cardiovascular system

• the cardiovascular system: transport, clotting, temperature control
• blood transports: oxygen (release energy stored as glucose) carbon dioxide(removes the waste product) nutrients (water, amino acids and glucose)
• blood clots blood: platelets clot blood forming scabs to stop bleeding and heal the body
• blood controls temperature: vasodilation (too hot), vasoconstriction (too cold) to maintain optimum temperature for the body to work efficiently
• Atria: collects blood as it comes into the heart
• Ventricles: pumps blood out of the heart
• Valves: makes sure that blood can't flow backwards
• septum: divides the heart into two halves
• adrenaline is a hormone that makes the heart beat faster during exercise
• adrenaline causes glycogen to be released by the liver and diverts blood away from the organs to the muscles during exercise
• vena cava->right atrium -> tricuspid valve -> right ventricle ->semi-lunar valve -> pulmonary -> pulmonary artery -> lungs -> pulmonary vein -> left atrium -> bicuspid valve ->left ventricle->semi-lunar valve -> aorta ->body
• Arteries


  Transport oxygenated blood from the heart to all parts of the body
• Arteries


  • Walls have to be thick because the blood is at a high pressure
• Veins


  Transport blood from all parts of the body to the heart
• Veins


  • Walls are thinner than artery walls because the blood is at a lower pressure
• Capillaries


  Transport blood through the body delivering oxygen to cells and removing Carbon dioxide
• Capillaries


  • Walls are thin to allow gas exchange to take place
• Haemoglobin is part of red blood cells
• arteries have small lumens
• veins have valves
• veins have large lumens
• capillaries have thin walls to allow gas exchange into the muscles and organs oxygenating them
• Heart rate


  The speed that the heart beats (70bpm)
• Stroke volume


  The volume of blood pumped out of the left ventricle during each systolic cardiac contraction
• Cardiac output is the quantity of blood pumped by the heart in a given time (measured in L/min. Stroke volume x heart rate) (5l/min)
• Blood pressure


  The pressure of the blood in the circulatory system
• Diastole


  The phase of the heart beat when the heart muscle relaxes and allows the chambers to fill with blood
• Systole


  The phase of the heartbeat when the heart muscle contracts and pumps blood from the chambers into the arteries
• vascular shunting: the redistribution of blood flow
• vascular shunting increases blood flow to active ares and diverts blood away from inactive areas during exercise
• at rest there is roughly 80% of blood flow to organs
• during exercise, there is increased blood flow to muscles (oxygen supply), skin (temperature control) and coronary heart vessels (due to increased blood flow/heart rate)
• during exercise there is decreased blood flow to organs (they are not a priority during exercise)
• vasodilation is the widening of blood vessels caused by the muscle cells relaxing resulting in the lumen becoming wider and blood flow increasing
• vasoconstriction is the narrowing of blood vessels by the muscle cells contracting resulting in the lumen becoming narrow and blood flow decreasing
• blow flow


  the volume of blood travelling through a vessel
• vasodilation needs to take place during exercise so skeletal muscles have higher blood flow and so more oxygen for respiration
• vasoconstriction needs to happen during exercise because it means there is less blood flow to the liver and digestive system which is less important during exercise and there is more blood for the skeletal muscles
• red blood cells make up 45-50% of the blood
• red blood cells carry oxygen and carbon dioxide