What is the difference between absorption ingestion digestion and egestion

Besides nutritional items, other substances may be ingested, including medications where ingestion is termed oral administration and substances considered inedible, such as insect shells.

Ingestion is also a common route taken by pathogenic organisms and poisons entering the body. Some pathogens transmitted via ingestion include viruses, bacteria, and parasites. Most commonly, this takes place via the fecal-oral route. An intermediate step is often involved, such as drinking water contaminated by feces or food prepared by workers who fail to practice adequate hand-washing. This is more common in regions where untreated sewage is prevalent. Diseases transmitted via the fecal-oral route include hepatitis A, polio, and cholera.

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. Mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes.

In chemical digestion, enzymes break down food into the small molecules the body can use. It is important to break down macromolecules into smaller fragments that are of suitable size for absorption across cell membranes.

Large, complex molecules of proteins, polysaccharides, and lipids must be reduced to simpler particles before they can be absorbed by the digestive epithelial cells. Different organs play specific roles in the digestive process. The animal diet needs carbohydrates, protein, and fat, as well as vitamins and inorganic components for nutritional balance. Digestive enzymes are enzymes that break down polymeric macromolecules into their smaller building blocks, in order to facilitate their absorption by the body.

Digestive enzymes are found in the digestive tracts of animals. Digestive enzymes are diverse and are found in the saliva secreted by the salivary glands, in the stomach secreted by cells lining the stomach, in the pancreatic juice secreted by pancreatic exocrine cells, and in the intestinal small and large secretions, or as part of the lining of the gastrointestinal tract.

Intestinal microflora benefit the host by gleaning the energy from the fermentation of undigested carbohydrates and the subsequent absorption of short-chain fatty acids. Intestinal bacteria also play a role in synthesizing vitamin B and vitamin K as well as metabolizing bile acids, sterols and xenobiotics. Mechanical and chemical digestion : Mechanical and chemical digestion of food takes place in many steps, beginning in the mouth and ending in the rectum.

The digestion of carbohydrates begins in the mouth. The salivary enzyme amylase begins the breakdown of food starches into maltose, a disaccharide. As the food travels through the esophagus to the stomach, no significant digestion of carbohydrates takes place.

The acidic environment in the stomach stops amylase from continuing to break down the molecules. The next step of carbohydrate digestion takes place in the duodenum.

The chyme from the stomach enters the duodenum and mixes with the digestive secretions from the pancreas, liver, and gallbladder. Pancreatic juices also contain amylase, which continues the breakdown of starch and glycogen into maltose and other disaccharides. These disaccharides are then broken down into monosaccharides by enzymes called maltases, sucrases, and lactases. The monosaccharides produced are absorbed so that they can be used in metabolic pathways to harness energy.

They are absorbed across the intestinal epithelium into the bloodstream to be transported to the different cells in the body. Our Faculty. Behind the Scene. Tutorix for Schools. Contact Us. Reseller Opportunity. Follow us. Vomiting is the opposite action of ingestion in which the unwanted or toxic materials are eliminated through the mouth. After ingestion, the food particles enter the digestive system.

The digestion of food occurs in two methods: mechanical digestion and chemical digestion. During mechanical digestion, food is broken down into small particles. Chemical compounds in food are broken down into smaller compounds during the chemical digestion. Both mechanical and chemical digestion facilitate the absorption of nutrients by the body. The physiology of the digestive system of animals is shown in figure 1. Figure 1: Animal Digestive System.

Protozoa are a type of unicellular eukaryotic animals. Their ingestion of food particles occurs by endocytosis. They use two endocytic pathways: phagocytosis or pinocytosis for ingestion. In phagocytosis , pseudopodia are formed surrounding the food particle.

The food particle is taken into the cell by forming a phagosome. Absorption is when the digested building blocks are now absorbed into the bloodstream or lymphatic system through the intestines and then transported to various cells, tissues, organs in the body. Elimination is when waste products produced during digestion and absorption or left over after use by cells, or undigested remaints is now expelled from the body either via the urinary system as urine, digestive system as faeces, respiratory system as gases or integumentary system as perspiration.

I am going to add one more concept, secretion, where glands secrete certain useful chemicals like enzymes or hormones that may aid in many life processes, including digestion. What is the difference between ingestion, digestion, absorption, and elimination? Biology Energy in Cells Autotrophs vs Heterotrophs.