He Cud. Alimentary bolus Are those foods that have been chewed and mixed in the mouth with saliva. Chewing helps reduce food particles to a size that is easily ingested; saliva and mucus also help reduce food particles, as well as moisturize to facilitate swallowing.
You also get a mixture of foods and solutions that go into the stomach, and once they get there, they mix with the gastric juices, and they are reduced in size. This mass of food is known as chyme.
The first step in the digestion process is chewing. When the food decomposes, it is lubricated with saliva and forms a cohesive mass known as the bolus. After swallowing, the bolus moves to the stomach and undergoes further disruption during gastric digestion.
The bolus process encompasses several elements, including formation and disintegration, both of which are key steps in the overall digestion process, because they control the rate at which food components and nutrients are ingested, which Are then absorbed and released into the body.
Once they enter the stomach, they are stacked in the curvature of the same according to the moment they were ingested. The layers begin to form in relation to the density and content of the solids.
During the digestion process, bowls are physically reduced in size, while being broken chemically because of the acidic and enzymatic conditions of the gastric secretions. The speed at which foods disintegrate, will control the way they empty into the stomach and pass into the intestines, where nutrients are absorbed.
Formation of the bolus
After ingesting a food product, it is processed in the oral cavity. The oral process consists of 4 fundamental steps:
In the first stage, the ingested food moves from the front of the mouth to the teeth, so that it can be broken down. The food particles are broken down by grinding with the teeth and mixing with the saliva.
This occurs fairly quickly and has the same duration in most foods, although it will be extended for the hardest.
Subsequently comes step 2 (transport), which occurs gradually during the treatment phase, where the particles are broken down into the appropriate size, and are transported to the back of the oral cavity to form a bolus, leaving the particles Great for breaking down.
Finally, stage 3 occurs after a bolus is formed and is here where it moves to the back of the tongue and prepares to swallow. This is repeated every time a food is eaten.
In summary, it would seem that digestion actually begins in the mouth, as saliva enzymes begin to break down carbohydrates (starch) by chewing the food, lubricating it later, making it warmer and easier to swallow and digest .
So, the teeth and mouth work together to turn every bite of food into a bolus that can be easily moved into the esophagus (the feeding tube). Meanwhile, the taste buds located in the mouth allow you to enjoy every bite, or on the contrary, to find the food of bad taste, according to that is the case. After the bolus is swallowed, it enters the esophagus where it is usually heated and lubricated as it moves into the stomach.
Size of the food bolus
The size of food particles in the bolus plays an important role not only in the ingestion and oral processing of this, but also in the additional digestion when the bolus reaches the stomach.
It has been shown that the different types of food and their physical characteristics, will produce various distributions of particles of various sizes before swallowing.
In most studies, the particle size of a product is determined by allowing a subject to chew before proceeding to the swallowing process, no matter how many times it does.
The traditional method of analyzing particle size distribution after chewing is by sieving using a set of sieves to determine the mass fraction of the particles in each part of the process.
However, in recent years, laser diffraction and image analysis, where particle size is measured using a computer system to calculate the size and shape of particles in an image, are becoming methods every time More potent for the determination of the particle size in which the bolus converts.
Texture of the cake
This element can be determined by a quantifiable method that acts on both the saliva and food interactions in the bolus and on the cohesive forces within the particles (process described above). However, the texture of the bolus is a property that has not been well investigated.
A few studies on cooked meatloaf attempted to quantify bolus texture and salivary secretion. In these they used meat bowls with"tender"textures and"hard"textures, varying by the use of different cooking processes. Individuals were instructed to chew the cooked meat pieces to vary the time intervals, and the posterior meat loaves were analyzed for a variety of properties, including salivary impregnation and shear stress.
The cutoff effort, an indication of bolus texture, was measured by recording the maximum effort gained by using an Instron Universal Testing Machine with a displacement of 60 mm / min. These studies found that by the end of the chewing cycle, meat with the hardest texture requires more chewing strokes and incorporation of more saliva than that of the more tender pieces of meat.
However, this difference was not seen until after seven seconds of chewing, when both bowls had the same amount of saliva incorporated. The cutting effort of the bowls decreased during chewing time for both meat textures. Before chewing and in the middle of the chewing cycle, the tenderest meat had a lower degree of hardness.
Before swallowing, two of the studies showed a significant difference in final chewing stress values between the different texture cakes. The third study showed a slight, but not significant, difference between shear values from initial bolus texture values.
These studies demonstrate the importance of the initial texture of foods in both the chewing cycle properties (duration, secreted saliva, among others) and also in the texture of the final cake.
This is consistent with many of the fundamental chewing studies that have shown that the properties of food material play an important role in their breakdown during oral digestion.
Since the properties of the material influence the final properties of bolus, they also play a role in the digestion processes in the stomach and the rest of the gastrointestinal tract.
Swallowing mechanism
The swallowing process consists of three phases, the first is voluntary and the second involuntary.
It begins with the oral stage which involves moving the particles of chewed food and saliva towards the back of the oral cavity through the tongue to create the food mixture, ie a bolus. During this phase, the pressure generated by the tongue pushing against the back of the oral cavity can rise to different levels.
The second phase, known as the pharyngeal phase, is an involuntary activation of the swallowing reflex to open and close the upper esophageal sphincter lasting about 0.7 seconds.
During this phase, the bolus is introduced into the esophagus by a peristaltic wave, where the pressures seen by the bolus can be at different levels in the pharynx.
The third, which is also called the esophageal phase, also involuntary, involves successive peristaltic contractions of the esophagus in order to transmit the bolus in the stomach, which leads to the beginning of the gastric digestion process.
Similarly, in swallowing, the tongue pushes the bolus into the pharynx (throat) and then into the esophagus, a muscular tube that connects the throat to the stomach, all to prevent food or fluid from entering the trachea and epiglottis (A small tissue) and close over the opening of the vocal cords and larynx during swallowing.
Once inside the esophagus, the peristalsis (wave-like contractions) of the smooth muscle takes the bolus to the stomach, which has two layers of smooth muscle, one outer (along) and one circular in the inner part, both Are contracted rhythmically to squeeze food through the esophagus, passing along the digestive tract, smooth muscles, aiding in the transportation of food.
conclusion
The properties of foods, are important throughout the digestion process, from the oral stage. The breakage that occurs during the chewing process will be greatly influenced by the texture and structure of the food.
Those properties, such as moisture and fat contents, will determine the amount of secreted saliva and the cohesive forces that will occur during the formation of the bolus.
After the bolus reaches the stomach, some starches will have been digested with the low pH in the stomach, some particles may become inactive while the gastric digestion process occurs.
During this process, the bolus is physically broken by the grinding and movements of the stomach caused by the peristaltic waves of the walls of the same.
The structure of the food is subdivided by the processes that occur at a determined rate, which causes them to leave the stomach, or can also influence the rate of gastric emptying, which is controlled by many factors, and can also be correlated with the response of Glucose from foods rich in starch, to continue the process and finally conclude the digestive process of food eaten.
References
- "Digestion in the Mouth, Pharynx and Esophagus". Boundless. Retrieved June 4, 2016.
- Jump up ^"Bolus - Definition and More from the Free Merriam-Webster Dictionary". Merriam-webster.com. Retrieved June 4, 2016.
- Jump up ^"bolus (biology) - Britannica Online Encyclopedia". Britannica.com. Retrieved June 4, 2016.