Why do we need a transport system?<br />IS2<br />
Functions<br />Transport nutrients, hormones and oxygen throughout the body<br />Carry waste away from cells (ex. CO2, urea)<br />Protect body from infection (it transports antibodies and white blood cells)<br />
Parts of Cardiovascular System<br />Heart<br />Blood<br />Blood Vessels<br />Arteries<br />Capillaries<br />Veins<br />
Heart<br />muscular pump located between your lungs. <br />a sac called pericardium encloses the heart. <br />4 chambers:<br />the two upper chambers, which receive blood returning to the heart, are called atria (singular, atrium). <br />the two lower chambers are called ventricles, which pump blood out of the heart. <br />
Valves<br />flaps of tissue that prevent blood from flowing backwards<br />located between the atria and ventricles and between the ventricles and the arteries leading from the heart<br />the opening and closing of the valves cause the “bump bump” sound of the heart.<br />
Blood Flow: 2 circuits/loops<br /><ul><li>Pulmonary Circuit carries oxygen-depleted blood from the heart to the lungs and oxygen-rich blood back to the heart.
Systemic Circuitcarries oxygen-rich blood from the heart to the rest of the body and oxygen-depleted blood back to the heart.
Heart->Body ->Heart</li></li></ul><li>Blood Vessels<br />Arteries: take blood (with high pressure) Away from the heart =<br />thick walls: help withstand high pressure<br />more smooth muscle: help pump blood, make the vessel more elastic<br />small space inside (increases pressure)<br />Veins: take blood (with low pressure) back to the heart<br />thinner walls compared to arteries: less smooth muscle<br />have valves to prevent backflow of blood<br />large space inside (decreases pressure)<br />Capillaries: connect arteries and veins/allow exchange of substances between blood and tissues<br />microscopic: only one cell at a time can go through them<br />single-celled wall: allows easy diffusion of substances<br />reach every cell in the body<br />
Pacemaker<br /><ul><li>Group of cells in the right atrium that can produce a contraction
Contraction stimulus is picked up by nerve cells and spread to the rest of the heart </li></li></ul><li>Nerves and Hormones<br />The pacemaker is controlled by:<br />nervous system<br />opposing nerves control the pacemaker by speeding it up and by slowing it down. <br />endocrine system<br />hormones secreted into the blood also control the pacemaker. <br />hormone epinephrine, also called adrenaline, increases heart rate when the body is under stress.<br />
Blood<br />connective tissue made up of cells and liquid.<br /> blood is pumped through the body by the heart<br />you have about 4-6 liters of blood<br /> it takes about 1 min for blood to make a complete circuit through the body.<br />
Blood Composition<br />Plasma is 90% water. <br />The other 10% contains: dissolved salts, proteins, hormones, CO2, antibodies, urea, sugar, etc...<br />RedBloodCells<br />Carryoxygento thecells<br />Containhemoglobin, a proteinthatstoresoxygen (hemoglobincontains IRON)<br />White BloodCells<br />Produceantibodies + destroypathogens = fightinfections<br />Platelets<br />Small fragmentsofcellsthathelp stopcutsfrombleeding<br />Release clottingfactorsthathelp formprotein threads calledfibrin<br />Fibrin threads trapplateletsandbloodcells to make a bloodclot.<br />
Blood Pressure<br />consistsoftwonumbers<br /><ul><li>SystolicPressure</li></ul>producedwhentheventriclescontract<br /><ul><li>DiastolicPressure</li></ul>producedwhentheheart relaxes<br />averagebloodpressure for healthyadults<br />120/80(120 over 80)<br />averageheart rate is about 70 beats per minute<br />
Atherosclerosis<br />slow build up of plaque (lipids, cholesterol)insidevessels<br />arteries become harder, less flexible<br />less space for blood<br />if coronary arteries are affected: heart attack might happen = heart cells die<br />Factors affecting coronary heart disease (CHD):<br />Age, race, heredity, gender, cholesterol levels, blood pressure, obesity, diabetes, smoking, sedentary lifestyle, stress<br />
Health<br />Cholesterol /fats might clog arteries = pressure inside vessel increases = hypertension/even heart attack<br />Salt also promotes hypertension<br />Regular exercise makes the heart stronger<br />Smoking increases blood pressure (nicotine is a stimulant = increases heart rate/tar accumulates all over lungs = make gas exchange more difficult/CO stick to red blood cells permanently)<br />