Quick Answer. The effects of caffeine start within 10 minutes after it is consumed, according to ScienceDaily. However, caffeine requires 45 minutes to reach its maximum concentration in the blood. Continue Reading.
The heart, blood, and blood vessels are the three structural elements that ... These nutrients enter the bloodstream by passing through the walls of the intestine.he heart, blood, and blood vessels are the three structural elements that ... These nutrients enter the bloodstream by passing through the walls of the intestine.
The lining of the small intestine is covered with microscopic projections called villi which dramatically increase its surface area. Molecules of nutrients dissolve in fluids in the intestine and pass into the villi. From there, nutrients pass through the thin walls of the blood vessels in the villi, and into the body.