1. Circulation

2. Primary Principle of Circulation
The primary fluid flow principle derives from Newton’s first and second laws of motion:
A fluid does not flow when the pressure is the same in all parts of it
A fluid flows only when its pressure is higher in one area than in another, and it flows always from its higher pressure area toward its lower pressure area

4. Arterial Blood Pressure
High pressure must be maintained in the arteries to keep blood flowing through the cardiovascular system.
The chief determinant of arterial blood pressure is the volume of blood in the arteries.
Arterial blood volume is directly proportional to arterial pressure.
An increase in arterial blood volume causes an increase in arterial pressure.

5. SV(volume/beat) x HR(beat/min) = CO(volume/min)
Cardiac Output
Cardiac output (CO) is determined by the volume of blood pumped out of the ventricles by each beat (stroke volume or SV) and by heart rate (HR)
SV(volume/beat) x HR(beat/min) = CO(volume/min)

6. Peripheral Resistance
Peripheral resistance is the resistance to blood flow caused by friction of blood passing through blood vessels.
Friction develops because of a characteristic of blood—its viscosity, or stickiness—and partly from the small diameter of arterioles and cappilaries.
Viscosity stems mainly from the red blood cells, but also from protein molecules present in the blood.

8. Aortic and carotid sinus pressoreflexes
These pressoreflexes operate in a feedback loop that maintains the homeostasis of blood pressure by decreasing the heart rate when the blood pressure surpasses the set point. 

9. Relative Blood Volumes

10. Blood Pressure Control Mechanisms
There are many factors that control the cardiovascular system.
An area in the medulla called the vasomotor center or vasoconstrictor center, will, when stimulated, initiate an impulse outflow via sympathetic fibers that ends in the smooth muscle surrounding resistance vessels, arterioles, venules, and veins, causing their constriction.

11. Changes in Local Blood Flow During Exercise

12. Venous Return to the Heart
Venous Pumps – the blood pumping action of respirations and skeletal muscle contraction
Total Blood Volume – the greater the total volume of blood, the greater the volume of blood returned to the heart.

13. Venous Return

14. Semilunar Valves Local blood pressure pushes flaps open
When pressure below the valve drops, blood flows backwards and the valve closes

15. Capillary Exchange and Total Blood Volume
Capillary exchange – the exchange of materials between plasma in the capillaries and the surrounding interstitial fluid of the systemic tissues.

17. Measuring Blood Pressure
The sphygmomanometer measures the amount of air pressure equal to the blood pressure in an artery.
The sounds that one hears when taking a blood pressure are called Korotkoff sounds.
The first sound indicates the systolic blood pressure and the last sound is an indication of the diastolic pressure.
Normal blood pressure is about 120 over 80 (120/80)

19. Mechanism of Pulse
Intermittent injections of blood from the heart into the aorta, which alternately increases and decreases the pressure in that vessel. If blood steadily poured out of the heart into the aorta, there would be no pulse.
The elasticity of the arterial walls, which allows them to expand with each injection of blood and then recoil. If the vessels were fashioned from rigid material, you would not be able to feel a pulse even tough there would still be a pressure change.

20. Where the Pulse Can Be Felt
The pulse can be felt whenever an artery lies near the surface and over a bone or other firm background.

21. Hypertension (High Blood Pressure)
Defined as a blood pressure of 140/90 and above
Risk factors include: genetics, sex, race, age, stress, high alcohol and caffeine intake, obesity, smoking and lack of exercise