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.
If you refer to the physical thing, nutrients is absorbed into the blood capillaries (other than fat molecules) and lacteals (fat molecules only) in the villi, which are lin â¦ ing the small intestine.his is a multifasceted question as there is no one place nutrients enter the bloodstream. If you are looking for a general answer, the gastrointestinal (GI) system digests an â¦ d places the digested nutrients in the body via the bowels (large and small) through extensive networks of capillaries.