2. distribution of nutrients and transport of wastes
3. maintenance of body temperature
4. circulation of hormones
Parts of the circulatory system:
1. heart: a pump that pushes the fluid though the blood vessels or spaces
2. blood vessels: a system of spaces throughout the body in which fluid moves
a. arteries: thick-walled, carry oxygenated blood around the body
b. arterioles: thinner, control blood flow to capillaries
c. capillaries: smaller vessels (0.4mm-1mm long, diameter less than 0.005mm) – red blood cells must travel through in single file, where gas exchange occurs
d. venules: larger vessels that capillaries merge into
e. veins: even larger vessels that venules merge into. These carry deoxygenated blood. Blood flow is reduced here, one-way valves, muscle contractions push blood back to the heart.
3. blood: a fluid in which materials are transported. Blood flows from heart to 2a-e, back to heart
Part 2: The Circulatory System
Why do we need a circulatory system?
Parts of the circulatory system: