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 A closed system of the heart and blood vessels  The heart pumps blood  Blood vessels allow blood to circulate to all parts of the body  The function.

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Presentation on theme: " A closed system of the heart and blood vessels  The heart pumps blood  Blood vessels allow blood to circulate to all parts of the body  The function."— Presentation transcript:

1  A closed system of the heart and blood vessels  The heart pumps blood  Blood vessels allow blood to circulate to all parts of the body  The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products

2  Location  Thorax between the lungs in the inferior mediastinum  Orientation  Pointed apex directed toward left hip  Base points toward right shoulder  About the size of your fist

3 Figure 11.1a–b

4 Figure 11.1c

5 Figure 11.2a

6  Pericardium—a double-walled sac  Fibrous pericardium is loose and superficial  Serous membrane is deep to the fibrous pericardium and composed of two layers Visceral pericardium Next to heart; also known as the epicardium Parietal pericardium Outside layer that lines the inner surface of the fibrous pericardium  Serous fluid fills the space between the layers of pericardium

7 Figure 11.2b Three layers Epicardium Outside layer This layer is the visceral pericardium Connective tissue layer Myocardium Middle layer Mostly cardiac muscle Endocardium Inner layer Endothelium

8

9 Figure 11.2c

10  Right and left side act as separate pumps  Four chambers  Atria Receiving chambers Right atrium Left atrium  Ventricles Discharging chambers Right ventricle Left ventricle

11 Figure 11.2c

12 Figure 11.4

13  Interventricular septum  Separates the two ventricles  Interatrial septum  Separates the two atria

14 Figure 11.2c

15  Allow blood to flow in only one direction to prevent backflow  Four valves  Atrioventricular (AV) valves—between atria and ventricles Bicuspid (mitral) valve (left side of heart) Tricuspid valve (right side of heart)  Semilunar valves—between ventricle and artery Pulmonary semilunar valve Aortic semilunar valve

16 Figure 11.2c

17  AV valves  Anchored in place by chordae tendineae (“heart strings”)  Open during heart relaxation and closed during ventricular contraction  Semilunar valves  Closed during heart relaxation but open during ventricular contraction  Notice these valves operate opposite of one another to force a one-way path of blood through the heart

18 Figure 11.5a, step 1 Blood returning to the atria, puts pressure against AV valves; the AV valves are forced open Ventricles Operation of the AV valves AV valves open (a)

19 Figure 11.5a, step 2 Blood returning to the atria, puts pressure against AV valves; the AV valves are forced open As the ventricles fill, AV valve flaps hang limply into ventricles Ventricles Operation of the AV valves AV valves open (a)

20 Figure 11.5a, step 3 Blood returning to the atria, puts pressure against AV valves; the AV valves are forced open As the ventricles fill, AV valve flaps hang limply into ventricles Atria contract, forcing additional blood into ventricles Ventricles Operation of the AV valves AV valves open (a)

21 Figure 11.5a, step 4 Ventricles contract, forcing blood against AV valve flaps (a)

22 Figure 11.5a, step 5 Ventricles contract, forcing blood against AV valve flaps AV valves close AV valves closed (a)

23 Figure 11.5a, step 6 Ventricles contract, forcing blood against AV valve flaps AV valves close Chordae tendineae tighten, preventing valve flaps from everting into atria AV valves closed (a)

24 Figure 11.5b, step 1 As ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open Aorta Pulmonary trunk Semilunar valve open Operation of the semilunar valves (b)

25 Figure 11.5b, step 2 As ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open Aorta Pulmonary trunk Semilunar valve open Semilunar valve closed As ventricles relax, and intraventricular pressure falls, blood flows back from arteries, filling the leaflets of semilunar valves and forcing them to close Operation of the semilunar valves (b)

26  Systemic circulation  Blood flows from the left side of the heart through the body tissues and back to the right side of the heart  Pulmonary circulation  Blood flows from the right side of the heart to the lungs and back to the left side of the heart

27 Figure 11.3

28  Arteries  Aorta Leaves left ventricle  Pulmonary arteries Leave right ventricle

29  Veins  Superior and inferior venae cavae Enter right atrium  Pulmonary veins (four) Enter left atrium

30 Figure 11.2c

31  Superior and inferior venae cavae dump blood into the right atrium  From right atrium, through the tricuspid valve, blood travels to the right ventricle  From the right ventricle, blood leaves the heart as it passes through the pulmonary semilunar valve into the pulmonary trunk  Pulmonary trunk splits into right and left pulmonary arteries that carry blood to the lungs

32  Oxygen is picked up and carbon dioxide is dropped off by blood in the lungs  Oxygen-rich blood returns to the heart through the four pulmonary veins  Blood enters the left atrium and travels through the bicuspid valve into the left ventricle  From the left ventricle, blood leaves the heart via the aortic semilunar valve and aorta

33 Figure 11.3

34  Blood in the heart chambers does not nourish the myocardium  The heart has its own nourishing circulatory system consisting of  Coronary arteries—branch from the aorta to supply the heart muscle with oxygenated blood  Cardiac veins—drain the myocardium of blood  Coronary sinus—a large vein on the posterior of the heart, receives blood from cardiac veins  Blood empties into the right atrium via the coronary sinus

35 1. What is the location of the heart in the thorax? 2. How does the function of the systemic circulation differ from that of the pulmonary circulation? 3. Why are the heart valves important? 4. Why might a thrombus in a corarnary artery cause a sudden death?

36 5. Draw a diagram of the heart showing the three layers composing its wall and its four chambers. Label each. Show where the AV and semilunar valves are. Show and label all blood vessels entering and leaving the heart chambers. 6. Trace a drop of blood from the time it enters the right atrium of the heart until it enters the left atrium. What is this circuit called? 7. What is the function of the fluid that fills the pericardial sac?

37 8. Define systole, diastole, stroke volume, and cardiac cycle. 9. How does the hearts ability to contract differ from that of other muscles of the body.


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