Cardiovascular System - Blood and Heart PDF

Cardiovascular System – Blood Chapter 16, Human Anatomy (LibreTexts) "Drops of Blood Medium" by unknown author is licensed under CC BY 3.0 Cardiovascular System • Components: • Blood → transports oxygen and nutrients throughout the body and removes waste products (i.e. carbon dioxide). • Heart →...

Cardiovascular System – Blood Chapter 16, Human Anatomy (LibreTexts) "Drops of Blood Medium" by unknown author is licensed under CC BY 3.0 Cardiovascular System • Components: • Blood → transports oxygen and nutrients throughout the body and removes waste products (i.e. carbon dioxide). • Heart → pumps blood throughout the body and to the heart itself • Blood Vessels → transport blood from the lungs to body tissues and vice versa Blood • Two types of fluid connective tissues: • Blood • Lymph • Blood: Cells circulate in a liquid extracellular matrix • Cells (formed elements): Erythrocytes (red blood cells), Leukocytes (white blood cells), Platelets • Extracellular matrix: Plasma • Functions of blood: • Transportation: transports nutrients, oxygen, carbon dioxide, hormones, vitamins, minerals, waste products • Protection: carries immune cells, antibodies and blood clotting agents • Regulation: helps regulate body temperature, pH levels Blood: A Fluid Connective Tissue Leukocyte "Blood A Fluid Connective Tissue" by OpenStax is licensed under CC BY 3.0 Red Blood Cell, Platelet, White Blood Cell "Blood Cells" by OpenStax is licensed under CC BY 3.0 Formed Elements Visible in a Sample of Blood "Figure_40_02_01" by OpenStax is licensed under CC BY 4.0 Plasma • 92% water • 7% proteins: act as carriers for molecules and hormones, help in immune defense (antibodies), help with blood clotting, act as enzymes and hormones • 1% electrolytes, nutrients, gases, waste products "Composition of Blood" by OpenStax is licensed under CC BY 3.0 Erythrocytes • Erythrocytes (also called red blood “cells”) transport oxygen and carbon dioxide between lungs and tissues • Do NOT contain a nucleus or organelles • Very small biconcave disc allows lots of surface area for gas exchange. • Lifespan of 120 days • Very flexible shape allows them to bend while going through capillaries • Line up in single file, termed Rouleau, as they pass through small blood vessels Shape of Erythrocytes "Jn7ws94a-2" by Annie Cavanagh is licensed under CC BY-SA 4.0 Hemoglobin • Erythrocytes are filled with red-pigmented protein called hemoglobin • Consists of four globin chains, each containing a heme group with an iron atom at the center • The heme group binds to oxygen and carbon dioxide "Hemoglobin" by OpenStax is licensed under CC BY 3.0 Erythrocyte Life Cycle Image "Erythrocyte Life Cycle" by OpenStax is licensed under CC BY 3.0 Blood Typing • The plasma membrane of cells contains glycans, which are polysaccharides (glyco) groups attached on glycoproteins and glycolipids. These glycans are also called surface antigens and are important to distinguish cells that are part of the body from foreign or dangerous invaders (virus, bacteria, fungi, etc). • Depending on which glycans are present on erythrocytes we can distinguish a variety of blood types (i.e. ABO and Rh). • Blood transfusion is used for patients with low levels of hemoglobin and introduces someone else’s cells into patient’s body • If the blood groups are NOT compatible, the antibodies (defensive proteins in plasma) of the recipient will flag the donor cells as if they were pathogens and prevent them from circulating. This process is called agglutination and will lead to the destruction of the donor’s cells • Also important for hemolytic disease of the newborn when pregnant mother is Rh- and fetus is Rh+ ABO Blood Groups "ABO Blood Groups" by OpenStax is licensed under CC BY 3.0 Hemolytic Disease of the Newborn "Erythroblastosis Fetalis" by OpenStax is licensed under CC BY 3.0 Leukocytes • Leukocytes (also called white blood cells) are important for the immune response • Neutrophils (50-70%) immune defenses • Lymphocytes (20-40%) antibodies production and foreign cells killers • Monocytes (2-8%) immune surveillance • Eosinophils (1-4%) defense against parasites (malaria, amoebas, etc) • Basophils (0.5-1%) inflammatory response “Blausen 0909 WhiteBloodCells" by Bruce Blaus is licensed under CC BY 3.0 Platelets • Platelets are cell fragments that attach to damaged blood vessels and help the blood clotting process "Blausen 0740 Platelets" by Bruce Blaus is licensed under CC BY 3.0 Blood Clot "Blood Clot" by Julie Jenks is a derivative from the original work of Daniel Donnelly and is licensed under CC BY 4.0 Hematopoiesis • Hematopoiesis: production of blood cells • Blood cells are produced in the red bone marrow from a common multipotent hematopoietic stem cell. "Hematopoietic System of the Bone Marrow" by Julie Jenks is licensed under CC BY 4.0 / A derivative from the original work Cardiovascular System - Heart Chapter 17, Human Anatomy (LibreTexts) "Human Heart Photo" by Patrick J. Lynch via OpenStax is licensed under CC BY 4.0) Function of the Heart • Acts as a pump to move nutrients and oxygen through the body. • Arteries carry blood away from the heart • Veins carry blood back to the heart • The arteries and veins entering and leaving the heart are called great vessels Dual System • Two circulatory systems: • Pulmonary: conveys deoxygenated (low in oxygen) blood to the lungs to pick up oxygen and release carbon dioxide • Systemic: moves oxygenated blood throughout the body to reach all cells • Heart is double pump: the pump on the right side of the heart is for pulmonary circulation and the one on the left side is for systemic circulation. "Dual System of Human Circulation" by OpenStax is licensed under CC BY 3.0 Location of the Heart • Slightly left of midline, posterior to sternum • Rotated so that right border sits anterior to left border • Base (superior border) of heart is formed by great vessels • Conical bottom end is apex "Heart Position in Thorax" by OpenStax is licensed under CC BY 3.0 Pericardium • Heart sits inside serous membrane called pericardium that composed of • Fibrous sac: very tough dense connective tissue • Parietal and visceral layers: two layers of epithelial tissue with tiny amount of water (serous fluid) in-between. • Visceral layer of pericardium = epicardium • Pericardium restricts heart movement, prevents bouncing and prevents heart overfilling with blood Pericardial Membranes and Layers of the Heart Wall "Heart Wall" by Julie Jenks is licensed under CC BY 4.0 / A derivative from the original work Myocardium and Endocardium • Myocardium: Cardiac muscle; thickest of the three layers. • Cells are Y-shaped with one nucleus per cell. • Cells are connected by intercalated discs that contain desmosomes and gap junctions to link cells electrically and mechanically so that impulses are sent immediately form one cell to next • Endocardium: Internal surface of heart chambers; simple squamous epithelium + areolar connective tissue "Cardiac Muscle" by Julie Jenks is licensed under CC BY 4.0 / A derivative from the original work / Micrograph provided by the Regents of the University of Michigan Medical School © 2012 External Anatomy of the Heart - I • Heart composed of four hollow chambers: • Two superior, smaller atria and two inferior, larger ventricles • Inferior border is made of right ventricle • Anterior part of each atrium forms an auricle External Anatomy of the Heart - II • Coronary sulcus: groove separating atria and ventricles • Anterior interventricular sulcus and posterior interventricular sulcus are located between the right and left ventricles • Located within the sulci are coronary vessels that supply the blood to the heart cells • Coronary arteries supply blood to heart muscle • Coronary veins return blood from heart tissue back to right atrium • Coronary sinus located on posterior side of heart that collects blood from the heart muscle (myocardium) External Anatomy of the Heart – Anterior View "Surface Anatomy of the Heart" by OpenStax is licensed under CC BY 3.0 External Anatomy of the Heart – Posterior View "Surface Anatomy of the Heart" by OpenStax is licensed under CC BY 3.0 Internal Anatomy of the Heart Aortic semilunar valve Pulmonary semilunar valve "Internal Anatomy of the Heart" by OpenStax is licensed under CC BY 3.0 Internal Anatomy of the Heart • Heart has four hollow chambers: right atrium, right ventricle, left atrium, left ventricle • Heart has four valves that permit unidirectional passage of blood • Two atrioventricular valves: their closure causes the first heart sound “lubb” • Two semilunar valves at base of great arteries: their closure causes the second heart sound “dupp” Right Atrium • Right atrium receives venous blood from heart and systemic circulation through three large veins: • Superior vena cava • Inferior vena cava • Coronary sinus • Interatrial septum: divides right atrium from left • Right atrioventricular valve (tricuspid valve): ensures one-way blood flow from right atrium to right ventricle through atrioventricular opening Right Ventricle • Right ventricle receives deoxygenated blood from right atrium • Interventricular septum: thick wall between right and left ventricles • Inner wall of each ventricle displays irregular muscular ridges called trabeculae carneae • Papillary muscles: cone-shaped muscle projections anchoring chordae tendineae • Chordae tendineae attach muscle to atrioventricular valve and prevent cusps from flipping into atrium when ventricle contracts • Pulmonary semilunar valve ensures one-way flow from ventricle to pulmonary trunk. The pulmonary trunk divides into right and left pulmonary arteries, which carry deoxygenated blood to the lungs. Chordae Tendineae and Papillary Muscles "Chordae Tendineae and Papillary Muscles" by OpenStax is licensed under CC BY 3.0 / A derivative from the original work Left Atrium • Oxygenated blood from the lungs travels through the pulmonary veins to the left atrium • Left atrioventricular valve (or mitral valve or bicuspid valve): controls flow through opening between left atrium and ventricle Left Ventricle • Left ventricle pumps blood through entire systemic circulation • Generates very high pressure • Aortic semilunar valve: controls flow from left ventricle to aorta Anatomical Differences Between Ventricles • The ventricles of the heart have thicker muscular walls than the atria. This is because blood is pumped out of the heart at greater pressure from these chambers compared to the atria. • The left ventricle also has a thicker muscular wall than the right ventricle, to ensure powerful contraction that pushes blood around the entire body • Enlargement of the heart also occurs in young athletes and can lead to hypertrophic cardiomyopathy, which can cause sudden death Comparative Thickness of Ventricular Myocardium "Ventricular Muscle Thickness" by OpenStax is licensed under CC BY 3.0 Heart Valves • Atrioventricular Valves: • Right Atrioventricular or Tricuspid Valve: between right atrium and right ventricle • Left Atrioventricular or Mitral or Bicuspid Valve: between left atrium and left ventricle • Semilunar Valves: • Aortic Valve: between left ventricle and ascending aorta • Pulmonary Valve: between right ventricle and pulmonary trunk "Heart Valves" by OpenStax is licensed under CC BY 3.0 Position of the Heart Valves during Ventricular Relaxation "Blood Flow Relaxed Ventricles" by OpenStax is licensed under CC BY 3.0 Position of the Heart Valves during Ventricular Contraction "Blood Flow Contracted Ventricles" by OpenStax is licensed under CC BY 3.0 Echocardiogram of Heart Valves Opening and Closing "Apikal4D" by Kjetil Lenes is licensed under CC BY-SA 3.0 Heart’s Conducting System • Heart exhibits autorhythmicity – it initiates its own heartbeats. For the heart to pump efficiently and the systemic and pulmonary circulations to operate in synchrony, the events in the cardiac cycle must be coordinated. • The conducting system consists of specialized cells that start and propagate electrical impulses to contractile cells. Four locations: • • • • Sinoatrial (SA) node Atrioventricular (AV) node Bundle of His Purkinje fibers Conducting System of the Heart "Conducting System of the Heart" by Julie Jenks is licensed under CC BY 4.0 / A derivative from the original work Orientation of Cardiac Muscle "Heart Musculature" by OpenStax is licensed under CC BY 3.0 Flow of Blood Through The Heart • Atria fill up with blood from the vena cava (into right atrium) and pulmonary veins (into left atrium). • Blood passes through atrioventricular valves and fills up the ventricles. • Blood passes through semilunar valves to go into pulmonary trunk (from right ventricle) and aorta (from left ventricle). "Figure 40 03 03" by OpenStax is licensed under CC BY 4.0 Clinical Anatomy: Myocardial Infarction • If a blockage (for example a dislodged plaque) occurs in the coronary arteries, this can lead to a myocardial infarction or "heart attack," which deprives the heart of oxygen. If medical intervention does not occur quickly, this can cause permanent damage to the cardiac muscle, or can result in cardiac arrest and death. • The symptoms of heart attack can be different depending on the individual. Individuals assigned male at birth often experience the "classic" symptoms of shooting pain down the left arm, intense pressure and pain in the chest. Individuals assigned female at birth are more likely to experience sudden nausea and vomiting and pain in the neck and jaw, sometimes, but not always, along with the classic symptoms. Clinical Anatomy: Pericarditis and Valve Dysfunction • Pericarditis is the inflammation of the pericardium which makes blood vessels leaky. The result is that fluid accumulates in pericardial cavity preventing heart from pumping fully. • Most common symptoms are chest pain, weakness and fatigue, weight loss. The cause of pericarditis can be due to bacterial and viral infection of the pericardium. • Heart valve disease occurs if one or more of your heart valves don't work well. • Birth defects, age-related changes, infections, or other conditions can cause one or more of your heart valves to not open fully (valve stenosis) or to let blood leak back into the heart chambers (valve regurgitation). Symptoms happen over time and include shortness of breath and swelling in extremities.