Circulatory system Sevinj Ahmadova Overview • Organization and evolution of the circulatory system - Open vs closed Circulatory system • Components of human Circulatory system - Pumping organ – heart - Blood vessels • Heart and circulation • Blood vessels and Blood pressure • Blood composition • Cardiovascular diseases • ECG Functions of Circulatory system • carries oxygen and nutrients • picks up waste from the cells: carbon dioxide, heat and excess water. From simple systems to complex systems Invertebrates Invertebrates Vertebrates • Fish – single circulation system of the vertebrates: blood flows unidirectionally from the twochambered heart through the gills and then the rest of the body. • Amphibians - two circulatory routes: one for oxygenation of the blood through the lungs and skin, and the other to take oxygen to the rest of the body. The blood is pumped from a three-chambered heart with two atria and a single ventricle. Vertebrates • Reptiles - two circulatory routes; blood is only oxygenated through the lungs. The heart is three chambered, but the ventricles are partially separated so some mixing of oxygenated and deoxygenated blood occurs except in crocodilians and birds. • Mammals and birds - heart with four chambers that completely separate the oxygenated and deoxygenated blood; it pumps only oxygenated blood through the body and deoxygenated blood to the lungs. Circulatory system components • Blood – carrying nutrients, gasses and waste products • Blood vessels – hold the blood • Heart – pumping organ that moves blood through vessels Double Circulation system blood travels through the heart twice during one complete circuit 1. Pulmonary system 2. Systemic system Heart structure • 4 chambers – Atria & Ventricles • Top chambers – Atria • Bottom chambers - Ventricles • Artery – Away from heart • Vein – Towards hearts • Left side of Heart – our Right *Septum – divides heart into R and L sides • Right side of Heart – our Left Heart https://www.youtube.com/watch?v=jBt5jZSWhMI • Vena cava – blood from the rest of body • Aorta – blood to the rest of body • Pulmonary vein – blood from lungs • Pulmonary artery – blood to lungs • Coronary arteries – supply O2 and nutrients to heart Double circulation • right side of the heart collects deoxygenated blood form the body and pumps it to the lungs. left side collects oxygenated blood from the lungs and pumps it to the body. Importance of double circulation • Oxygenated blood is kept separate from deoxygenated blood via septum. • The blood pressure in the systemic circulation is kept higher than that in the pulmonary circulation. • left ventricle has a thicker wall - it pumps blood under higher pressure to the body and delivers oxygenated blood effectively to all parts of the body. • right ventricle has a thinner wall and pumps blood to the lungs under lower pressure – to avoid damage of lung ECG: https://www.abpischools.org.uk/full-screen-animation/625/623 Blood vessels Arteries • Carry blood at high pressure away from the heart • Carry oxygenated blood (exclusion: the pulmonary artery) • Have thick muscular walls containing elastic fibres • Have a narrow lumen to maintain high pressure • Speed of flow is fast Veins • Carry blood at low pressure towards the heart • Carry deoxygenated blood (exclusion: the pulmonary vein) • Have thin walls • Have a large lumen as blood pressure is low • Contain valves to prevent the backflow of blood as it is under low pressure • Speed of flow is slow Arteries vs Veins vs Capillaries Capillaries • Carry blood at low pressure within tissues • Carry both oxygenated and deoxygenated blood • Have walls that are one cell thick • Have ‘leaky’ walls • Speed of flow is slow FUN FACTS • If laid end to end, your blood vessels would stretch out to about 161,000 km! (About 4 times the distance around the equator!) • In just under thirty seconds, your blood moves (circulates) through your entire body. It reaches every one of your trillions of cells. Important blood vessels Components of the Blood • Plasmatransport • Red blood cellstransport • White blood cellsimmune • Plateletsimmune Functions of blood components • Plasma - transport of carbon dioxide, digested food (nutrients), urea, mineral ions, hormones and heat energy • Red blood cells - transport of oxygen around the body • White blood cells - immune defense of the body by carrying out phagocytosis and antibody production • Platelets - blood clotting (https://www.abpischools.org.uk/full-screenanimation/614/612) Lymph fluids • The walls of the capillaries are so thin that water, dissolved solutes and dissolved gases easily leak out of them / pass through the walls from the plasma into the tissue fluid surrounding the cells • Cells exchange materials (such as water, oxygen, glucose, carbon dioxide, mineral ions) across their cell membranes with the tissue fluid surrounding them by diffusion, osmosis or active transport • More fluid leaks out of the capillaries than is returned to them, and this excess of leaked fluid surrounding the capillaries then passes into the lymphatic system, becoming lymph fluid Blood pressure • Systole – heart walls contract, the heart becomes smaller, squeezing blood out. • Diastole – heart walls relax, the heart becomes larger, allowing blood to flow into the atria and ventricles. Heart diseases • coronary arteries supply heart with nutrients • coronary heart disease - when plaques by fatty deposits are formed and coronary arteries get (partially or completely) blocked.(https://www.abpischools.org.uk/f ull-screen-animation/624/621) • Partial blockage severe chest pains called angina • Complete blockage a heart attack https://www.abpischools.org.uk/full-screen-animation/630/629 – stent insertion Death causes in the world and Azerbaijan • https://ourworldindata.org/causes-of-death
