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CHAPTER 23 Circulation

CHAPTER 23 Circulation. Artery and vein, cross-section. Blood smear. It transports O 2 and nutrients to cells It takes away CO 2 and other wastes. Circulatory system. made up of 3 parts organ heart tissues & cells blood vessels arteries veins capillaries blood red blood cells

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CHAPTER 23 Circulation

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  1. CHAPTER 23Circulation Artery and vein, cross-section • Blood smear • It transports O2 and nutrients to cells • It takes away CO2 and other wastes

  2. Circulatory system • made up of 3 parts • organ • heart • tissues & cells • blood vessels • arteries • veins • capillaries • blood • red blood cells • plasma

  3. The circulatory system associates intimately with all body tissues • Capillaries are microscopic blood vessels • They form an intricate network among the tissue cells Capillary Redbloodcell

  4. The circulatory system associates intimately with all body tissues II • No substance has to diffuse far to enter or leave a cell Capillary Diffusion ofmolecules INTERSTITIALFLUID Tissuecell

  5. The cardiovascular system has two circuits • The pulmonary circuit • conveys blood between the heart and gas-exchange tissues • The systemic circuit • carries blood between the heart and the rest of the body

  6. Circulation of Blood Circulationto lungs • 2 part system • Circulation to lungs(pulmonary) • blood gets O2 from lungs • drops off CO2 to lungs • brings O2-rich blood from lungs to heart • Circulation to body(systemic) • pumps O2-rich blood to body • picks up nutrients from digestive system • collects CO2 & cell wastes lungs heart body Circulationto body

  7. The human heart • 4-Chambered heart • atria (atrium) • thin wall • collection chamber • receive blood • ventricles • thick wall pump • pump blood out leftatrium rightatrium rightventricle leftventricle

  8. Lub-dub, lub-dub • 4 valves in the heart • flaps of connective tissue • prevent backflow • Heart sounds • closing of valves • “Lub” • force blood against closed AV valves • “Dub” • force of blood against semilunar valves • Heart murmur • leaking valve causes hissing sound • blood squirts backward through valve SL AV AV

  9. Blood’s path through the heart • 1. vena cavae • 2. right atrium • 3. valve • 4. right ventricle • 5. valve • 6. pulmonary artery (to lungs) • 7. pulmonary veins • 8. left atrium • 9. valve • 10. left ventricle • 11. valve • 12. aortalargest blood vessel in the body.

  10. Blood vessels arteries veins artery arterioles venules arterioles capillaries venules veins

  11. Arteries: Built for their job • Arteries • blood flows away from heart • thicker walls • provide strength for high pressure pumping of blood • elastic & stretchable • maintains blood pressure even when heart relaxes

  12. Major arteries aorta carotid= to head to brain & left arm to right arm to body pulmonaryartery pulmonaryartery=to lungs coronary arteries

  13. Veins: Built for their job Blood flows toward heart • Veins • blood returns back to heart • thinner-walled • blood travels back to heart at low speed & pressure • why low pressure? • far from heart • blood flows because muscles contract when we move • squeeze blood through veins • valves in large veins • in larger veins one-way valves allow blood to flow only toward heart Openvalve Closed valve

  14. Major Veins superiorvena cava= from upper body pulmonaryvein= from lung pulmonaryvein = from lung inferiorvena cava= from lower body

  15. Structure-function relationship • Capillaries • very thin walls • allows diffusion of materials across capillary • O2, CO2, H2O, food, waste body cell waste CO2 O2 food

  16. The heart contracts and relaxes rhythmically • Diastole • Blood flows from the veins into the heart chambers • Systole • The atria briefly contract and fill the ventricles with blood • Then the ventricles contract and propel blood out

  17. The pacemaker sets the tempo of the heartbeat • The SA node (pacemaker) generates electrical signals that trigger the contraction of the atria • The AV node then relays these signals to the ventricles heart pumping controlled by electrical impulses signal also transmitted to skin = EKG electrocardiogram

  18. Connection: What is a heart attack? • A heart attack is damage that occurs when a coronary feeding the heart is blocked Aorta Rightcoronaryartery Leftcoronaryartery Blockage Dead muscle tissue

  19. Cardiovascular diseases are the leading cause of death in the United States • Blood vessel blockage is usually due to blood clots • Atherosclerosis: Growths called plaques develop in the inner wall of the arteries, narrowing their bore • In some cases, plaques also become hardened by calcium deposits, leading to arteriosclerosis, commonly known as hardening of the arteries Connectivetissue Plaque Smoothmuscle Epithelium

  20. Women & Heart Disease Death rates for heart disease per 100,000 women, 2002 • Heart disease is 3rd leading cause of death among women aged 25–44 years & 2nd leading cause of death among women aged 45–64 years. Risk factors • Smoking • Lack of exercise • High fat diet • Overweight

  21. Blood exerts pressure on vessel walls • Blood pressure depends on • cardiac output • resistance of vessels • Pressure is highest in the arteries • It drops to zero by the time the blood reaches the veins Systolicpressure Diastolicpressure Relative sizes andnumbersof blood vessels

  22. Three factors keep blood moving back to the heart • muscle contractions • breathing • one-way valves

  23. Connection: Measuring blood pressure can reveal cardiovascular problems • Blood pressure is measured as systolic and diastolic pressures • Hypertension is persistent systolic pressure higher than 140 mm Hg and/or diastolic pressure higher than 90 mm Hg • It is a serious cardiovascular problem

  24. STRUCTURE AND FUNCTION OF BLOOD • Blood consists of cells suspended in plasma • Plasma is an aqueous solution of various substances

  25. Blood Cell production ribs, vertebrae, breastbone & pelvis • Stem cells • “parent” cells in bone marrow • differentiate into many different types of cells white blood cells white bloodcells red bloodcells

  26. Blood & blood cells • Blood is a tissue of fluid & cells • plasma • liquid part of blood • dissolved salts, sugars, proteins, and more • cells • red blood cells (RBC) • transport O2 in hemoglobin • white blood cells (WBC) • defense & immunity • platelets • blood clotting

  27. Red blood cells • transport oxygen • Small round cells • produced in bone marrow • 5 liters of blood in body • 5-6 million RBC in drop of human blood • last 3-4 months (120 days) • filtered out by liver • ~3 million RBC destroyed each second

  28. Hemoglobin • Protein which carries O2 • 250,000 hemoglobins in 1 red blood cell O2 O2 O2 O2

  29. White blood cells help defend the body • White blood cells (leukocytes) • function both inside and outside the circulatory system • They fight infections and cancer

  30. Blood clots plug leaks when blood vessels are injured • When a blood vessel is damaged, platelets respond • They help trigger the formation of an insoluble fibrin clot that plugs the leak

  31. Connection: Stem cells offer a potential cure for leukemia and other blood cell diseases • All blood cells develop from stem cells in bone marrow • Such cells may prove valuable for treating certain blood disorders

  32. Have a heart?Ask Questions!!

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