If you check out my squidoo lens www.squidoo.com/hair-beauty-and-health you will find more information informing you on how your hair, body, and health is more connected than you may know or realize this is so because the human body blood and lymph vessels are the energy & nutrient supply line to the human body skin and hair follicles. Until the time that the Catagen Phase reaches the blood vessels nourish the cells in the hair bulb which forms the base of the hair follicle and the hair bulb has living cells that divide and grow to build the hair shaft as it deliver hormones that modify your hair growth as well as structure at different of life during the hair growth cycle phase pattern.
The main components for regulating as well as promoting hair growth are your Hair Follicle, Dermal Papilla, and Dermal Sheath and they have structures that complement each other to help keep your hair growing as well as functioning normal and healthy. These structures are your Sebaceous Glands: which produces the human body natural conditioner called "sebum," Arrector Pili Muscle: which is a soft muscle that is responsible for making your hair stand up by raising the hair to catch the heat your warm stem cells gives off as part of a conjunction with this muscle, and the Capillaries: which are tiny blood vessels connected at the bottom of your hair bulb that provides the essential nutrients for your hair shaft which is the hair itself which is made up of three layers of dead hard protein called "Keratin" which is formed at the top of the hair bulb. Image source www.nileherb.blogspot.com/2008/09/hair-radiant-99.html the three layers of skin image.