THE CIRCULATORY SYSTEM

1. THE CIRCULATORY SYSTEM

2. THE CIRCULATORY SYSTEM • The heart and blood vessels make up a blood transportation network called as circulatory system • Functions • Transport materials needed by cells • Oxygen • Glucose • Remove waste materials from cells • Carbon dioxide • urea

3. Major Components • Heart • Continuously circulates blood • Blood vessels • Arteries- blood away from heart • Veins- blood back to the heart • Capillaries-where interchange of oxygen, nutrients, waste products occurs. • Blood • Fluid that fills the circulatory system

4. The Heart • The human heart has four chambers • Left and right ventricle • Left and right atrium • The left side of the heart pumps oxygenated blood to the body • while the right side of the heart pumps deoxygenated blood to the lungs

6. After passing through the capillaries of the lungs, the blood which is now oxygenated returns to the heart in the pulmonary veins. From lungs

7. The left atrium receives blood from the pulmonary veins.

8. Blood passes through the mitral valve into the left ventricle.

9. Contraction of the left ventricle pushes blood through the aortic semilunar valve into the aorta. Blood travels to all regions of the body. Torest of body

10. Deoxygenated blood returns from the rest of the body through the superior and inferior vena cava.

11. The right atrium receives the deoxygenated blood.

12. Blood then enters the right ventricle through the tricuspid valve.

13. Contraction of the right ventricle pushes blood through the pulmonary semilunar valve into the pulmonary arteries in which it travels to the lungs. To lungs

14. Blood Vessels

15. Arteries • Carry blood from the heart and distribute it to the body . • TYPES OF ARTERIES • Elastic • Muscular • Arterioles

16. Arteries • Elastic – “conducting arteries” . Are the largest type . Examples are aorta And its major branches • Muscular – “distributing arteries”. examples are brachial artery and femoral artery • Arterioles – smallest type - lead to capillary beds

17. Capillaries • Capillaries are simple endothelial lining tubes connecting arterial and venous side of circulation. • There are three types of capillaries: • continuous • fenestrated • sinusoids

18. Capillary Beds

19. Continuous Capillaries • Continuous capillaries are abundant in the skin and muscles • Endothelial cells are connected with tight junctions

20. Continuous Capillaries Figure 19.3a

21. Fenestrated Capillaries • Found wherever active capillary absorption or filtrate formation occurs (e.g., small intestines, endocrine glands, and kidneys) • Characterized by: • An endothelium with pores (fenestrations)

22. Fenestrated Capillaries Figure 19.3b

23. Sinusoids • Highly modified, leaky, fenestrated capillaries with large lumens • Found in the liver, spleen, bone marrow, lymphoid tissue, and in some endocrine organs • Allow large molecules (proteins and blood cells) to pass between the blood and surrounding tissues

24. Sinusoids Figure 19.3c

25. Veins • Veins return blood from the capillary beds to the heart. • Types of veins • Large veins . Example are SVC,IVC • Medium size veins . Example are veins of limbs • Small veins are venules

27. venaecomitantes • veins that accompany deep arteries

28. Vascular Anastomoses • Anastomoses provide alternate pathways (collateral channels) for blood to reach a given region • If one branch is blocked, the collateral channel can supply the area with adequate blood supply

30. Uploaded By.... M.Farrukh Fayyaz