Circulatory System

1. By: Casey, Gianna, Kaitlyn, Emma Circulatory System

2. What really is blood?

3. Red Blood Cells: • Carry oxygen through body and also carries carbon dioxide to lungs • Also known as erythrocytes • Consists of protein hemoglobin, which allows cells to carry oxygen • Made in bone marrow and lives typically for 120 days White Blood Cells: Known as leukocytes Protect against illnesses Made in bone marrow → constantly being produced due to short lifespan Stored in blood and lymphatic tissue Five different types of white blood cells → monocytes, lymphocytes, neutrophils, basophils, eosinophils

6. Plasma • Liquid portion of blood • Protein-salt solution where platelets/blood cells are stored • 92% water and majority of blood composition Platelets Fibrinogen • Tiny blood cells that help your blood clot; damaged blood cells let out signals to platelets • Process of platelets spreading over blood cell to form clot= adhesion; platelets develop sticky tendrils that adhere to the site of clot • Made in bone marrow • Also called thrombocytes • Help in the process of blood clotting • Created in the liver • Soluble protein that is released into the bloodstream • Converts into fibrin, an insoluble protein • Fibrin forms covering over wounds Process of blood clotting starts with platelets, which then activates fibrinogen at the clotting site

8. 2. The Circulatory Systems

9. Open Circulatory System Closed Circulatory System • Blood is not confined within vessels; fills cavities and surrounds tissues • Common to molluscs and arthropods • Organisms with open systems use their tracheal systems to transport oxygen • Blood is enclosed in vessels such as capillaries, veins, and arteries • A heart pumps blood throughout the organism • Vertebrates and a select few invertebrates have closed circulatory systems

11. 3. Basic Components of the Circulatory System

12. Open Circulatory System

13. Hemocoel • The body cavity in between organs where Hemolymph circulates through • Directly supplies organs with oxygen and nutrients

14. Hemolymph • Hemolymph is a circulating tissue that contains blood and lymph • Similar to blood • Supplies the organs with oxygen

15. Sinuses • A system of connected hollow cavities in your skull • There is no concrete function of what sinuses do, one theory is that they humidify the air we breathe in • 4 types of sinuses • Maxillary Sinus • Frontal Sinus • Ethmoid Sinus • Sphenoid Sinus • Lined with a thin layer mucus

16. Heart • The heart pumps oxygenated blood to the body deoxygenated blood to the lungs • Creates the Coronary Circulation system which provides the heart with blood

17. Ostia • A small opening, especially one of entrance into a hollow organ or canal • Allow water and nutrients to flow into the tissues of the organ

18. Closed Circulatory System

19. Arteries • Blood vessels that deliver oxygenated blood from heart to body tissues • Three layers: • intima (inner layer lined by endothelium) • media (layer of muscle that accommodates high pressures) • adventitia (connective tissue that holds arteries in place)

20. Arterioles • Small-diameter blood vessel that branches out from an artery and tapers off into capillaries; 1-2 layers of muscle + are primary site of vascular resistance • Transport blood from arteries to capillaries • Main regulators of blood flow and pressure • Smooth muscle helps the arteriole contract/helps to circulate blood

21. Capillaries • Fine branching blood vessels that form networks between arterioles and venules. • Oxygen, nutrients, and waste are exchanged between blood and tissues through capillaries

22. Blood vessels that carry deoxygenated blood from tissues to the heart (not including pulmonary/umbilical veins, which carry oxygenated blood) Venules Veins • Very small veins, typically collecting blood from the capillaries • Allows deoxygenated blood to flow from capillaries into the veins

25. Blood enters the heart through the superior and inferior vena cavas • Second largest vein in the body • Carries deoxygenated blood from upper half of body to the right atrium • Carries deoxygenated blood from body parts below the diaphragm to the right atrium of the heart. Superior Vena Cava Inferior Vena Cava

26. Next, the blood from the vena cavas is emptied into the right atrium • Passes deoxygenated blood from the pulmonary veins into the right ventricle Right Atrium

27. From the right atrium, blood is pumped through the Right AV Valve or the Tricuspid Valve Right AV Valve • The function of the valve is to prevent backflow of blood into the right atrium

28. After passing through the Right AV valve, blood is pumped into the Right Ventricle Right Ventricle • Responsible for pumping deoxygenated blood to the lungs

29. From the Right Ventricle, blood flows through the Pulmonary Valve Pulmonary Valve • A one way valve that allows blood to leave the heart through the arteries

30. After going through the Pulmonary Valve, blood flows through the Pulmonary Trunk Pulmonary Trunk • Major vessel stemming from the right ventricle • Branches into right and left pulmonary arteries • Transmit carbon dioxide-rich blood from the right ventricle to the lungs

31. From the Pulmonary Trunk, blood goes through the left and right Pulmonary Arteries Pulmonary Arteries • Bring deoxygenated blood to the lungs • Left and Right arteries From the arteries, Blood flows to the lungs where it will become oxygenated. Once it becomes oxygenated it begins its journey back to the heart

32. On the way back to the heart, blood first flows through the Pulmonary Veins Pulmonary Veins • Return oxygenated blood from lungs to left atrium • There are 4 Pulmonary veins, 2 from each lung

33. From the Pulmonary Veins, blood flows into the Left Atrium Left Atrium • Pass oxygenated blood from the pulmonary veins into the left ventricle

34. Interventricular Septum • As the blood flows into the left ventricle there is a stout wall that separates the left and right ventricle. • Separates the newly oxygenated blood fromthedeoxygenated blood

35. After the Left Atrium, Blood flows through the Left AV valve or the Mitral Valve Left AV Valve • It regulates blood flow from the left atrium into the left ventricle

36. After passing through the Left AV Valve blood flows into the Left Ventricle Left Ventricle • Receives oxygenated blood and pumps it to tissues all over the body

37. From the Left Ventricle, blood will pass through the Aortic Semilunar Valve Aortic Semilunar Valve • Prevents blood backflow into the heart (like a door); separates ventricles from major arteries

38. Next Blood will flow to the Aorta • Artery from left ventricle that ends at left side of the body, forking into iliac arteries • Largest artery in the body • Broken down into four sections: ascending aorta, aortic arch, descending thoracic aorta, and abdominal aorta

39. Ascending Aorta Aortic Arch Descending Aorta • Portion of the main artery that bends between ascending/descending aorta; has three branches that feed separate arteries. • Leaves the heart and then curves into descending aorta • Begins at curve of aortic arch • Travels down through chest; supplies blood to ribs and other abdominal structures • Splits into iliac arteries • Carries oxygenated blood from heart to the organs and muscles of chest, abdomen, pelvis and lower limbs

41. Cardiac/Heart Cycle The cardiac cycle is the sequence of events that occur when the heart beats. Two main phases: • Diastole: when the heart ventricles are relaxed • Systole: when the ventricles contract

42. Autorhythmic Cells: contract without any external stimulation • Hyperpolarization: membrane potential more negative • Depolarization: membrane potential more positive • If channels leak Na+ + K into cell → depolarizing • At threshold, If channels close, Ca2+ rushes in • Repolarize with K channels

43. Cardiac/Heart Cycle The heart has two nodes that are instrumental in cardiac conduction, which is the electrical system that powers the cardiac cycle. • Sinoatrial (SA) Node • Atrioventricular (AV) Node

44. SA Node • “Pacemaker of the heart”; coordinates heart contractions • Upper right wall of the right atrium • Generates nerve impulses that travel throughout heart wall causing both atria to contract • Parasympathetic (slow)/sympathetic (accelerate) autonomic nerves send signals to SA node • Example: exercise

45. AV Node The electrical signal generated by the SA node moves from cell to cell down through the heart until it reaches the atrioventricular node (AV node) • Gate that slows the electrical current before the signal is permitted to pass down through to the ventricles • Delay ensures the atria have a chance to fully contract before the ventricles are stimulated → prevent atrial fibrillation

46. Bundle of His Fibers Impulses from the AV node are passed along to atrioventricular bundle fibers • Bundle of His: splits into two bundles near the top of the ventricles, each bundle branch continues down the center of the heart, carries impulses to the left and right ventricles.

47. Purkinje Fibers Specialized fiber branches found just beneath the endocardium (inner heart layer) of the ventricle walls • Extend from bundle of his to left and right ventricles • Rapidly relay cardiac impulses to the myocardium → ventricles contract

48. Lymphatic System The lymphatic system is a network of vessels and tissues that carry a clear fluid called lymph. • Open system with fluid moving in one direction • Makes sure leaked blood returns back to bloodstream • When fluid leaks from blood vessels it either returns to cardiovascular system or is collected by lymph vessels • Vessels are connected to lymph nodes where lymph is filtered

49. Systemic vs. Pulmonary Circuits • Systemic circulation begins with oxygenated blood flow from left ventricle to aorta • After cells are deoxygenated (spread throughout body), this blood returns to right atrium • Right atrium → right ventricle • As blood flows from the right ventricle to the pulmonary arteries, the pulmonary circuit begins • Pulmonary circuit utilizes pulmonary arteries and veins to carry deoxygenated blood to lungs where it is restored with oxygen