digestion

Examples of digestion in the following topics:

• 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).

• Digestion and Absorption

  • Mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes.
  • Different organs play specific roles in the digestive process.
  • Digestive enzymes are found in the digestive tracts of animals.
  • The digestion of carbohydrates begins in the mouth.
  • Digestion of carbohydrates is performed by several enzymes.

• Digestive Systems

  • Animals use the organs of their digestive systems to extract important nutrients from food they consume, which can later be absorbed.
  • 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 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).
  • This diagram shows a generalized animal digestive system, detailing the different organs and their functions.

• Vertebrate Digestive Systems

  • Vertebrates have evolved more complex digestive systems to adapt to their dietary needs.
  • Humans and many animals have a monogastric digestive system .
  • The process of digestion begins with the mouth and the intake of food.
  • 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 System: Mouth and Stomach

  • The extensive chemical process of digestion begins in the mouth.
  • A large part of digestion occurs in the stomach .
  • Further protein digestion takes place in the small intestine.
  • Digestion of food begins in the (a) oral cavity.
  • Enzymes in the saliva begin to digest starches and fats.

• Hormonal Responses to Food

  • 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.
  • Understanding the hormonal control of the digestive system is an important area of ongoing research.
  • Hormones, such as secretin and cholecystokinin, play important roles in digestive processes.
  • These hormones are released from endocrine tissue to generate specific controls in the digestion of chyme.

• 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

• Lysosomes

  • Lysosomes are organelles that digest macromolecules, repair cell membranes, and respond to foreign substances entering the cell.
  • If no food is provided, the lysosome's enzymes digest other organelles within the cell in order to obtain the necessary nutrients.
  • In addition to their role as the digestive component and organelle-recycling facility of animal cells, lysosomes are considered to be parts of the endomembrane system.
  • They are so common in animal cells because, when animal cells take in or absorb food, they need the enzymes found in lysosomes in order to digest and use the food for energy.
  • Lysosomes are not needed in plant cells because they have cell walls that are tough enough to keep the large/foreign substances that lysosomes would usually digest out of the cell.

• Pancreas

  • The pancreas produces digestive enzymes and hormones, which are important in blood sugar regulation and other body functions.
  • It contains both exocrine cells that excrete digestive enzymes and endocrine cells that release hormones.
  • As a digestive organ, the pancreas secretes pancreatic juice containing digestive enzymes that assist the absorption of nutrients and the digestion in the small intestine.

• Herbivores, Omnivores, and Carnivores

  • These animals have evolved digestive systems capable of digesting large amounts of plant material.
  • Since some parts of plant materials, such as cellulose, are hard to digest, the digestive tract of herbivores is adapted so that food may be digested properly.
  • They have long and complex digestive tracts to allow enough space and time for microbial fermentation to occur.
  • Some herbivores contain symbiotic bacteria within their intestines to aid with the digestion of the cellulose found in plant cell walls.