Heart Anatomy - FoAP Cardiovascular System

Heart Anatomy Erin Kelly [email protected]  Learning Objectives 1. Describe the anatomical location of the heart 2. Identify the structure and function of the pericardium 3. Describe the structure and function of the three layers of the heart wall 4. Describe the structure and...

Heart Anatomy Erin Kelly [email protected]  Learning Objectives 1. Describe the anatomical location of the heart 2. Identify the structure and function of the pericardium 3. Describe the structure and function of the three layers of the heart wall 4. Describe the structure and function of the four heart chambers 5. Identify the major blood vessels that enter and exit the heart 6. Explain the structure and function of the heart valves 7. Explain the pathway of blood flow through the heart and differentiate between the systemic and pulmonary circuits Heart Anatomy- Video 1 TOPICS COVERED Anatomical location of the heart Pericardium Heart Wall LINK: https://youtu.be/Yy2eDma96p8  Learning Objectives 1. Describe the anatomical location of the heart 2. Identify the structure and function of the pericardium 3. Describe the structure and function of the three layers of the heart wall Location of the Heart BASE OF ICE CREAM The heart is located within the mediastinum APEX OF ICE CREAM BASE OF HEART Right lung Left lung Heart Diaphragm APEX OF HEART Pericardium Membrane which surrounds and protects the heart Two main parts: 1. Fibrous pericardium (superficial) – tough and protective Confines heart to mediastinum but still allows sufficient movement 2. Serous pericardium (deep) – thin and delicate, reduces friction. 1. Parietal layer (fused with fibrous pericardium) 2. Visceral layer (epicardium) – adheres to surface of heart 3. Pericardial cavity – space between the two layers. Pericardium Pericardium Fibrous pericardium Pericardium Parietal layer Pericardial cavity Serous pericardium Visceral layer Heart wall Layers of Heart Wall The wall of the heart is composed of three layers: 1. Epicardium (outer) – visceral serous pericardium 2. Myocardium (middle) – cardiac muscle 3. Endocardium (inside) – smooth endothelial layer Layers of Heart Wall Epicardium (visceral serous pericardium) Myocardium Endocardium Heart Anatomy- Video 2 TOPICS COVERED Chambers of the heart Blood vessels Heart valves Blood flow through the heart LINK: https://youtu.be/YSCoRIdUd_k  Learning Objectives 4. Describe the structure and function of the four heart chambers 5. Identify the major blood vessels that enter and exit the heart 6. Explain the structure and function of the heart valves 7. Explain the pathway of blood flow through the heart and differentiate between the systemic and pulmonary circuits Chambers of the Heart Left atrium Two atria (superior) Receive blood from body Right atrium Ejects blood to ventricle Two ventricles (inferior) Eject blood to body or lungs Right ventricle Left ventricle  Superior vena cava Right Atrium Receives deoxygenated blood from 1. Superior vena cava (from upper body) 2. Inferior vena cava (from lower body) Pumps blood to right ventricle Right atrium Inferior vena cava Right ventricle Right Ventricle Received deoxygenated blood from right atrium Left pulmonary artery Pumps deoxygenated blood into pulmonary trunk Right pulmonary artery Pulmonary trunk Body ↓ Right atrium ↓ Right atrium Right ventricle ↓ Pulmonary trunk ↓ Pulmonary arteries (left and right) ↓ Right ventricle Lungs  Left pulmonary vein Left Atrium Right pulmonary vein Received oxygenated blood from pulmonary veins (from lungs) Left atrium Pumps oxygenated blood to left ventricle Left Ventricle Received oxygenated blood from left atrium Aorta Pumps oxygenated blood to aorta → body Left atrium Lungs (oxygenated) ↓ Left ventricle Pulmonary veins ↓ Left atrium ↓ Left ventricle ↓ Aorta ↓ Body Left vs Right Ventricle ANTERIOR Right ventricle The right and left ventricles eject equal volumes of blood. Right ventricle - pumps blood a short distance to the lungs at lower pressure. Left ventricle - pumps to all other parts of the body at higher pressure Left ventricle The anatomy of the two ventricles confirms this functional difference — the muscular wall of the left POSTERIOR ventricle is thicker than the wall of the right ventricle  Auricles Auricle of Auricle of left atrium right atrium Auricle = ear-like On anterior surface of each atria Wrinkled pouchlike structures Increases volume of the atria  Learning Objectives 6. Explain the structure and function of the heart valves  Heart Valves Aortic valve (SL valve) Heart has four valves Pulmonary valve 2 x atrioventricular (AV) valves (SL valve) 2 x semilunar (SL) valves Bicuspid valve (AV valve) Open and close due to pressure changes as heart contracts and relaxes Help ensure one-way blood flow Tricuspid valve (AV valve) Atrioventricular Valves Between an atrium and ventricle Tricuspid valve – right Bicuspid valve – left Prevent back flow of blood into atria when ventricles contract Structures Cusps Cusp Papillary muscles Chordae tendineae Chordae tendineae Papillary muscle Atrioventricular Valves Left atrium BICUSPID VALVE CUSPS Open Closed CHORDAE TENDINEAE Left Slack Taut ventricle PAPILLARY MUSCLES Relaxed Contracted Bicuspid valve open Bicuspid valve closed (ventricle relaxed) (ventricle contract) Semilunar Valves Between an ventricles and blood vessel Aortic valve Pulmonary valve – right ventricle and pulmonary trunk Aortic valve – left ventricle and aorta Prevent back flow of blood into ventricles Pulmonary valve  PULMONARY VALVE (closed) PULMONARY VALVE (closed) AORTIC VALVE (closed) AORTIC VALVE (closed) BICUSPID TRICUSPID VALVE (open) VALVE (open) SUPEROIR VIEW OF HEART – ATRIA HAVE BEEN REMOVED  RECAP - Heart Valves Aortic valve (SL valve) Heart has four valves Pulmonary valve 2 x atrioventricular (AV) valves (SL valve) 2 x semilunar (SL) valves Bicuspid valve (AV valve) Open and close to pressure changes as heart contracts and relaxes Help ensure one-way blood flow Tricuspid valve (AV valve)  Learning Objectives 7. Explain the pathway of blood flow through the heart and differentiate between the systemic and pulmonary circuits  9. Systemic capillaries of head and upper limbs 4. Pulmonary 4. Pulmonary 10. 8. capillaries of capillaries of left lung right lung 3. 5. 6. 5. 1. Key: Oxygen-rich blood 7. Oxygen-poor blood 2. 10. 9. Systemic capillaries of trunk and lower limbs Systemic vs Pulmonary Circulation Pulmonary circulation Moves blood between the heart and the lungs Right side of the heart – leaves via pulmonary arteries Systemic circulation Moves blood between the heart and the body Left side of the heart – leaves via aorta  LUNGS vena cava pulmonary veins Right Left Atrium Atrium Right Left Ventricle Ventricle pulmonary trunk aorta BODY LUNGS BODY  Heart Physiology Erin Kelly [email protected] Learning Objectives 1. Describe electrical conduction system of the heart 2. Describe a normal electrocardiogram tracing, name the individual waves and state what each represents 3. Describe the phases of the cardiac cycle 4. Explain what causes the heart sounds 5. Define cardiac output, explain how it is calculated, and describe how it is regulated. Heart Physiology - Video 1 TOPICS COVERED Diastole and systole The conduction system of the heart Electrocardiogram (ECG) LINK: https://youtu.be/uWnLAApcr5Q  Learning Objectives 1. Describe electrical conduction system of the heart 2. Describe a normal electrocardiogram tracing, name the individual waves and state what each represents  Diastole vs Systole Ventricle Diastole Ventricle Systole Phase of relaxation (ventricles fill) Phase of contraction (blood leaves)  Learning Objectives 1. Describe electrical conduction system of the heart Conduction System of the Heart Network of specialised cardiac muscle fibers called autorhythmic fibers 1. Generate action potentials that trigger heart contraction 2. Form the condition system for action potentials to travel through As the action potential travels through the heart it causes the heart to contract Conduction System of the Heart 1. Sinoatrial (SA) node 2. Atrioventricular (AV) node 3. Atrioventricular (AV) bundle 4. Right and left bundle branches 5. Purkinje fibres  Learning Objectives 2. Describe a normal electrocardiogram tracing, name the individual waves and state what each represents  Electrocardiogram (ECG) Recording of the electrical signals as they move through the heart SA node Electrical events 1. Atrial Depolarisation – movement of action AV node potential through atria AV bundle 2. Ventricle Depolarisation – movement of action potential through ventricle 3. Venticle Repolarisation – recharging of Right and left ventricles after action potential bundle branches Purkinje fibres P Wave = Atrial depolarisation T Wave P Wave QRS Complex = Ventricle depolarisation T Wave = Ventricle repolarisation Key: QRS Complex  ECG Segment Graphic Depiction Electrical Activity Mechanical Activity Atrial systole P Wave Atrial depolarisation (contraction) Ventricle systole QRS Complex Ventricle depolarisation (contraction) Start of ventricle Ventricle repolarisation T Wave diastole (relaxation) Heart Physiology - Video 2 TOPICS COVERED Cardiac cycle Heart sounds LINK: https://youtu.be/GS7en2XZoec  Learning Objectives 3. Describe the phases of the cardiac cycle 4. Explain what causes the heart sounds  Learning Objective 3. Describe the phases of the cardiac cycle  Cardiac Cycle All of the events associated with one heartbeat In each cardiac cycle, the atria and ventricles alternately contract and relax 1. Relaxation Period 2. Atrial Systole 3. Ventricle Systole  Cardiac Cycle 1. Relaxation period (0.4 sec) All 4 chambers in diastole Blood flows into atria 2. Atrial systole (ventricle diastole) (0.1 sec) Atria contract and force blood into ventricles AV valve are open 3. Ventricular systole (atrial diastole) (0.3 sec) Ventricles contract and force blood into arteries AV valves are closed SL valves are open  Learning Objective 4. Explain what causes the heart sounds  Heart Sounds – Auscultations Turbulent blood hitting against the closed valves Two sounds that can be heart with a stethoscope S1: Lubb – blood hitting closed AV valves (ventricular systole) S2: Dupp – blood hitting closed SL valves (ventricular diastole) Pause – relaxion phase  R P ECG T Q S 0.1 sec 0.3 sec 0.4 sec Relaxation Cardiac cycle Atrial systole Ventricular systole period Heart sounds S1 S2 S3 S4 Mechanical activity Atrial Ventricle Ventricular Atria Ventricular Atrial contraction contraction ejection filling filling contraction Heart Physiology - Video 3 TOPICS COVERED Cardiac output LINK: https://youtu.be/soGQ2RFcO8w  Learning Objective Understand cardiac output and stroke volume  Cardiac Output (CO) Volume of blood ejected from the left (OR right) ventricle each min Units = mL/min Depended on Stoke Volume (SV) - The volume of blood ejected from the left (or right) ventricle during each contraction (mL/beat) Heart Rate (HR) – The number of beats per minute (beats/min) CO = SV x HR  Calculating Cardiac Output CO (mL/min)= SV (mL/beat) × HR (beats/min) In a typical resting adult male Stroke volume is approx. 70 mL/beat Heart rate is approx. 75 beats/min. Therefore, average cardiac output is: CO= 70 mL/beats × 75 beats/min = 5250mL/min = 5.25L/min  CARDIAC OUTPUT (ml/min) Stroke Volume Heart Rate (ml/beat) (beat/min) Preload Afterload Contractility Autonomic NS Hormonal Other Factors that increase stroke volume or heart rate will increase cardiac output  BLOOD Erin Kelly [email protected]  Blood Video 1 TOPICS COVERED Functions and components of blood Red and white blood cells Haemostasis Blood groups LINK: https://youtu.be/BcNWGCpbM5A Learning Objectives 1. Describe the composition and functions of blood 2. Describe the structure and function of red blood cells (erythrocytes) 3. Understand the function of leukocytes 4. Describe the process of haemostasis 5. Understand the blood groups Functions of blood 1. Transportation O2, CO2, nutrients, hormones 2. Regulation pH and temperature 3. Protection clotting, antibodies and white blood cells Components of blood 1. Plasma (55%) Suspension medium Plasma 2. Formed elements (45%) Red blood cells (erythrocytes) (99%) White blood cells and platelets White blood cells (leukocytes) Platelets Red blood cells 16. Describe the structure and function of red blood cells (erythrocytes) Red Blood Cells (RBC) Transport O2 and CO2 Biconcave disk - increases surface area and flexibility No nucleus or other organelles - saves space for oxygen Contain haemoglobin oxygen (and carbon dioxide) carrying protein White Blood Cells (WBC) Immune function - combat invading microbes. Contain nucleus and organelles No haemoglobin Elevated levels can indicate an infection  Never Let Monkeys Eat Bananas Neutrophils Lymphocytes Monocytes Eosinophils Basophils 17. Describe the process of haemostasis Haemostasis Sequence of responses that stops bleeding Process involves 1. Vascular spasm Contraction of smooth muscle in vessel walls to reduce blood flow 2. Platelet plug formation Plug fills the gap in the injured blood vessel wall slows bleeding 3. Blood clotting (coagulation) Plugs the injured blood vessel and stops blood loss Platelets Red blood cell Platelet Help stop blood loss by forming a platelet plug 1. Platelets stick to damaged vessel 2. Start to release chemicals 3. Chemicals activate nearby platelets and these platelets stick to original platelets 4. Platelet plug is formed Example of a positive feedback loop Blood Clotting (coagulation) Fibrin threads Red blood cell Platelets alone can not stop bleeding from vessel wall. Clot must form at the site of injury. Coagulation is the process of turning liquid blood into a gel Series of chemical reactions that results in the formation of fibrin threads Fibrin threads trap the formed elements of blood and creates a blood clot 18. Understand the blood groups. Blood Groups - ABO Based on two antigens - A and B Blood Groups - ABO Blood plasma contains antibodies called agglutinins Agglutinins react with the A or B antigens if the two are mixed Blood Transfusions Blood is the most easily shared of human tissues Whole blood or blood components (RBC or plasma only) Transfusions must be from a compatible blood type Incompatible transfusions can result in agglutination (clumping) Rh Blood Group Named after Rh antigen found in the Rhesus monkey Rh+ (Rh positive) Rh antigen Rh- (Rh negative) Rh antigen. Normally blood does not contain any Rh antibodies Rh (+) Positive Rh (-) Negative BUT if Rh- receives an Rh+ transfusion the immune system starts to make anti-Rh antibodies that will remain in the blood. Frequency of Blood Types Blood Vessels Erin Kelly [email protected] Learning Objectives 1. Compare and contrast the structure and function of the three types of blood vessels (arteries, capillaries and veins) 2. Define vasoconstriction and vasodilation 3. Define blood pressure and explain the factors that influence blood pressure.  Blood Vessels – Video 1 TOPICS COVERED Structure of blood vessels Arteries Capillary beds Veins LINK: https://youtu.be/XtYQ4gN31CE 1. Compare and contrast the structure and function of the three types of blood vessels (arteries, capillaries and veins)  ARTERY VEIN TUNICA INTERNA: Endothelium Basement membrane Internal elastic lamina Valve TUNICA MEDIA: Smooth muscle External elastic lamina TUNICA EXTERNA Lumen Lumen Lumen Endothelium Basement membrane CAPILLARY Arteries Carry blood AWAY from the heart Thick tunica media Smooth muscle- regulation of lumen size via vasoconstriction and vasodilation Elastic tissue - allow for walls to stretch Under higher pressure  Capillaries Red blood cell Exchange vessels Site of exchange of nutrients and waste between blood and surrounding cells Small diameter – slows blood flow Capillary Lack tunica media and externa - Single layer of endothelium and connective tissue Veins TUNICA INTERNA: Return blood to the heart Endothelium Thin walls compared to arteries Basement membrane Valve Contain valves Lower pressure than arteries TUNICA MEDIA: Smooth muscle TUNICA EXTERNA Lumen  SUMMARY ARTERIES VEINS CAPILLARIES Send blood away from Exchange of gasses nutrients Function Return blood to the heart heart and wastes Pressure High Low Low Wall thickness Thick Thin Extremely thin (single cell) Three Three One Tunica interna Tunica interna Tunica interna Wall layers Tunica media Tunica media Tunica externa Tunica externa Muscle and elastic fibers Large amounts Small amounts None Valves No Yes No  Blood Vessels – Video 2 TOPICS COVERED Vasoconstriction and vasodilation Blood pressure Factors that influence blood pressure LINK: https://youtu.be/qethrkkOlAE 2. Define vasoconstriction and vasodilation 3. Define blood pressure, and explain the factors that influence blood pressure. Blood Pressure The pressure exerted by blood on the walls of a blood vessel (mm Hg) Generated by contraction of ventricles Blood pressure falls as distance from left ventricle increases Blood flows from higher pressure to lower pressure The greater the pressure difference the greater the blood flow. Factors That Affect Blood Pressure 1. Blood volume - Total amount of blood in the cardiovascular system ↑ Blood Volume = ↑ Blood Pressure 2. Cardiac output - Volume of blood being ejected from left ventricle per min ↑ Cardiac Output = ↑ Blood Pressure 3. Vascular resistance - Opposition to blood flow due to friction between blood and the walls of blood vessels  Vascular Resistance (R) Opposition to blood flow due to friction between blood and the walls of blood vessels. Depended on 1. Size of the lumen – vasodilation and vasoconstriction 2. Blood viscosity (thickness) 3. Total vessel length ↑ Resistance = ↑ Blood Pressure  Thank you Questions or comments [email protected]