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Revision notes on the Blood & Circulation

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´╗┐STAGE I: BIOLOGY A Blood & Circulation Consists of: Heart Blood ? carries oxygen and carbon dioxide. Contains of red blood cells, oxygen, urea (waste products ? they travel down to the kidneys.), white blood cells (immunity), carbon dioxide, water, insulin (helps control blood sugar levels) ? In the blood vessel oxygen is given to cells and they return CO2 back into the blood vessel. Blood ? transport nutrients Transport waste to kidney Antibodies Heat distribution Blood vessels ? arteries, veins, capillaries (found in lungs ? alveoli.) Blood is transported in a closed circuit Multiple functions Single Circulatory System ? Fish Deoxygenated blood travels from veins into atrium into ventricle then into gills where it turns into oxygenated blood then travels into aorta to systemic capillaries then into veins and the process occur again. ...read more.


Septum ? divider of the two chambers of the heart ? to keep both types away from each other ? types: oxygenated blood (left) and deoxygenated blood (right) Double Circulatory System: Deoxygenated blood Enters the heart through the Vena Cava (superior and inferior) Exits the heart though the Pulmonary Artery Oxygenated blood Enters the heart through the pulmonary vein Exits the heart throughout aorta. Coronary Circulation: Cardiac muscle has its own blood supply. (Coronary arteries and veins.) Small arteries are easily blocked by cholesterol buildup leading to a heart attack. Affected by a number of factors. Cardiac Cycle: Blood moves through the heart in a series of contractions and relaxations of cardiac muscle Contraction of cardiac muscle ? Systole Relaxing of cardiac muscle ? Diastole The Atrio-Ventricular (AV) valves control the passage of blood from an atrium to a ventricle. ...read more.


thick walls as the blood from the heart comes from a very high pressure therefore they need to be thick to withstand that pressure), blood travels at high pressure, no valves (because the blood is traveling at such high pressure therefore it cant travel backwards), carries oxygenated blood. Diseases: plaque builds up in artery if one doesn?t exercise much; therefore there is a decrease in blood flow. Arteriole: branches from the arteries, feed blood into the capillaries, can constrict or dilate under nerve control, carry oxygenated blood. Capillaries: thin; thickness of 1 cell (they are thin due to diffusion), brings blood in contact with body tissues, blood travels at low pressure (to allow sufficient time for diffusion to occur), permits substances to pass through. Venule: carries blood from capillaries to veins, blood travels at low pressure. Veins: carry blood towards the heart, have thin walls, blood travel at low pressure, deoxygenated blood, have semilunar valves. ...read more.

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