles and joints, and emotions. Input from receptors causes action potentials that stimulate respiratory muscles. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 86  Generation of Rhythmic Ventilation 1. Increasing inspiration - Once inspiration begins, more and more neurons are activated resulting in progressively stronger stimulation of the respiratory muscles. Lasts about 2 seconds. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 87  Generation of Rhythmic Ventilation 1. Stopping inspiration - neurons stimulating muscles of respiration also stimulate neurons responsible for stopping inspiration. They receive input from the pontine respiratory group and stretch receptors in the lungs. Inhibitory neurons inhibits respiratory muscles and relaxe respiratory muscles. Results in expiration. Lasts about 3 seconds. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 88  Factors Affecting Respiratory Rate Decrease in Po2 (hypoxia) causes an increase in respiratory rate. Increase in Pco2 (hypercapnia) causes an increase in rate and depth of ventilation. Decrease in Pco2 (hypocapnia ) causes a decrease in rate of ventilation. Chemoreceptors in the medulla oblongata and blood vessels near the heart respond to changes in Pco2 and pH. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 89  Factors Affecting Respiratory Rate 2 Increases in CO2 cause decreases in pH. Central chemorectors in the medulla oblongata detect changes in CO2. Carotid and aortic bodies in blood vessels detect changes in pH. Decreases in pH cause increases in the rate and depth of breathing which restores CO2 and pH to normal levels. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 90  Factors Affecting Respiratory Rate Hering-Breuer reflex limits the depth of inspiration preventing overinflation of the lungs. Depends on stretch receptors in the bronchi and bronchioles Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 91  Regulation of Blood pH Figure 15.17 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 92  Nervous and Chemical Mechanisms of Breathing Figure 15.18 Access the text alternative for slide images Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 93 Anatomy and Physiology of the Respiratory System Notes: Diagrams & Illustrations | Osmosis Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 94  END Because learning changes everything.® www.mheducation.com