Biological Sciences
Blood vessels
Blood vessels are a vital part of the circulatory system, responsible for transporting blood throughout the body. They include arteries, which carry oxygenated blood away from the heart; veins, which return deoxygenated blood back to the heart; and capillaries, where the exchange of nutrients and waste products occurs between the blood and tissues. These vessels play a crucial role in maintaining overall health and homeostasis.
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9 Key excerpts on "Blood vessels"
eBook - PDF- Gerard J. Tortora, Bryan H. Derrickson(Authors)
- 2016(Publication Date)
- Wiley(Publisher)
737 The cardiovascular system contributes to homeostasis of other body systems by transporting and distributing blood throughout the body to deliver materials (such as oxygen, nutrients, and hormones) and carry away wastes. The structures involved in these important tasks are the Blood vessels, which form a closed system of tubes that carries blood away from the heart, transports it to the tissues of the body, and then returns it to the heart. The left side of the heart pumps blood through an estimated 100,000 km (60,000 mi) of Blood vessels. The right side of the heart pumps blood through the lungs, enabling blood to pick up oxygen and unload carbon dioxide. Chapters 19 and 20 described the composition and functions of blood and the structure and function of the heart. In this chapter, we focus on the structure and functions of the various types of Blood vessels; on the forces involved in circulating blood throughout the body; and on the Blood vessels that constitute the major circulatory routes. Q Did you ever wonder why untreated hypertension has so many damaging effects? The Cardiovascular System: Blood vessels and Hemodynamics Blood vessels, Hemodynamics, and Homeostasis CHAPTER 21 Blood vessels contribute to homeostasis by providing the structures for the flow of blood to and from the heart and the exchange of nutrients and wastes in tissues. They also play an important role in adjusting the velocity and volume of blood flow. 738 CHAPTER 21 The Cardiovascular System: Blood vessels and Hemodynamics tissue outer covering. The three structural layers of a generalized blood vessel from innermost to outermost are the tunica interna (intima), tunica media, and tunica externa (adventitia) (Figure 21.1). Modifications of this basic design account for the five types of Blood vessels and the structural and functional differences among the various vessel types.
- Andrew Kuntzman, Gerard J. Tortora(Authors)
- 2015(Publication Date)
- Wiley(Publisher)
23.1 BLOOD VESSEL STRUCTURE AND FUNCTION 595 Arteries and Arterioles 595 Capillaries 595 Venules and Veins 597 23.2 BLOOD FLOW THROUGH Blood vessels 599 Blood Pressure 599 Resistance 600 Regulation of Blood Pressure and Blood Flow 600 23.3 CHECKING CIRCULATION 603 Pulse 603 Measurement of Blood Pressure 603 23.4 CIRCULATORY ROUTES 603 Systemic Circulation 603 Pulmonary Circulation 605 EXHIBIT 23.1 THE AORTA AND ITS BRANCHES 606 EXHIBIT 23.2 THE ARCH OF THE AORTA 608 EXHIBIT 23.3 ARTERIES OF THE PELVIS AND LOWER LIMBS 610 EXHIBIT 23.4 VEINS OF THE SYSTEMIC CIRCULATION 612 EXHIBIT 23.5 VEINS OF THE HEAD AND NECK 614 EXHIBIT 23.6 VEINS OF THE UPPER LIMBS 615 EXHIBIT 23.7 VEINS OF THE LOWER LIMBS 617 Hepatic Portal Circulation 619 Fetal Circulation 620 23.5 AGING AND THE CARDIOVASCULAR SYSTEM 620 EXHIBIT 23.8 CONTRIBUTIONS OF THE CARDIOVASCULAR SYSTEM TO HOMEOSTASIS 622 KEY MEDICAL TERMS ASSOCIATED WITH Blood vessels 623 Physical activity helps to protect the cardiovascular system in many ways. It improves blood cholesterol levels and blood sugar regulation. People who exercise regularly have lower rates of inflammation, and less inflammation suggests lower risk of artery disease. The cardiovascular system contributes to the homeostasis of other body systems by transporting and distributing blood throughout the body to deliver materials such as oxygen, nutrients, and hormones and to carry away wastes. This transport is accomplished by Blood vessels, which form closed circulatory routes for blood to travel from the heart to body organs and back again. Arteries progressively branch and form microscopic Blood vessels called capillaries that form an efficient exchange surface for oxygen, nutrients, and the returning waste. Capillaries then slowly enlarge to form veins, which are under less pressure since they are farther from the heart . Veins rely mostly on the action of actively contracting muscles in the body to push blood up the limbs against gravity.
eBook - PDF- Gerard J. Tortora, Mark Nielsen(Authors)
- 2016(Publication Date)
- Wiley(Publisher)
Furthermore, the small, permeable vessels that supply the tissues are so intimately distributed among the trillions of body cells that even the most minor tissue damage leads to the rupture of small vessels. This chapter focuses on the structure and functions of the various types of Blood vessels and how they work together to form the major circulatory routes of the human body. • 464 14.1 ANATOMY OF Blood vessels O B J E C T I V E S • Describe the basic structure of a blood vessel. • Contrast the structure of arteries, arterioles, capillaries, venules, and veins. • Compare the functions of arteries, arterioles, capillaries, venules, and veins. • Distinguish between elastic (conducting) arteries and muscular (distributing) arteries. • Describe the types of capillaries and their functions. The five main types of Blood vessels are arteries, arterioles, capillaries, venules, and veins. Arteries (AR-ter-e ¯z; ar-=air; ter-=to carry) carry blood away from the heart to other organs. A learning trick to help you remember this is artery=away. Large, elastic arteries leave the heart and divide into medium- sized, muscular arteries that branch out into the various re- gions of the body. Medium-sized arteries then divide into small arteries, which in turn divide into still smaller arteries called arterioles (ar-TER-e ¯-o ˉ ls). As the arterioles enter a tissue, they branch into numerous tiny vessels called blood capillaries (KAP-i-lar′-e ¯z=hairlike), or simply capillaries. The thin walls of capillaries allow exchange of substances between the blood and body tissues. Groups of capillaries within a tissue reunite to form small veins called venules (VEN-u ¯ls=little veins). These in turn merge to form progressively larger Blood vessels called veins. Veins (VA ˉ NZ) are the Blood vessels that convey blood from the tissues back to the heart. Angiogenesis (an′-je ¯-o ˉ -JEN-e-sis; angio-=blood vessel; genesis- =production) refers to the growth of new Blood vessels.
- Gerard J. Tortora, Bryan H. Derrickson(Authors)
- 2017(Publication Date)
- Wiley(Publisher)
637 The cardiovascular system contributes to homeostasis of other body systems by transporting and distributing blood throughout the body to deliver materials (such as oxygen, nutrients, and hormones) and carry away wastes. The structures involved in these important tasks are the Blood vessels, which form a closed system of tubes that carries blood away from the heart, transports it to the tissues of the body, and then returns it to the heart. The left side of the heart pumps blood through an estimated 100,000 km (60,000 mi) of Blood vessels. The right side of the heart pumps blood through the lungs, enabling blood to pick up oxygen and unload carbon dioxide. Chapters 19 and 20 described the composition and functions of blood and the structure and function of the heart. In this chapter, we focus on the structure and functions of the various types of Blood vessels; on the forces involved in circulating blood throughout the body; and on the Blood vessels that constitute the major circulatory routes. Q Did you ever wonder why untreated hypertension has so many damaging effects? 21.1 Structure and Function of Blood vessels OBJECTIVES • Contrast the structure and function of arteries, arterioles, capillaries, venules, and veins. • Outline the vessels through which the blood moves in its passage from the heart to the capillaries and back. • Distinguish between pressure reservoirs and blood reservoirs. The five main types of Blood vessels are arteries, arterioles, capillar- ies, venules, and veins (see Figure 21.17). Arteries (AR-ter-ēz; ar- = air; -ter- = to carry) carry blood away from the heart to other organs. Large, elastic arteries leave the heart and divide into medium-sized, muscular arteries that branch out into the various regions of the body. Medium-sized arteries then divide into small arteries, which in turn divide into still smaller arteries called arterioles (ar-TE - R-ē-ōls).
eBook - PDF- Gerard J. Tortora, Bryan H. Derrickson(Authors)
- 2018(Publication Date)
- Wiley(Publisher)
369 CHAPTER 16 The Cardiovascular System: Blood vessels and Circulation Amble Design/Shutterstock Looking Back to Move Ahead... • Diffusion (Section 3.3) • Medulla Oblongata (Section 10.4) • Antidiuretic Hormone (Section 13.3) • Mineralocorticoids (Section 13.7) • Great Vessels of the Heart (Section 15.1) The cardiovascular system contributes to the homeostasis of other body systems by transporting and distributing blood throughout the body to deliver materials such as oxygen, nutrients, and hormones and to carry away wastes. This transport is accomplished by Blood vessels, which form closed circulatory routes for blood to travel from the heart to body organs and back again. In Chapters 14 and 15 we discussed the composition and functions of blood and the structure and function of the heart. In this chapter, we examine the structure and functions of the different types of Blood vessels that carry the blood to and from the heart, as well as factors that contribute to blood flow and regulation of blood pressure. 16.1 Blood Vessel Structure and Function OBJECTIVES • Compare the structure and function of the different types of Blood vessels. • Describe how substances enter and leave the blood in capillaries. • Explain how venous blood returns to the heart. There are five types of Blood vessels: arteries, arterioles, capillaries, venules, and veins (Figure 16.1 and Figure 16.8). Arteries (AR-ter-ēz) carry blood away from the heart to body tissues. Two large arteries— the aorta and the pulmonary trunk—emerge from the heart and branch out into medium-sized arteries that serve various regions of the body. These medium-sized arteries then divide into small arteries, which, in turn, divide into still smaller arteries called arterioles (ar-TE - R- ē-ōls). Arterioles within a tissue or organ branch into numerous micro- scopic vessels called blood capillaries (KAP-i-lar′-ēz) or simply capillaries.
eBook - PDF- Craig Freudenrich, Gerard J. Tortora(Authors)
- 2011(Publication Date)
- Wiley(Publisher)
4. Outline thepulmonaryandhepaticportal circulations. Blood vessels Are the Body’s Plumbing LEARNING OBJECTIVES 1. Compare thestructureandfunctionofthe differenttypesofbloodvessels. Overview of systemic Blood vessels • Figure 11.10 There are five types of Blood vessels that carry blood away from the heart to the tissues and return it to the heart. The systemic Blood vessels transport blood to tissues, but the distribution of blood between the heart and the various types of Blood vessels is uneven. W hile the job of the heart is to pump the blood and generate pressure for blood flow, the Blood vessels transport and distribute blood to and from the various tissues. From the heart to the tissues, various types of Blood vessels form a series of branching tubes where single large vessels div- vide into numerous smaller ones (Figure 11.10). From the cells to the heart, small narrow Blood vessels combine into larger ones. The types of vessels include arteries, ar- terioles, capillaries, venules, and veins. Video BloodVesselsAretheBody’sPlumbing321 In brief, Blood vessels have three functions. 1. Blood vessels form a closed system of tubes that carries blood away from the heart (in arteries), transports it through the tissues of the body (in arterioles, capillaries, and venules) and then returns it to the heart (in veins). 2. Exchange of substances between the blood and body tissue cells occurs as blood flows through the capillaries. 3. Nutrients and oxygen diffuse from the blood through interstitial fluid into tissue cells. Waste products, including carbon dioxide, diffuses from tissue cells through interstitial fluid into the blood. Let's start by looking at arteries. Arteries and Arterioles Are Thick-Walled Vessels The walls of arteries and arterioles are thick and have three layers of tissues, or tunics. These three layers sur- round the lumen, or hollow area through which the blood flows (Figure 11.11).
eBook - PDF- Gerard J. Tortora, Mark Nielsen(Authors)
- 2020(Publication Date)
- Wiley(Publisher)
494 CHAPTER 14 The Cardiovascular System: Blood vessels Q Did you ever wonder why untreated hypertension has so many damaging effects? You can find out following Section 14.7. Introduction If you have ever planted a large garden, you probably know all about the importance of irrigation. At its simplest, an irriga- tion system is a network of channels or furrows that delivers needed water from one main source to the roots of all of a gar- den’s plants. Similarly, the body’s Blood vessels form an exten- sive network of “irrigation channels” to deliver needed fluid—in this case the homeostatically maintained blood—to every cell in the body. In fact, this vascular network is part of one of the most phenomenal irrigation networks imaginable. Emanating from a muscular pump, the heart, these vessels form an exten- sive system of tubular roadways that carry nourishing blood away from the heart toward the tissues, then make a U-turn through small permeable vessels at the tissue level. Here, life- supporting exchanges occur between the blood and surround- ing cells, including O 2 and nutrient delivery and waste pickup. The waste-laden fluid then flows back to the heart through a set of return vessels with routes that parallel those of the deliv- ery vessels. This circular pattern of flow to and from the heart constitutes the vascular component of the cardiovascular sys- tem. This system of tubular roadways is so incredibly extensive that, if all of the individual vessels were placed end-to-end, they would extend about 60,000 miles, roughly three times the circumference of the earth. Furthermore, the small, permeable vessels that supply the tissues are so intimately distributed among the trillions of body cells that even the most minor tis- sue damage leads to the rupture of small vessels. This chapter focuses on the structure and functions of the various types of Blood vessels and how they work together to form the major circulatory routes of the human cardiovascular system.
eBook - PDF- Kathleen A. Ireland(Author)
- 2018(Publication Date)
- Wiley(Publisher)
capillary bed An interwoven mat of capillaries threading through a tissue. venules Small veins that drain blood from capillaries to larger veins. Eye of Science / Science Source 280 CHAPTER 13 The Cardiovascular System as thick as arterial walls. The blood in the veins is moving with barely any pressure, so the veins do not need to be terribly strong. Despite the low pressure, the blood continues to flow toward the heart. Part of the reason is fluid dynamics: fluids flow easily from a smaller vessel to a larger one, where there is less friction from the ves- sel walls. Returning the blood from the legs to the heart poses a spe- cial challenge because the flow must counteract gravity, with almost no help from the heart. Blood does not pool or flow backward in the legs, because a series of valves in the large veins prevent reverse flow. Also, the contraction of skeletal muscle squeezes the veins and creates a pumping action, pushing blood up toward the heart. Exercise is often prescribed to move blood and prevent edema of the lower extremities. Different Circulatory Pathways Have Specific Purposes In general, blood travels from the heart in arteries to capillary beds, and comes back to the heart from those capillary beds in veins. While following this pattern, blood can take one of two pathways from the heart: the pulmonary circuit toward the lungs or the systemic circuit toward the tissues. The purpose of the pulmonary circuit is to exchange carbon dioxide in the blood for oxygen from the environ- ment. The systemic circuit brings this oxygen (and nutrients) to the tissues and then removes carbon dioxide from them. The Pulmonary Circuit Exchanges Carbon Dioxide for Oxygen in the Lungs The pulmonary circuit extends from the right side of the heart to the capillary beds of the lungs and on to the left atrium, as shown in Figure 13.10. Blood entering the right atrium is low in oxygen, having just returned from the body.
- Gerard J. Tortora, Bryan H. Derrickson, Brendan Burkett, Gregory Peoples, Danielle Dye, Julie Cooke, Tara Diversi, Mark McKean, Simon Summers, Flavia Di Pietro, Alex Engel, Michael Macartney, Hayley Green(Authors)
- 2021(Publication Date)
- Wiley(Publisher)
The primary function of capillaries is the exchange of substances between the blood and interstitial fluid. Because of this, these thin-walled vessels are referred to as exchange vessels. CHAPTER 21 The cardiovascular system: Blood vessels and haemodynamics 953 Capillaries are found near almost every cell in the body, but their number varies with the metabolic activity of the tissue they serve. Body tissues with high metabolic requirements, such as muscles, the brain, the liver, the kidneys, and the nervous system, use more O 2 and nutrients and thus have extensive capillary networks. Tissues with lower metabolic requirements, such as tendons and ligaments, contain fewer capillaries. Capillaries are absent in a few tissues, such as all covering and lining epithelia, the cornea and lens of the eye, and cartilage. The structure of capillaries is well suited to their function as exchange vessels because they lack both a tunica media and a tunica externa. Because capillary walls are composed of only a single layer of endothelial cells (see figure 21.1e) and a basement membrane, a substance in the blood must pass through just one cell layer to reach the interstitial fluid and tissue cells. Exchange of materials occurs only through the walls of capillaries and the beginning of venules; the walls of arteries, arterioles, most venules, and veins present too thick a barrier. Capillaries form extensive branching networks that increase the surface area available for rapid exchange of materials. In most tissues, blood flows through only a small part of the capillary network when metabolic needs are low. However, when a tissue is active, such as contracting muscle, the entire capillary network fills with blood. Throughout the body, capillaries function as part of a capillary bed (figure 21.3), a network of 10–100 capillaries that arises from a single metarteriole. In most parts of the body, blood can flow through a capillary network from an arteriole into a venule as follows.
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