Ingestion is the process of downloading or expelling undigested materials or food from the body as feces. In unicellular organisms, the materials are simply expelled from the cell, while in multicellular organisms, food follows the path of the digestive system until it is expelled through the anus.
Ingestion should not be confused with excretion, defined as a process of eliminating toxic materials, excess substances, or waste products from the body.
Process of animal management
The human digestive system is responsible for processing food. This system is primarily composed of the gastrointestinal tract, also known as the digestive tract, and a series of accessory organs, such as the pancreas, which also assist the digestive tract.
The process begins when food enters the gastrointestinal tract through the mouth. This first step is known as ingestion.
Food is then broken down through digestion. Mechanical decomposition begins in the mouth with the teeth, and chemical decomposition is aided by enzymes in saliva and on the tongue that break down food.
Food digested in the mouth is known as a food bolus. The bolus now travels through the esophagus to the stomach and then to the small intestine for further digestion.
The digested food is then absorbed through the walls of the small intestine into the blood, and thus each absorbed particle travels to the places in the body where it is needed.
Only small, soluble substances can pass through the intestinal wall. The end products of digestion are glucose, fatty acids, glycerol, and amino acids. Minerals and vitamins do not require digestion, so they are absorbed directly into the blood.
By the end of the small intestine, nutrients have been absorbed by the watery stream. Remaining substances, such as indigestible food, are transferred to the large intestine.
Onset of ejaculation
Ingestion occurs in the large intestine. The intestine is responsible for absorbing water bound to indigestible substances, and this material becomes the waste that becomes feces.
Feces are composed primarily of cellulose, bacteria, water, and fiber. The latter component cannot be digested by humans and is part of the cell wall of plants. Feces not only contain waste but can also contain materials that are toxic to the body.
Ingestion begins when waste is transferred and accumulated in the rectum until the body is stimulated to evacuate the waste through the anus. Stool is broken down by bacteria in the large intestine and is usually firm or solid.
Ingestion is controlled by the anal sphincter, composed of the internal and external sphincters . The internal sphincter is a continuation of the internal rectus muscle. This sphincter has involuntary control.
The external sphincter has somatic innervation or voluntary activity. When the anal canal is empty, the anal sphincter contracts. Conversely, when waste accumulates in the rectum, the anal sphincter stretches, allowing the expulsion of feces.
References
- Dictionary of biology (2008). Egestion
- Lucy, A. (2017). Differences between excretion and ingestion. My Tutor LTD UK
- Scientific Learning Organization (2011). The human digestive system.
- BBC Life (2014). Diet, drugs and health. KS3 Revision Bites .
- Saint Charles College (2014). The digestive system.
- Chawla, J. (2017). Anal sphincter electromyography and sphincter function profiles.” Background, Indications, Contraindications. MedScape.
- Keeton, W., and Harvey, D. (2016). Human digestive system. Encyclopedia Britannica.
- Bowel Control Consultancy (2011). Rectum and muscles.