1. Circulatory system Premedical 26

2. The circulatory system carries blood and dissolved substances to and from different places in the body. The heart has the job of pumping these things around the body. The heart pumps blood and substances around the body in tubes called blood vessels.

3. How does this system work? lungs head & arms liver digestive system kidneys legs pulmonary artery aorta pulmonary vein main vein LeftRight

4. Lungs Body cells double circulatory system lymphatic system the right side of the system deals with deoxygenated blood. the left side of the system deals with oxygenated blood.

6. The Heart These are arteries. They carry blood away from the heart. This is a vein. It brings blood from the body, except the lungs. Coronary arteries, the hearts own blood supply The heart has four chambers 2 atria 2 ventricles

8. Thoracic cavity between the lungs and is contained in the pericardial sac Epicardium – outer layer of heart wall Endocardium – inner layer that consists of endothelial cells, which line the heart, covers the heart valves, and lines the blood vessels. Myocardium – middle layer composed of cardiac muscle.

10. The Heart left ventricle left atrium right atrium right ventricle valve Artery from lungs artery to head and body vein to lungs vein from head and body valve

11. The AV valve on the right side of the heart is called the tricuspid valve because it has three leaflets (cusps). The AV valve on the left side of the heart is called the bicuspid valve (or mitral valve) because it has two leaflets. the pulmonary valve the aortic valve

12. How does the heart work? blood from the body blood from the lungs The heart beat begins when the heart muscles relax and blood flows into the atria. STEP ONE

13. The atria then contract and the valves open to allow blood into the ventricles. How does the heart work? STEP TWO

14. How does the heart work? The valves close to stop blood flowing backwards. The ventricles contract forcing the blood to leave the heart. At the same time, the atria are relaxing and once again filling with blood. The cycle then repeats itself. STEP THREE

15. Blood pressure is a force exerted by circulating blood on the walls of blood vessels. During each heartbeat, BP varies between a maximum (systolic) and a minimum (diastolic) pressure. Systole is a phase where the myocardium is contracting in a coordinated manner in response to an endogenous electrical stimulus Diastole is the period of time when the heart fills with blood after systole.

16. Classification of blood pressure for adults Categorysystolic, mmHgdiastolic, mmHg Hypotension< 90< 60 Normal 90 – 120and 60 – 80 Prehypertension121 – 139or 81 – 89 Stage 1 Hypertension140 – 159or 90 – 99 Stage 2 Hypertension≥ 160or ≥ 100

17. There are 3 types of blood vessels a. ARTERY b. VEIN c. CAPILLARY

18. The ARTERY thick muscle and elastic fibres the elastic fibres allow the artery to stretch under pressure the thick muscle can contract to push the blood along.

19. The VEIN thin muscle and elastic fibres veins have valves which act to stop the blood from going in the wrong direction. body muscles surround the veins so that when they contract to move the body, they also squeeze the veins and push the blood along the vessel.

20. The CAPILLARY the wall of a capillary is only one cell thick they exchange materials between the blood and other body cells. The exchange of materials between the blood and the body can only occur through capillaries.

21. arteryvein capillaries body cell The CAPILLARY capillary bed A collection of capillaries is known as a capillary bed.

22. The semi-permeable membrane of capillary walls allows nutrients, oxygen, and water to diffuse from the blood to the tissues. Waste products, like carbon dioxide, diffuse from the tissues into the blood.

23. Veins have valves prevent the blood from reversing flow the return flow of blood to the heart when blood pressure is low the aorta, the largest artery in the body blood from the stomach, pancreas, small intestine, and spleen goes through the liver for filtration

24. This portion of the systemic system is known as the hepatic portal system. The gastric vein (stomach), splenic vein (spleen), pancreatic vein (pancreas), and mesenteric veins (small intestines) empty into the portal vein that carries the blood to the liver. the hepatic vein carries blood to the inferior (caudal) vena cava

26. The lymphatic system is part of the immune system and acts as a secondary (accessory) circulatory system. remove excess fluids from body tissues, absorb fatty acid and transport fat to circulatory system, and produce immune cells (lymphocytes, monocytes, and plasma cells).

27. Flow of Blood & Lymph Within Tissue

28. As the collecting lymph vessel accumulates lymph from more and more lymph capillaries in its course, it becomes larger and is called the afferent lymph vessel as it enters a lymph node. Here the lymph percolates through the lymph node tissue and is removed by the efferent lymph vessel. An efferent lymph vessel may directly drain into one of the (right or thoracic) lymph ducts

29. Both the lymph ducts return the lymph to the blood stream by emptying into the subclavian veins

30. lymphoid tissue : spleen, thymus, bone marrow and the lymphoid tissue associated with the digestive system.

31. Lymph nodes filter foreign substances, such as bacteria and cancer cells, before it is re- entered into the blood system through the larger veins. Lymph nodes act as the body’s first defense against infection.

32. Photo from U. S. Federal Government courtesy of Wikipedia. lymph node has a fibrous outer covering (capsule), a cortex, and a medulla

33. www.worldofteaching.com