Homeostasis

All living organisms require complex set of interacting metabolic chemical reactions to maintain a constant environment. This include the simplest unicellular (prokaryote) organism to the most sophisticated organisms such as humans, animals and plants (eukaryote).

Homeostasis refers to any process that living things utilise to maintain stable internal environments, which are essential for survival. Homeostasis describes how living organisms maintain constant temperature, balance between acidity and basicity (pH) and maintain levels of water, minerals, vitamins, proteins, lipids, carbohydrates and blood – oxygen levels. Factors that affect homeostasis include strenuous exercise and survival in warm and cold climates. These factors affect temperature,

These contractions are believed to be caused or triggered by high concentrations of the hormone Ghrelin. Ghrelin is a peptide, which is produced by ghrelin cells in the gastrointestinal tract. It acts as a neuropeptide in the central nervous system, which is a small protein – like molecule, used by neurons to communicate with each other. Additionally, they influence the activity of the brain in specific ways, such as recognising rewards, metabolism, reproduction and social behaviours. Other than causing hunger, ghrelin plays a vital role in regulating the distribution and rate of use of energy. Ghrelin might also be secreted if the blood sugar levels are low, which can occur if food is not consumed for prolonged periods. The secretion of ghrelin acts on the hypothalamic brain cells, which leads to increased hunger, increased gastric acid secretion and gastrointestinal mobility to prepare the body for food intake. - lateral

There are two types of buffering agents, which include extracellular and intracellular buffers. Bicarbonate and ammonia can be classified as extracellular buffers, while intracellular buffers consists of proteins and phosphate groups.

Acid has a significant effect in the digestion of proteins. Gastric acid, whose main component is HCL, is secreted by the cells, which line the stomach as a primary response when proteins and fats are ingested. The main purpose of the acid is to break down the long chains of amino acid, however, this process is time consuming, therefore, digestive enzymes are secreted, which act as catalysts. Pepsin, Gastrin and gastric lipase are some of the enzymes that are