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UNIT B: Human Body Systems Chapter 8: Human Organization Chapter 9: Digestive System Chapter 10: Circulatory System and Lymphatic System: Section 10.4 Chapter 11: Respiratory System Chapter 12: Nervous System Chapter 13: Urinary System Chapter 14: Reproductive System

Chapter 10: Circulatory System and Lymphatic System UNIT B Chapter 10: Circulatory System and Lymphatic System Chapter 10: Circulatory System and Lymphatic System In this chapter, you will learn about the structure and function of the circulatory system and lymphatic system. What is the composition of blood, including blood cells? What organs and structures control the flow of blood throughout the body? Chapter opener figure background: There are three different blood doping techniques used. One method involves the transfusion of blood from a donor or from a sample of an athlete’s own blood collected at an earlier date. This method boosts the quantity of red blood cells, which are also called erythrocytes, in the blood. Another method involves the injection of erythropoietin (EPO), a hormone naturally produced by the kidneys, to increase the rate of maturation of red blood cells. The third method involves the use of hemoglobin-based oxygen carriers (HBOCs), which are blood substitutes that can also carry oxygen. Each of these methods of blood doping has important medical uses aside from their illegal use in sports. In 2013, Lance Armstrong confessed to long-term blood doping and the use of banned substances. Blood doping involves artificially boosting the blood’s ability to bring more oxygen to muscles. Aerobic capacity and endurance improve where there are additional red blood cells available to carry oxygen. TO PREVIOUS SLIDE

10.4 The Vascular Pathways UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10.4 10.4 The Vascular Pathways The circulatory system includes two circuits. Pulmonary circuit: circulates blood through the lungs Systemic circuit: circulates blood to the body tissues pulmonary circuit: part of the circulatory system that circulates blood through the lungs systemic circuit: part of the circulatory system that circulates blood to body tissues TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10.4 Figure 10.15 Path of blood. This symbolic and not-to-scale drawing shows the path of blood in the pulmonary and systemic circuits. The pulmonary arteries and veins take blood from the right (blue) to the left (red) side of the heart. Tracing blood from the digestive tract to the right atrium in the systemic circuit involves the hepatic portal vein, the hepatic vein, and the inferior vena cava. The blue-coloured vessels carry O2-poor blood, and the red-coloured vessels carry O2-rich blood; the arrows indicate the direction of blood flow. TO PREVIOUS SLIDE

The Pulmonary Circuit UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10.4 The Pulmonary Circuit Pulmonary circuit: circulates blood to lungs Blood from all regions of the body first collects in the right atrium. Blood passes into the right ventricle, which pumps it into the pulmonary trunk. Pulmonary trunk divides into right and left pulmonary arteries, which branch into arterioles. Arterioles take blood to the pulmonary capillaries, where gas exchange occurs. Blood passes through pulmonary venules, which lead to pulmonary veins that enter the left atrium. TO PREVIOUS SLIDE

The Systemic Circuit UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10.4 The Systemic Circuit Systemic circuit: circulates blood to body tissues. The aorta and venae cavae serve as the major pathways for blood in the systemic circuit TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10.4 The path of systemic blood to any organ in the body begins in the left ventricle. Trace the path of blood to and from the legs: left ventricle  aorta  common iliac artery  femoral artery  leg capillaries  femoral vein  common iliac vein  inferior vena cava  right atrium Figure 10.16 Major arteries (red) and veins (blue) of the systemic circuit. This representation of the major blood vessels of the systemic circuit shows how the systemic arteries and veins are arranged in the body. The superior and inferior venae cavae take their names from their relationship to which organ? TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10.4 Blood Pressure As blood passes through the blood vessels in the body, it exerts pressure against the vessel walls (blood pressure). Systolic pressure: results from blood being forced into arteries when ventricles contract (ventricular systole) Diastolic pressure: results from pressure in the arteries when ventricles fill with blood (ventricular diastole) Blood pressure can be measured with a sphygmomanometer, which has a pressure cuff that determines the amount of pressure required to stop the flow of blood through an artery Expressed in millimetres of mercury as a fraction of systolic pressure over diastolic pressure (e.g., 120/80 mm Hg) blood pressure: a measurement of the force of blood pushing against the inside wall of blood vessels TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10.4 Blood pressure decreases as blood flows from the aorta into the arteries, arterioles, and capillaries. Blood is under minimal pressure in capillaries since capillaries have a high total cross-sectional area. Figure 10.17 Blood velocity and blood pressure. In capillaries, blood is under minimal pressure and has the least velocity. Blood pressure and velocity drop off because capillaries have a greater total cross-sectional area than arterioles. TO PREVIOUS SLIDE

UNIT B Blood pressure in the veins is low. Chapter 10: Circulatory System and Lymphatic System Section 10.4 Blood pressure in the veins is low. Valves prevent the backward flow of blood in veins, and muscle contraction is sufficient to move blood toward the heart. Figure 10.18 Cross section of a valve in a vein. a. Pressure on the walls of a vein, exerted by skeletal muscles, increases blood pressure within the vein and forces the valve open. b. When external pressure is no longer applied to the vein, blood pressure decreases, and back pressure forces the valve closed. Closure of the valve prevents the blood from flowing in the opposite direction. TO PREVIOUS SLIDE

Check Your Progress UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10.4 Check Your Progress Identify which arteries carry O2-poor blood. Name the major blood vessels through which blood flows to the lungs and other parts of the body. Describe blood flow in an artery versus a vein. ANSWERS 1. The pulmonary arteries carry oxygen-poor blood.   2. Blood flows to the lungs via the pulmonary arteries and returns to the heart via the pulmonary veins. Blood flows to the body via the aorta and returns via the superior and inferior vena cava. 3. Blood flows in one direction in the arteries due to the pumping of the heart, and it flows in one direction in veins mainly due to muscle contraction and the presence of valves that prevent it from moving in the opposite direction. TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10.4 TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10.4 TO PREVIOUS SLIDE