1. Blood Circulation Physiology

2. Vascular System O Blood circulates inside blood vessels O Comprises the vascular system O Arteries O Carries blood AWAY from the heart O Vein O Carries blood TOWARD the heart O Capillaries O Connect arteries and veins and is the site of gas exchange O Oxygen is delivered to tissues

3. Branches O The aorta is the major artery of the heart O Eventually it will branch into arterioles O These arterioles feed into capillary beds O Beds drained by venules, which eventually turn into veins

4. True or False O All veins carry deoxygenated blood.

5. Structural Differences O Arteries have thicker walls than veins O Arteries are closer to the pumping action and must be able to expand and recoil O The pressure is higher so the walls must be stronger O Veins have thinner walls than arteries O The pressure in these vessels is much lower O Capillary walls are 1 cell-layer thick O This enables easy gas exchange

6. O If you were to cut a major vein, the blood would flow in a steady stream from the wound O If you were to cut a major artery, the blood would produce rapid spurts of blood O Yes, it would squirt at you!

7. Pulse O The alternating expansion and recoil that occurs with every beat of the left ventricle creates a pressure wave that travels throughout all of the arteries O Known as a pulse O Average: 70-80 beats per minute O Influenced by activity, postural changes, and emotions

8. Blood Pressure O What is blood pressure? O The pressure the blood exerts against the inner walls of the blood vessels O The force that keeps blood circulating continuously even between heart beats

9. Blood Pressure O Impacted by genetics, race, family history, diet, exercise, age

10. O When the ventricles contract, they force blood into large, thick-walled elastic arteries that expand as the blood is pushed into them O The high pressure in these arteries forces the blood to continually move to areas where the pressure is lower O Blood pressure is highest in large arteries and continues to drop throughout the pathway

11. O Predict: Where is the blood pressure the lowest? O The vena cava O It is the last stop—the last vein—in the human body

12. Measuring Blood Pressure O The heart continually alternately contracts and relaxes O On-and-off flow of blood in arteries causes the blood pressure to rise and fall during each beat O Systolic pressure: the pressure in the arteries at the peak of ventricular contraction O Diastolic pressure: the pressure when the ventricles are relaxing

13. Blood Pressure O Reported in millimeters of mercury O mm Hg O Therefore, a blood pressure of 120/80 translates to: O 120 mm Hg during systole (ventricular contraction) O 80 mm Hg during diastole (ventricular relaxation)

14. Variations in Blood Pressure O Normal ranges O Systolic: 110-140 mmHg O Diastolic: 75-80 mmHg

15. O Hypotension: low blood pressure O Generally considered by to a systolic BP below 100 mmHg O Doesn’t always indicate a disease; it could just mean you are in good physical condition O Could also hint at poor nutrition, circulatory shock

16. O Hypertension: sustained elevated arterial pressure of 140/90 mmHg O Indicates that the heart is being overworked O Could lead to hypertrophy of the heart O Could also be because of atherosclerosis O Hardening of the arterial walls often as a result of cholesterol buildup