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.
Since most all nutrients that a human needs are absorbed via the digestive system. All carbohydrates, proteins, and fats are absorbed in the small intestine.    Thin â¦ gs are absorbed throughout the entire system, with the exception of the esophagus. Some glucose, for example, can be absorbed in the mouth. Water, alcohol, and some nutrients are absorbed in the stomach. Most nutrient absorption occurs in the small intestine. Water and some minerals and vitamins are absorbed in the colon. Most vitamin K is produced by bacteria in the colon and absorbed there. 33 people found this useful. 1  The Five Major Parts of the Brain At its most basic, the brain controls the body.