1. Chapter 42- Circulation Introduction The heart is a muscular pump that drives the circulation of blood throughout the body. The blood flows through a closed circuit of vessels to every tissue in the body, delivering oxygen from the lungs and nutrients from the digestive tract, and picking up wastes for disposal. © 2018 Pearson Education, Inc.

3. 42.1 Circulatory systems facilitate exchange with all body tissues Gastrovascular cavities function in digestion and transport. In open circulatory systems, a heart pumps fluid through open-ended vessels to bathe tissue cells directly. In closed circulatory systems, a heart pumps blood, which travels through arteries to capillaries to veins and back to the heart. © 2018 Pearson Education, Inc.

4. Figure 23.1a Pores Tubular heart

5. 42.1 Circulatory systems facilitate exchange with all body tissues The cardiovascular system of a fish includes a heart with two main chambers: 1.The atrium receives blood from veins. 2.The ventricle pumps blood to gills via large arteries. Large arteries branch into arterioles, small vessels that give rise to capillaries. Networks of capillaries called capillary beds infiltrate every organ and tissue in the body. © 2018 Pearson Education, Inc.

6. Figure 23.1b Artery (O 2 -rich blood) Capillary beds Arteriole Venule Vein Atrium Gill capillaries Artery (O 2 -poor blood) Ventricle Heart

7. Circulatory systems facilitate exchange with all body tissues Checkpoint question What are the key differences between an open circulatory system and a closed circulatory system? © 2018 Pearson Education, Inc.

8. Vertebrate cardiovascular systems reflect evolution A fish’s two-chambered heart pumps blood in a single circulation. Land vertebrates have double circulation with a pulmonary and a systemic circuit. Amphibians and many reptiles have three- chambered hearts. Birds and mammals have four-chambered hearts. © 2018 Pearson Education, Inc.

9. Figure 23.2a Gill capillaries Ventricle Atrium Body capillaries

10. © 2018 Pearson Education, Inc. Figure 23.2b Lung and skin capillaries Pulmocutaneous circuit Atrium RightLeft Systemic circuit Systemic capillaries Atrium Ventricle

11. © 2018 Pearson Education, Inc. Figure 23.2c Pulmonary circuit Atrium Ventricle Right Left Systemic circuit Lung capillaries Atrium Ventricle Systemic capillaries

12. Checkpoint question What is the difference between the single circulation of a fish and the double circulation of a land vertebrate? © 2018 Pearson Education, Inc.

14. 42.2 VISUALIZING THE CONCEPT: The human ardiovascular system illustrates the double circulation of mammals Blood flow through the double circulatory system of humans drains from the superior vena cava (from the head and arms) or inferior vena cava (from the lower trunk and legs) into the right atrium, moves out to the lungs via the pulmonary artery, returns from the lungs to the left atrium through the pulmonary vein, and leaves the heart through the aorta. © 2018 Pearson Education, Inc.

15. Figure 23.3_2 Capillaries of head, chest, and arms Pulmonary artery Aorta Lung capillaries Pulmonary vein Left atrium Left ventricle Aorta Superior vena cava Pulmonary artery Pulmonary vein Right atrium Right ventricle Inferior vena cava Oxygen-rich blood Oxygen-poor blood Capillaries of abdominal region and legs 3 2 3 4 4 2 5 4 1 2 3 1 3

16. Checkpoint question Why does blood in the pulmonary veins have more O 2 than blood in the venae cavae, which are also veins? © 2018 Pearson Education, Inc.

17. Animation: Path of Blood Flow in Mammals © 2018 Pearson Education, Inc.

18. The heart contracts and relaxes rhythmically During diastole of the cardiac cycle, blood flows from the veins into the heart chambers. During systole, contractions of the atria push blood into the ventricles, and then stronger contractions of the ventricles propel blood into the large arteries. © 2018 Pearson Education, Inc.

19. The heart contracts and relaxes rhythmically Heart valves prevent the backflow of blood. The volume of blood that each ventricle pumps per minute is the cardiac output. Heart rate is the number of heartbeats per minute. © 2018 Pearson Education, Inc.

20. Figure 23.4a To lung Right atrium Left atrium From lung Semilunar valve Atrioventricular (AV) valve From lung Semilunar valve Atrioventricular (AV) valve Right ventricle Left ventricle

21. How should heart disease be treated? A heart attack is damage or death of cardiac muscle tissue and usually results from a blocked coronary artery. More than half of all deaths in the United States are caused by cardiovascular disease— disorders of the heart and blood vessels. A stroke is the death of brain tissue due to the lack of O 2 resulting from the rupture or blockage of arteries in the head. © 2018 Pearson Education, Inc.

22. How should heart disease be treated? Arteries of most victims of a stroke or heart attack became impaired gradually by a chronic cardiovascular disease known as atherosclerosis. During the course of this disease, fatty deposits called plaques develop in the inner walls of arteries, narrowing the passages through which blood can flow. Researchers use randomized studies to determine the best way to treat patients with atherosclerosis of the coronary arteries. © 2018 Pearson Education, Inc.

23. Figure 23.6a Superior vena cava Pulmonary artery Aorta Right coronary artery Left coronary artery Blockage Dead muscle tissue

24. © 2018 Pearson Education, Inc. Figure 23.6b Connective tissue Smooth muscle Blood clotPlaque Epithelium LM 180 ×

25. © 2018 Pearson Education, Inc. Figure 23.6c Plaque Artery Stent Increased blood flow

26. © 2018 Pearson Education, Inc.

27. 42.3 The structure of blood vessels fits their functions Arteries have elastic fibers that recoil after stretching and contain a thick layer of smooth muscle in their walls that can constrict and reduce blood flow. Veins have thinner walls and lower blood pressure and velocity. One-way valves permit blood to flow only toward the heart. Capillaries have thin walls and exchange gas and fluid with the interstitial fluid. © 2018 Pearson Education, Inc.

28. Figure 23.7a Capillary Epithelium Smooth muscle Connective tissue Artery Epithelium Extracellular matrix Epithelium Smooth muscle Connective tissue Valve Vein Arteriole Venule

29. © 2018 Pearson Education, Inc. Figure 23.7b LM 770 × Red blood cell Capillary

30. Checkpoint question How does the structure of a capillary relate to its function? © 2018 Pearson Education, Inc. Capillary Interstitial fluid Diffusion of O 2 and nutrients Tissue cell Diffusion of CO 2 and other wastes

31. Blood pressure and velocity reflect the structure and arrangement of blood vessels Blood pressure depends on cardiac output and the resistance of vessels. Pressure is highest in the arteries. Blood velocity is slowest in the capillaries. Skeletal muscle contractions and one-way valves keep blood moving through veins to the heart. Checkpoint question If blood pressure in the veins drops to zero, why does blood velocity increase as blood flows from venules to veins? © 2018 Pearson Education, Inc.

32. Figure 23.8b Direction of blood flow in vein Valve (open) Contracting skeletal muscle Valve (closed)

33. Arteriole diameter and precapillary sphincters control the distribution of blood Smooth muscles in arteriole walls can influence blood pressure by changing the resistance to blood flow out of the arteries and into arterioles. By opening and closing precapillary sphincters, blood flow to capillary beds in particular regions can be increased or decreased. Checkpoint question What two mechanisms restrict the distribution of blood to a capillary bed? © 2018 Pearson Education, Inc.

34. Figure 23.10 Precapillary sphincters Thoroughfare channel Arteriole Sphincters are relaxed. Capillaries Venule Thoroughfare channel Arteriole Sphincters are contracted. Venule 1 2

35. Capillaries allow the transfer of substances through their walls Capillaries are the only blood vessels with walls thin enough for substances to cross. Blood pressure forces fluid and small solutes out of the capillary at the arterial end. Osmotic pressure draws in fluid at the venous end, because the blood has a higher concentration of solutes than the interstitial fluid. Excess fluid is returned to the circulatory system through lymph vessels. © 2018 Pearson Education, Inc.

36. Figure 23.11a Colorized SEM 6350x

37. Checkpoint question Explain how a severe protein deficiency in the diet that decreases the concentration of blood plasma proteins can cause edema, the accumulation of fluid in body tissues. © 2018 Pearson Education, Inc. Tissue cells Arterial end of the capillary Blood pressure Venous end of the capillary Interstitial fluid Net fluid movement out of the capillary Fluid enters a lymph vessel Osmotic pressure

38. © 2018 Pearson Education, Inc.

39. 42.4 Blood consists of red and white blood cells suspended in plasma Plasma contains various inorganic ions, proteins, nutrients, wastes, gases, and hormones. Red blood cells (erythrocytes) transport O 2 bound to hemoglobin. White blood cells (leukocytes) fight infections. Some are phagocytes, which engulf and digest bacteria. Platelets are cell fragments that are involved in the process of blood clotting. © 2018 Pearson Education, Inc.

40. Figure 23.12 Plasma (55%) Constituent Water Major functions Solvent for carrying other substances Osmotic balance, pH buffering, and maintaining ion concentration of interstitial fluid Osmotic balance and pH buffering Clotting Defense Lipid transport Ions (e.g., sodium, calcium, potassium, magnesium, chloride, and bicarbonate) Plasma proteins Albumin Fibrinogen Immunoglobulins (antibodies) Apolipoproteins Substances transported by blood Nutrients (e.g., glucose, fatty acids, vitamins) Waste products of metabolism Respiratory gases (O 2 and CO 2 ) Hormones Red blood cells (erythrocytes) Cell type Centrifuged blood sample Cellular elements (45%) Number per µ L (mm 3 ) of blood 5,000–10,000 Functions Defense and immunity White blood cells (leukocytes) Basophils Eosinophils Lymphocytes Neutrophils Platelets Monocytes 250,000– 400,000 Blood clotting 5–6 millionTransport of O 2 and some CO 2

41. Too few or too many red blood cells can be unhealthy Adequate numbers of red blood cells are essential for healthy body function. Anemia can be caused by abnormally low amounts of hemoglobin or a low number of red blood cells and causes fatigue due to lack of oxygen in tissues. The hormone erythropoietin (EPO) stimulates the bone marrow to produce more red blood cells. © 2018 Pearson Education, Inc.

42. Checkpoint question Why might increasing the number of red blood cells result in greater endurance and speed? © 2018 Pearson Education, Inc. Colorized SEM 2,500 ×

43. Stem cells offer a potential cure for blood cell diseases Unspecialized adult stem cells differentiate into blood cells in red marrow inside bones. When a stem cell divides, one daughter cell remains a stem cell and the other can take on a specialized function. Leukemia is cancer of leukocytes. Blood stem cells produce all types of blood cells and can be transplanted to treat blood cell diseases. © 2018 Pearson Education, Inc.

44. Figure 23.15 Stem cells (in bone marrow) Lymphoid stem cells Myeloid stem cells Erythrocytes Basophils Platelets Eosinophils Lymphocytes Monocytes Neutrophils

45. Stem cells offer a potential cure for blood cell diseases Checkpoint question Why would a leukemia patient’s bone marrow need to be destroyed and then replaced with a transplant? © 2018 Pearson Education, Inc.

46. You should now be able to 1.Describe the general functions of a circulatory system. 2.Compare the structures and functions of gastrovascular cavities, open circulatory systems, and closed circulatory systems. 3.Compare the cardiovascular systems of a fish, an amphibian, reptiles, and a mammal. 4.Describe the pathway of blood through the mammalian cardiovascular system. © 2018 Pearson Education, Inc.

47. You should now be able to 5.Distinguish between diastole and systole. 6.Define a heart attack and cardiovascular disease. 7.Relate the structure of blood vessels to their function. 8.Explain how and why blood pressure changes as blood moves away from the heart. 9.Explain how blood is moved back to the heart. © 2018 Pearson Education, Inc.

48. You should now be able to 11.Explain how blood flow through capillaries is regulated. 12.Explain how the structure of a capillary relates to its functions. 13.Describe the components of blood and their functions. © 2018 Pearson Education, Inc.

49. You should now be able to 15.Describe the structure, function, and production of red blood cells. 16.Explain how stem cells in bone marrow produce different types of blood cells and offer cures for cell diseases. © 2018 Pearson Education, Inc.

50. Figure 23.UN02 p. a. b. o. n. c. d. m. l. k. j. e. f. g. h. i.