| A | B |
|---|
| coronary artery | carries blood to the heart itself |
| pulse | relaxing and contraction of artery |
| diffusion | movement of molecules from area of greater concentration to area of lower concentration |
| blood pressure | force of blood against the walls of the arteries |
| structure of artery walls | very thick; three cell layers; smooth inside, muscle middle, outer is flexible connective tissue |
| function of arteries | carry blood away from the heart to all parts of the body |
| structure of capillaries | only one cell thick |
| function of capillaries | exchange materials between the blood and body cells |
| structure of veins | thinner walls; three cell layers; smooth, muscle, and connective tissue outer layer |
| function of veins | return blood to the heart |
| what causes blood pressure? | contraction of ventricles to force blood |
| size of blood vessels | from width of human hair to width of thumg |
| length of blood vessels | almost 100,000 km |
| which blood vessels have the highest pressure? | arteries |
| why do arteries get wider? | to allow more blood flow to a particular area |
| why do arteries get narrower? | to decrease blood flow to a particular area |
| what helps blood flow back to the heart? | contraction (squeezing) of skeletal muscles; valves keep flow moving in one direction |
| why is blood pressure highest in the aorta? | it is nearest the contracting ventricle |
| why is blood pressure lower in the legs? | further from the beating heart |
| sphgmomanometer | instrument that measures blood pressure |
