What happenes to food after it is ingested by an animal?

Answer 1

If the the animal you are talking about is humans, then here's what happenned to the food:

In the mouth, the teeth would be grinding the food to break it down into smaller pieces and thus increasing the surface area to volume ratio for the food. The food would then have salivary amylase to work on them. The Saliva amylase would act on the starch and change them into glucose (Simple form of sugar). Then the Mucin in saliva softens the food before your toungue rolls the food in to a ball called boli to enable easier swallowing.

In the Oesophagus (Gullet), the food is pushed down through the muscular tube and when the back contracts , the front relaxes and thus causing the food to move downwards into the stomach. And important note is that no digestion takes place here.

When the food has reached the stomach, Gastric Juices,(Hydrocloric acid) stop all salivary amylase acting on the food and produces Protease to start digesting the Proteins from Proteins to Polypeptides. Also, this is where most of the germs are killed before it enters asorbtion in the S.I . But before that, the food undergoes a series of tumbling in the stomach and there would be a substance called mucus to protect the walls of the stomach to prevent the stomach from being corroded. After about 4~5 hours, the food you have eaten has turned from a solid form into somewhat like a thick soup.

After the food has been digested in the stomach, it would be moved through a small opening phyloric sphicter into the Small Intestine (S.I). The small intestine is filled with tiny villis, and on each villis contains a few hundreds of micro villis. This is to ensure that Surface Area to volume ratio and that Diffusion and Osmosis could occur more effectively and effieciently. The small intestine contains of three parts, Deodenum, Jejunum and Heum. These parts makes out above 6 metres of your small intestine which allows diffusion , osmosis and active transport to happen and asorb all the food. In the Intestine, Pancreas produces Pancreatic juices and Intestine produces intestinal juice to digest all the remaining proteins, starch, maltose into Amino acids and Glucose which is the simplest form for asorbtion. After this, the food is then asorbed before it is transported to you liver which produces bile to emulsify fat molecules into 3 fatty acids and 1 glycerol molecule. and the food would be Detoxify to ensure that the food would not be "Poisoned". The toxins would then be passed out as Urea or Urine. After most nutrients is asorbed, it would go to the Large intestine.

In the large intestine, the water, nutrients and minerals from the food would be asorbed and brought to your liver for processing to reuse this process is also called Assimilation. After that is done, the food would be called faeces and would be stored in the rectum ( not anus) before it is passed through the anus which is also called Ejection.

So in a nutshell how stuffs work,

Mouth > Oesophagus > Stomach > Small Intestine > Large intestine > Rectum > Anus

Ingestion > Digestion > Asorbtion > Assimilation > Ejection

Igestion > Mouth & maybe Oesophagus

Digestion > Stomach & Small Intestine

Assimilation > Small & Large Intestine

Ejection > Rectum & Anus