Human Body Activities – Digestive System - Homeschool Den Homeschool Den Human Body Activities – Digestive System by homeschooldenadmin · October 23, 2013 We had an amazing time studying the Digestive System. We did a whole range of hands-on activities from making our own epiglottis to seeing how the digestive tract works (how nutrients pass through). We made “fake”vomit, measured out the length of the digestive system and more! I also made notebook for the kids as we went through this unit. Our Digestive System Packet is 40+pages has worksheets and activities on the following areas: Part I: Digestive System — Mouth Part II: Digestive System — Swallowing, How the epiglottis works Part III: Digestive System — The Digestive Tract This packet also include lapbook pieces for interactive notebooks. Here are some of the materials that are included in the Digestive System Packet: The activity directions for “How long is the digestive tract” The kids were impressed with just how long the digestive tract is!!!

The Digestive System Unit Packet now includes lapbook/notebook pieces: Also included are worksheets and our hand-on activities of the mouth You will also find worksheets and activity ideas about swallowing, the epiglottis and choking in this packet: We included all of our hands-on activity ideas in this packet as well: To purchase all of the worksheets you see above click the button below. Once you pay for this packet, you will immediately receive a link to download this file (which will open in a browser window). You will also receive an email from Sendowl (the service I use), which will have a link you can click on to download the Digestive System Unit. (It will say, “You can download your digital products…” with a clickable link.) Of course, if you have any issues just email me at — liesl at homeschoolden dot com. You can also reach me by using the contact form on the blog or can reach me over at our Homeschool Den Facebook Page . $4.00 We had two books we really used a lot for these units: Human Anatomy Coloring Book (affiliate link) has pages you can print out and color in.

And the The Body Book: Easy-to-Make Hands-on Models That Teach (affiliate link) has really neat models that you can make. We did the joints, bones of the body (see our model here) , and some other things, but more about those in those other posts. Disclosure: Please note that some of the links in this post are affiliate links, and at no additional cost to you, I will earn a commission if you decide to make a purchase. Overview of the Human Body Systems We started this unit with a fun album called the Human Body Rock (we borrowed it from the library, but it’s available at Amazon) that we listened to as we made our two trips to the doctors last week (for LD’s allergy shots). The first song goes over the body systems in a fun, general way and we used that as a spring-board for talking about all the systems. We reviewed all the Human Body Systems. Find out more about our Human Body Systems Packet here: I also made a chart and we wrote down some of the lyrics to the song.

immune system — defends our body skeletal system — all your bones excretory system — cleans our body of poisons muscular system — all your muscles endocrine system is in control of the thyroid glands digestive system — mouth and stomach respiratory system — delivers your oxygen nervous system — is your control center circulatory system — is your life pump that keeps your blood flowing What is Qi in Chinese Medicine 1. The Concept of Qi What is meant by Qi? The concept of Qi is based on the ancient Chinese initial understanding of natural phenomena. That is, Qi is the most basic substance of which the world is comprised. Everything in the universe results from the movements and changes of Qi. This concept was introduced into TCM and became one of its characteristics. After a comprehensive survey of the statements on Qi in TCM documents, we have come to the conclusion that the meaning of Qi in TCM has two aspects. One refers to the vital substances comprising the human body and maintaining its life activities, such as the Qi of water and food (food essence), the Qi of breathing (breathing nutrients) and so on.

The other refers to the physiological functions of viscera and bowels, channels and collaterals, such as the Qi of the heart, the lung, the spleen and the stomach and so on. The Qi here referred to, is specifically the physiological functions of these viscera and bowels. 2. The Formation of Qi The Qi in the human body is different in classification and formation. But, generally speaking, it has no more than two sources. One is the innate vital substance one inherits from one's parents before birth. The other is the food essence and fresh air one receives from air, water and food in the natural world. The materials obtained in the two ways above have to be processed and transformed by the viscera and bowels before becoming the Qi of the human body. The process for Qi to be formed is as follows The innate vital substance acted on by the kidney comes out of the gate of life (the portion between the two kidneys) and goes up to the middle warmer. There it combines with the food essence coming from the spleen and continues upwards until it combines with the fresh air inhaled by the lung. Finally it turns into Qi.

It is easy to see from the above that the Qi of the human body is formed through the joint work of the kidney, the spleen, the stomach and the lung in combining the innate vital substance taken from one's parents, the food essence received from water and food, and the fresh air obtained from nature. 3. The Functions of Qi Different kinds of Qi have different functions. Generally speaking, they can be summarized as follows: 1) Promoting Action Qi is a sort of essence full of vitality. It can help activate the growth and development of the human body, promote the physiological functions of each viscus, bowel, channel, collateral, tissue and organ and speed up the formation and circulation of blood and the metabolism of body fluid as well. For example, if the above functions are weakened as a result of the deficiency of Qi (vital energy), the following will occur: late and slow growth and development of the human body or senilism; weakened functions of viscera and bowels, channels and collaterals, tissues and other organs; insufficient blood formation or stagnation in blood vessels; and disturbance in the metabolism of body fluid.

2) Warming Action Nan Jing (Classic on Medical Problems) says: "Qi has a warming action." Qi is the main source of the heat needed by the human body. The body keeps its constant temperature mainly through the warming action of its Qi. A deficiency of Qi can cause lowered body temperature, intolerance to cold and cold limbs. 3) Defending Action The defending action of Qi is shown in two aspects. One is to guard the surface of the skin against the exopathogen. The other is to combat the invading exopathogen so as to ward it off. When the defending function of Qi is normal, the exopathogen has difficulty in invading the body, even though it may obtain entry, it is not certain to cause any disease. If it does cause a disease, this disease is easy to cure. When the defending function of Qi becomes weaker, when the ability of the human body to fight the exopathogen is lowered, the body is easily invaded and diseases are caused. And what is more, these diseases are hard to cure. 4) Consolidating and Governing Action By "consolidating and governing action", we mean that Qi has the ability to command, control and consolidate the liquid substances and organs in the abdominal cavity.

This is done by: a. Keeping blood flowing within, not extravasating out of; the vessels; b. Controlling and adjusting the secretion and excretion of sweat, urine and saliva, and preventing the body fluid from escaping; c. Consolidating and storing sperm and preventing emission and premature ejaculation; d. Consolidating the organs so as to prevent them from descending. A decrease in the above functions of Qi may cause various kinds of hemorrhage, spontaneous perspiration, polyuria, salivation, spermatorrhea, premature ejaculation, prolapse of the stomach, kidney and uterus. The consolidating and governing action and the promoting action of Qi oppose each other and yet also complement each other. On the one hand, Qi has the function of promoting the circulation of blood, and the transportation and distribution of body fluid. On the other hand, it also has the function of controlling and adjusting the movement, secretion and excretion of liquid substances in the body. The coordination and balance of these two functions are essential for maintaining normal blood circulation and water metabolism within the body. 5) Promoting Metabolism and Transformation "Qi hua" is a specific term in the science of TCM.

It refers, in general, to various kinds of changes taking place in the body under the action of Qi. Specifically, it refers to the metabolism of fundamental substances, vital energy, blood and body fluid, and the transformations which can occur between them. For example, vital energy, blood and body fluid are formed in the following manner: ingested food is changed into food essence, and food essence is, in turn, transformed into vital energy, blood or body fluid, and these can then be changed into any one of the others according to the physiological need of the body. The waste from the eaten food and the products produced in the course of metabolism are changed, separately, into feces, urine and sweat which are ready to be removed from the body. All these are the specific manifestations of the action of the activity of Qi. The dysfunction of Qi in performing its action will affect the whole metabolism of the body. That is to say, it will affect the digestion, absorption, transformation and transportation of food: the formation, movement and transformation of vital energy, blood and body fluid; and the excretion of feces, urine and sweat; thus causing various symptoms associated with abnormal metabolism.

In short, the process in which Qi performs its functions is the process in which the substances in the body are metabolized, and in which the substances and energy are transformed. Although the above five functions of Qi are different, they enjoy close cooperation and mutual support. 4. The Movement of Qi The various functions of Qi are all performed by its movement. TCM calls the movement of Qi as "functional activities of Qi". Different types of Qi move in different ways. Theoretically, however, we can put them in four basic ways: ascending, descending, exiting and entering. Ascending refers to the movement from below; descending, from above; exiting, from the interior; and entering from the exterior. These movements of Qi are vital to life. Once they stop, life comes to an end. They are not only seen in promoting and activating various kinds of physiological activities in the human body, but also seen in motivating the physiological activities of the viscera and bowels, channels and collaterals, tissues and other organs. For example, while the lung performs its function, exhaling is exiting, inhaling is entering, dispersing is ascending and keeping the inspired air flowing downward is descending.

Of course, this doesn't mean each organ functions in all four types of movement. Some organs only function in a particular one. For instance, it is appropriate for the Qi of the spleen to ascend and the Qi of the stomach to descend. However, in view of all the physiological activities of the body, the four movements of Qi have to be coordinated and balanced. Only in this way can the physiological functions of the human body remain nor-~a1 In TCM, the physiological state in which the four basic movements of Qi are coordinated and balanced is called "harmonious functional activities of Qi". When they are uncoordinated and unbalanced it is called "disharmonious functional activities of Qi". Because the movements of Qi differ, the disharmonious functional activities of Qi are shown in various ways. For example, over-ascending is known as "the abnormal rising of Qi"; not descending on time, "the non-descending of Qi"; not ascending on time or over-descending, "the sinking of Qi".

Exiting too much because it is unable to be contained is known as "the escape of Qi", while an accumulation inside due to its being unable to exit is known as "the accumulation of Qi" or "depressed Qi", and even "closed Qi" when the accumulation is more severe. If Qi has difficulty in moving or its flow is even partially obstructed it is called "the stagnation of Qi". As to individual internal organs, the examples of the disharrn6-nious functional activities of Qi are as follows: the non-descending of the Qi of the lung, the sinking of the Qi of the spleen, the adverse rising of the Qi of the stomach, the nonconsolidation of the Qi of the kidney, etc. 5. The Classification of Qi The Qi of the human body is classified into the following categories: 1) Inborn Qi Inborn Qi is also called "primordial Qi" or "genuine Qi". It is the most important and fundamental of all. (1) Formation Inborn Qi comes mainly from the innate essence stored in the kidney. But it also depends on the supplement and nourishment of the acquired essence developed in the spleen and stomach.

This is what The Acupuncture Therapy And The Relation Between Healthy Energy And Pathogen, a chapter of Miraculous Pivot, says: "The inborn Qi is received from heaven and combined with food essence to nourish the body." (2) Movement The inborn Qi commences from "the vital gate", the portion between the two kidneys, passes the triple warmer and circulates throughout the body. It goes inward to the five viscera and six bowels and outward to the muscles and skin, i.e., the superficial layer of the body. It goes everywhere and acts on all parts of the body. (3) Functions The inborn Qi has the functions of both activating growth and development and promoting the functional activities of all the viscera and bowels, channels and collaterals, tissues and other organs. Therefore, the inborn Qi is the motivating power of the vital activities of the human body. Sufficient inborn Qi causes normal growth and development of the body and heal-thy and vigorous activities of all the functions of the body. Insufficient inborn Qi leads to late and slow growth and development, and reduces all physiological functions. This is indicated by lassitude, general debility and susceptibility to diseases.

2) Pectoral Qi Digestive System: Hands-On Activities – Esophagus, Stomach, Small Intestines - Homeschool Den Digestive System: Hands-On Activities – Esophagus, Stomach, Small Intestines by homeschooldenadmin · May 6, 2013 We did a lot of hands-on activities over the course of two or three weeks. I’m going to put them all into one post. Esophagus Activities: Does food fall down to the stomach? We proved that muscles helped move the food bolus down to the tummy with this quick upside-down activity. Everyone took turns standing on their hands, chewing up a cracker and swallowing. We also did this lying on our sides. Yes, the food travels to the stomach, no matter what direction the esophagus is pointing. As food is swallowed, the muscles in the esophagus contract and relax. This activities with panty hose showed how the food is pushed down with the rhythmical muscle movement. Stomach Activities: After food is swallowed, it collects in the stomach where stomach acid and food enzymes mix. Muscles in the stomach wall squeeze the food around to mix it.

Make your own vomit: The kids were keen to do this quick activity that I saw on Zelda’s wondeful blog, Homeschool Escapade , a couple of years ago. We used the recipe she suggested: 1/4 cup water 1/2 mashed banana 1/2 cup carrot, finely chopped (we were out, so we used a red pepper) 1 or two cookies or crackers, crushed (we used 3 so each kid could do their own) 1/8 cup vinegar (we were out, so we used lemon juice as our stomach acid) 1 tsp baking soda Of course, it all fizzed, but after it was done we were all SO GROSSED OUT!!! What do you think? Looks pretty disgusting, doesn’t it? (Zelda does a lot of hands-on, wonderful activities with her kids, be sure to go check out her blog, Homeschool Escapade .) Stomach Noises: As the stomach wall squeeze and mix the food mixture, it makes a lot of noises. We took turns listening to each other’s tummies.

The kids said they could here a lot of noise, but unfortunately without my hearing aid in, I couldn’t hear much (though I’ve certainly heard my own rumble from time to time!!) Small intestines: Using panty hose we squeezed some cooked oatmeal down through our “intestines.” We noticed how some small particles, “nutrients,” were able to make their way out of the lining of our “intestines.” We pulled out our SmartLab Toys Squishy Human Body (affiliate link.) and spent time looking over all the internal organs. This product by Smart Lab is really fun. The kids love it and it has held up well. I have a few more things to share with you about this unit, but I need to bring this post to a close for now.

The digestive system packet I made for this portion of our unit is now available as part of our Digestive System student packet: 40+ Page Digestive System Student Worksheet Packet with Hands-On Activity Ideas Our 40+ Page Digestive System Packet has worksheets and activities that cover the following areas: Part I: Digestive System — Mouth Part II: Digestive System — Swallowing, How the epiglottis works Part III: Digestive System — The Digestive Tract This packet also include lapbook pieces for interactive notebooks. Once you pay for this packet, you will immediately receive a link to download this file (which will open in a browser window). You will also receive an email from Sendowl (the service I use) to your PayPal email address, which will have a link you can click on to download the Digestive System pdf. (It will say, “You can download your digital products…” with a clickable link.) Of course, if you have any issues just email me at — liesl at homeschoolden dot com. You can also reach me by using the contact form on the blog or can reach me over at our Homeschool Den Facebook Page .

$4.00 Worksheets on the Digestive Tract Lapbook/notebook pieces: Also included are worksheets and our hand-on activities of the mouth You will also find worksheets and activity ideas about swallowing, the epiglottis and choking in this packet: We included all of our hands-on activity ideas in this packet as well: Again, to purchase all of the worksheets you see above click the button below. This will send you to paypal: $4.00 Once you pay for this packet, you will immediately receive a link to download this file (which will open in a browser window). You will also receive an email from Sendowl (the service I use), which will have a link you can click on to download the Digestive System pdf. (It will say, “You can download your digital products…” with a clickable link.) Of course, if you have any issues just email me at — liesl at homeschoolden dot com. You can also reach me by using the contact form on the blog or can reach me over at our Homeschool Den Facebook Page . Related Posts That Might Be of Interest: Human Body Systems –We started this unit with an overview of all the body systems.

That’s because we only cover one unit about the human body each year. Last year, for example, we studied the circulatory system. ( Human Body Unit: Heart and Circulatory System Activities ) Macmillan ELT | The Human body: The digestive system The Human body: The digestive system The pupils practise words related to the digestive system. Author: Borja Uruñuela To study the human digestive system. Materials Post-it™ notes, 6-8 pictures/flashcards of food, aAn enlarged diagram of the digestive system similar to the one in Activity 2, The Human body: The digestive system Worksheet Language focus Present simple, parts of the body Content Show more Instruction What’s missing? Put the pictures/flashcards of food up on the board and go through the words with the class. Bring two children to the front of the class and ask them to close their eyes or turn around so that they can’t see the board. Turn over or hide one of the food pictures and encourage the class to ask them What’s missing? The two children open their eyes and say what’s missing on the board. Continue with other pairs of children.

Completing The Human body: The digestive system Worksheet Activity 1 Write the parts of the body from Activity 1 on Post-its™. Bring two children to the front of the class. Label one of the children with one of the Post-its™, eg stick the word arm on his/her arm. Encourage the other child to stick another Post-it™ in the appropriate place. Invite some more children to continue with the rest of the Post-its™. Go through the parts of the body with the class and get them to repeat the words. Ask the children How many hands have you got? One or two? Two! How many feet have you got? Two! How many heads have you got? One! etc. Ask the children to write the words and numbers in Activity 1. Answers: body (1); head (1); feet (2); hands (2); arms (2); legs (2); eyes (2); ears (2); mouth (1); nose (1) Extra activity The children write the names of different parts of the body on Post-its™ and then label each other (in pairs). Fast finishers The children draw the parts of the body from Activity 1.

Activity 2 Show the children the food pictures and ask one child Do you like (apples)? Yes, I do / No, I don’t. Encourage the child to ask another child the same question. Let them continue 3 or 4 times and then change the picture. The children continue this chain drill with different kinds of food. Put an enlarged diagram of the digestive system on the board or copy the one in Activity 2 (the children should be familiar with the digestive system and the words in their own L1 may be very similar to the English words). Draw an apple on the board. Ask the children What do you eat with? Do you eat with your eyes? No! I eat with my mouth. So, this (point to the mouth) is the … mouth! Write mouth next to the mouth on your diagram of the digestive system (or write 1. mouth if your diagram is numbered like the one in Activity 2). Continue with the oesophagus, etc. What’s number two? Oesophagus. What’s number three? etc. Go through the words and get the children to repeat them. Ask the children to write the words in Activity 2.

Answers: 1-mouth; 2-oesophagus; 3-stomach; 4-small intestine; 5-large intestine Activity 3 Point to the diagram on the board and explain how the apple goes though the digestive system (either in L1 or L2) until the children understand the process and are familiar with the new vocabulary. 17 Reinforce their understanding by asking the children Stomach? and elicitingThree! Continue with other parts of the digestive system and then encourage the children to continue in small groups. Read the first two sentences in Activity 3 and encourage the children to read the rest. Ask the children to do Activity 3. They write the sentences and number them following the numbering in Activity 2. Answers: a The food is in the stomach – 3; b The food is in the large intestine – 5; c The food is in the oesophagus – 2; d The food is in the mouth – 1; e The food is in the small intestine – 4 Extra activity/Fast finishers The children draw and label a simple version of the digestive system in their notebooks.

Downloads Stomach, Gallbladder and Pancreas | Interactive Anatomy Guide Home > Digestive System > Digestive System of the Lower Torso > Stomach, Gallbladder and Pancreas Stomach, Gallbladder and Pancreas The stomach, gallbladder, and pancreas are three of the most important digestive organs in the human body. These organs work together to produce and store secretions that digest our food into its most basic building blocks. Once digested, these small molecules pass into our intestines to be absorbed and to feed our body’s tissues. These three major organs also produce hormones that help to coordinate their functions and even lead to the feeling of fullness after consuming a meal.... Move up/down/left/right: Click compass arrows Rotate image: Click and drag in any direction, anywhere in the frame Identify objects: Click on them in the image Full Stomach, Gallbladder and Pancreas Description [Continued from above] . . .

Anatomy of the Stomach, Gallbladder, and Pancreas Stomach A hollow muscular organ about the size of 2 closed fists, the stomach is located inferior to the diaphragm and lateral to the liver on the left side of the abdominal cavity. The stomach forms part of the gastrointestinal tract between the esophagus and the duodenum (the first section of the small intestine). The wall of the stomach contains several layers of epithelium, smooth muscle, nerves, and blood vessels. The innermost layer of the stomach is made of epithelium containing many invaginations known as gastric pits. The cells of the gastric pits produce gastric juice - an acidic mixture of mucus, enzymes and hydrochloric acid. The hollow portion of the stomach serves as the storage vessel for food before it moves on to the intestines to be further digested and absorbed. At the inferior end of the stomach is a band of smooth muscle called the pyloric sphincter. The pyloric sphincter opens and closes to regulate the flow of food into the duodenum. Gallbladder The gallbladder is a 3-inch long pear-shaped sac located on the posterior border of the liver.

Connected to the bile ducts of the liver through the cystic duct , the gallbladder receives bile transported from the liver for storage on a regular basis to prepare for the digestion of future meals. During digestion of a meal, smooth muscles in the walls of the gallbladder contract to push bile into the bile ducts that lead to the duodenum. Once in the duodenum, bile helps with the digestion of fats. Pancreas The pancreas is a 6-inch long heterocrine gland located inferior to the stomach and surrounded by the duodenum on its medial end. This organ extends laterally from the duodenum toward the left side of the abdominal cavity, where it tapers to a point. The pancreas is considered a heterocrine gland because it has both endocrine and exocrine gland functions. Small masses of endocrine cells known as pancreatic islets make up around 1% of the pancreas and produce the hormones insulin and glucagon to regulate glucose homeostasis in the blood stream. The other 99% of the pancreas contains exocrine cells that produce powerful enzymes that are excreted into the duodenum during digestion.

These enzymes together with water and sodium bicarbonate secreted from the pancreas are known as pancreatic juice. Physiology of the Stomach, Gallbladder, and Pancreas Digestion The stomach, gallbladder, and pancreas work together as a team to perform the majority of the digestion of food. Food entering the stomach from the esophagus has been minimally processed – it has been physically digested by chewing and moistened by saliva, but is chemically almost identical to unchewed food. Upon entering the stomach, each mass of swallowed food comes into contact with the acidic gastric juice, which contains hydrochloric acid and the protein-digesting enzyme pepsin. These chemicals begin working on the chemical digestion of the molecules that make up the food. At the same time, the food is mixed by the smooth muscles of the stomach wall to increase the amount of contact between the food and the gastric juice. The secretions of the stomach also continue the process of moistening and physically softening the food until the food becomes an acidic semi-liquid material known as chyme. At this point, the stomach begins to push the chyme through the pyloric sphincter and into the duodenum.

In the duodenum , the bulk of digestion is completed thanks to the preparation of chyme by the stomach and the addition of secretions from the gallbladder and pancreas. Bile from the gallbladder acts as an emulsifier to break large masses of fats into smaller masses. Pancreatic juice contains bicarbonate ions to neutralize the hydrochloric acid of chyme. Enzymes present in the pancreatic juice complete the chemical digestion of large molecules that began in the mouth and stomach. The completely digested food is then ready for absorption by the intestines . Storage The stomach, gallbladder, and pancreas all function together as storage organs of the digestive system. The stomach stores food that has been ingested and releases it in small masses to the duodenum. The release of small masses of food at a time improves the digestive efficiency of the intestines, liver, gallbladder, and pancreas and prevents undigested food from making its way into feces. As they are accessory organs of the digestive system, the gallbladder and pancreas have no food passing through them. They do, however, act as storage organs by storing the chemicals necessary for the chemical digestion of foods.

The gallbladder stores bile produced by the liver so that there is a sufficient supply of bile on hand to digest fats at any given time. The pancreas stores the pancreatic juice produced by its own exocrine glands so that it is prepared to digest foods at all times. Secretion The stomach, gallbladder, and pancreas all share the common function of secretion of substances from exocrine glands. The stomach contains 3 different exocrine cells inside of its gastric pits: mucous cells, parietal cells, and chief cells. Mucous cells produce mucus and bicarbonate ion that cover the surface of the stomach lining, protecting the underlying cells from the damaging effects of hydrochloric acid and digestive enzymes. Parietal cells produce hydrochloric acid to digest foods and kill pathogens that enter the body through the mouth. Chief cells produce the protein pepsinogen that is turned into the enzyme pepsin when it comes into contact with hydrochloric acid. Pepsin digests proteins into their component amino acids. The mixture of mucus, hydrochloric acid, and pepsin is known as gastric juice. Gastric juice mixes with food to produce chyme, which the stomach releases into the duodenum for further digestion.

The gallbladder stores and secretes bile into the duodenum to aid in the digestion of chyme. A mixture of water, bile salts, cholesterol, and bilirubin, bile emulsifies large masses of fats into smaller masses. These smaller masses have a higher ratio of surface area to volume when compared to large masses, making it easier for them to be digested. The pancreas stores and secretes pancreatic juice into the duodenum to complete the chemical digestion of food that began in the mouth and stomach. Pancreatic juice contains a mixture of enzymes including amylases, proteases, lipases, and nucleases. Carbohydrates entering the small intestine are broken down into monosaccharides by enzymes such as pancreatic amylase, maltase, and lactase. Proteins in the duodenum are chemically digested into amino acids by pancreatic enzymes such as trypsin and carboxypeptidase. Pancreatic lipase breaks triglycerides into fatty acids and monoglycerides. The nucleic acids DNA and RNA are broken down by nucleases into their component sugars and nitrogenous bases.

Hormones Several hormones are used to regulate the functions of the stomach, gallbladder, and pancreas. The hormones gastrin, cholecystokinin, and secretin are secreted by organs of the digestive system in response to the presence of food and change the function of the stomach, gallbladder, and pancreas. Our pancreas produces the hormones insulin and glucagon to affect the behavior of cells throughout the body. Gastrin is a hormone produced by the walls of the stomach in response to the filling of the stomach with food. Food stretches the stomach walls and raises the normally acidic pH of the stomach. G cells in the gastric glands of the stomach respond to these changes by producing gastrin. G cells release gastrin into the blood where it stimulates the exocrine cells of the stomach to produce gastric juice. Gastrin also stimulates smooth muscle tissue of the gastrointestinal tract to increase the mixing and movement of food. Finally, gastrin relaxes the smooth muscles that form the pyloric sphincter, causing the pyloric sphincter to open. The opening of the pyloric sphincter allows food stored in the stomach to begin entering the duodenum for further digestion and absorption in the intestines.

Cholecystokinin (CCK), a hormone produced in the walls of the small intestine , is released into the bloodstream in response to the presence of chyme in the intestine that contains high levels of proteins and fats. Proteins and fats are more difficult for the body to digest than carbohydrates are, so CCK is important in making changes to the digestive system to handle these types of foods. CCK travels through the bloodstream to the stomach, where it slows the emptying of the stomach to give the intestines more time to digest the protein- and fat-rich chyme. CCK also stimulates the gallbladder and pancreas to increase their secretion of bile and pancreatic juice to improve the digestion of fats and proteins. Finally, CCK is detected by receptors in the satiety center of the hypothalamus that control the feeling of hunger. The satiety center reads the presence of CCK as an indication that the body is no longer hungry for food. Secretin is another hormone produced by the intestinal walls, but unlike CCK, it is produced in response to the acidity of chyme that the stomach releases into the duodenum.

Secretin flows through the bloodstream to the stomach, where it inhibits the production of hydrochloric acid by parietal cells. Secretin also binds to receptors in the gallbladder and pancreas, stimulating them to secrete increased amounts of bile and pancreatic juice. Sodium bicarbonate present in pancreatic juice neutralizes the acidity of the chyme to prevent damage to the walls of the duodenum and provides a neutral pH environment for the digestion of chyme. Insulin is a hormone produced by the beta cells of the pancreatic islets of the pancreas. The pancreas produces insulin in response to the presence of high levels of glucose in the blood. Insulin stimulates cells, particularly in the liver and skeletal muscles , to absorb glucose from the blood and use it as an energy source or store it as glycogen. Insulin also stimulates adipocytes to absorb glucose to build triglycerides for energy storage. Our body produces higher levels of insulin following a meal in order to remove glucose molecules from the blood before they can reach high concentrations and become toxic to the body’s cells. Glucagon is a hormone produced by the alpha cells of the pancreatic islets of the pancreas.

Glucagon acts as an antagonist to insulin by stimulating the release of glucose into the bloodstream to raise blood glucose levels between meals. Hepatocytes in the liver store glucose in large macromolecules known as glycogen. Glucagon binding to receptors on hepatocytes triggers the breakdown of glycogen into many glucose molecules, which are then released into the bloodstream. Prepared by Tim Taylor, Anatomy and Physiology Instructor Stomach Click to View Pic Stomach The stomach is the main food storage tank of the body. If it were not for the stomach’s storage capacity, we would have to eat constantly instead of just a few times each day. The stomach also secretes a mixture of acid, mucus, and digestive enzymes that helps to digest and sanitize our food while it is being stored. Anatomy of the Stomach Gross Anatomy The stomach is a rounded, hollow organ located just inferior to the diaphragm in the left part of the abdominal cavity. Located between the esophagus and the duodenum, the stomach is a roughly crescent-shaped enlargement of the gastrointestinal tract. The inner layer of the stomach is full of wrinkles known as rugae (or gastric folds ).

Rugae both allow the stomach to stretch in order to accommodate large meals and help to grip and move food during digestion. The stomach can be divided into four regions based on shape and function: The esophagus connects to the stomach at a small region called the cardia. The cardia is a narrow, tube-like region that opens up into the wider regions of the stomach. Within the cardia is the lower esophageal sphincter, a band of muscle tissue that contracts to hold food and acid inside of the stomach. The cardia empties into the body of the stomach, which forms the central and largest region of the stomach. Superior to the body is a dome shaped region known as the fundus. Inferior to the body is a funnel shaped region known as the pylorus. The pylorus connects the stomach to the duodenum and contains the pyloric sphincter. The pyloric sphincter controls the flow of partially digested food (known as chyme) out of the stomach and into the duodenum. Microscopic Anatomy Microscopic analysis of the stomach’s structure reveals that it is made of several distinct layers of tissue: the mucosa, submucosa, muscularis, and serosa layers.

The innermost layer of the stomach is known as the mucosa, and is made of mucous membrane. The mucous membrane of the stomach contains simple columnar epithelium tissue with many exocrine cells. Small pores called gastric pits contain many exocrine cells that secrete digestive enzymes and hydrochloric acid into the lumen, or hollow region, of the stomach. Mucous cells found throughout the stomach lining and gastric pits secrete mucus to protect the stomach from its own digestive secretions. The mucosa of the stomach is much thicker than the mucosa of the other organs of the gastrointestinal tract due to the depth of the gastric pits. Deep inside the mucosa is a thin layer of smooth muscle known as the muscularis mucosae. The muscularis mucosae layer allows the mucosa to form folds and increase its contact with the stomach’s contents. Surrounding the mucosa is the submucosa layer of the stomach. The submucosa is made up of various connective tissues, blood vessels, and nerves. Connective tissues support the tissues of the mucosa and connect it to the muscularis layer. The blood supply of the submucosa provides nutrients to the wall of the stomach.

Nervous tissue in the submucosa monitors the contents of the stomach and controls smooth muscle contraction and secretion of digestive substances. The muscularis layer of the stomach surrounds the submucosa and makes up a large amount of the stomach’s mass. The muscularis is made of 3 layers of smooth muscle tissue arranged with its fibers running in 3 different directions. These layers of smooth muscle allow the stomach to contract to mix and propel food through the digestive tract. The outermost layer of the stomach surrounding the muscularis layer is the serosa – a thin serous membrane made of simple squamous epithelial tissue and areolar connective tissue. The serosa has a smooth, slippery surface and secretes a thin, watery secretion known as serous fluid. The smooth, wet surface of the serosa helps to protect the stomach from friction as it expands with food and moves to mix and propel the food. Physiology of the Stomach Storage In the mouth , we chew and moisten solid food until it becomes a small mass known as a bolus. When we swallow each bolus, it then passes through the esophagus to the stomach where it is stored along with other boluses and liquids from the same meal.

The size of the stomach varies from person to person, but on average it can comfortably contain 1-2 liters of food and liquid during a meal. When stretched to its maximum capacity by a large meal or overeating, the stomach may hold up to 3-4 liters. Distention of the stomach to its maximum size makes digestion difficult, as the stomach cannot easily contract to mix food properly and leads to feelings of discomfort. After the stomach has been filled with food from a meal, it stores the food for about 1-2 hours. During this time, the stomach continues the digestive process that began in the mouth and allows the intestines, pancreas , gallbladder , and liver to prepare to complete the digestive process. At the inferior end of the stomach, the pyloric sphincter controls the movement of food into the intestines. The pyloric sphincter is normally closed to keep food and stomach secretions within the stomach. Once chyme is ready to leave the stomach, the pyloric sphincter opens to allow a small amount of chyme to pass into the duodenum . This process, known as gastric emptying, slowly repeats over the 1-2 hours that food is stored in the stomach.

The slow rate of gastric emptying helps to spread out the volume of chyme being released from the stomach and maximizes the digestion and absorption of nutrients in the intestines . Secretion The stomach produces and secretes several important substances to control the digestion of food. Each of these substances is produced by exocrine or endocrine cells found in the mucosa. The main exocrine product of the stomach is gastric juice – a mixture of mucus, hydrochloric acid, and digestive enzymes. Gastric juice is mixed with food in the stomach to promote digestion. Specialized exocrine cells of the mucosa known as mucous cells secrete mucus into the lumen of the stomach and into the gastric pits. This mucus spreads across the surface of the mucosa to coat the lining of the stomach with a thick, acid- and enzyme-resistant barrier. Stomach mucus is also rich in bicarbonate ions, which neutralize the pH of stomach acid. Parietal cells found in the gastric pits of the stomach produce 2 important secretions: intrinsic factor and hydrochloric acid. Intrinsic factor is a glycoprotein that binds to the vitamin B12 in the stomach and allows the vitamin to be absorbed in the small intestine .

Vitamin B12 is an essential nutrient for the formation of red blood cells. Hydrochloric acid protects the body by killing pathogenic bacteria naturally found in food. Hydrochloric acid also helps to digest proteins by denaturing them into an unfolded shape that is easier for enzymes to digest. The protein digesting enzyme pepsin is activated by exposure to hydrochloric acid inside the stomach. Chief cells, also found within the gastric pits of the stomach, produce two digestive enzymes: pepsinogen and gastric lipase. Pepsinogen is the precursor molecule of the very potent protein-digesting enzyme pepsin. Because pepsin would destroy the chief cells that produce it, it is secreted in its inactive pepsinogen form. When pepsinogen reaches the acidic pH found in the stomach thanks to hydrochloric acid, it changes shape and becomes the active enzyme pepsin. Pepsin then breaks dietary proteins into their amino acid building blocks. Gastric lipase is an enzyme that digests fats by removing a fatty acid from a triglyceride molecule. G cells are endocrine cells found at the bottom of the gastric pits.

G cells release the hormone gastrin into the bloodstream in response to many stimuli, such as signals from the vagus nerve ; the presence of amino acids in the stomach from digested proteins; and the stretching of the stomach wall during a meal. Gastrin travels through the blood to various receptor cells throughout the stomach where it stimulates the glands and muscles of the stomach. Glandular stimulation by gastrin leads to increased secretion of gastric juice to increase digestion. Stimulation of smooth muscles by gastrin leads to stronger contractions of the stomach and the opening of the pyloric sphincter to move food into the duodenum. Gastrin also binds to receptor cells in the pancreas and gallbladder where it increases the secretion of pancreatic juice and bile. Digestion Digestion in the stomach can be divided into 2 classes: mechanical digestion and chemical digestion. Mechanical digestion is the physical division of a mass of food into smaller masses while chemical digestion is the chemical conversion of larger molecules into smaller molecules. The mixing action of the stomach walls allows mechanical digestion to occur in the stomach. The smooth muscles of the stomach produce contractions known as mixing waves that mix the boluses of food with gastric juice.

This mixing leads to the production of the thick liquid known as chyme. While food is being physically mixed with gastric juice to produce chyme, the enzymes present in the gastric juice chemically digest large molecules into their smaller subunits. Gastric lipase splits triglyceride fats into fatty acids and diglycerides. Pepsin breaks proteins into smaller amino acids. The chemical digestion begun in the stomach will not be completed until chyme reaches the intestines, but the stomach prepares hard-to-digest proteins and fats for further digestion. Hormonal control The activity of the stomach is under the control of several hormones that regulate the production of stomach acid and the release of food into the duodenum. Gastrin, produced by the G cells of the stomach itself, increases the activity of the stomach by stimulating increased gastric juice production, muscle contraction, and gastric emptying through the pyloric sphincter. Cholecystokinin (CCK), produced by the mucosa of the duodenum, is a hormone that acts to slow gastric emptying by contracting the pyloric sphincter. CCK is released in response to food rich in proteins and fats, which are difficult for the body to digest.

By inhibiting gastric emptying, CCK allows food to be stored in the stomach longer to promote improved digestion by the stomach and to give the pancreas and gallbladder time to release enzymes and bile to increase digestion in the duodenum. Secretin, another hormone produced by the duodenum's mucosa, responds to the acidity of chyme entering the duodenum from the stomach. Secretin travels through the bloodstream to the stomach where it slows the production of gastric juice by the exocrine glands of the mucosa. Secretin also promotes the production of pancreatic juice and bile that contain acid-neutralizing bicarbonate ions. The net effect of secretin is to protect the intestines from the damaging effects of acidic chyme. Prepared by Tim Taylor, Anatomy and Physiology Instructor

Question: """Peptic"" refers to which activity of the human body?"
Answer: Digestion