 Movements are recorded by a pen attached to the lid of the chamber – this writes on a rotating drum, creating a spirometer trace  The soda lime in the tube the subject breaths into absorbs carbon dioxide  Total volme of gas Inside the chamber decreases over time  The air breathed out is a mixture of 02 and CO2. CO2 is absorbed by soda lime, so only o2 in chamber that is inhaled by subject

 Multicellular organisms need transport systems  Single celled organisms can get all the substances they need by diffusion across their outer membrane  Harder to supply all cells with everything they need-multicellular- as they are relatively big and they have a low surface area to volume ratio  Multicellular organisms (mammals) are also very active. Large number of organisms are respiring very quickly, so need a constant rapid supply of o2 and glucose  For a good supply multicellular organisms need a transport system, circulatory system mammals

 Fish have a single circulatory system, blood only passes through the heart once for each complete circuit of the body  The heart pumps blood to the gills to pick o2 and then on through the rest of the body to deliver o2 in a single circuit  Rest of body  gills  heart  rest of…  Rest of body to heart deoxy  Heart to gills deoxy  Gill to rest of.. Oxy pg 34 cgp

 Right side of heart pumps blood to lungs to pick up o2  From lungs it travels to the left side of the heart, which pumps it to the rest of the body  When blood returns to the heart, it enters the right side.  Pg 34 cgp

 Vertebrates have closed- blood is enclosed inside blood vessels  Heart pumps blood into arteries. These branch out into millions of capillaries  Substances like o2 and glucose diffuse from the blood in the capillaries into the body cells, but the blood stays inside the blood vessels as it circulates  Veins take blood back to heart

 Blood isn’t enclosed inside blood vessels, flows freely through body cavity  The heart is segmented. It contracts in a wave, starting from the back, pumping the blood into a single main artery  The blood flows around the insect’s organs, gradually making its way back into the heart segments through a series of valves  Circulatory system supplies the insect’s cell with nutrients, and transports things like hormones around the body. Done by a system of tube called the tracheal system

 Consists of two muscular pumps  The right side of the heart pumps deoxy blood to the lungs and the left side pumps oxy blood to the rest of the body  The atrioventricular valves link the atria to the ventricles  Semi lunar valves link the ventricles to the pulmonary artery and aorta- they stop blood flowing the wrong way  They only open one way  If there’s high pressure behind a valve its forced open  If the pressure is higher in front, its forced shut pg 36

 Heart is mainly muscle  4 chambers have different functions. The more work a heart chamber has to do, the more muscle it need, so thicker wall  Left ventricle: has thicker/muscular walls than right ventricle, because requires more power as it has to pump blood around the whole body. Right side only needs to get blood to lungs that are nearby  Ventricles have thicker walls than atria, as they have to push blood out of the heart whereas atria only needs to push blood a short distance into ventricles

 1) ventricles relax atria contracts  Ventricles are relaxed, atria fill with blood, which decreases their volume and increases the pressure.  High pressure in atria causes atrioventricular valves to open allowing blood to flow into ventricles  Atria then contract, decreasing their volume and increasing pressure even further  Forcing the remaining blood out

 2) ventricles contract, atria relax  The pressure is higher in ventricles than in the atria  So atrioventricular valves close to prevent backflow  High pressure in ventricles opens the semi lunar valves  Blood is forced out into the pulmonary artery and aorta

 3) ventricles relax, atria relax  Increasing their volume and lowering the pressure in the heart chambers  Higher pressure in the pulmonary artery and aorta causes semi lunar valve to close, preventing backflow  Tehn atria fill with blood again due to the high pressure in the vena cava and pulmonary vein  Then cycle starts over again…. pg 37

 Cardiac muscle is ‘myogenic’- can contract and relax without receiving signals from nerves.  Pattern of contractions controls the regular heartbeat  1) process starts in Sino-atrial node (SAN) which in in walls of right atrium  2)SAN is like pacemaker- sets rhythm of heartbeat, by sending regular waves of electrical activity to the atria walls  3)Causes left and right atria to contract at the same time  4)band of non-conducting collagen tissue prevents waves of electrical activity from being passed directly from the atria to the ventricles pg 38 cgp

 5) Instead waves of electrical ativity are transferred from the SAN to the atrioventricular node (AVN)  6) ANV passes waves of electrical activity onto bundle of His. There is slight delay before AVN reacts, to make sure the ventricles contract after the atria have emptied  7) Bundle of His- group of muscle fibres responsible for conducting the waves of electrical activity to the finer muscle fibres in the right and left ventricle walls, called purkyne tissue  8) Purkyne tissue- carries waves of electrical activity into muscular walls of the right and left ventricles, causing them to contract simultaneously, from the bottom up. Pg 38 cgp

 A machine that records the hearts electrical activity  The heart muscle depolarises(loses electrical charge) when it contracts  Repolarises (regains charge) when it relaxes  Trace produced by an electrocardiograph is called an electrocardiogram (ECG)  Page 38/39 cgp for diagnosis; heart

 3 types:- arteries, capillaries, veins  Arteries carry blood from the heart to the rest of the body  Walls are tick and muscular and have elastic tissue to cope with the high pressure produced by the heartbeat  Inner lining (endothelium) is folded, allowing artery to expand- also helps to cope with high pressure  All arteries carry oxy blood except for the pulmonary arteries, which take deoxy blood to the lungs

 Capillaries- smallest of the blood vessels  Substances like glucose and oxygen are exchanged between cells and capillaries, so they are adapted for efficient diffusion  E.g. Their walls are only 1 cell thick  Capillaries connect to veins

 Veins take blood back to heart at low pressure  They’re wider than equivalent arteries, with very little elastic or muscle tissue  Contain valves to stop blood flowing backwards  Blood flow through veins is helped by contraction of the body muscles surrounding them  All veins carry deoxy blood, except for pulmonary veins, which carry oxy blood to the heart from the lungs.

 Fluid that surrounds cells in tissues  Is made from substances that leave the blood e.g. o2, h2o, nutrients  Cells take in o2 and nutrients from tissue fluid, and releases metabolic waste into it  In a capillary bed (network of capillaries in an area of tissue) substances move out of the capillaries, into the tissue fluid by pressure filtration

 Pressure filtration  1) at start of capillary bed, nearest the arteries, the pressure inside the capillaries is greater than the pressure in the tissue fluid  This difference in pressure forces fluid out of the capillaries and into the spaces around the cells, forming tissue fluid

 2) as fluid leaves, pressure reduces in the capillaries  So pressure is much lower at the end of the capillary bed thats nearest to the veins

 3) due to fluid loss, water potential at the end of the capillaries nearest the veins is lower than the water potential in tissue fluid  So some water re-enters the capillaries from the tissue fluid at the vein end by osmosis