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Circulatory system made up of 3 parts organ heart tissues & cells blood vessels arteries veins capillaries blood red blood cells plasma Your Blood: Transport Fluid Blood is a tissue of fluid & cells Transports O2 and nutrients to cells Takes away CO2 and other wastes Aids in fighting disease Helps maintain body temp. Your Blood: Transport Fluid Blood composition: Plasma: 55% (liquid part) Blood cells: 45% (red, white, & platelets Blood Cell production Stem cells “parent” cells in bone marrow differentiate into many different types of cells ribs, vertebrae, breastbone & pelvis white blood cells white blood cells red blood cells Red blood cells: Oxygen carriers Bioconcave disc shaped, most numerous No nucleus when mature; ‘live’ ≈120 days 5-6 million RBC in one drop of human blood Produced in red marrow of long bones contain hemoglobin that enables transport of O2 Hemoglobin Protein which binds O2 250,000 hemoglobin in 1 red blood cell O2 O2 O2 O2 White blood cells: Infection fighters Largest blood cell play a major role in protecting your body from foreign substances. White Blood Cells Platelets: Blood clotting Smallest (fragments) help form blood clot after an injury. Short-lived Blood vessels arteries veins artery arterioles venules capillaries arterioles venules veins Arteries: Built for pressure Arteries blood flows away from heart thicker walls provide strength for high pressure pumping of blood elastic & resistant maintains blood pressure even when heart relaxes Major arteries aorta carotid = to head to brain & left arm to right arm pulmonary artery coronary arteries to body pulmonary artery = to lungs Veins: Built for flexibility Veins Blood flows toward heart blood returns back to heart Open valve thinner-walled blood travels back to heart at low speed & pressure far from heart blood flows because muscles Closed contract when we move valve squeeze blood through veins one-way valves in larger veins allow blood to flow only towards heart Major Veins superior vena cava = from upper body pulmonary vein = from lung pulmonary vein = from lung inferior vena cava = from lower body Structure-function relationship Capillaries very thin walls; one cell layer thick allows diffusion of materials across capillary wall O2, CO2, H2O, food, waste waste body cell CO2 O2 food Your Heart: The Vital Pump Atria: upper chamber which receive blood that pump blood to ventricles Ventricles: muscular walled chambers which pump blood from heart left atrium right atrium left right ventricle ventricle Circulation of Blood 2 part system 1. Circulation to lungs blood gets O2 from lungs drops off CO2 to lungs brings O2-rich blood from lungs to heart 2. Circulation to body pumps O2-rich blood to body picks up nutrients from digestive system collects CO2 & cell wastes Circulation to lungs lungs heart body Circulation to body Blood’s path through the heart 1. vena cava 2. right atrium 3. valve 4. right ventricle 5. valve 6. pulmonary artery (to lungs) Blood’s path through the heart 7. pulmonary veins 8. left atrium 9. valve 10. left ventricle 11. valve 12. aorta: largest blood vessel in the body Heartbeat regulation The surge of blood through an artery is called a pulse. Pacemaker: initiates heartbeat & generates an electrical impulse that spreads over both atria. Sino atrial node (Pacemaker node) Blood pressure the force that the blood exerts on the blood vessels Blood pressure is measured as systolic (ventricles contract) and diastolic (ventricles relax) pressures Control of the heart A portion of the brain called the medulla oblongata regulates the rate of the pacemaker, speeding or slowing its nerve impulses. Medulla oblongata Control of the heart If the heart beats too fast, the medulla oblongata sends signals that slow the pacemaker. If the heart beat slows down the medulla oblongata sends signals to speed up the pacemaker and increase the heart rate. Medulla oblongata Circulatory System & Homeostasis ATP Homeostasis keeping the internal environment of the body balanced need to balance food & O2 in need to balance energy (ATP) production need to balance CO2 & waste out food O2 CO2 waste Circulatory System & Homeostasis ATP Exercise heart beat faster need more ATP bring in more O2 & food; remove food more CO2 & waste out O2 Disease poor lung or heart function = heart beat faster need to work harder to bring in O2 & food & remove wastes CO2 waste Cardiovascular disease Atherosclerosis & Arteriosclerosis deposits inside arteries (plaques) develop in inner wall of the arteries, narrowing their channel normal artery hardening of arteries Cardiovascular disease Atherosclerosis & Arteriosclerosis increase blood pressure increase risk of heart attack, stroke, kidney damage normal artery hardening of arteries Cardiovascular health Risk Factors genetics diet high animal fat exercise & lifestyle smoking lack of exercise bypass surgery Women & Heart Disease Death rates for heart disease per 100,000 women, 2002 Risk factors Smoking Lack of exercise High fat diet Overweight 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. 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