Cardiovascular System PDF - Curtin University

How do things get around the body? Cardiovascular system Part 1 of 2 Dr. Arpana Dhar [email protected] WARNING This material has been reproduced and communicated to you by or on behalf of Curtin University in accordance with section 113P of the Copyright Act 1968 (the Act) The material in this...

How do things get around the body? Cardiovascular system Part 1 of 2 Dr. Arpana Dhar [email protected] WARNING This material has been reproduced and communicated to you by or on behalf of Curtin University in accordance with section 113P of the Copyright Act 1968 (the Act) The material in this communication may be subject to copyright under the Act. Any further reproduction or communication of this material by you may be the subject of copyright protection under the Act. Do not remove this notice. Please note that these unit materials contain images/videos of cadaveric material obtained under the Anatomy Licence held by the Anatomy Facility at Curtin University and are bound by the regulations of the Anatomy Act of Western Australia (1930). These images/videos are for study purposes only and must not be shared or distributed outside of this Blackboard site as this constitutes a breach of the Anatomy Act. A breach of the Anatomy Act is considered to be student misconduct and is dealt with in accordance with Statute No.10 Student Discipline. 2 Specific Learning Objectives Describe the position of the heart within the mediastinum. Describe the major anatomical structures of the heart including its coverings, chambers and valves. Describe the flow of blood through the heart. Describe how a heartbeat is generated. Differentiate between systemic and pulmonary circulation. Describe the effects of exercise on cardiac output. List the components of blood. Describe the transport of carbon dioxide and oxygen in the blood. Textbook readings VanPutte, C.L., Regan, J.L. & Russo, A.F. (2020). Seeley’s Anatomy and Physiology (12th edition). New York, USA: McGraw-Hill pages pages pages pages 648-656 677-690 and 703-705 720-730 853-855 Chapter Chapter Chapter Chapter 19: 20: 21: 23: pages pages pages pages 644-651 673-686 and 701-702 718-726 847-850 VanPutte, C.L., Regan, J.L. & Russo, A.F. (2014). Seeley’s Anatomy and Physiology (10th edition). New York, USA:McGraw-Hill 19: 20: 21: 23: VanPutte, C.L., Regan, J.L. & Russo, A.F. (2017). Seeley’s Anatomy and Physiology (11th edition). New York, USA:McGraw-Hill Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter 19: 20: 21: 23: pages pages pages pages 637-644 665-678 and 691 709-718 836-838 VanPutte, C.L., Regan, J.L. & Russo, A.F. (2010). Seeley’s Anatomy and Physiology (9th edition). New York, USA:McGraw-Hill Chapter Chapter Chapter Chapter 19: 20: 21: 23: pages pages pages pages 646-653 674-688 and 700-702 718-727 845-847 Components of Cardiovascular system  Blood   Heart Blood vessels – arteries, veins, capillaries Functions of Cardiovascular system 1. 2. 3. Transport Gases – Oxygen, carbon dioxide, nitrogen Nutrients – glucose, amino acids, vitamins, proteins, lipids Metabolic wastes – urea, uric acid, creatinine, ammonium ions Regulatory molecules – hormones, enzymes Processed molecules – proteins, enzymes, carbohydrates, lipids Protection Inflammation Phagocytosis Antibodies Platelets for clotting Regulation Fluid balance pH Body temperature Blood pressure Exchange between blood, extracellular fluid and cells Heart 1. Function Pump - generate pressure in the blood Routes blood – separate pulmonary and systemic circulation 2. One way flow Regulate blood supply Protection rib cage, protective membranes, fluids 3. Location Heart - location Thoracic cavity, obliquely in mediastinum, medial to two lungs, superior to diaphragm Size of closet fist, about 300g Blunt cone, 2/3rd towards left side of midline rounded end is apex, anteriorly & inferiorly pointed, above diaphragm broader end is base, directed posteriorly and slightly superiorly Heart - pericardium Fibrous pericardium: tough fibrous outer layer, prevents over distention; acts as anchor. Serous pericardium: thin, transparent, inner layer, simple squamous epithelium. Parietal pericardium: lines the fibrous outer layer Visceral pericardium: covers heart surface The two are continuous and have a pericardial cavity between them filled with pericardial fluid Anterior view – heart with pericardium intact Heart - morphology Anterior and posterior side Sulci (grooves) Coronary sulcus Anterior interventricular sulcus Posterior interventricular sulcus Major vessels Pericardial & epicardial fat Pericardial fat – between visceral and parietal pericardium Epicardial fat – between outer layer of myocardium and visceral layer of pericardium (epicardium) Superior chambers (collecting) – Atria Inferior chambers (discharging)– Ventricles Thin atrial walls & thicker ventricular walls – palpation Heart - wall Three layers of tissue Epicardium - Serous membrane; simple squamous epithelium over areolar tissue, smooth outer surface of heart Myocardium - Middle layer, thickest, composed of cardiac muscle cells – contractility Endocardium - Smooth inner surface of heart chambers, simple squamous epithelium over areolar tissue, covers valve surface & continuous with endothelium Heart - anatomy Interventricular septum – separation between two ventricles Pectinate muscles: muscular ridges in auricles Inter atrial septum - wall between the atria. Contains a depression, and atrial wall fossa ovalis, a remnant of the fetal opening (foramen ovale) between the atria Left ventricle wall much thicker than right ventricle wall Trabeculae carnae: muscular ridges and columns on inside walls of ventricles Heart - chambers Right atrium Thin-walled receiving chamber, most part on posterior side Auricles are extensions to increase volume Contain pectinate muscles for large force of contraction receives deoxygenated blood returning from the body through three openings Superior and inferior vena cavae, coronary sinus Right ventricle Pumping chamber, most part on anterior side Thick walled than atria Receives deoxygenated blood from right atrium Opens to pulmonary trunk Contains trabeculae carnae Heart - chambers Left atrium Thin-walled receiving chamber, most part on posterior side, forms heart’s base Auricles are extensions to increase volume Contain pectinate muscles for large force of contraction Receive oxygenated blood returning from lungs through four openings Four pulmonary veins Left ventricle Pumping chamber, forms apex and posteroinferior aspect Thickest walled chamber in the heart Receives oxygenated blood from left atrium Opens to aorta Contains trabeculae carnae Heart – great vessels Blood into the heart: Into Right Atrium – by superior and inferior vena cava from systemic circulation and coronary sinus from coronary circulation (deoxygenated) Into Left Atrium – by left and right pulmonary veins from pulmonary circulation (oxygenated) Blood out of the heart: Out of right ventricle – by pulmonary trunk to pulmonary circulation (deoxygenated) Out of left ventricle – by aorta to systemic circulation (oxygenated) Heart - valves Atrioventricular (AV) valves Valves between atria and ventricles Valves have leaf-like cusps Cusps attached to papillary muscles by tendons – Tricuspid valve chordae tendineae Open valves have a canal – atrioventricular canal Right side has three cusps (tricuspid, Rt AV valve) Left side has two cusps (bicuspid, Lt AV valve, Mitral) Bicuspid valve When valve is open, blood flows from A  V When it is closed, blood exits ventricle Heart - valves Semilunar (SL) valves Pulmonary SL valve Valves at the base of large vessels/ exit of ventricles Valves are cup shaped Pulmonary SL valve – at the base of pulmonary trunk Aortic SL valve – at the base of aorta When cups are filled, valves close, stops backflow When cups are empty, valve is open, blood exits heart Aortic SL valve Heart - valves Functions Valves - Prevent backflow of blood Chordae tendineae – strings connecting valve cusps to papillary muscles, prevent AV valves from bulging into atria Papillary muscles – pillar-like muscles in ventricles, prevent prolapse of AV valves Heart - valves The valves open and close due to changes in blood pressure within heart chambers Heart – blood flow Heart – pump Pulmonary circulation – deoxygenated blood is transported to lungs for oxygenation and then returned to heart Deoxygenated blood, enters right atrium and flows into right ventricle. Exits heart through Pulmonary trunk. Pulmonary trunk divides into left and right pulmonary arteries. Blood travels to right and left lung – gas exchange. Oxygenated blood travels in left or right pulmonary veins and enters the left atrium. Systemic circulation – oxygenated blood is transported to body tissues and then returned to heart Oxygenated blood enters left atrium. Blood flows into left ventricle. Left ventricle contracts and pushes blood out of heart through aorta. Aorta branches into Ascending aorta, Aortic arch, Descending aorta. Blood is delivered to all cells and tissues in the body for gas/nutrient/fluid exchange. Deoxygenated blood travels back to heart and re-enters right atrium through vena cava. Coronary circulation – part of systemic circulation that supplies only heart Test your knowledge: anatomy of the CVS Organise the following structures in order as the blood would flow from tissues back into systemic circulation including all the vessels, chambers and valves. 1 7 4 8 2 10 Test your knowledge: anatomy of the CVS Organise the following structures in order as the blood would flow from tissues back into systemic circulation including all the vessels, chambers and valves (answer) 1 6 Pulmonary Trunk 13 7 9 Pulmonary Veins 2 Aortic Semilunar Valve Right Atrium 4 5 8 10 2 3 10 14 1 Pulmonary Semilunar Valve 11 Left AV (bicuspid) Valve Left Atrium 4 Right Ventricle Right AV (tricuspid) Valve 7 Pulmonary Arteries (R&L) Aorta (systemic circulation) SVC & IVC 12 8 Left Ventricle Pulmonary capillaries Compendium questions 1. What is carried by the circulation and how? 2. What is the driving force for movement of fluid around the body? 3. What are the anatomical structures of the heart and how does the left side of the heart differ from the right? 4. What structures does blood pass through as it travels through the heart? 5. How does the heart help the lungs do their job? 6. How are increased metabolic demands of tissues met by changes to blood circulation? 7. What are the layers that surround the heart and where is the heart located within the thoracic cavity? 8. How are arteries and veins similar and different? 9. Describe the basic components of blood. How do things get around the body? Cardiovascular system Part 2 of 2 Dr. Arpana Dhar [email protected] WARNING This material has been reproduced and communicated to you by or on behalf of Curtin University in accordance with section 113P of the Copyright Act 1968 (the Act) The material in this communication may be subject to copyright under the Act. Any further reproduction or communication of this material by you may be the subject of copyright protection under the Act. Do not remove this notice. Please note that these unit materials contain images/videos of cadaveric material obtained under the Anatomy Licence held by the Anatomy Facility at Curtin University and are bound by the regulations of the Anatomy Act of Western Australia (1930). These images/videos are for study purposes only and must not be shared or distributed outside of this Blackboard site as this constitutes a breach of the Anatomy Act. A breach of the Anatomy Act is considered to be student misconduct and is dealt with in accordance with Statute No.10 Student Discipline. 2 Specific Learning Objectives Describe the position of the heart within the mediastinum. Describe the major anatomical structures of the heart including its coverings, chambers and valves. Describe the flow of blood through the heart. Describe how a heartbeat is generated. Differentiate between systemic and pulmonary circulation. Describe the effects of exercise on cardiac output. List the components of blood. Describe the transport of carbon dioxide and oxygen in the blood. Textbook readings VanPutte, C.L., Regan, J.L. & Russo, A.F. (2020). Seeley’s Anatomy and Physiology (12th edition). New York, USA: McGraw-Hill pages pages pages pages 648-656 677-690 and 703-705 720-730 853-855 Chapter Chapter Chapter Chapter 19: 20: 21: 23: pages pages pages pages 644-651 673-686 and 701-702 718-726 847-850 VanPutte, C.L., Regan, J.L. & Russo, A.F. (2014). Seeley’s Anatomy and Physiology (10th edition). New York, USA:McGraw-Hill 19: 20: 21: 23: VanPutte, C.L., Regan, J.L. & Russo, A.F. (2017). Seeley’s Anatomy and Physiology (11th edition). New York, USA:McGraw-Hill Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter 19: 20: 21: 23: pages pages pages pages 637-644 665-678 and 691 709-718 836-838 VanPutte, C.L., Regan, J.L. & Russo, A.F. (2010). Seeley’s Anatomy and Physiology (9th edition). New York, USA:McGraw-Hill Chapter Chapter Chapter Chapter 19: 20: 21: 23: pages pages pages pages 646-653 674-688 and 700-702 718-727 845-847 Cardiac cycle Contraction of heart produces the pressure Blood moves through circulatory system from areas of higher to lower pressure Cardiac cycle Repetitive contraction (systole) and relaxation (diastole) of heart chambers – moves blood through the heart and body. Blood flow is proportional to metabolic needs of tissues. Brain, kidneys, liver, exercising skeletal muscle – very high. Cardiac output = Heart rate x Stroke Volume Nervous System control: Maintains blood pressure and thus blood flow. Re-routing blood flow e.g., increase in BP with exercise Re-route blood flow away from skin and viscera towards brain and cardiac muscle in response to blood loss / injury Hormonal Control: Epinephrine (adrenaline) from adrenal gland – increase HR and SV, vasoconstriction in response to stress Conducting system Cardiac conduction system – internal pacemaker & nerve like pathway through myocardium Action potential – a rapid change in membrane potential. Acts as an electrical signal / impulse. Action potentials spread through the conducting system of the heart to all cardiac muscle cells – as a result the cardiac muscle cells contract. Blood is ‘pumped’. The heart can generate its own action potentials. Auto-rhythmicity – repetitive contractions, caused by autorhythmic contractile cells Sinoatrial node (SA) – pacemaker Atrioventricular node (AV) Atrioventricular bundle Right and left bundle branches Purkinje fibres in ventricular walls The Heart – conducting system Sinoatrial node (SA) – pacemaker Atrioventricular node (AV) Atrioventricular bundle Right and left bundle branches Purkinje fibres in ventricular walls Blood - composition Blood - cells Erythrocytes Leukocytes Red Blood cells (RBC) White blood cells (WBC) Biconcave disc shaped , 7.5 µm Complete cells, nuclei & organelles non-nucleated, no organelles Various types Contain haemoglobin (Hb), a pigmented protein Carries oxygen – from lungs to tissues, to haemoglobin Carries carbon dioxide – from tissues to lungs, 7% in plasma, 23% attached to haemoglobin, 70% as HCO3- monocytes, eosinophils, basophils Mainly help in protection - phagocytosis, immune response (cell mediated, antibody 1.5% dissolved in plasma & 98.5% attached e.g., neutrophils, lymphocytes, mediated), develop into macrophages, release histamines etc. Blood vessels - overview Arteries Take blood away from the heart Contain blood under pressure Elastic, Muscular, Arterioles Capillaries site of exchange with tissues (interstitial fluid) Veins Take blood to the heart Blood not under pressure Thinner walls than arteries, contain less elastic tissue less smooth muscle venules, small, medium, large Blood vessels - histology Tunica intima (interna): Endothelium, basement membrane, lamina propria, Elastic tissue Tunica media: smooth muscle cells and elastin arranged circularly. Smooth muscle changes diameter of the lumen. Elastic tissue allows distension and recoil. Vasoconstriction: smooth muscles contract, decrease in blood flow Vasodilation: smooth muscles relax, increase in blood flow Tunica externa (adventitia): connective tissue (CT), transitions from dense to loose CT as it merges with surrounding tissue Blood vessels Arteries Veins Carry blood away from the heart to tissues Carry blood to the heart from tissues Located deep in the muscle Located closer to the surface of your body Have very thick walls Have thinner walls than arteries Carry oxygenated and deoxygenated blood Carry deoxygenated and oxygenated blood Have no valves Contain valves to prevent backflow of blood Carry blood under high pressure Carry blood under very low pressure (8-10 mm Hg) Round lumen, hold shape Flat lumen, look collapsed Blood vessels - capillaries Smallest of the three blood vessel types Capillary wall consists of endothelial cells (simple squamous epithelium), basement membrane and a delicate layer of loose C.T. Continuous. No gaps between endothelial cells, less permeable to large molecules than other capillary types. E.g., muscle, nervous tissue. Fenestrated. Have pores in endothelial cells called fenestrae, highly permeable. e.g., intestinal villi, glomeruli of kidney Sinusoidal. Large diameter, irregular incomplete wall of endothelial cells, less basement membrane. e.g., endocrine glands, liver (large molecules cross their walls). Capillary exchange Cells are bathed in interstitial fluid (extracellular fluid) Transport (diffusion) in and out of cells requires a pressure gradient Interstitial fluid needs constant turnover Extracellular / interstitial fluid Intracellular fluid Intravascular fluid (blood plasma) Capillary exchange Capillary exchange: the movement of substances into and out of capillaries Diffusion: Oxygen, hormones, nutrients diffuse from a high concentration in the capillary to low concentration in the interstitial fluid. Lipid soluble substances (O2, CO2, steroid hormones, fatty acids) - diffuse through plasma membrane of endothelial cells Water soluble (glucose, amino acids)- diffuse through intercellular spaces or through fenestrations of capillaries. Very small spaces between cells – very few molecules can pass – e.g., blood brain barrier. Large spaces between endothelial cells – proteins and whole cells can pass e.g., liver or spleen. Lymphatic system Lymphoid organs – spleen, thymus, tonsils, Lymphoid tissues and cells – MALT, Peyer’s patches, lymphocytes (B and T cells) Lymph Lymphatic ducts, trunks, vessels, capillaries Lymph nodes Linking – Cardiovascular-Lymphatic Capillary permeability, blood pressure, and osmotic pressure affect movement of fluid from capillaries. Fluid moves out of capillaries into interstitial (intercellular) space and most returns to capillaries. The fluid which remains in tissues is picked up by the lymphatic capillaries then eventually returned to venous circulation. Maintains blood volume, pressure, fluid balance The lymphatic system - edema Edema (oedema): swelling caused by excess fluid accumulation in body tissues (interstitial space). Causes Problems with capillaries, heart failure, kidney disease, liver problems, pregnancy, Problems with lymphatic system, standing or walking a lot in hot weather, eating too much salt. If capillaries become ‘leaky’ to blood, proteins can leak into the interstitial fluid. This increases the osmotic pressure (osmolarity) outside the capillary and draws more fluid from the capillaries into the interstitial fluid. Test your knowledge Put the following events in order as they happen during conduction of heart Action potential pass through the AV node Action potentials are carried by the Purkinje fibres Action potentials travel along AV bundle into interventricular septum Action potentials originate in the sinoatrial (SA) node Action potentials descend to the apex of each ventricle along bundle branches Action potentials are carried to bundle branches to the ventricular walls and papillary muscles AV bundle divides into right and left bundle branches Action potentials travel across wall of atrium and to AV node Test your knowledge Put the following events in order as they happen during conduction of heart Action potential pass through the AV node Action potentials are carried by the Purkinje fibres Action potentials travel along AV bundle into interventricular septum Action potentials originate in the sinoatrial (SA) node Action potentials descend to the apex of each ventricle along bundle branches Action potentials are carried to bundle branches to the ventricular walls and papillary muscles 3 7 4 1 8 AV bundle divides into right and left bundle branches 5 Action potentials travel across wall of atrium and to AV node 2 6 Compendium questions 1. What is carried by the circulation and how? 2. What is the driving force for movement of fluid around the body? 3. What are the anatomical structures of the heart and how does the left side of the heart differ from the right? 4. What structures does blood pass through as it travels through the heart? 5. How does the heart help the lungs do their job? 6. How are increased metabolic demands of tissues met by changes to blood circulation? 7. What are the layers that surround the heart and where is the heart located within the thoracic cavity? 8. How are arteries and veins similar and different? 9. Describe the basic components of blood.