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Basic Human Needs Oxygenation Ventilation/Perfusion. Basic Needs: Oxygenation. Oxygenation. Oxygen is required to sustain life, primary basic human need The cardiac & respiratory systems function to supply the body’s oxygen demands
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Oxygenation Oxygen is required to sustain life, primary basic human need The cardiac & respiratory systems function to supply the body’s oxygen demands Cardiopulmonary physiology involves delivery of deoxygenated blood to the right side of the heart & to the pulmonary system
Electrical/conduction Mechanical/pump What are the 2 mechanisms that drive the function of the heart?
Myocardial Pump Pumping action of heart is essential to maintenance of oxygen delivery Decreased effectiveness of pumping action is a result of disease ( MI, CHF, Cardiomyopathy) Results in diminished pumping action (stroke volume)
Myocardial Pump Chambers of the heart fill during diastole & empty during systole Myocardial fibers have contractile properties that enable them to stretch during filling In healthy heart the stretch is proportionally related to the strength of contraction Frank-Starling Law of the Heart
Myocardial Blood Flow Unidirectional 4 Heart valves ensure forward flow Atrioventricular (mitral & tricuspid) Open during ventricular filling (diastole), blood flows from atria into ventricles
Myocardial Blood Flow Review Semilunar valves (aortic & pulmonic) Open during systolic phase Closure of atrioventricular valves & closure of semilunar valves constitute normal heart sounds “Lub” or S1=Closing of atrioventricular valves just before the contraction of the ventricles (systole) “Dub” or S2=Closing of Semilunar valves after the ventricles have emptied and heart enters the filling phase (diastole)
Coronary Artery Circulation Right Coronary Artery Left Coronary Artery Circumflex
Systemic Circulation LV to aorta to arteries to arterioles to capillaries Oxygen exchange occurs at the capillary level Waste product exchange occurs here also and exits via venous system back to lungs
Blood Flow Regulation Cardiac Output Cardiac Index Stroke Volume
Stroke Volume Preload Myocardial Contractility Afterload
Conduction System Rhythmic relaxation & contraction of atria & ventricles Dependent on continuous transmission of electrical impulses Influenced by ANS (Sympathetic & parasympathetic)
Conduction System Originates in the sinoatrial node (SA node) Intrinsic rate of 60-100 beats per minute Electrical impulses transmitted through atria along intra-nodal pathways to AV node
Conduction System AV node mediates impulses between atria & ventricles Intrinsic rate 40-60 beats per minute AV node assists atrial emptying by delaying the impulses before transmitting it through to the Bundle of His & Perkinje fibers
Conduction System Intrinsic rate of Purkinje fibers 20-40 beats per minute EKG reflects the electrical activity of conduction system Normal Sinus Rhythm Physiology of NSR
Respiratory Physiology Structure & Function Respiratory Gas Exchange
Structure & Function Ventilation-Process of moving gases into and out of the lung Requires coordination of the muscular & elastic properties of lungs & thorax as well as intact innervation Diaphragm-Major muscle of inspiration, innervated by phrenic nerve (3rd cervical vertebrae)
Structure & FunctionWork of Breathing Degree of compliance of lungs Airway resistance Presence of active expiration Use of accessory muscles of respiration
Lung Compliance Ability of lungs to distend or expand in response to increased intra-alveolar pressure, the ease in which lungs are inflated Compliance is decreased in pulmonary fibrosis, emphysema Lung compliance is affected by surface tension of alveoli, surfactant lowers surface tension.
Airway Resistance Pressure difference between the mouth & the alveoli in relation to the rate of flow of inspired gas Airway resistance increased in airway obstruction, asthma, tracheal edema
Structure & Function Accessory Muscles Assist in increasing lung volume during inspiration Scalene & sternocleidomastoid (inspiration) COPD patients use these frequently Abdominal muscles Trapezius muscle and pectoralis play minor role
Pulmonary Circulation Move blood to and from the alveolocapillary membrane for gas exchange Begins at pulmonary artery which receives deoxygenated blood from RV Flow continues to PA to pulmonary arterioles to pulmonary capillaries where blood comes in contact with alveolocapillary membrane
Respiratory Gas Exchange Diffusion-movement of molecules from an area of higher concentration to areas of lower concentration (oxygen & CO2) Occurs at the alveolocapillary level Rate of diffusion affected by thickness of membrane Increased thickness: COPD, pulmonary edema, pulmonary infiltrates, effusions
Oxygen Transport Consists of lung & cardiovascular system Delivery depends on O2 entering lungs (ventilation) And blood flow to lungs & tissues (perfusion) Rate of diffusion V/Q ratio O2- carrying capacity
Oxygen Transport O2 transport capacity affected by hemoglobin Oxyhemoglobin CO2 Transport-diffuses into RBC’s & is rapidly hydrated into carbonic acid
Regulation Of Respiration CNS control rate, depth, & rhythm Change in chemical content of O2, CO2 can stimulate chemorecptors which regulate neural regulators to adjust rate & depth of ventilation to maintain normal Arterial Blood Gases.
Factors Affecting Cardiopulmonary Functioning Physiological Age Medications Stress Developmental Lifestyle Environmental
Factors Affecting Oxygenation: Physiologic Any factor that affects cardiopulmonary functioning directly affects the body’s ability to meet O2 demands Physiologic factors include: decreased O2 carrying capacity, hypovolemia, increased metabolic rate, & decreased inspired O2 concentration
Conditions Affecting Chest Wall Movement Pregnancy Obesity Trauma Musculoskeletal Abnormalities Neuromuscular Disease CNS Alterations Influences of Chronic Disease
Alterations in Cardiac Functioning Disturbances in Conduction Altered Cardiac Output Impaired Valvular Function Impaired Tissue Perfusion (Myocardial)
Disturbances of Conduction Dysrhythmias-deviation from NSR Classified by cardiac response origin of impulse Tachycardia Bradycardia Supraventricular dysrhythmias Junctional dysrhythmias Ventricular dysrhythmias
Altered Cardiac Output Left-sided heart failure Right-sided heart Failure