Cardio 2 - Blood Vessels.pptx

Introduction to the Human Body Tenth Edition Gerard J. Tortora Bryan H. Derrickson Chapter 16 The Cardiovascular System: Blood Vessels and Circulation Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. The Cardiovascular System: Blood Vessels and Circulation  Blood vessel structure and f...

Introduction to the Human Body Tenth Edition Gerard J. Tortora Bryan H. Derrickson Chapter 16 The Cardiovascular System: Blood Vessels and Circulation Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. The Cardiovascular System: Blood Vessels and Circulation  Blood vessel structure and function  Blood flow through blood vessels  Circulatory routes  Checking circulation  Aging and the cardiovascular system Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. BLOOD VESSEL STRUCTURE AND FUNCTION Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Blood Vessel Structure and Function There are five types of blood vessels: arteries, arterioles,  capillaries, venules, and veins.  Arteries carry blood away from the heart to body tissues.  Their walls consist of three layers: endothelium, smooth muscle (middle layer) and an outer connective tissue layer.  The middle muscle layer gives arteries their two major properties, elasticity and contractility.   Elasticity allows the blood vessels to expand and recoil to withstand and maintain pressure on the blood  Contractility depends on the extent of muscle contraction:  Vasoconstriction is a decrease in the diameter of the blood vessel lumen and vasodilation is an increase. Arteries are high pressure vessels Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Blood Vessel Structure and Function  Arterioles are small arteries that deliver blood to capillaries.  Through constriction and dilation, arterioles play a key role in regulating blood flow from arteries into capillaries and have the greatest effect on resistance  Autoregulation is the ability of a tissue to automatically adjust its blood flow to match its metabolic demands. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Comparative Structure of Blood Vessels Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Blood Vessel Structure and Capillaries are microscopic blood vessels that connect Function  arterioles to venules. Consist of endothelium only  They are known as exchange vessels because they permit the exchange of nutrients and wastes between the body’s cells and the blood.  Capillary blood hydrostatic pressure “pushes” fluid out of capillaries into interstitial fluid (filtration).  Blood colloid osmotic pressure “pulls” fluid into capillaries from interstitial fluid (reabsorption).  The lymphatic system collects any excess ISF and drains it back into the blood to maintain blood volume Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Capillaries Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Capillary Exchange Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Animation: Capillary Exchange You must be connected to the internet to run this animation. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Blood Vessel Structure and Function Venules are similar in structure to arterioles; their walls are  thinner near the capillary end and thicker as they progress toward the heart.  Veins are structurally similar to arteries, but their middle and inner layers are thinner. The outer layer of veins is the thickest layer. The lumen of a vein is wider than an artery.  Veins are low pressure vessels: can pool blood  In some veins, the inner layer folds inward to form valves that prevent the backflow of blood. Weak venous valves can lead to varicose veins.  Venous return refers to the movement of blood from capillaries to venules to veins back to the atria of the heart. This is aided by the skeletal muscle pump, and breathing (the respiratory pump). Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Skeletal Muscle Pump Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. BLOOD FLOW THROUGH BLOOD VESSELS Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Blood Flow Through Blood Vessels Blood flows from regions of higher pressure to regions of lower  pressure; the greater the pressure difference, the greater the blood flow.  Blood pressure is highest in the aorta and progressively declines as blood flows towards the right atrium, where pressure is near zero  Contraction of the ventricles generates blood pressure (BP), the pressure exerted by blood on the walls of a blood vessel. (mm Hg).  Blood pressure depends in part on the total volume of blood in the cardiovascular system (about 5 liters).  Vascular resistance is the opposition to blood flow due to friction between blood and the walls of blood vessels. It depends on three factors: size of the blood vessel lumen, blood viscosity, and total blood vessel length. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Blood Pressure Changes Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Animation: Vascular Regulation You must be connected to the internet to run this animation. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Blood Flow Through Blood Vessels  Several interconnected negative feedback systems control blood pressure and blood flow by adjusting heart rate, stroke volume, vascular resistance, and blood volume.  The cardiovascular (CV) center in the medulla oblongata helps regulate heart rate and stroke volume.  The CV center also controls the neural and hormonal negative feedback systems that regulate blood pressure and blood flow to specific tissues. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Blood Flow Through Blood The CV center also receives input from three main types of sensory Vessels receptors: proprioceptors, baroreceptors, and chemoreceptors.   Proprioceptors, which monitor movements of joints and muscles, provide input to the CV center during physical activity to cause a rapid increase in heart rate.  Baroreceptors (pressure receptors) are located in the aorta, internal carotid arteries and other large arteries in the neck and chest. They send impulses to the cardiovascular center to regulate blood pressure (Baroreceptor reflex)  Chemoreceptors (chemical receptors) that monitor blood levels of O2, CO2, and H+ are located in the two carotid bodies in the common carotid arteries and in the aortic body in the arch of the aorta.  Low O2, high CO2 or H+ stimulate the CV center to respond by increasing sympathetic stimulation of arterioles and veins, producing vasoconstriction and an increase in B.P. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. The Cardiovascular Center Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Blood Flow Through Blood  Vessels Several hormones help regulate blood pressure and blood flow by altering cardiac output, changing vascular resistance, or adjusting the total blood volume. The following hormones are involved:     Renin–angiotensin–aldosterone (RAA) system – kidneys secrete the enzyme renin to increase B.P. Epinephrine and norepinephrine – sympathetic stimulation increases cardiac output. Antidiuretic hormone (ADH) – hypothalamus and post. pituitary causes increased blood volume, vasoconstriction and increased B.P. Atrial natriuretic peptide (ANP) –causes decreased blood volume, vasodilation and lowers B.P. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Negative Feedback Regulation of Blood Pressure Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Animation: Negative Feedback Control of Blood Pressure You must be connected to the internet to run this animation. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. CIRCULATORY ROUTES Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Circulatory Routes  Blood vessels are organized into circulatory routes that carry blood throughout the body.  The two major circulatory routes are the systemic circulation and the pulmonary circulation.  The systemic circulation includes the arteries and arterioles that carry (distribute) blood containing O2 and nutrients from the left ventricle to systemic capillaries throughout the body, plus the veins and venules that return blood containing CO2 and wastes to the right atrium i.e. drain the tissues.  Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Circulatory Routes  All systemic arteries branch from the aorta. The parts of the aorta include: the ascending aorta, the arch of the aorta, the thoracic aorta, and the abdominal aorta  Deoxygenated blood returns to the heart through the systemic veins. All veins of the systemic circulation empty into the superior vena cava, inferior vena cava, or the coronary sinus, which, in turn, empty into the right atrium. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.  The pulmonary circulation takes deoxygenated blood from the right ventricle to the lungs via the pulmonary trunk and pulmonary arteries and returns oxygenated blood from the lungs to the left atrium via the pulmonary veins. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Schemati c of Circulator y Routes Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Anatomy Overview: Comparison of Circulatory Routes You must be connected to the internet to run this animation. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. The Aorta and Its Branches Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Major Systemic Arteries  Subclavians  Brachials  Radials  Ulnars  Carotids  Celiac trunk  Renals  Mesenterics  Iliacs  Femorals  Popliteals The Aorta and Its Branches Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Arteries of the Pelvis and Lower Limbs Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Veins of the Systemic Circulation Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Major Systemic Veins                Vena cava Brachiocephalic Jugular Subclavian Cephalic Basilic Median cubital Hepatic and portal Mesenteric Splenic Gastric Renal Iliac Saphenous Femoral Veins of the Head and Neck Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Veins of the Head and Neck Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Circulatory Routes   The hepatic portal circulation collects deoxygenated blood from the veins of the gastrointestinal tract and spleen and directs it into the hepatic portal vein of the liver. This routing allows the liver to extract and modify nutrients and detoxify harmful substances in the blood. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Hepatic Portal Circulation Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Hepatic Portal Circulation Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Circulatory Routes   Fetal circulation involves the exchange of materials between fetus and mother via the placenta. The fetus derives O2 and nutrients from and eliminates CO2 and wastes into maternal blood. Lungs and digestive system are not functional in the fetus: therefore, the fetal circulation bypasses the organs of these systems    Ductus venosus carries nutrient and O2 –rich blood from the placenta via the umbilical vein pass the liver into the inferior vena cava In the heart, the foramen ovale shunts blood from the RA directly into the LA (becomes the fossa ovalis) and the ductus arteriosus shunts blood from the pulmonary trunk into the aorta (becomes ligamentum arteriosum) Aorta then distributes blood the body, which ultimately drains into the placenta via the two umbilical arteries Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Fetal Circulation Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. CHECKING CIRCULATION Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Checking Circulation  Pulse is the alternate expansion and elastic recoil of an artery with each heartbeat. It may be felt in any artery that lies near the surface or over a hard tissue.  A normal pulse rate is about 75 beats per minute.  Blood pressure is the pressure exerted by blood on the wall of an artery when the left ventricle undergoes systole and then diastole. It is measured by a sphygmomanometer and the ausculatory method  Systolic blood pressure (SBP) is the force of blood recorded during ventricular contraction. Diastolic blood pressure (DBP) is the force of blood recorded during ventricular relaxation. The normal blood pressure of a young adult male is less than 120/80. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Checking Circulation  Pulse (Pressure) Points Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. AGING AND THE CARDIOVASCULAR SYSTEM Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Aging and the Cardiovascular  System General changes in the cardiovascular system   associated with aging include increased stiffness of the aorta, reduction in cardiac muscle fiber size, progressive loss of cardiac muscular strength, reduced cardiac output, a decline in maximum heart rate, and an increase in systolic blood pressure. Coronary artery disease (CAD) is the major cause of heart disease and death in older Americans. Congestive heart failure (CHF), and atherosclerosis increases with age. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Aging and the Cardiovascular System About 50 million Americans have hypertension, or persistently  high blood pressure. It is the most common disorder affecting the heart and blood vessels and is the major cause of heart failure, kidney disease, and stroke.  Shock is a failure of the cardiovascular system to deliver enough O2 and nutrients to meet metabolic needs.  An aneurysm is a thin, weakened section of the wall of an artery or a vein that bulges outward, forming a balloon-like sac. Common causes are atherosclerosis, syphilis, congenital blood vessel defects, and trauma. If untreated, the aneurysm enlarges and the blood vessel wall becomes so thin that it bursts. The result is massive hemorrhage, severe pain, stroke, or death. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.