3. Circulatory System Consists of… Blood Vessels Blood Heart

4. What are the 3 types of circulation? System – between heart to body systems Pulmonary – between heart & lungs Coronary – between heart & heartS Two Pathways Pulmonary Circulation –Carries blood to lungs and back Systemic Circulation –Carries blood to body and back

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 now lets look inside the heart

8. 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

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

10. 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

11. Coronary Circulation Slide 11.12 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Blood in the heart chambers does not nourish the myocardium  The heart has its own nourishing circulatory system  Coronary arteries  Cardiac veins  Blood empties into the right atrium via the coronary sinus

12. What is coronary circulation? The flow of blood to and from the tissues of the heart When the coronary circulation is blocked, oxygen and nutrients cannot reach all the cells of the heart. This can cause a heart attack

14. Trace the pathway of blood from heart to lungs and back. A.Blood, high in carbon dioxide and low in oxygen, returns from the body to the heart. It enters the right atrium through the superior and inferior vena cava.

15. Trace the pathway of blood from heart to lungs and back. B. The right atrium contracts, forcing the blood into the right ventricle. When the right ventricle contracts, the blood leaves the heart and goes through the pulmonary artery to the lungs. The pulmonary arteries are the only arteries that carry blood that is high in carbon dioxide

16. Trace the pathway of blood from heart to lungs and back. C. Oxygen-rich blood travels from the lungs through the pulmonary vein and into the left atrium. The pulmonary veins are the only veins that carry oxygen- rich blood.

17. Trace the pathway of blood from heart to lungs and back. D. The left atrium contracts and forces the blood into the left ventricle. The left ventricle contracts, forcing the blood out of the heart and into the aorta.

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

21. Arteries: carries blood Away from heart –Large –Thick-walled, Muscular –Elastic –Oxygenated blood Exception Pulmonary Artery –Carried under great pressure –Steady pulsating Arterioles: smaller vessels, enter tissue

22. The ARTERY thick muscle and elastic fibres Arteries carry blood away from the heart. the elastic fibres allow the artery to stretch under pressure the thick muscle can contract to push the blood along.

23. Arteries: Built for high pressure pump Arteries –thicker walls provide strength for high pressure pumping of blood –narrower diameter –elasticity elastic recoil helps maintain blood pressure even when heart relaxes

24. The VEIN Veins carry blood towards from the heart. 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.

25. Veins: Built for low pressure flow Veins –thinner-walled –wider diameter blood travels back to heart at low velocity & pressure lower pressure –distant from heart –blood must flow by skeletal muscle contractions when we move »squeeze blood through veins –valves in larger veins one-way valves allow blood to flow only toward heart Open valve Blood flows toward heart Closed valve

26. Veins: Carries blood to heart –Carries blood that contains waste and CO 2 Exception pulmonary vein –Blood not under much pressure –Valves to prevent much gravity pull Venules: larger than capillaries

27. The CAPILLARY Capillaries link Arteries with Veins 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.

28. Capillaries –Smallest vessel –Microscopic –Walls one cell thick –Nutrients and gases diffuse here

29. Capillaries: Built for exchange Capillaries –very thin walls lack 2 outer wall layers only endothelium –enhances exchange across capillary –diffusion exchange between blood & cells

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

31. Blood Pressure Slide 11.36 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Measurements by health professionals are made on the pressure in large arteries  Systolic – pressure at the peak of ventricular contraction  Diastolic – pressure when ventricles relax  Pressure in blood vessels decreases as the distance away from the heart increases

32. Cardiac cycle systolic ________ diastolic pump (peak pressure) _________________ fill (minimum pressure) 1 complete sequence of pumping –heart contracts & pumps –heart relaxes & chambers fill –contraction phase systole ventricles pumps blood out –relaxation phase diastole atria refill with blood 110 ____ 70

33. Congestive Heart Failure (CHF) Decline in pumping efficiency of heart Inadequate circulation Progressive, also coronary atherosclerosis, high blood pressure and history of multiple Myocardial Infarctions Left side fails = pulmonary congestion and suffocation Right side fails = peripheral congestion and edema