Digestive systems

• The digestive system is the organ system that breaks down food into nutrients, which are then absorbed by the body.
• Swallowing involves peristalsis, a wave-like contraction of muscles that propels food through the esophagus towards the stomach.
• Saliva contains enzymes such as amylase, which break down carbohydrates into simple sugars.
• Digestion begins with chewing or mastication, where food is broken up mechanically to increase its surface area for chemical breakdown.
• Swallowing involves moving food through the esophagus to the stomach by peristalsis (muscle contractions).
• In the small intestine, bile from the liver and pancreatic juice from the pancreas contain enzymes that further break down fats, proteins, and carbohydrates.

  
• TYPES OF DIGESTION

  1. Intracellular: this of course when digestion takes place inside the cell within a food vacuole. Simple unicellular organisms like amoeba and paramecium digest their food intracellularly
  2. Extracellular: this occurs when digestion takes place in the guts. The gut cavity is an extension of the external environment as such food in the gut is considered being outside the animals body
• NOTE;

  Hydra from the phylum Ceolenterata or Cnidaria is capable of both intracellular and extracellular digestion
• PROCESS OF DIGESTION

  Digestion is the number of processes that modify food within and animals body in order to make the nutrients and organic molecules accessible for cellular function
• Classification of Animals According to their Diet

  1. Herbivores: animals whose primary food source is plant based examples dear cricket caterpillar goat cattle etc. Herbivores can be further divided into frugivores (fruit eaters),granivores(grain and seed feeders),nectivores(nectar feeders),folivores(leaf eaters)
  2. Carnivores: Animals that eat other animals e.g lion, snake, spider, ladybug
  3. Omnivores: Animals that eat both plants and animal derived foods e.g humans, chicken, cockroach, crayfish
• The process of digestion begins with ingestion which is the taking in of food into the mouth.
• Digestion continues with mechanical breakdown where food is mechanically broken down into smaller pieces using teeth and jaws.
• Chemical breakdown is the next stage in digestion where food is chemically broken down into simpler substances using enzymes produced by the saliva and gastric juices.
• Absorption is the final stage in digestion where the digested products are absorbed across the walls of the alimentary canal into the bloodstream.
• Defecation is the process where waste materials are eliminated from the body via the rectum and anus.