Digestive And Mechanical Digestion

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Digestion can be described as food being broken down into its most basic and simple components so that we can absorb the nutrients to give us energy and nutrition. Digestion occurs in what is known as the gastrointestinal (GI) tract which consists of the mouth, esophagus, stomach, small intestine, large intestine (colon), and other important organs such as salivary glands, the liver, pancreas, and gallbladder.
Digestion first occurs with food entering the mouth. Food is usually comprised of three macronutrients: carbohydrates, fats (lipids), and proteins. In the mouth mechanical digestion via the grinding of food between teeth and movement of the tongue help mix the food with fluid excreted by salivary glands in the mouth known as saliva.
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Segmentation (the sloshing motion that mixes chyme with the enzymes and chemical fluids in the small intestine) and pendular movement (a constrictive wave that involves forward and reverse movements and enhances nutrient absorption) will be the main contributors to mechanical digestion in the small intestine. The liver, gallbladder, and pancreas secrete enzymes, fluids, and hormones which will help in the chemical digestion of the macronutrients into their simplest components so that they can be absorbed by the body via villi and microvilli (known as the brush border) and eventually circulated through the blood stream and lymph …show more content…
The pancreas releases pancreatic amylase to break down the remaining starch units into maltose. The remaining disaccharides – maltose, sucrose, and lactose – are then broken down into monosaccharides –glucose, fructose, and galactose – via brush border enzymes such as maltase, sucrose, and lactase within the microvilli. The remaining monosaccharides are absorbed directly into the bloodstream for storage in the liver as glycogen via glycogenesis (fructose and galactose are also converted to glucose so that they can be converted to glycogen after) which will be then used as energy for cells (in the form of glucose) via a process called gylcogenolysis later. Excess glucose will be converted and stored as fat.
The majority of the chemical digestion of fat takes place in the small intestine but requires the help of secretions from the liver, gallbladder, and pancreas. The liver creates bile and stores it in the gallbladder. During digestion in the small intestine, the liver and gallbladder release bile to help emulsify fat which helps the enzyme pancreatic lipase breakdown the remaining fat molecules into monoglycerides and fatty acids so that they can be packaged into micelles which will transport the fats through the bloodstream or lymph system via lipoproteins such as

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