Types of circulatory systems

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2 Types of circulatory systems Open system Mostly invertebrates Low pressure Haemocoel Suitable for small organisms Closed system Vertebrates High pressure Blood remains in blood vessels Separate tissue fluid

3 Closed circulatory system Vertebrates High pressure Blood remains in blood vessels Separate tissue fluid Heart arteries arterioles capillaries venules veins heart Exchange occurs between capillaries and body tissues

4 Component Structure function Heart Muscular organ Acts as a pump that keeps the blood flowing through the body in one direction Blood vessels Blood Network of tubular structures Type of connective tissue, consisting of red blood cells, white blood cells and platelets in a matrix of blood plasma Contains the blood as it circulates throughout the body Transports: O 2 and CO 2 to and from the lungs Absorbed nutrients from small intestine to liver Hormones from the endocrine glands to the target organs Waste products like urea from liver to kidney Heat from the liver and muscles to the rest of the body Lymphatic vessels Lymph Network of tubular structures Colourless fluid derived from tissue fluid Contains the lymph as it circulates throughout the body Acts as an additional drainage system that transports lymph to the immune organs and into the bloodstream Contains white blood cells to fight infections Transports products of fat digestion from small intestines into the blood stream

5 Double circulatory system Advantages: Pumped to lungs constantly to be oxygenated Creates a high pressure oxygen supplied and wastes removed

6 Protection of the heart

7 External view of the heart superior vena cava aorta pulmonary vein right atrium inferior vena cava right ventricle pulmonary artery pulmonary vein coronary artery left ventricle

8 Internal structure of the heart

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10 superior vena cava (transports blood from the head) The vena cava carries deoxygenated blood from the body to the right atrium inferior vena cava (transports blood from rest of body)

11 The right atrium collects deoxygenated blood and pumps it to the right ventricle right atrium

12 The right ventricle pumps deoxygenated blood to the lungs right ventricle

13 The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs Pulmonary artery

14 The septum separates the left and right sides of the heart septum

15 The pulmonary veins carry oxygenated blood from the lungs to the left atrium Pulmonary veins

16 The left atrium collects the oxygenated blood and pumps it to the left ventricle Left atrium

17 The left ventricle pumps oxygenated blood to the body via the aorta Left ventricle

18 The aorta carries the oxygenated from the left ventricle to the rest of the body Aortic arch Aorta

19 Atrio-ventricular valves prevent backflow of blood into the atria when ventricles contract Tricuspid valves Bicuspid valve (mitral valve) Tendonous cords

20 The semi-lunar valves prevent backflow of blood from the arteries into the ventricles Pulmonary semi-lunar valve Aortic semi-lunar valve

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22 FUNCTION OF THE HEART To pump blood around the body so that all living cells can receive oxygen and other nutrients and release excretory products to be transported away

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25 Transport systems in Humans Circulatory system Lymphatic system Functions of the transport system of humans Lungs Digestive system Oxygen Carbon dioxide food Human body cells Require food and oxygen to release energy Waste products get produced Urine Sweat Kidneys Sweat

26 HOW IS THE HEART RATE CONTROLLED?

27 How does the heart beat 1 Sinoatrial node (Pacemaker) SA node 2 Atrioventricular node 3 Atrioventricular Bundle (Bundle of His) 4 Left & Right Bundle branches 5 Bundle Branches / Purkinje fibres

28 The SA node (patch of specialised cells) gives the heart the signal to start beating The AV node and Purkinje fibres (septum) form a conduction system which keep the heart beating regularly

29 Electrical signal starts from SA node and spreads through the walls of the atria Signal spreads to the AV node Once the atria relax the signal travels down the Purkinje fibres This causes the ventricles to contract from the bottom up, squeezing the blood up into the arteries

30 The Cardiac Cycle Systole - contraction Diastole - relaxation

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32 The sino-atrial node (SA node)sends electrical impulses to the muscle fibres of both the left and right atria. The two atria contract at the same time. The tricuspid and bicuspid valves open. The blood flows into the two ventricles which are relaxed. The SA node acts as a pacemaker causing the heart to beat at a slower or faster rate depending on the body s needs.

33 The two ventricles contract at same time. The blood is forced into the aorta and pulmonary artery. The tricuspid and bicuspid valves close. This prevents blood from flowing back into the atria.

34 Both the atria and ventricles relax. The semi-lunar valves at the base of the aorta and pulmonary artery close, preventing blood from flowing back into the ventricles from the aorta or pulmonary artery. Blood enters the atria through the superior and inferior vena cavae and pulmonary veins.

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36 Pulse The pulse is the regular expansion and contraction of an artery

37 BLOOD PRESSURE SYSTOLIC BLOOD PRESSURE as the left ventricle contracts, blood is pushed into the aorta, stretching the elastic walls. The maximum pressure reached in the aorta when the ventricles contract is the called systolic pressure DIASTOLIC BLOOD PRESSURE - during diastole the walls of the aorta recoil. This keeps up the pressure on the reduced blood volume forcing blood into smaller vessels. This lower pressure in the aorta when the ventricles relax is called diastolic pressure baumanometer

38 BLOOD VESSELS

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40 ARTERIES Pump blood from the heart to all the cells of the body Pump oxygenated blood Control the distribution of blood High pressure Pressure reservoirs

41 VEINS Pump blood from the cells to the heart Have valves to prevent backflow Low pressure Pump deoxygenated blood

42 Capillaries Easy diffusion of substances between blood and cells Allow phagocytes (white blood cell) to move in and out

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46 Artery Vein Capillary Blood is under a high pressure Blood is not under a high pressure Blood is not under a high pressure Does not have valves Does have semi-lunar valves Does not have valves Has thick muscular walls Has thin muscular walls Has a single layer of cells in the walls for easy diffusion Has a smaller lumen then veins Carries blood away from the heart Oxygenated blood except pulmonary arteries Has a large lumen Carries blood to the heart Deoxygenated blood except pulmonary veins Has a very narrow lumen Produces tissue fluid at the capillary beds Exchanges O2 & CO2 between plasma & tissue fluid Leads to capillaries Leads from capillaries Branches of arteries and join up to form veins

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48 Varicose veins Thrombosis

49 Effect of exercise on heart rate When you exercise, cellular respiration increases so more CO 2 is produced This lowers the ph of the blood Impulse is sent via sensory neurons to the medulla oblongata Responds by telling the SA node to beat quicker. Why?

50 THE LYMPHATIC SYSTEM

51 The lymphatic system is a circulatory system that transports lymph throughout the body. Unlike the blood circulatory system, the lymphatic system has no pump. It is a drainage system.

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54 Lymph Is the body fluid containing white blood cells, chief lymphocytes, that is drained from the tissue spaces by the lymphatic vessels

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56 Blood plasma and white blood cells leak out of the capillaries and return to the blood circulation system In between body tissues are blood capillaries and lymphatic capillaries Blood plasma that leaks out of the capillaries and surrounds body tissues it is called tissue fluid Tissue fluid that drains into the lymph vessels is called lymph. Lymph capillaries join to form lymph vessels Lymph vessels flow through lymph nodes Lymph nodes contain many white blood cells immunity Lymph nodes: neck, armpits, groin Lymph is returned to the circulatory system via a vein in the neck Flow is uni-directional because of valves

57 Constituents of lymph Water Solutes proteins, salts, glucose, urea Fat White blood cells lymphocytes and macrophages Lymphocytes B and T B produce antibodies that enter blood to fight germs T variety of functions Macrophages trap and digest foreign matter and harmful bacteria by phagocytosis

58 Functions Of The Lymph System Helps maintain the fluid balance Helps defend the body against infection Transports absorbed fat lacteals in villi absorb fat

59 CIRCULATORY DISEASES

60 Diseases and disorders Diseases of the cardiovascular system can be serious and are a major cause of death, seeing as blood is the manner in which all your cells in the body receive useful substances and get rid of waste products. Sometimes causes are genetic, but lifestyle is also a major contribution to diseases and disorders. These are smoking, drinking, lack of exercise, obesity etc.

61 Examples of diseases and disorders Anaemia When a person has too few red blood cells due to a lack of iron. The person appears pale with no energy. Leukaemia A type of blood cancer that causes uncontrolled division of the leucocytes (white blood cells). Blood pressure Hypertension is high blood pressure and hypotension is low blood pressure. In high blood pressure, the heart has to work harder, which can lead to stroke, heart attack or kidney disease. In low blood pressure, a person feels dizzy and has fainting spells.

62 Angina, arteriosclerosis Angina is chest pain associated with too little oxygen being delivered to the heart muscles. This can be associated with arteriosclerosis which is a narrowing of the arteries due to arteriosclerotic plaque. Heart attack and strokes In a heart attack, the coronary arteries, supplying oxygen to the heart, become blocked or they spasm. The heart no longer has enough oxygen to work and stops pumping. In a stroke, a clot may form and block one of the arteries to the brain, starving it of oxygen, or a blood vessel may burst as a result of a blockage or hypertension and weakening of the artery walls.

63 Coronary artery disease Heart attack coronary artery is blocked or cut off heart is starved of oxygen and the tissue dies High risk factors: High blood pressure, smoker, obesity, high blood cholesterol, diabetes, stress, sedentary lifestyle, diet high in sugar and fat and low in fruit and vegetables Sex- male, middle-age, high achiever personality, genetic predisposition

64 Atherosclerosis Hardening of the arteries, also called atherosclerosis, is a common disorder. It occurs when fat, cholesterol, and other substances build up in the walls of arteries and form hard structures called plaques.

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66 Treatment Coronary artery bypass graft Coronary angioplasty

67 Atherslerosis treated with: Balloon angioplasty (with or without stent) Laser angioplasty (breaks up thrombus) Coronary by-pass Heart transplant Irregular heartbeat treated with: Pacemaker (regulates heartbeat if too slow or too fast)

68 Valve replacements (repair or replace valves) Heart transplant (receive heart from recently deceased person commonly brain dead)

69 Stroke Thrombosis in a brain artery brain cells get cut off form oxygenated blood Symptoms paralysis on one side of the body Difficulties speaking/swallowing Problem seeing properly Unconsciousness

70 Sudden rupture of blood vessel in the brain sudden death, same symptoms as above Rupture of blood vessel inside skull but outside brain pressure severe headache brain cells could die