1. The Cardiovascular System

2. Physiology of Circulation

3. Compare and Contrast – Arteries & Veins

4. Arteries - Characteristics
Thicker tunica media – smooth muscle layer
Smaller lumen
Elastic – stretch and recoil as blood is pumped through
High pressure
Carry blood away from heart

5. Veins - Characteristics
Thin tunica media (smooth muscle layer)
Larger lumen
Rely on other structures to help return blood to heart
Valves
Skeletal muscle
Pressure changes in thoracic cavity

6. Arterial Pulse
Pulse: the alternating expansion and recoil of artery as the left ventricle contracts
Usually equals pulse rate
Normal pulse rate: bpm
Pressure points: pulse points compressed to stop blood flow

7. Blood Pressure
Pressure blood exerts against the inner walls of the blood vessels
Blood flows from aorta  arteries arterioles  capillaries  venules  veins  vena cava
Pressure is strongest at the aorta, and zero at the vena cava

8. You Decide:
Which was cut in the man – an artery or vein? How do you know?

9. Measuring Blood Pressure
Systolic pressure: pressure in arteries at the peak of ventricular contraction
Diastolic pressure: pressure when ventricles relax
normal BP: 120 (systolic)/80 (diastolic)

10. Factors affecting blood pressure
Peripheral resistance
Friction encountered as blood flows through vessels
Age, weight, time of day, exercise, body position, emotional state, drugs
Neural factors
Sympathetic system causes vasoconstriction of vessels which increases blood pressure
Renal factors (kidneys)
Alter blood volume
As BP increases above normal, kidneys excrete more water into urine

11. Factors Continued Temperature Chemicals Diet
Cold causes vasoconstriction, heat is a vasodilator
Chemicals
Nicotine causes vasoconstriction (increases bp), alcohol causes vasodilation (decreases bp)
Diet
Low salt, saturated fats and cholesterol help prevent hypertension (high bp)