All organism cells need nutrients to grow and function. Heterotrophic organisms, can`t produce their own nutrients. They obtain them from food. Multicelullar organisms have a lot of organs. Those organs are grouped in different systems that do diverse functions. 5 important systems work together to help our organism being correct: Digestive system, Respiratory system, Circulatory system, Excretory system, Lymphatic system.
* Digestive proccess: Like all animals, human beings obtain sugars, fats and proteins from food. This is done thanks to the digestive system. 3 phases are done here: Digestion, Absortion and Expulsion of waste.
The food can move from the digestive tract thanks to the peristaltic movements.
*Digestive system: (1)The digestive tract. Is 8 meters long. Is the place where is done the digestion and it starts in the mouth and finishes in the anus.(2) Accesory glands. A)Liver: Is located in the top right of the abdomen. It creates bile that then it goes to gallblader. Bile helps digesting fats and most toxic molecules.B) The pancrea: It produces hormones(insulin and glucagon) which relulates the amount of glucose in the bloodstream.It also secrets pancreatic juice, which enters in duodenum. This contains digestive enzymes and sodioum bicarbonate, which neutralised the acidic chyme.
* Stages of the digestion in food:
-Mouth= The food entres in our organism from here. The mouth do this two functions: Salivation(saliva is created by salivary glands. It has enzymes and saliva helps to cut the food.(Chemical)) and Masication( With our teeth we cut the food(phisical)). All this, produces a food bolus
-Pharynx= Is a duct that takes part in respiratory and digestive system.The food bolus swallows to the Esophagus thanks to the Epiglotis and to peristaltic movements
-Stomach= The gastric digestion starts. Here, phisically and chemicaly digestions occur simultaneously. The walls of the stomach move the food(peristaltic) and the gastric juices cut the food bolus. This creates a chyme(a pulp)
-Large intestine= Some food it is not neccesary so it goes to the large intestine. Here it does ascending transverse and descending colom and it is expuls from the anus.