Circulation. Chapter 37 Part 2

Transcription

1 Circulation Chapter 37 Part 2

2 37.7 Pressure, Transport, and Flow Distribution Contracting ventricles put pressure on the blood, forcing it through a series of vessels Arteries carry blood from ventricles to arterioles Arterioles control blood distribution to capillaries Capillaries exchange substances Venules collect blood from capillaries Veins deliver blood back to heart

3 Human Blood Vessels

4 Fig a, p. 648

5 outer coat smooth muscle basement membrane endothelium Artery elastic tissue elastic tissue Fig a, p. 648

6 Fig b, p. 648

7 outer coat smooth muscle rings over elastic tissue basement membrane endothelium Arteriole Fig b, p. 648

8 Fig c, p. 648

9 basement membrane endothelium Capillary (venules have a similar structure) Fig c, p. 648

10 Fig d, p. 648

11 outer coat smooth muscle, elastic fibers basement membrane endothelium Vein valve Fig d, p. 648

12 Blood Pressure Blood pressure The pressure exerted by blood on the walls of blood vessels Highest in arteries, then declines through circuit Rate of blood flow depends on the difference in blood pressure between two points, and resistance to flow

13 Blood Pressure in the Systolic Circuit

14 arteries capillaries veins arterioles venules Fig , p. 648

15 Blood Flow Thick, elastic arteries smooth out variations in blood pressure during the cardiac cycle Arterioles respond to signals from the autonomic and nervous systems, and to chemical signals, to direct blood flow to different parts of the body

16 Distribution of Cardiac Output in a Resting Person

17 100% lungs heart s right half heart s left half liver 6% digestive tract 21% kidneys 20% skeletal muscle 15% brain 13% skin 9% bone 5% cardiac muscle 3% all other regions 8% Fig , p. 649

18 Controlling Blood Pressure Blood pressure depends on total blood volume, how much blood the ventricles pump (cardiac output), and whether arterioles are constricted or dilated Receptors in the aorta and carotid arteries monitor blood pressure and send signals to the medulla, which regulates cardiac output and arteriole diameter

19 Measuring Blood Pressure

20 Animation: Measuring blood pressure

21 37.8 Diffusion at Capillaries, Then Back to the Heart Capillary A cylinder of endothelial cells, one cell thick Capillary beds are diffusion zones, where blood exchanges substances with interstitial fluid Hydrostatic pressure moves materials out (ultrafiltration) Osmotic pressure moves water in (capillary reabsorption)

22 Fluid Movement at a Capillary Bed

23 blood to venule blood from arteriole high pressure causes outward flow A cells of tissue inward-directed osmotic movement B Fig (a-b), p. 650

24 Venous Pressure Venules deliver blood from capillaries to veins Veins deliver blood to the heart Large-diameter, blood volume reservoirs Valves help prevent backflow Amount of blood in veins varies with activity level

25 Venous Valve Action

26 Fig a, p. 651

27 venous valve Fig a, p. 651

28 Fig b, p. 651

29 blood flow to heart valve open valve closed Fig b, p. 651

30 Fig c, p. 651

31 valve closed valve closed Fig c, p. 651

32 Key Concepts Blood Vessel Structure and Function The heart pumps blood rhythmically, on its own Adjustments at arterioles regulate how blood volume is distributed among tissues Exchange of gases, wastes, and nutrients between the blood and tissues takes place at capillaries

33 37.9 Blood and Cardiovascular Disorders Red blood cell disorders Anemias, beta-thalassemias, polycythemia White blood cell disorders Infectious mononucleosis, leukemias, lymphomas Clotting disorders Hemophilia, thrombus, embolus

34 Blood and Cardiovascular Disorders Atherosclerosis Buildup of lipids in the arterial wall that narrows the lumen, may rupture and trigger heart attack

35 Fig a, p. 652

36 wall of artery, cross-section unobstructed lumen of a normal artery Fig a, p. 652

37 Fig b, p. 652

38 atherosclerotic plaque blood clot sticking to plaque narrowed lumen Fig b, p. 652

39 Clogged Coronary Arteries

40 coronary artery Fig a, p. 653

41 aorta coronary artery blockage location of a shunt made of a section taken from one of the patient s other blood vessels Fig b, p. 653

42 Blood and Cardiovascular Disorders Hypertension a silent killer Chronic blood pressure above 140/90 High blood pressure and atherosclerosis increase the risk of heart attack and stroke

43 Blood and Cardiovascular Disorders Arrhythmias abnormal heart rhythms EKGs record electrical activity of cardiac cycle

44 one normal heartbeat a time (seconds) b c bradycardia (here, 46 beats per minute) tachycardia (here, 136 beats per minute) ventricular fibrillation d Fig , p. 653

45 Risk Factors Cardiovascular disorders are the leading cause of death in the United States Risk factors Tobacco smoking, family history, hypertension, high cholesterol, diabetes mellitus, obesity, age, physical inactivity, gender

46 37.9 Key Concepts When the System Breaks Down Cardiovascular problems include clogged blood vessels or abnormal heart rhythms Some problems have a genetic basis; most are related to age or life-style

47 37.10 Interactions With the Lymphatic System Vessels and organs of the lymphatic system interact closely with the circulatory system Lymph vascular system Lymph capillaries and vessels that collect water and solutes from interstitial fluid and deliver them to the circulatory system

48 Three Functions of the Lymph Vascular System Returns fluids and plasma proteins that leak out of capillaries to the circulatory system Delivers fats absorbed from the small intestine to the blood Transports cellular debris, pathogens, and foreign cells to lymph nodes

49 Lymphoid Organs and Tissues Lymph nodes Organs that filter lymph before it enters blood and identify pathogens Tonsils in throat and adenoids in nasal cavity Respond to inhaled pathogens

50 Lymphoid Organs and Tissues Spleen Filters pathogens and worn out blood cells from blood Thymus gland Matures T lymphocytes essential to the immune system

51 Components of the Lymphatic System

52 Fig a, p. 654

53 Tonsils Defense against bacteria and other foreign agents Right Lymphatic Duct Drains right upper portion of the body Thymus Gland Site where certain white blood cells acquire means to chemically recognize specific foreign invaders Thoracic Duct Drains most of the body Spleen Major site of antibody production; disposal site for old red blood cells and foreign debris; site of red blood cell formation in the embryo Some Lymph Vessels Return excess interstitial fluid and reclaimable solutes to the blood Some Lymph Nodes Filter bacteria and many other agents of disease from lymph Bone Marrow Marrow in some bones is production site for infectionfighting blood cells (as well as red blood cells and platelets) Fig a, p. 654

54 Fig b, p. 654

55 lymph capillary interstitial fluid flaplike valve made of overlapping cells at tip of lymph capillary capillary bed Fig b, p. 654

56 Fig c, p. 654

57 lymph trickles past organized arrays of lymphocytes valve (prevents backflow) Fig c, p. 654

58 Animation: Human lymphatic system

59 Animation: Lymph vascular system

60 37.10 Key Concepts Links With the Lymphatic System A lymph vascular system delivers excess fluid that collects in tissues to the blood Lymphoid organs cleanse blood of infectious agents and cellular debris

61 Animation: Capillary forces

62 Animation: Examples of ECGs

63 Animation: Vein function

64 Animation: Vessel anatomy

65 ABC video: Pollution and Women s Health

66 ABC video: A new medicine for stroke victims

67 ABC video: Second-Chance Heart

68 ABC video: Heart Healthy

69 Video: And then my heart stood still