chemical digestion

Examples of chemical digestion in the following topics:

• Digestion and Absorption

  • In order for nutrients (carbohydrates, lipids, vitamins) to be absorbed for energy, food must undergo chemical and mechanical digestion.
  • Digestion is the mechanical and chemical break down of food into small organic fragments.
  • In chemical digestion, enzymes break down food into the small molecules the body can use.
  • Digestive enzymes are found in the digestive tracts of animals.
  • Mechanical and chemical digestion of food takes place in many steps, beginning in the mouth and ending in the rectum.

• Digestive System: Mouth and Stomach

  • The extensive chemical process of digestion begins in the mouth.
  • A large part of digestion occurs in the stomach .
  • This highly-acidic environment is required for the chemical breakdown of food and the extraction of nutrients.
  • Chemical digestion is facilitated by the churning action of the stomach.
  • Digestion of food begins in the (a) oral cavity.

• Digestive System: Small and Large Intestines

  • The bulk of chemical digestion and nutrient absorption occurs in the jejunum.
  • The anus, an opening at the far-end of the digestive tract, is the exit point for the waste material.
  • The organs discussed above are those of the digestive tract through which food passes.
  • The pancreas is another important gland that secretes digestive juices.
  • Describe the parts of the digestive system from the small intestine through the accessory organs

• Vertebrate Digestive Systems

  • Humans and many animals have a monogastric digestive system .
  • The enzymes present in saliva also begin to chemically break down food.
  • Most of the chemical digestion and absorption happens in the intestine, while the waste is excreted through the cloaca.
  • The digestive enzymes of these animals cannot break down cellulose, but microorganisms present in the digestive system can.
  • This is the site where the roughage is fermented and digested.

• Digestive Systems

  • During digestion, food particles are broken down to smaller components which will later be absorbed by the body.
  • The digestive system is one of the largest organ systems in the human body.
  • The cells of the human body all require a wide array of chemicals to support their metabolic activities, from organic nutrients used as fuel to the water that sustains life at the cellular level.
  • The digestive system not only effectively chemically reduces the compounds in food into their fundamental building blocks, but also acts to retain water and excrete undigested materials.
  • The functions of the digestive system can be summarized as follows: ingestion (eat food), digestion (breakdown of food), absorption (extraction of nutrients from the food), and defecation (removal of waste products).

• Types and Functions of Proteins

  • These enzymes are essential for chemical processes like digestion and cellular metabolism.
  • The substrates are the reactants that undergo the chemical reaction catalyzed by the enzyme.
  • These enzymes include amylase, which catalyzes the digestion carbohydrates in the mouth and small intestine; pepsin, which catalyzes the digestion of proteins in the stomach; lipase, which catalyzes reactions need to emulsify fats in the small intestine; and trypsin, which catalyzes the further digestion of proteins in the small intestine.
  • Some proteins function as chemical-signaling molecules called hormones.
  • Other proteins act as receptors to detect the concentrations of chemicals and send signals to respond.

• Ingestion

  • Mastication, or chewing, is an extremely important part of the digestive process, especially for fruits and vegetables, as these have indigestible cellulose coats which must be physically broken down.
  • Also, digestive enzymes only work on the surfaces of food particles, so the smaller the particle, the more efficient the digestive process .
  • While the food is being mechanically broken down, the enzymes in saliva begin to chemically process the food as well.
  • Describe the process of ingestion and its role in the digestive system

• Hormonal Responses to Food

  • The system is made of a series of glands that produce chemicals called hormones.
  • These hormones are chemical mediators released from endocrine tissue into the bloodstream where they travel to target tissue and generate a response.
  • In the duodenum, digestive secretions from the liver, pancreas, and gallbladder play an important role in digesting chyme during the intestinal phase.
  • Foods high in lipids (fatty foods) take a long time to digest.
  • Hormones, such as secretin and cholecystokinin, play important roles in digestive processes.

• The Role of Energy and Metabolism

  • Metabolism is the set of life-sustaining chemical processes that enables organisms transform the chemical energy stored in molecules into energy that can be used for cellular processes.
  • Plants convert light energy from the sun into chemical energy stored in molecules during the process of photosynthesis.
  • Some of these chemical reactions are spontaneous and release energy, whereas others require energy to proceed.
  • For every action that requires energy, many chemical reactions take place to provide chemical energy to the systems of the body, including muscles, nerves, heart, lungs, and brain.
  • Carnivores eat the herbivores, and decomposers digest plant and animal matter.

• Invertebrate Digestive Systems

  • Invertebrates can be classified as those that use intracellular digestion and those with extracellular digestion.
  • The simplest example of digestion intracellular digestion, which takes place in a gastrovascular cavity with only one opening.
  • The alimentary canal is a more advanced digestive system than a gastrovascular cavity and carries out extracellular digestion.
  • Because the food has been broken down exterior to the cells, this type of digestion is called extracellular digestion.
  • Their food is broken down in their digestive tract (extracellular digestion), rather than inside their individual cells (intracellular digestion).