As soon as the food gets to a mouth, process of its digestion and food immediately begins turns to the energy necessary for our organism.
Processing and food mastering occurs in a digestive path. It is a tube in length about 9 m, having two aperture, - a mouth through which the food, and analnoe an aperture through which a waste is deduced arrives. The digestive path consists of several bodies: a mouth, drinks, a gullet, a stomach and intestines. Each of them plays a special role in the course of digestion.
In process of food passage on all path, on what day or two, enzimy - the substances developed by live cages and promoting chemical transformations leaves, - get through walls of digestive organs and mix up with food, accelerating its splitting. Only after that the organism can use its power resources.
The Digestive path begins in a mouth. Though the food is here very not for long, but this body posesses rather important role as its transformation here begins.
Lips are carried out by some functions, major of which – food forwarding in a mouth in the most economic way. Lips are penetrated by set of the nervous terminations and possess a hypersensibility to size, the invoice and temperature of that we eat. In a mouth the food in the most careful image (in an ideal) is chewed in homogeneous weight. Thus muscles of lips and cheeks are reduced, helping language to move it that does not remain not chewed slices.
Not less important role in the course of meal is played by a teeth. At 8 forward cutters - on 4 from above and from below - sharp gear edges that it was more convenient to bite off. 4 canines - on one from each party from cutters - tear off food pieces. 8 premoljarov - small "фтющэ№§" a teeth - and 12 most distant molars crush it. Chewing increases a food surface thanks to what salivary enzimam it is easier to begin its splitting on molecules. The saliva arrives in a mouth from three pairs special glands. It klejkovatoe the substance almost on 98% consists of water and times of personal enzymes, including amilazy which will transform food carbohydrates (starch) in monosaharidy; ptialina, too splitting starch; and destroying bacteria lizotsima. Water, in turn, dissolves some components of food. The mouth always is a little humidified by a saliva which is not supposing friction mindalina of language, a teeth and cheeks the friend about the friend at conversation. But at the sight of, a smell or even thoughts on meal at us that is called, slobbers flow. After the portion of food is chewed and partially split by salivary enzymes, language forms it in ready for proglatyvanija a lump.
Then language pushes a food lump in a drink, a brawny back wall of a nose, a mouth and a throat, and therefrom it gets to a gullet beginning somewhere in the middle of a neck. The gullet connects a mouth to a stomach.
The Trachea (a respiratory tube) too opens in a drink, and that the food casually has not got there at a sigh, it is closed at the moment of swallowing. The throat is closed with nadgortannikom - hrjashchevidnym a shoot behind language, - tightly closing an input in a trachea. At the same time the nasopharynx is closed by a soft palate. And then language by means of other pharyngeal muscles with force pushes a food lump in a gullet. If the food slice casually gets to a trachea, it there and then will be back thrown out in a mouth in a fit of coughing.
Swallowing begins as any movement but as soon as language and shchechnye muscles will push a food lump to a drink, reflex action which cannot be supervised begins. The waves of muscular reductions named peristaltikoj, push food downwards on a gullet. Thus gravity almost does not play a role, therefore it is possible to eat and drink, standing on a head or being in space in full weightlessness.
The Gullet represents a brawny tube with circular muscles, or sfinkterami, on both ends. Top sfinkter reveals, when the food passes downwards from drinks then it is closed, and peristaltika prozhimaet food in a stomach. Glands in gullet walls allocate special slime that the food easily sliped downwards.
Kardialnyj sfinkter in the bottom end of a gullet supervises an input in a stomach. Pressure in a stomach above, than in a gullet, therefore is important, that at the moment of disclosing kardialnogo sfinktera stomach contents were not pushed out in a gullet. That it has not occurred, the small site of smooth muscles of a gullet is reduced just at the moment of food receipt in a stomach, raising pressure so that stomach contents were not splashed out back. Having passed a portion of food in a stomach, kardialnyj sfinkter it is again closed. Here the food is longer, than in a gullet. A stomach - it similar to a bag of delay a bag in the form of the letter " J " consisting of three functional departments: kardialnogo, ground and privratnikovogo. Each department has enough clear boundary and allocates different gastric juice. All stomach is located in a strong muscular cover. Being reduced, it mixes particles of food with the gastric juice decomposing it on chemical components. These muscular reductions are supervised by the nervous system, in particular a wandering nerve which regulates development and allocation of digestive enzymes. Ready to leave a stomach the food looks like the dense liquid similar to milk called by a chemical moustache.
The Originality of a stomach that is the unique body allocating a considerable quantity of strong acids. One of them - hydrochloric - helps an organism to acquire fibers, to sterilise food and to kill bacteria. But it can cause a number of illnesses, in particular nesvarenie and a stomach ulcer. Surplus of acid can corrode stomach walls through.
Mastering of fibers
The beginning of mastering of fibers concerns number of the major functions of a stomach. The enzyme named pepsinom which is developed by cages of ground department of a stomach is engaged in this business, first of all. Pepsin starts to split up long chains of albuminous molecules for the small fragments named proteozami and peptonami. Splitting of fibers begins in a stomach, but before full end of this difficult and surprising process the food should pass still a long way.
But if pepsin splits fibers why it does not destroy at the same time a stomach wall? After all they, finally, too consist of fiber. The answer, probably, that pepsin is first allocated in the inactive form called pepsinogenom not to admit destruction of those cages which develop it. And hydrochloric acid is necessary for transformation pepsinogena in active pepsin which occurs only after pepsinogen will mix up with gastric juice. Stomach cages are protected by a mucous membrane forming a barrier between this juice and walls of a stomach. And only if this protective barrier fails, nepsin and hydrochloric acid can corrode through stomach walls, forming an ulcer.
Allocation of gastric juice is supervised by nerves and hormones. The first portions are allocated under the influence of nervous stimulation at the sight of, a smell or taste of meal so the stomach is ready to accept food still before it there will get. If nishcha and does not arrive, it is possible to wait for troubles from allocated, but the acid which have not found application. But if the food nevertheless has arrived, its presence stimulates the further secretion as which initiator the hormone gastrin acts. It is developed privratnikovym by department of a stomach in the presence of albuminous food, and also nerves which are stimulated with any type of food.
Walk on guts
After all food is carefully processed in a chemical moustache, on the average stomach department powerful waves peristaltiki, pushing semidigested kashitsu to the gatekeeper arise. It is one more valve in the form of a muscular ring which is on guard at an input in a duodenal gut (the first department of small intestines).
When pressure in a stomach above, than in a duodenal gut, a chemical moustache is pushed out through the gatekeeper. With each wave peristaltiki to a duodenal gut gets from 2 to 5 ml of a chemical moustache, and on full deducing in intestines of gastric contents leaves from 2 till 6 o'clock. To the food rich with carbohydrates, the pair of clocks suffices, mainly albuminous food passes longer, and fat - longest. Though the stomach performs huge work, only a little bit of food arrives from it directly in blood. Through its walls in an organism arrives only a few waters, the salts, some medicines and alcohol. The rest is split in small intestines and soaked up through its walls.
Though in culture of many people the loud eructation is considered indecent, she plays a useful role in the course of digestion. The gas formed in a stomach from swallowed with food or drink of air, collects in the top department of a stomach while kardialnyj sfinkter will not let out it in a gullet. Therefrom it is expelled through a mouth by active muscular reduction accompanied by well familiar sound.