2007-03-17 15:56:57 · 4 answers · asked by Ruby Georgie 3 in Science & Mathematics ➔ Biology
In humans, digestion begins in the oral cavity where food is chewed (mastication) with the teeth. The process stimulates exocrine glands in the mouth to release digestive enzymes such as salivary amylase, which aid in the breakdown of starch. Chewing (mechanical catabolism) also causes the release of saliva, which helps condense food into a bolus that can be easily passed through the esophagus. The esophagus is about 20 centimeters (about eight inches) long. Saliva also begins the process of chemical catabolism, hydrolysis. Once food is chewed properly, the food is swallowed. The bolus is pushed down by the movement called peristalsis, which is an involuntary wave-like contraction of smooth muscle tissue, characteristic of the digestive system. The mechanism for swallowing is co-ordinated by the swallowing centre in the medulla oblongata and pons. The reflex is initiated by touch receptors in the pharynx as a bolus of food is pushed to the back of the mouth by the tongue. The uvula is a small flap that hangs from the roof of the mouth. During swallowing it and the soft palate retract upward and to the rear to close the nasopharynx, which prevents the food from entering the nasal passages by triggering closure of the soft palate. When swallowed, the food enters the pharynx, which makes special adaptations to prevent choking or aspiration when food is swallowed. The epiglottis is a cartilage structure that closes temporarily during swallowing, preventing food and liquids from entering the trachea.
2007-03-17 15:59:40 · answer #1 · answered by Anonymous · 0⤊ 0⤋
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Mouth
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It has been suggested that this article or section be merged with mouth (human). (Discuss)
For the Merril Bainbridge song, see Mouth (song).
For mouth of a river, see river delta.
The human mouth.
The human mouth.
The mouth, also known as the buccal cavity or the oral cavity, is the orifice through which an organism takes in food and water.
Contents
[hide]
* 1 Location
* 2 Anatomy
* 3 Uses
* 4 See also
[edit] Location
In all mammals, the mouth is forward-facing in the face. Non-mammals have mouths in other locations (i.e. the mouth of the planarium is in the middle of its belly). Some animals, such as the cnidarians, the brachiopods, and the planaria, do not have a separate anus, and thus expel waste through the mouth.
[edit] Anatomy
Most animals have a complete digestive system, with a mouth at one end and an anus at the other. Which end forms first in ontogeny is a criterion used to classify animals into protostome and deuterostome. In arthropods, they are external modified legs; in gnathostomata vertebrates they are internal.
[edit] Uses
Look up Mouth in
Wiktionary, the free dictionary.
Generally the mouth is used to intake food, though it has other uses.
* In snakes, the mouth is used to inject venom through fangs
* Many animals lacking opposable thumbs the mouth is used to hold objects, including food
[edit] See also
* Mouth (human)
This page contains multiple definitions of the same term, and a user has therefore recommended this page for disambiguation in the near future.
Retrieved from "http://en.wikipedia.org/wiki/Mouth"
Categories: Articles to be merged since March 2007 | Mouth | Animal anatomy
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2007-03-17 16:05:21 · answer #2 · answered by Anonymous · 0⤊ 0⤋
As far as chemical digestion goes, only carbohydrates start to be digested in the mouth (proteins in the stomach, lipids in the small intestine). When the carbs enter your mouth, salivary amylase starts to break polysaccharides into disaccharides and some glucose.
2007-03-17 16:31:09 · answer #3 · answered by toeysgirl 2 · 0⤊ 0⤋
breaking down of food particles with the help of enzymes in to slimpler units.
2007-03-17 16:07:42 · answer #4 · answered by Anonymous · 0⤊ 0⤋