L9 Cardiovascular and Pulmonary System PDF

Cardiovascular and Respiratory System HPHS4072 Anatomy and Physiology in Rehabilitation 1  Content 1) Cardiovascular: Composition of Blood Blood vessels Structure of heart and functions Cardiac cycle - Respiratory: Structu...

Cardiovascular and Respiratory System HPHS4072 Anatomy and Physiology in Rehabilitation 1  Content 1) Cardiovascular: Composition of Blood Blood vessels Structure of heart and functions Cardiac cycle - Respiratory: Structures and functions of upper & lower respiratory system Mechanics of Breathing Gas Exchange and gas transport 2 Cardiovascular System 3  Systems lymphatic system Circulatory System = cardiovascular Functions : 1) Functions: Transportation of respiratory gases, delivery of nutrients and hormones, and waste removal. 2) Temperature regulation, clotting, and immune function. Include cardiovascular and lymphatic systems 3) Heart pumps blood thru cardiovascular system Blood vessels carry blood from heart to cells and back Includes arteries, arterioles, capillaries, venules, veins 4) Lymphatic system picks up excess fluid filtered out in capillary beds and returns it to veins Its lymph nodes are part of immune system 4 Composition of Blood > - connective tissue (cells) CGuids) 128 Blood = rbz + plasma- + Total blood volume is about 5L ↳ omen men > - + 36 468 - 41-53 % hormones + protein Consists of + ions formed elements (cells) Red blood cells (RBCs) comprise most of formed elements red blood cells % of RBCs in centrifuged blood sample = hematocrit Hematocrit is 36-46% in women; 41-53% in men plasma (fluid part) straw-colored liquid consisting of H2O and dissolved solutes Includes ions, metabolites, hormones, antibodies 5  + hormones 1) H20 + proteins Plasma proteins a) : albuming (60 - 800) osmotic pressure (osmosis) & maintain vessel (H20) High water potential within blood > - balance H20 , ions low water potential Plasma proteins constitute 7-9% of plasma b) globulins > - antibodies -Firs 3 types: albumins, globulins, and fibrinogen > - clotting Albumin accounts for 60-80% (in7-9%) Creates colloid osmotic pressure (osmotic pressure caused by proteins) to maintain blood volume #and pressure F Globulins carry lipids Gamma globulins are antibodies Fibrinogen serves as clotting factor Converted to fibrin Serum is fluid left when blood clots 6 Formed Elements: RBCs and WBCs leukocytes (rbs) Are erythrocytes (RBCs) and leukocytes (WBCs) & errythrocytes (vi) ↓ RBCs are flattened biconcave discs a) flattered biconcave discs - S Bells I cells (diffusion) Shape provides increased surface area for diffusion b) X nuclaus + X Mitochondia Lack nuclei and mitochondria C) 280 million hemoglobin (combine Each RBC contains 280 million hemoglobin molecules #A About 300 billion(三千億) RBCs are produced each day 7  Platelety (thrombocytes) Formed Elements a) smallest elements 1) X nucleus , X true cells - Platelets (thrombocytes) I C) blood clots 2) fragments of megakaryocytes Are smallest of formed elements, lack nucleus, are not true cells Are fragments of megakaryocytes(巨核細胞) from bone marrow Constitute most of mass of blood clots Survive 5-9 days #J 8  Structure of > - connective Smooth tissue muscle Blood Vessels > - > - elastin (3 layers connective at Externa : smooth Media : muscle Interna as endothelium : b) membrane delastin arteries us veins D trick wall Arteries arteriola capillary venue -> reins > Arteries > + - - Carry blood away from heart Large arteries are muscular and elastic Contain lots of elastin gas , - 2) "Y surface area 11 Veins Carry blood to heart Contain majority of blood in circulatory system gastrocnemius Very compliant (expand readily) Contain very low pressure (about 2mm Hg) Insufficient to return blood to heart Aneed : Blood is moved toward heart by contraction of surrounding skeletal muscles (skeletal muscle pump) e 1-way venous valves ensure blood moves only toward heart V values > avoid backflow - or blood 12 An Introduction to the Cardiovascular System Fit Pulmonary circulation is path of blood from right ventricle through lungs and back to heart Systemic circulation is path of right left blood from left ventricle to body and back to heart Flow rate through systemic circulation = flow rate through pulmonary circuit 13 Pulmonary and Systemic Circulations Blood coming from tissues àsuperior and inferior vena cavae which empties into right atrium, then goes to right ventricle which pumps it through pulmonary arteries to lungs Oxygenated blood from lungs passes " through pulmonary veins to left atrium, then to left ventricle which pumps it through aorta to body 14 Structure of Heart Heart Wall: Epicardium (Outer Layer) Visceral(內臟) pericardium (臟層) (心外膜) Covers the heart Myocardium (心肌) (Middle Layer) Muscular wall of the heart Concentric layers of cardiac muscle tissue Endocardium (Inner Layer) Simple squamous epithelium (flat and thin epithelial cells) 15 Figure 20-4a The Heart Wall. middle layer Myocardium I Pericardial Parietal cavity pericardium(壁層) (cardiac muscle tissue) Dense fibrous layer Cardiac muscle cells Areolar tissue Connective tissues Mesothelium Artery outer layer centralrus water lyer Vein Endocardium Epicardium Endothelium (visceral Areolar tissue pericardium) Mesothelium Areolar tissue all rt w Hea a A diagrammatic section through the heart wall, showing the relative positions of the epicardium, myocardium, and endocardium. The proportions are not to scale; the thickness of the myocardial wall has been greatly reduced. 16 Structure of Heart Characteristics of Cardiac Muscle Cells Small size Single, central nucleus Branching interconnections between cells Intercalated discs > - collect inpulse rapily Intercalated discs Cardiac muscle tissue c 17 Figure 20-5b Cardiac Muscle Cells. No need Intercalated disc Gap junction Z-lines bound to opposing plasma membranes Desmosomes b Structure of an intercalated disc 18  Structure of Heart Heart has 4 chambers 2 atria (singular: atrium) aorta semilunar value Vena receive blood from venous card system 2 ventricles pump blood to arteries bicuspid value 2 sides of heart are 2 pumps separated by muscular septum thickerThe I left right 19 Figure 20-4b The Heart Wall. Atrial musculature Ventricular musculature b Cardiac muscle tissue forms concentric layers that wrap around the atria or spiral within the walls of the ventricles. 20 Structure of Heart Cardiac (fibrous) skeleton A layer of dense connective tissue Encircle the heart valves and bases of pulmonary trunk and aorta Structurally and functionally separate ventricles and atria electrically insulate the ventricular cells from atrial cells 21 Structure of Heart Structural Differences between Left ventricle the Left and Right Ventricles Right ventricle wall is thinner, Right ventricle develops less pressure than left ventricle Right ventricle is pouch-shaped, left ventricle is round a A diagrammatic sectional view through the heart, showing the relative thicknesses of the two ventricles. Notice the pouch-like shape of the right ventricle and the greater thickness of the left ventricle. 22 Figure 20-7b Structural Differences between the Left and Right Ventricles. Right Left ventricle ventricle Dilated Contracted b Diagrammatic views of the ventricles just before a contraction (dilated) and just after a contraction (contracted). 23 Atrioventricular Valves (AV) Blood flows from atria into ventricles thru 1-way atrioventricular (AV) > Ar value valves blood : artium - Semilunar + Venaa ventricle > - value > - as Between right atrium and ventricle is tricuspid valve Between left atrium and ventricle is bicuspid or mitral valve 24 Semilunar Valves Seminlunar valves including pulmonary and aortic valves prevent the backflow of blood from pulmonary arteries and aorta into right and left ventricles, respectively. 25  Functions of the valves Opening and closing of valves results from pressure differences High pressure of ventricular contraction is prevented from everting AV valves by contraction of papillary muscles which are connected to AVs by chorda tendinea During ventricular contraction blood is pumped through aortic and pulmonary semilunar valves Close during relaxation I fill with blood relax and Diastole : phase of heart musse ↓ out of heart to the arteries muscle contract and blood purps phase Systole : 26  Figure 20-8a Valves of the Heart (Part 1 of 2). Transverse Sections, Superior View, Atria and Vessels Removed Diastole :Artium ventricle & POSTERIOR > AV values relax - open Cardiac Left AV (bicuspid) skeleton valve (open) RIGHT LEFT VENTRICLE VENTRICLE Relaxed ventricles M Right AV (tricuspid) valve (open) Aortic valve to Aarth (closed) Pulmonary to pulmonary attery ANTERIOR valve (closed) a When the ventricles are relaxed, the AV valves are open and the semilunar valves are closed. The Aortic valve closed chordae tendineae are loose, and the papillary muscles are relaxed. 27 Figure 20-8a Valves of the Heart (Part 2 of 2). Frontal Sections through Left Atrium and Ventricle Pulmonary Ventricle relax veins blood artium > AU value : - open LEFT ATRIUM > - ventricle Relaxed ventricles Left AV (bicuspid) valve (open) Chordae Aortic valve tendineae (loose) (closed) Papillary muscles (relaxed) LEFT VENTRICLE (relaxed and filling with blood) a When the ventricles are relaxed, the AV valves are open and the semilunar valves are closed. The chordae tendineae are loose, and the papillary muscles are relaxed. 28 Figure 20-8b Valves of the Heart (Part 1 of 2). Right AV Cardiac Left AV (tricuspid) valve skeleton (bicuspid) valve (closed) (closed) LEFT RIGHT Contracting ventricles VENTRICLE VENTRICLE Aortic valve (open) Pulmonary valve (open) b When the ventricles are contracting, the AV valves are closed and the semilunar valves are open. In the frontal section notice the attachment Aortic valve open of the left AV valve to the chordae tendineae and papillary muscles. 29 Figure 20-8b Valves of the Heart (Part 2 of 2). Aorta LEFT Contracting ventricles ATRIUM Aortic sinus Left AV (bicuspid) valve (closed) Aortic valve (open) Chordae tendineae (tense) diastole F Papillary muscles (contracted) Left ventricle (contracted) b When the ventricles are contracting, the AV valves are closed and the semilunar valves are open. In the frontal section notice the attachment of the left AV valve to the chordae tendineae and papillary muscles. 30 Cardiac Cycle Repeating pattern of contraction and relaxation of heart Systole refers to contraction phase Diastole refers to relaxation phase Both atria contract simultaneously; ventricles follow 0.1-0.2 sec later 31 Cardiac Cycle continued End-diastolic volume is volume of blood in ventricles at end of diastole Stroke volume is amount of blood ejected from ventricles during systole End-systolic volume is amount of blood left in ventricles at end of systole Frank-Starling Law: stroke volume increases as the end-diastolic volume increases (increased blood volume will stretch ventricular wall à force of contraction increases) 32 Cardiac Cycle continued Heart Sounds S1 Loud sounds close Produced by AV valves (contraction of ventricles) S2 Loud sounds close Produced by semilunar valves (relaxation of ventricles) 33 Figure 20-18b Heart Sounds. 120 Semilunar Semilunar valves open valves close 90 Aorta Pressure (mm Hg) 60 Left ventricle Left AV valves AV valves 30 atrium close open 0 semilinar value close S1 Av values close artium centricle > - S2 ventricle toaorta S4 S3 S4 Heart sounds “Lubb” “Dupp” b The relationship between heart sounds and key events in the cardiac cycle 34 Respiratory System 35 Components of the Respiratory System Five Functions of the Respiratory System 1. Provides extensive gas exchange surface area between air and circulating blood gas exchange 2. Moves air to and from exchange surfaces of lungs 3. Protects respiratory surfaces from outside environment 4. Produces sounds 5. Participates in olfactory sense 36 Components of the Respiratory System Upper Respiratory System Nose Nasal cavity Sinuses Organization of the Tongue Pharynx Esophagus Respiratory System Lower Respiratory System The respiratory system is Clavicle Larynx divided into: Trachea Upper respiratory system – Bronchus above the larynx Lower respiratory system – Bronchioles below the larynx Smallest bronchioles Ribs Right Left lung lung Alveoli Diaphragm 37 Components of the Trachea Cartilage Respiratory System plates Left primary bronchus The Respiratory Tract Visceral pleura Consists of a conducting portion Secondary bronchus Conducting portion (air pathway) From nasal cavity to terminal Tertiary bronchi bronchioles Consists of a respiratory portion Smaller The respiratory bronchioles and bronchi alveoli Bronchioles Terminal bronchiole Alveoli in a Respiratory pulmonary lobule bronchiole Respiratory portion Bronchopulmonary segment 38 Alveoli Smooth Respiratory bronchiole Alveolar duct muscle Alveolus Alveoli Alveolar sac Elastic Are air-filled pockets within the lungs fibers Where all gas exchange takes place Large surface area to increase diffusion rate Capillaries The basic structure of the distal end of a single lobule. A network of capillaries, supported by elastic fibers, surrounds each alveolus. Respiratory bronchioles are also wrapped by smooth muscle cells that can change the diameter of these airways. 39 Alveolar Epithelium Type II Type I pneumocyte pneumocyte Alveolar Epithelium yas exchange site Alveolar (type I preumocytes) macrophage Consists of simple squamous epithelium - Elastic (one cell think) fibers Consists of thin, delicate type I pneumocytes patrolled by alveolar macrophages (dust cells) (phagocytosis of dust) Alveolar macrophage Majority of gas exchange occurs in type I Capillary pneumocytes Contains type II pneumocytes (septal Endothelial cells) that produce surfactant cell of capillary A diagrammatic view of alveolar structure. A single capillary may be involved in gas exchange with several alveoli simultaneously. 40 Respiration Respiration Refers to two integrated processes 1. External respiration Includes all processes involved in exchanging O2 and CO2 with the environment 2. Internal respiration Result of cellular respiration Involves the uptake of O2 and production of CO2 within individual cells 41 Respiration Three Processes of External Respiration 1. Pulmonary ventilation (breathing) 2. Gas diffusion Across membranes and capillaries alveolar capillaries diffusion : & 3. Transport of O2 and CO2 alveali Between alveolar capillaries Between capillary beds in other tissues 42 Respiration External Respiration Internal Respiration Pulmonary ventilation O2 transport Tissues Gas Gas diffusion diffusion Lungs Gas Gas diffusion diffusion CO2 transport 43 Pulmonary Ventilation (Breathing) Pulmonary Ventilation Is the physical movement of air in and out of respiratory tract Provides alveolar ventilation The Movement of Air Atmospheric pressure The weight of air Has several important physiological effects 44 Pulmonary Ventilation Gas Pressure and Volume Boyle’s Law Defines the relationship between gas pressure and volume (presure is the reciprocal of the volume) P = 1/V pat In a contained gas: External pressure forces molecules closer together Movement of gas molecules exerts pressure on container 45 Pulmonary Ventilation Pressure and Airflow to the Lungs Air flows from area of higher pressure to area of lower pressure A Respiratory Cycle Consists of: An inspiration (inhalation) An expiration (exhalation) Inspiration > downward contract - 1) diaphragm mosile contract- > outward 2) intercostal musse ↑ + 3) volume , pressure 4) lung pressure (atomspheric pressure 5) air in 46 Pulmonary Ventilation Pulmonary Ventilation Causes volume changes that create changes in pressure Volume of thoracic cavity changes With expansion or contraction of diaphragm or rib cage 47 Inhalation : Ribs and sternum elevate outward Diaphragm contracts downward volone T , pressure t air , in As the rib cage is elevated or the diaphragm is depressed, the volume of the thoracic cavity increases. 48  Thoracic wall Parietal pleura Pleural fluid Visceral pleura Lung Poutside = Pinside Pressure outside and inside are equal, so no air movement occurs At rest, prior to inhalation. 49  Volume increases Poutside > Pinsidevi, pt Pressure inside decreases, so air flows in Inhalation. Elevation of the rib cage and contraction of the diaphragm increase the size of the thoracic cavity. Pressure within the thoracic cavity decreases, and air flows into the lungs. 50  Volume decreases Poutside < Pinside vX , p Pressure inside increases, so air flows out Exhalation. When the rib cage returns to its original position and the diaphragm relaxes, the volume of the thoracic cavity decreases. Pressure increases, and air moves out of the lungs. 51 Pulmonary Ventilation Compliance An indicator of expandability Low compliance requires greater force High compliance requires less force Factors That Affect Compliance Connective tissue structure of the lungs Level of surfactant production Mobility of the thoracic cage 52 Pulmonary Ventilation Pressure Changes during Inhalation and Exhalation Can be measured inside or outside the lungs Normal atmospheric pressure 1 atm = 760 mm Hg 53 Mechanics of Breathing The Respiratory Cycle Cyclical changes in intrapleural pressure operate the respiratory pump Which aids in venous return to heart Tidal Volume (VT) Amount of air moved in and out of lungs in a single respiratory cycle 54  INHALATION EXHALATION +2 Trachea Intrapulmonary pressure (mm Hg) +1 0 a Changes in intrapulmonary pressure during a single −1 respiratory cycle Bronchi F Intrapleural −2 Lung pressure (mm Hg) −3 Diaphragm −4 Ent b Changes in intrapleural pressure during a single −5 respiratory cycle t Right pleural Left pleural −6 cavity cavity Tidal volume (mL) 500 250 c A plot of tidal volume, the amount of air moving into and out of the lungs during a single respiratory cycle 0 1 2 3 4 Time (sec) 55 Mechanics of Breathing (normal quiet) Muscles Used in Inhalation Diaphragm Contraction draws air into lungs 75 percent of normal air movement External intercostal muscles Assist inhalation 25 percent of normal air movement Accessory muscles assist in elevating ribs 56 accessory muscles needed for forced inhalation (during exercise) Accessory Primary Respiratory Muscles Respiratory Muscles Sternocleidomastoid External intercostal muscle muscles Scalene muscles Accessory Pectoralis minor Respiratory Muscles muscle Internal intercostal Serratus anterior muscles muscle Transversus thoracis muscle Primary Respiratory Muscles External oblique muscle Diaphragm Rectus abdominis Internal oblique muscle 57 Mechanics of Breathing (forced exhalation) Muscles Used in Exhalation Internal intercostal and transversus thoracis muscles Depress the ribs Abdominal muscles Abs Compress the abdomen Force diaphragm upward 58 Lung Volume Measurements Respiratory Performance and Volume Relationships Total lung volume is divided into a series of volumes and capacities useful in diagnosing problems Four Pulmonary Volumes 1. Resting tidal volume (Vt) 2. Expiratory reserve volume (ERV) > - dignosis 3. Residual volume 4. Inspiratory reserve volume (IRV) Measured by spirometry 59 Lung Volume Measurements Resting Tidal Volume (Vt) (500mL) In a normal respiratory cycle Expiratory Reserve Volume (ERV) After a normal exhalation (to lower limit) Residual Volume After maximal exhalation Minimal volume (in a collapsed lung) Inspiratory Reserve Volume (IRV) After a normal inspiration (to upper limit) 60 Gas Exchange Gas Exchange Occurs between blood and alveolar air Across the respiratory membrane Depends on: 1. Partial pressures of the gases 2. Diffusion of molecules between gas and liquid 61 Gas Exchange Partial Pressures in Alveolar Air and Alveolar Capillaries Blood arriving in pulmonary arteries has: Alveolar Low PO O S 2 High PCO 2 The concentration gradient causes: O2 to enter blood * CO2 to leave blood Capillaries Rapid exchange allows blood and alveolar air to reach equilibrium 62  External Respiration PO2 = 40 Alveolus PCO2 = 45 Respiratory membrane Systemic Pulmonary PO2 = 100 circuit circuit O2 PCO2 = 40 CO 2 Pulmonary capillary PO2 = 100 PCO2 = 40 Systemic circuit 63 Systemic Pulmonary circuit circuit Internal Respiration Interstitial fluid Systemic circuit PO2 = 95 PCO2 = 40 PO2 = 40 O 2 PCO2 = 45 CO 2 PO2 = 40 Systemic capillary PCO2 = 45 64 Gas Transport Gas Pickup and Delivery Blood plasma cannot transport enough O2 or CO2 to meet physiological needs Red Blood Cells (RBCs) Transport O2 to, and CO2 from, peripheral tissues air sacs Remove O2 and CO2 from plasma, allowing gases to diffuse into blood 65 Oxygen Gas Transport Oxygen Transport O2 binds to iron ions in hemoglobin (Hb) molecules In a reversible reaction New molecule is called oxyhemoglobin (HbO2) + Oz Each RBC has about 280 million Hb molecules Each binds four oxygen molecules > 4 Heme Ihemoglobin - :. binds four 02 66 Oxygen Gas Transport Environmental Factors Affecting Hemoglobin PO of blood 2 Blood pH > affect - activity Temperature Metabolic activity within RBCs 67 Carbon Dioxide Gas Transport Carbon Dioxide Transport (CO2) Y Is generated as a by-product of aerobic metabolism (cellular respiration) CO2 in the bloodstream can be carried three ways 1. Converted to carbonic acid 2. Bound to hemoglobin within red blood cells 3. Dissolved in plasma CO2 68 Carbon Dioxide Gas Transport Carbonic Acid Formation 70 percent is transported as carbonic acid (H2CO3) Which dissociates into H+ and bicarbonate (HCO3-) Hydrogen ions bind to hemoglobin Bicarbonate Ions Move into plasma by an exchange mechanism (the chloride shift) that takes in Cl- ions without using ATP 69 Carbon Dioxide Gas Transport CO2 Binding to Hemoglobin 23 percent is bound to amino groups of globular proteins in Hb molecule Forming carbaminohemoglobin 1 Transport in Plasma 7 percent is transported as CO2 dissolved in plasma 70 Figure 23-22 Carbon Dioxide Transport in Blood. D CO2 diffuses 7% remains into the dissolved in bloodstream plasma (as CO2) 93% diffuses into RBCs 23% binds to Hb, 70% converted to forming H2CO3 by carbonic carbaminohemoglobin, anhydrase Hb CO2 RBC * -H + H2oz- H2CO3 dissociates H2(z into H+ and HCO3− H+ removed by buffers, H+ Cl− especially Hb HCO3− moves out of RBC in PLASMA exchange for Cl− (chloride shift) 71