Biological Sciences
Circulatory System
The circulatory system is a network of organs and vessels that transports blood, nutrients, and oxygen throughout the body. It consists of the heart, blood vessels, and blood. The system plays a crucial role in maintaining homeostasis by delivering essential substances to cells and removing waste products.
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11 Key excerpts on "Circulatory System"
eBook - PDF- Mary Ann Clark, Jung Choi, Matthew Douglas(Authors)
- 2018(Publication Date)
- Openstax(Publisher)
40 | THE Circulatory System Figure 40.1 Just as highway systems transport people and goods through a complex network, the Circulatory System transports nutrients, gases, and wastes throughout the animal body. (credit: modification of work by Andrey Belenko) Chapter Outline 40.1: Overview of the Circulatory System 40.2: Components of the Blood 40.3: Mammalian Heart and Blood Vessels 40.4: Blood Flow and Blood Pressure Regulation Introduction Most animals are complex multicellular organisms that require a mechanism for transporting nutrients throughout their bodies and removing waste products. The Circulatory System has evolved over time from simple diffusion through cells in the early evolution of animals to a complex network of blood vessels that reach all parts of the human body. This extensive network supplies the cells, tissues, and organs with oxygen and nutrients, and removes carbon dioxide and waste, which are byproducts of respiration. At the core of the human Circulatory System is the heart. The size of a clenched fist, the human heart is protected beneath the rib cage. Made of specialized and unique cardiac muscle, it pumps blood throughout the body and to the heart itself. Heart contractions are driven by intrinsic electrical impulses that the brain and endocrine hormones help to regulate. Understanding the heart’s basic anatomy and function is important to understanding the body’s circulatory and respiratory systems. Gas exchange is one essential function of the Circulatory System. A Circulatory System is not needed in organisms with no specialized respiratory organs because oxygen and carbon dioxide diffuse directly between their body tissues and the external environment. However, in organisms that possess lungs and gills, oxygen must be transported from these specialized respiratory organs to the body tissues via a Circulatory System.
eBook - PDF- Julianne Zedalis, John Eggebrecht(Authors)
- 2018(Publication Date)
- Openstax(Publisher)
31 | THE Circulatory System Figure 31.1 Just as highway systems transport people and goods through a complex network, the Circulatory System transports nutrients, gases, and wastes throughout the animal body. (credit: modification of work by Andrey Belenko) Chapter Outline 31.1: Overview of the Circulatory System 31.2: Components of the Blood 31.3: Mammalian Heart and Blood Vessels 31.4: Blood Flow and Blood Pressure Regulation Introduction Most animals are complex multicellular organisms that require a mechanism for transporting nutrients throughout their bodies and removing waste products. The Circulatory System has evolved over time from simple diffusion through cells in the early evolution of animals to a complex network of blood vessels that reach all parts of the human body. This extensive network supplies the cells, tissues, and organs with oxygen and nutrients, and removes carbon dioxide and waste, which are byproducts of respiration. At the core of the human Circulatory System is the heart. The size of a clenched fist, the human heart is protected beneath the rib cage. Made of specialized and unique cardiac muscle, it pumps blood throughout the body and to the heart itself. Heart contractions are driven by intrinsic electrical impulses that the brain and endocrine hormones help to regulate. Understanding the heart’s basic anatomy and function is important to understanding the body’s circulatory and respiratory systems. Because one in four deaths in the United States is due to heart disease, billions of dollars are spent each year researching ways to prevent and treat it. For example, researchers have been trying to find a way to get damaged cardiac muscle to repair itself. A team of researchers at the Weizmann Institute of Science recently discovered that activating a protein called ERBB2 causes heart cells in adult mice to regenerate. The research team is continuing their research to determine how this knowledge might be applied to human medicine.
eBook - ePubThe Human Body
Linking Structure and Function
- Bruce M. Carlson, Bruce M. Carlson(Authors)
- 2018(Publication Date)
- Academic Press(Publisher)
Chapter 10The Circulatory System
Abstract
The Circulatory System consists of blood, the heart and blood, and lymphatic vessels. Blood is formed from stem cells in the bone marrow. The heart pumps blood through its four chambers with the help of valves, which prevent backflow. A conducting system, composed of modified cardiac muscle cells, regulates the nature and frequency of the heartbeat. The structure of the walls of large arteries provides the resiliency to modify the pressures of blood leaving the heart so that blood flow is more even. Smooth muscle in the walls of smaller arteries is also important in regulating blood pressure and the regional distribution of blood. Exchange of gasses and metabolites occurs in capillary beds throughout the body. A network of veins collects blood and returns it to the heart. Most of the blood volume resides in the veins. Lymphatic vessels collect tissue fluids and white blood cells and return them to the circulation through two major ducts. Homeostasis within the Circulatory System is regulated by sensors in the carotid body and carotid sinus.Keywords
Circulatory System; blood; erythrocyte; leukocyte; platelet; plasma; hematopoiesis; heart; atrium; ventricle; conducting system; valves; blood vessel; artery; vein; capillary; lymphatic vessel; blood pressure; coronary circulation; skin circulation; spleen; carotid body; carotid sinusVery simply put, the function of the Circulatory System is to circulate. With very few exceptions (e.g., cartilage, epithelia), the Circulatory System penetrates all areas of the body. Only a few tens of micrometers, at most, separate cells of the body from terminal branches of the Circulatory System.In contrast to most arthropods, which have an open circulation, all vertebrates possess closed Circulatory Systems. A closed Circulatory System consists of three principal components: a pump, a series of closed pipes leading from and back to the pump, and a medium—usually liquid—to be circulated. In vertebrates, the pump is the heart; the outflowing pipes are the arteries, which are connected to the inflowing veins by an extensive network of capillaries; the liquid medium is the blood. In addition, a separate lymphatic system drains tissue fluid from many parts of the body and carries it into the general circulation.
eBook - PDFIntroductory Biomechanics
From Cells to Organisms
- C. Ross Ethier, Craig A. Simmons(Authors)
- 2007(Publication Date)
- Cambridge University Press(Publisher)
4 The Circulatory System We now turn our attention to the system that transports the blood: the heart and blood vessels. From an engineering viewpoint, the Circulatory System consists of a remarkably complex branching network of tubes that convey the blood ( the vasculature ; Fig. 4.1), and two pulsatile pumps in series to force the blood through the tubes (the heart). The vasculature consists of arteries, arterioles, capillaries, venules, and veins . On average, no cell in the body is more than approximately 40 μ m away from a capillary, and almost every tissue is thoroughly invested with a capillary network. A typical human contains approximately 5 liters of blood, and at rest the heart pumps approximately 6 l/min; consequently, on average, blood circulates throughout the body about once per minute. In this chapter, we emphasize the operation of the components of the Circulatory System, how they interact with one another, and how they work in concert to deliver blood to target tissues. 4.1 Anatomy of the vasculature For reasons to be described below, it is conventional to divide the vasculature into two parts: the pulmonary and systemic circulations. The loop from the right heart, through the lungs, and back to the left heart is known as the pulmonary circulation; the loop from the left heart to the body and back to the right heart is the systemic circulation. Both the pulmonary and systemic vasculature have a similar topology. Blood is supplied in large vessels (arteries), which branch to form smaller arteries, and finally arterioles and capillaries (Fig. 4.2, color plate). The capillaries then join together to form the venules, which in turn form to join larger and larger veins which eventually return the blood to the heart (Fig. 4.2). Typical vessel sizes for the vasculature are shown in Fig. 4.2 for humans and Table 4.1 for dogs. It is handy to remember that in humans the diameter of the largest artery, the aorta, is a little larger than one inch (2.54 cm).
eBook - PDF- Gerard J. Tortora, Mark Nielsen(Authors)
- 2020(Publication Date)
- Wiley(Publisher)
443 Mark Nielsen Steve Gschmeissner/Science Source 444 CHAPTER 12 The Cardiovascular System: Blood 12.1 Functions of Blood OBJECTIVES • Define cardiovascular system. • Outline the functions of blood. The cardiovascular system (cardio- = heart; vascular = blood or blood vessels) consists of three interrelated components: blood, the heart, and blood vessels. The branch of science con- cerned with the study of blood, blood-forming tissues, and the disorders associated with them is hematology (hēm-a-TOL- ō-jē; hema- or hemato- = blood; -logy = study of). Blood is a liquid connective tissue composed of cells and a liquid extracellular matrix and is closely related to other body fluids. In fact, many of the extracellular body fluids (including interstitial fluid, lymph plasma, cerebrospinal fluid, and aque- ous humor) arise from the blood during development and are continually replenished by it. The extracellular fluids that nourish, protect, and exchange materials with every cell of the body are derived from the blood, renewed by the blood, and returned to the blood. Based on these relationships, blood has three general functions: 1. Transportation. Blood transports inhaled oxygen from the lungs to the cells of the body and carries carbon dioxide from the body cells to the lungs for exhalation. It carries nutrients from the digestive canal to body cells and hor- mones from endocrine glands to cells throughout the body. Blood also transports heat and waste products to the lungs, kidneys, and skin for elimination from the body. 2. Regulation. Circulating blood helps maintain homeosta- sis in all body fluids. Blood plays a role in the regulation of pH through buffers. (Buffers are chemicals that convert strong acids or bases into weak ones.) It also assists in the adjustment of body temperature; the heat-absorbing and coolant properties of the water in blood plasma and its variable rate of flow through the skin allow excess heat to be lost from the blood to the environment.
eBook - PDF- Lynn Hoeltke(Author)
- 2017(Publication Date)
- Cengage Learning EMEA(Publisher)
Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-300 99 Each body system works simultaneously to provide other body systems the necessary prod -ucts or energy they need. The Circulatory System is the transportation system for the body to transfer substances and waste from one system to another. There are two parts of the Circulatory System: the pulmonary system and the systemic system (Figureuni00A04.1). The pul -monary system circulates the blood through the lungs, where the blood is enriched with oxygen and the waste carbon dioxide is removed. The systemic system supplies the cells with oxygen, fats, carbohydrates, and other energy sources while at the same time removing waste products. The phlebotomist must be most knowledgeable of the Circulatory System. The remainder of this chapter discusses the Circulatory System in detail. To be prepared to collect blood, the phlebotomist must understand the system that carries this blood: the Circulatory System. The bone marrow is the primary factory for production of blood cells. The lymph nodes, thymus, and spleen are also sites for the production of blood cells. The function of blood is to carry oxygen to body tissues and to remove the waste product carbon dioxide. The blood also carries nutrients to all parts of the body and moves the products to the lungs, kidneys, liver, and skin. An adult body that weighsuni00A0150uni00A0pounds (lb.) (68 kilograms) contains approximately 5uni00A0liters of blood. Blood volume varies depending on the size of the individual. A preterm infant weighing 1uni00A0kilogram (2.2uni00A0lb.) will have only 100uni00A0milliliters (mL) of blood. During one blood draw only 2.5uni00A0percent of an individual’s blood can be taken. For a preterm infant that would be 2.5uni00A0milliliters of blood. No more than 5uni00A0percent of the total patient’s blood volume should be taken within a 30-day period.
eBook - PDF- Arthur B. Ritter, Vikki Hazelwood, Antonio Valdevit, Alfred N. Ascione(Authors)
- 2011(Publication Date)
- CRC Press(Publisher)
207 5 The Cardiovascular System 5.1 Introduction The.cardiovascular.system.consists.of.the. heart .and.the. systemic circulation . . While.many.important.organ.systems.such.as.the.lungs,.kidneys,.and.brain. are. not. part. of. the. cardiovascular. system,. much. of. the. work. in. biomedical . engineering.centers.on.the.cardiovascular.system . .Therefore,.we.have.cho-sen. to. use. this. system. to. develop. and. illustrate. some. basic. principles. of. biomechanics and hemodynamics .in.both.large.vessels.and. myocardium . .These. principles. can. readily. be. applied. to. other. organ. systems,. vessels,. and. cel-lular.processes.by.considering.their.individual.anatomical.arrangement.and. functional.properties . The.cardiovascular.system.is.too.complex.to.be.described.in.simple.terms . . For.example,.to.describe.the.heart.simply.as.a.mechanical.pump.is.a.gross. oversimplification.as.anyone.who.has.tried.to.develop.an.artificial.heart.will. testify. .Yet,.one.of.the.primary.functions.of.the.ventricles.is.to.circulate.blood . . There.are.two.types.of.descriptions.of.the.cardiovascular.system,.which.are. most. prevalent .in.the.literature.depending.on.the.focus.of.the.discussion:. ana-tomical .and. functional . .Anatomical.descriptions.are.useful.for.orientation.and. to.justify.the.geometry.to.be.used.in.the.analysis . .Functional.descriptions.are. usually.concerned.only.with.those.functional.properties.of.the.organ.or.tissue,. which.are.to.be.analyzed.or.modeled.(e .g., .blood–tissue.transport.of. macro-molecules .in.the.coronary. microcirculation ). .Within.these.general.guidelines,. both.anatomical.and.functional.descriptions.can.become.quite.detailed . Figure.5 .1 .is.a.schematic.diagram.of.the.circulatory.system.(which.includes. the.cardiovascular.system) . .The.following.observations.will.help.us . •. The.vessels.form.a.series–parallel.flow.network . .Flow.through.the. network.is.a.function.of.the.impedance.(resistive.and. capacitive .prop-erties).
eBook - PDF- Ian Peate, Suzanne Evans, Amy Byrne, Will Deasy, Michele Dowlman, Pauline Gillan, Siva Purushothuman, Dan Wadsworth(Authors)
- 2021(Publication Date)
- Wiley(Publisher)
CHAPTER 8 The Circulatory System TEST YOUR PRIOR KNOWLEDGE • Compare and contrast arteries and veins. • List the formed elements of the blood. • List the functions of the blood cells. • Discuss the life cycle of a red blood cell. • List the functions of the lymphatic system. LEARNING OBJECTIVES After reading this chapter you will be able to: 8.1 discuss the normal composition of blood 8.2 list the functions and explain the life cycle of the red blood cells, white blood cells and platelets 8.3 describe some of the differences between an artery and a vein 8.4 discuss the functions of the lymphatic circulation. Body map Blood vessels: Artery Vein Heart Introduction The Circulatory System is a complex system which deals with the distribution of nutrients, gases, electrolytes and hormones, as well as the removal of waste products of metabolism and other substances. The Circulatory System includes the heart, the blood, the blood vessels and the lymphatic system. The blood vessels transport blood around the body. Blood consists of formed elements within a fluid portion called plasma. The blood vessels form a network that allows blood to flow from the heart to all living cells and back to the heart. Blood has numerous functions including the transportation of nutrients, respiratory gases such as oxygen and carbon dioxide, metabolic wastes such as urea and uric acid, hormones, electrolytes and antibodies. As the blood is circulating throughout the body, cells are constantly exchanging nutrients, hormones, electrolytes, oxygen and other substances with it, as well as excreting unwanted wastes into the blood. Blood is transported throughout the body by a network of blood vessels, some of which lead away from and some which return to the heart. The main types of blood vessels include arteries, arterioles, capillaries, venules and veins; each is designed to carry out a specific role(s).
- Ian Peate, Claire Leader(Authors)
- 2024(Publication Date)
- Wiley-Blackwell(Publisher)
• Preservation of circulating blood volume. • Protection against blood loss and body fluids through the mechanism of clotting, in which platelets and plasma proteins play a vital role in the coagulation pathway. The Circulatory System encompasses the systemic, pulmonary and portal circulations in addition to the fetal and placen- tal circulation established during pregnancy. Central to the Circulatory System is the heart, a muscular pump that moves approximately 4000–7000 l of blood through the body each day (Shier et al. 2016). Blood is transported on a continual basis through the heart, arteries, arterioles, veins, venules and a capillary network. The Systemic and Pulmonary Circulations Through the systemic circulation, oxygen-rich (oxygenated) blood is pumped away from the heart via arteries to provide oxygen for all living cells, and veins carry deoxygenated blood back to the heart, where it is pumped to the lungs for reoxy- genation via the pulmonary Circulatory System. The pulmonary circulation refers to the part of the Circulatory System that circulates deoxygenated blood returning from the body from the right side of the heart to the lungs for oxygenation and then to the left side of the heart where it begins its journey back via the systemic circulation. As well as enabling oxygenation of the blood, the pulmonary circuit also permits carbon dioxide to be released and exhaled from the body via the lungs. Figure 9.1 shows a diagram of the Circulatory System, depicting the heart and major blood vessels. The arteries (red) carry oxygenated blood from the heart, and the veins (blue) carry deoxygenated blood back to the heart. Blood is trans- ported through the Circulatory System largely because of the pressure generated by the contractions of the heart (Wylie 2005). Stroke volume, heart rate and cardiac output increase during pregnancy.
eBook - PDF- Gerard J. Tortora, Mark Nielsen(Authors)
- 2016(Publication Date)
- Wiley(Publisher)
The extracellular fluids that nourish, protect, and exchange materials with every cell of the body are derived from the blood, renewed by the blood, and returned to the blood. Based on these relationships, blood has three general functions: 1. Transportation. Blood transports oxygen from the lungs to the cells of the body and carries carbon dioxide from the body cells to the lungs for exhalation. It carries nutrients from the gastrointestinal tract to body cells and hormones from endocrine glands to cells throughout the body. Blood also transports heat and waste products to the lungs, kid- neys, and skin for elimination from the body. 2. Regulation. Circulating blood helps maintain homeostasis in all body fluids. Blood plays a role in the regulation of pH through buffers. (Buffers are chemicals that convert strong acids or bases into weak ones.) It also assists in the adjustment of body tem- perature; the heat-absorbing and coolant properties of the water in blood plasma and its variable rate of flow through the skin allow excess heat to be lost from the blood to the environment. Blood osmotic pressure also influences the water content of cells, mainly through interactions of dissolved ions and proteins. 3. Protection. Blood can clot (become gel-like), which protects against its excessive loss from the cardiovascular system after an injury. In addition, white blood cells protect against disease Blood samples for laboratory testing may be obtained in several ways. The most common procedure is venipuncture (ve ¯n′-i-PUNK- chur), withdrawal of blood from a vein using a needle and collecting tube, which contains various additives. A tourniquet is wrapped around the arm above the venipuncture site, which causes blood to accumu- late in the vein. This increased blood volume makes the vein stand out. Opening and closing the fist further causes it to stand out, making the venipuncture more successful.
eBook - PDF- Laurie Kelly McCorry(Author)
- 2008(Publication Date)
- Routledge(Publisher)
the. tissues . . Finally,. it. contributes. to. the. actions. of. the. immune. system. by. transporting. antibodies. and. leukocytes. to. areas. of. infection . . Overall,. the. . circulatory. system. plays. a. vital. role. in. the. maintenance. of. optimal. condi-tions.for.cell.and.tissue.function . All.tissues.are. perfused . .In.other.words,.all.tissues.receive.blood.flow . .The. amount.of.blood.that.flows.through.each.tissue,.however,.depends.upon.that. tissue’s.function . .For.example,.many.tissues,.such.as.the.heart,.the.brain,.and. the.skeletal.muscles,.receive.a.blood.flow.that.is.sufficient.to.supply.their.met-abolic.needs . .When.metabolic.activity.increases,.as.it.does.during.exercise,. blood. flow. to. these. tissues. increases. accordingly . . Other. tissues,. however,. receive.a.blood.flow.that.is.in.significant.excess.of.their.metabolic.needs . .These. tissues,.including.the.kidneys,.the.organs.of.the.digestive.system,.and.the. skin,.have.important.homeostatic.functions . .Among.other.vital.activities,.the. kidneys.filter.the.blood.and.remove.waste.products,.the.organs.of.the.diges-tive.system.absorb.nutrients.into.the.blood,.and.thermoregulation.involves. the.control.of.blood.flow.to.the.body.surface.where.heat.is.eliminated . .These. functions.are.carried.out.most.effectively.and.efficiently.when.the.involved. tissues. receive. an. abundant. blood. flow . . Under. normal. resting. conditions,. the. kidneys,. which. account. for. only. 1%. of. the. body’s. weight,. receive. 20%. of.the.cardiac.output.(CO),.the.gastrointestinal.tract.receives.approximately. 27%.of.the.CO,.and.the.skin.receives.6%.to.15%.of.the.blood.pumped.by.the. heart.per.minute . .Because.these.tissues.receive.more.blood.than.they.need. to.support.metabolic.activity,.they.can.easily.tolerate.a.sustained.decrease. in.blood.flow . .During.exercise.when.the.metabolic.demand.of.the.working. skeletal.muscles.and.the.heart.increases.substantially,.blood.flow.is.directed.
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