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.
In the jejunum, fat, starch and proteins from the food material are broken down and absorbed by the intestinal lining. The lining is covered with millions of tiny villi, or finger-like projections, that greatly increase the surface area, allowing nutrients to be more efficiently absorbed into the bloodstream. In the ileum, which is the last part of the small intestine, water and nutrients (such as vitamin B12) are absorbed.