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Please DO NOW

Explore the cardiovascular system's functions, components, and disorders. Understand arteries, pulse, vasoconstriction, and more. Learn the structure of blood vessels and the essential roles they play.

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Please DO NOW

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  1. Please DO NOW • How often does your heart beat per minute? • How much blood does your heart pump per minute? • What distance would your blood vessels have if you joined them end to end?

  2. The Cardiovascular and Lymphatic Systems & Cardiovascular Disorders Chapters 12 & 12a http://watchlearnlive.heart.org/CVML_Player.php?moduleSelect=hrtatk

  3. Chapter Overview • Cardiovascular System – Functions • Components of the cardiovascular system – heart and associated blood vessels • Arteries – Pulse, Vasoconstriction, vasodilation, aneurysm • Normal Blood Pressure – hypotension and hypertension • Location of the heart and layers of the heart wall • Structure of the heart – KNOW LOCATION of all chambers and valves, • HEARTBEAT – systole and diastole • Pulmonary and Systemic circuits • Coronary arteries and veins • Cardiac Cycle - KNOW THE SEQUENCE OF blood flow through the heart • Risk factors of CVDs – Disorders - atherosclerosis, heart attack, heart failure • Cardiac arrhythmias – tachycardia, bradycardia, atrial and ventricular fibrillation • Lymphatic System – components, functions, capillaries, lymph nodes, lymphoid organs

  4. The Cardiovascular System • The cardiovascular system is built to rapidly transport blood to every living cell in the body • The cardiovascular system is composed of • Blood vessels • Heart • This system distributes blood, delivers nutrients, and removes wastes

  5. Figure 12.1 A diagrammatic view of the cardiovascular system.

  6. Blood Vessels • Blood passes through the following loop of vessels moving away from the heart • Arteries • Arterioles • Capillaries • Venules • Veins • Blood returns to the heart from the venules and veins

  7. The Heart and Blood Vessels Make up the Cardiovascular System Large-diameter veins Large-diameter arteries Small venules Narrower arterioles Extracellular fluid (ECF) Capillaries Capillaries Body Cells

  8. Figure 12.2 The structure of blood vessels.

  9. Please DO NOW…(w/o notes or textbook) • Use the following terms to put the flow of blood in the correct order as it leaves the heart. • Small venules • Narrower arterioles • Large diameter veins • Capillaries • Large diameter arteries • Capillaries • Body cells

  10. The Heart and Blood Vessels Make up the Cardiovascular System Large-diameter veins Large-diameter arteries Small venules Narrower arterioles Extracellular fluid (ECF) Capillaries Capillaries Body Cells

  11. Arteries • Thick, muscular vessels that carry blood away from the heart to body tissues • Layers • Inner—endothelium • Middle • Elastic fibers—allow the artery to stretch and return to its original shape • Smooth muscle—allows the artery to contract • Outer—connective tissue

  12. Arteries • Pulse • Pressure wave created by the alternate expansion and contraction of the arteries • Moves along the arteries with each heartbeat • The pulse rate is the same as the heart rate http://www.youtube.com/watch?v=W5K_HR6hxMY http://www.youtube.com/watch?v=mDBgPPwOUW8

  13. List and describe the three layers that make up the arteries?

  14. Arteries • Vasoconstriction • Smooth muscle of the middle layer contracts and the diameter of the lumen narrows, reducing blood flow • Vasodilation • Smooth muscle of the middle layer relaxes and the diameter of the lumen increases, increasing blood flow Heavy smokers often develop abnormally high blood pressure. Nicotine in tobacco is a potent vaso constrictor. Explain the connection between these two facts, including what kind of blood vessels are likely affected.

  15. Arteries • Aneurysm • Occurs when the wall of an artery is weakened and swells outward • The primary risk is that it will burst, causing blood loss • If it does not burst, then it can form life-threatening clots

  16. Figure 12a.2 Aneurysm

  17. Arteries • Arterioles, the smallest arteries • Same 3 layers, but few elastic fibers and thinner outer layer • Have 2 very important regulatory functions: • Prime controllers of blood pressure • Serve as gatekeepers to capillary networks • Constantly responding to input from hormones, nervous system, local conditions

  18. Please DO NOW…. • Without notes or textbook…… • What is the difference between vasoconstriction and vasodilation? • What would cause a aneurysm to form?

  19. Capillaries • Connect arterioles and venules • Primary function: exchange of materials between blood and body cells • Plasma membrane is selective • Some substances have to pass through via the slits between cells

  20. Capillaries • Capillary bed – network of capillaries servicing a particular area • 10-100 capillaries • Entrance (arterial side) is guarded by a ring of muscle, precapillary sphincter • Acts as valve that open/close beds • Brings capillaries very close to nearly every tissue • Very narrow, RBCs must squeeze through single file • Slow flow rate = more exchange time

  21. LET’S REVIEW…….. • What is the primary function of capillaries? • Some substances that cross the capillary walls do not pass through the endothelial cells (due to its selective membrane). Explain how these substances are able to get across.

  22. Veins • Venule – smallest kind of vein • Capillaries merge to form • Venules join to form larger veins • Vein – blood vessels that return blood to heart • Veins vs. arteries: thinner walls, larger lumen than equal sized arteries • Differences allow veins to hold larger volume

  23. How does blood get back to the heart from lower body parts?? • 3 mechanisms • Valves in veins prevent backflow of blood • Contraction of skeletal muscle squeezes veins • Breathing causes pressure changes

  24. Stop and Think • If an artery is cut, blood is lost in rapid spurts. In contrast, blood loss through a cut vein has an even flow. • What accounts for these differences?

  25. Heart Structure - Layers • Myocardium • The wall of the heart • Mostly cardiac muscle tissue • Endocardium • Thin lining of the cavities of the heart • Reduces resistance to blood flow through the heart • Pericardium • Thick fibrous sac that holds the heart • surrounds, protects, and lubricates the heart

  26. Please DO NOW…….no notes/txt book • What are the 3 mechanisms that help blood get back to the heart from lower body parts? • The heart has three layers. What are they AND what purpose/function do each of them serve? • 5 minutes

  27. Heart Structure • The septum separates the two halves of the heart • Each half has two chambers • Atrium—smaller and thin-walled • Ventricle—larger and more muscular http://www.youtube.com/watch?v=tEjH-xXCNe4

  28. Fig. 7-3a, p. 124

  29. Heart Valves • Valves (two pairs) • Atrioventricular (AV) valves: separate the atria from the ventricles • Semilunar valves: separate the ventricles from the exit vessels • Heart’s “lub-dup” sounds come from the valves • “Lub”—closing of the AV valves • “Dup”—closing of the semilunar valves

  30. Figure 12.8 The valves of the heart.

  31. Heart Valves • AV valves: • Tricuspid valve • On the right side of the heart, has three flaps • Bicuspid (or mitral) valve • On the left side of the heart, has two flaps • Semilunar valves • Aortic semilunar valve: between left ventricle and aorta • Pulmonary semilunar valve: between right ventricle and pulmonary artery • Prevent the backflow of blood into the ventricles

  32. Fig. 7-3b, p. 124

  33. Figure 12.7 The human heart. (a) Photograph (b) Location. (c) Blood flow (d) diagram.

  34. Fig. 7-3a, p. 124

  35. Two Circuits of Blood Flow • The right side of the heart • Contains blood low in oxygen • Pumps blood through the pulmonary circuit • Transports blood to and from the lungs • The left side of the heart • Contains blood rich in oxygen • Pumps blood through the systemic circuit • Transports blood to and from body tissues

  36. Figure 12.9 Circuits of blood flow.

  37. Video – Heart structure and circulation • Follow along with the person on the video as they color in the heart • Label the different structures • Label the direction for blood flow

  38. Coronary Circulation • Coronary circulation nourishes the heart muscle • Coronary arteries • The first two arteries that branch off the aorta and branch extensively • Bring oxygen and nutrients to the heart muscle • Coronary veins • Blood passes through capillary beds, enters coronary veins, and flows into the right atrium

  39. Figure 12.10 Coronary circulation.

  40. Cardiac Cycle • All chambers relax and blood passes through atria into ventricles • Atria contract • Ventricles contract • Heart relaxes, and the cycle begins again • Contraction is called systole • Relaxation is called diastole

  41. Figure 12.11 The cardiac cycle.

  42. The cardiac cycle represents one complete heartbeat. • Explain the events that take place with one heartbeat.

  43. Direction of Blood Flow • Superior and inferior vena cava • Right atrium • Right ventricle • Pulmonary artery • Pulmonary veins • Left atrium • Left ventricle • Aorta

  44. Please DO NOW…… • No notes or textbook • Describe the cardiac cycle • What takes place for one heartbeat to occur? • You have 5 minutes

  45. Where do contraction signals come from???? Internal conduction

  46. Electrocardiogram (ECG) • The electrical activity that accompanies each heartbeat can be visualized in an ECG tracing • Consists of 3 distinguishable deflection waves

  47. P wave = spread of electrical signal over atria and atrial contraction that follows • QRS wave = spread of electrical signal over ventricles and ventricular contraction • T wave = return of ventricles to the electrical state that preceded contraction • Pattern is remarkably consistent in healthy people • Abnormal patterns can indicate heart problems

  48. Blood Pressure • The force exerted by the blood against the walls of the blood vessels (e.g., 120/80) • Can be measured using a sphygmomanometer • Measures pressure in the brachial artery of the arm • Systolic pressure • Highest pressure in the artery during each heartbeat (ventricles are contracting) • About 120 mm Hg in a healthy adult http://www.youtube.com/watch?v=qWti317qb_w

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