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.
Water and nutrients are absorbed into the blood by the villi of the small intestine. Water is then filtered from the blood by the kidneys. well nutrients are absorbed mostly in the small intestine...but you said this takes place in the urinary system..