Abdullah A Alrumayh BSc EMS MSc Cardiovascular Lecturer Department of Basic Sciences PSCEMS httpfacksuedusaaalrumayh Learning Objectives Discuss the relevance of understanding the function and structure of the respiratory system to conditions commonly found in the field ID: 932822
Download Presentation The PPT/PDF document "Chapter 5 The Respiratoy System" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Chapter 5The Respiratoy System
Abdullah A. AlrumayhBSc EMS, MSc Cardiovascular, Lecturer Department of Basic Sciences, PSCEMShttp://fac.ksu.edu.sa/aalrumayh
Slide2Learning Objectives
Discuss the relevance of understanding the function and structure of the respiratory system to conditions commonly found in the field.State the primary functions of the respiratory system.Identify the organs of the respiratory system and describe their functions.
Describe the structure and function of the larynx and the speaking mechanism.
Slide3Learning Objectives
State the roles of visceral and parietal pleura in respiration.
State the changes in air pressure within the thoracic cavity during respiration.
Describe the factors that influence the respiration rate.
Identify the respiratory areas of the brain that control inspiration as well as exhalation.
Slide4Learning Objectives
Explain the diffusion of gases in external and internal respiration. Explain how respiration affects the pH of certain body fluids.Describe how oxygen and carbon dioxide are transported in the blood.
Slide5The Respiratory System
Includes the organs and structures associated with breathing, gas exchange, and the entrance of air into the body
These structures are divided into two groups:
Upper airway
Lower airway
Slide6The upper Airway
Inspired air flows into the body through either the nose or
mouth
Slide7Nasopharynx
The nasal cavity
Nasopharynx and nasal passages, including the
turbinates
Warm, filter, and humidify air
Nasal mucosa
Olfactory receptors
Extends from the internal nares to the uvula
Slide8External nares or nostrils
The external openings of the nasopharynx Internal naresThe posterior opening from the nasopharynx into the pharynxNasal septumSeparates the nasopharynx into two partsHard palate
Nasopharynx Cont.
Slide9Nasopharynx Cont.
Conchae
Three bony ridges contained within the lateral walls of the nasopharynx
Turbinates
Bony convolutions formed by the conchae that help maintain laminar flow
Meatus
Passageway below each turbinate
Slide10Oropharynx
The oral cavityAir enters more rapidly and directly
Air is less moist
Extends from the uvula to the epiglottis
Slide11Pharynx
The throatPoint where the nasopharynx and oropharynx connect posteriorly to form a common cavity
Composed of the nasopharynx, oropharynx, and the laryngopharynx
Leads to the separate openings of the respiratory system and the digestive system
Slide12Lower Airway
Structures of the lower airway
Larynx
Trachea
Mainstem bronchi
Secondary bronchi
Bronchioles
Alveolar duct
Alveoli
Lungs
Slide13Larynx
The voice boxA rigid, hollow structure made of cartilageThyroid cartilage (Adam’s apple)
Vestibular folds
Superior portion of the vocal cords (false vocal cords)
Slide14Larynx
True vocal cords
Inferior portion of the vocal cords
Glottis
The true vocal cords plus the opening between them
Slide15Trachea
The windpipeExtends downward anterior to the esophagusBranches into right and left mainstem bronchi at the level of the fifth thoracic vertebraCarina
A projection of the lowest portion of the tracheal cartilage
Slide16Mainstem Bronchi
Beyond the carina, air enters the lungs through the mainstem bronchi.
Hilum
Point of entry for the bronchi, vessels, and nerves into each lung
Mainstem bronchi divide into secondary bronchi.
Lead to separate lobes of the lung
Secondary bronchi branch into tertiary bronchi.
Continue to branch, eventually becoming bronchioles
Slide17Bronchioles
Very small subdivisions of the bronchi
Respiratory bronchioles
Develop from the final branching of the bronchiole
Each respiratory bronchiole divides to form alveolar ducts.
Alveolar duct
End in clusters known as alveoli
Slide18Alveoli
Alveoli Tiny sacs of lung tissue in which gas exchange takes placeLung contains approximately 300 million alveoli.
Alveolocapillary membrane
Lies between the alveolus and the capillary
Very thin, consisting of one cell layer
Slide19Lungs
The primary organs of breathingRight lung has three lobes
Upper lobe
Middle lobe
Lower lobe
Left lung has two lobes
Lingula – portion of the left lung that forms the equivalent of the middle lobe in the right lung
Slide20Lungs
Pleura Membranes of connective tissue that envelop the lungs and line the pleural cavity
Pleural cavity
Inner borders of the rib cage
Visceral pleura
Parietal pleura
Slide21Lungs
Pleural spacePotential space that exists between the visceral and parietal pleuraNormally, the two membranes are close together and a space does not exist
Hemothorax
A collection of blood in the pleural space
Hemopneumothorax
A collection of blood & air in the pleural space
Slide22Lungs
Blood flow in the lung – two waysDeoxygenated blood in the heart flows from the right ventricle to the lungs via the pulmonary arteries. Blood supply for the lung tissue
Bronchial arteries
Bronchial veins
Slide23Respiration
Ventilation – process of moving air in and out of the lungsInspiration = inhalation
Expiration = exhalation
Atmospheric pressure
The force that moves air into the lungs
Normal air pressure = 760 mm Hg
Pressure on the inside of the lungs and alveoli is almost equal to outside air pressure.
Slide24Respiration
When inside pressure decreases, atmospheric pressure pushes outside air into the airways.Phrenic nerve impulses stimulate the diaphragm to contract.Thoracic cavity enlarges, internal pressure falls, atmospheric pressure forces air into the airways
Slide25Respiration
There is an opposing effect in the alveoli.Surface tension is created by the attraction of water molecules.SurfactantA mixture of lipids and proteinsWhen deeper breath is required, muscles contract more forcefully.
Slide26Expiration
Occurs because of the elastic recoil of tissues as well as surface tension
Diaphragm lowers, compressing the abdomen.
Lungs, thoracic cage, and abdominal organs return to original shapes.
Slide27Expiration
Diaphragm is pushed upward.Surface tension decreases the diameters of the alveoli, increasing alveolar pressure.Air inside the lungs is forced out.Normal resting exhalation is a passive process.
Slide28Respiratory Volumes andCapacities
Total volume of the lungs can be divided into volumes and capacities.Useful for diagnosing problems with ventilationSpirometer A device used to measure air volumes during breathing.
Slide29Respiratory Volumes
Tidal volume – volume of air inspired during a single respiratory cycleInspiratory reserve volume – additional air that enters the lungs during forced inspirationExpiratory volume – additional air that is expelled upon forceful expiration
Residual volume – volume of air remaining in the respiratory passages and lungs after any level of expiration
Slide30Respiratory Capacities
Respiratory capacity – combination of two or more respiratory volumesVital capacity – combination of the inspiratory reserve volume and the expiratory reserve volumeInspiratory capacity – tidal volume plus inspiratory reserve volume
Functional residual capacity
– expiratory reserve volume plus residual volume
Total lung capacity
– vital capacity plus residual volume
Slide31Respiratory Volumes
Slide32Control of Breathing
Respiratory control has both involuntary and voluntary components.Involuntary centers of the brain regulate respiratory muscles.Respiratory minute volume is adjusted in response to sensory information from the lungs, respiratory tract, and a variety of other sites.
Slide33Respiratory Areas of the Brain
Located in the medulla oblongataThe main signal for the body to increase respiration is an increase in CO2 concentration in the blood.Voluntary control of respiration reflects activity in the cerebral cortex.
Affects output of the respiratory center in the medulla oblongata and pons or of motor neurons in the spinal cord
Slide34Respiratory Areas of the Brain
Medullary respiration centerConsists of the dorsal and ventral respiratory groups and the respiratory group of the ponsDorsal respiratory groupImportant in stimulating the muscles of inspiration
Slide35Respiratory Areas of the Brain
Ventral respiratory group
Controls other respiratory muscles
Pontine respiratory group (pons)
May also control the basic rhythm of breathing
Slide36Respiratory Areas of the Brain
Factors that affect breathing rate and depthCertain chemicalsEmotional statesLung stretching capacityLevels of physical activity
Slide37Respiratory Areas of the Brain
Central chemoreceptors in the medulla oblongata sense carbon dioxide and hydrogen ion changes in the CSF.Peripheral chemoreceptors in the carotid bodies and aortic bodies sense changes in blood oxygen levels and increase breathing rate.
Slide38Respiratory Areas of the Brain
Inflation reflexOccurs when stretched lung tissues stimulate stretch receptors in the visceral pleura, bronchioles, and alveoliDuration of inspiratory movements is shortenedEmotional upset usually increases breathing rate.If breathing stops, blood levels of carbon dioxide and hydrogen ions rise and oxygen levels fall.Hyperventilation
Deep, rapid breathing that lowers blood carbon dioxide levels
Prolonged breath holding causes abnormally low blood oxygen levels.
Slide39Gas Exchange
Alveoli carry on exchange of gasses between air and blood.Alveoli – microscopic air sacs clustered around the distal ends of the alveolar ductsEach alveolus consists of a tiny space inside a thin wall.The inner lining of the alveolus is made up of a simple squamous epithelium.
Dense networks of capillaries are found near each alveolus.
Slide40Gas Exchange
Respiratory membraneAt least two thicknesses of epithelial cells and a fused basement membrane layer separating the air in the alveolus from the blood in a capillaryWhere blood and alveolar air exchange gases
Slide41Diffusion
Process by which a gas dissolves in a liquidOccurs from regions of highest pressure toward regions of lower pressureThe pressure of a gas determines how it diffuses from one region to another.Carbon dioxide diffuses from blood into alveolar air.Oxygen diffuses from alveolar air into blood. As long as breathing continues, alveolar partial oxygen pressure stays relatively constant, at 104 mm Hg.
Slide42Diffusion
PaO2 = partial pressure of oxygenPaCO2 = partial pressure of carbon dioxide
Slide43About 98% of oxygen transported by blood binds the iron-containing protein hemoglobin in red blood cells.Remainder dissolves in plasmaIn the lungs, oxygen that dissolves in blood combines rapidly with the iron atoms of hemoglobin to form oxyhemoglobin.
Gas Transport
Slide44Gas Transport
As PaO
2
decreases, oxyhemoglobin molecules release oxygen, diffusing into nearby cells that have depleted their oxygen supplies in cellular respiration.
Slide45Gas Transport
Carbon dioxide levels increase in blood as blood becomes more acidic or blood temperatures rises.Causes more release of oxygenMore oxygen is released to skeletal muscles during physical exercise.Increases carbon dioxide concentrationDecreases pHRaises temperature
Slide46Gas Transport
HypoxiaA deficiency of oxygen reaching the tissuesMay be caused by hypoxemia, anemic hypoxia, inadequate blood flow, or cellular defects
Slide47Gas Transport
Blood transport carbon dioxide to the lungs either as:Carbon dioxide dissolved in plasmaPart of a compound formed by bonding to hemoglobinA bicarbonate ionThe amount of dissolved carbon dioxide in the plasma is determined by its partial pressure.The higher the partial pressure of carbon dioxide in the tissues, the more of it will go into solution.Only about 7% of carbon dioxide transported by the blood is in this form.
Slide48Carbon dioxide differs from oxygen in that it bonds with the amino groups of the “globin” or protein portion of these molecules. Hemoglobin can transport both oxygen and carbon dioxide at the same time.
CarbaminohemoglobinFormed when carbon dioxide loosely bonds with hemoglobinDecomposes readily in regions of low carbon dioxide partial pressureGas Transport
Slide49Gas Transport
Bicarbonate ionsFormed by the most important carbon dioxide transport mechanismCarbon dioxide reacts with water to form carbonic acidCarbonic anhydraseAn enzyme in red blood cells that speeds the reaction of carbon dioxide and waterResults in carbonic acid that releases hydrogen and bicarbonate ionsNearly 70% of carbon dioxide transported by the blood is in this form
Slide50Gas Transport
Carbon dioxide diffuses into the alveoli in response to relatively low partial pressure of carbon dioxide in alveolar air.Hydrogen and bicarbonate ions in red blood cells simultaneously recombine to form carbonic acid.Quickly yields carbon dioxide and water
Slide51Summary
Slide52Ref.
Anatomy, Head and Neck, Nasal Concha: https://www.ncbi.nlm.nih.gov/books/NBK546636/Anatomy and Normal Microbiota of the Respiratory Tract: https://courses.lumenlearning.com/microbiology/chapter/anatomy-and-normal-microbiota-of-the-respiratory-tract/ANS Control of Breathing: https://www.apsubiology.org/anatomy/2020/2020_Exam_Reviews/Exam_3/CH22_ANS_Control_of_Breathing.htmTRANSPORT OF GASES: https://opentextbc.ca/anatomyandphysiology/chapter/22-5-transport-of-gases/