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The pharynx (pl.: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates, though its structure varies across species. The pharynx carries food to the esophagus and air to the larynx.
The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). Digestion involves the breakdown of food into smaller and smaller components, until they can be absorbed and assimilated into the body.
Digestion is a complex process controlled by several factors. pH plays a crucial role in a normally functioning digestive tract. In the mouth, pharynx and esophagus, pH is typically about 6.8, very weakly acidic. Saliva controls pH in this region of the digestive tract.
The mucosa is the innermost layer of the gastrointestinal tract. It surrounds the cavity of the tract and comes into direct contact with digested food . The mucosa is made up of three layers: [1] The epithelium is the innermost layer. It is where most digestive, absorptive and secretory processes occur.
The pharynx leads to the esophagus, a muscular tube that delivers food to the stomach, where some preliminary digestion occurs; here, the digestion is extracellular. From the stomach, food passes to the small intestine , where a battery of digestive enzymes continue the digestive process.
The function of the GI tract is to process ingested food by mechanical and chemical means, extract nutrients and excrete waste products. The GI tract is composed of the alimentary canal, that runs from the mouth to the anus, as well as the associated glands, chemicals, hormones, and enzymes that assist in digestion.
Food taken in through the mouth is digested to extract nutrients and absorb energy, and the waste expelled at the anus as feces. Gastrointestinal is an adjective meaning of or pertaining to the stomach and intestines. Most animals have a "through-gut" or complete digestive tract.
Nearly all fish have jaws and may seize food with them but most feed by opening their jaws, expanding their pharynx and sucking in food items. The food may be held or chewed by teeth located in the jaws, on the roof of the mouth, on the pharynx or on the gill arches. [13] Orange-eyed tree frog calling. Nearly all amphibians are carnivorous as ...