Pathophysiology of the Digestive System and Treatments for Dietary Diseases

Diagram of digestive system

Pharynx

Mouth

Oesophagus

Stomach

Liver

Pancreas

Gall bladder

Jejunum

Ileum

Duodenum

Large intestine

Small intestine

Rectum

Anus

Colon

Caecum

Appendix

Anal canal

Functions of the digestive system’s features

Mouth

The mouth is the start of the digestive system. The mouth is where food is chewed and broken down into very small pieces. The salvia in the mouth is mixed with the food to easily help digest the food. After the food is digested it is absorbed in the small intestine. The intense smell of foods causes the salivary glands in the mouth to produce salvia. This causes the mouth to water and increase salvia when tasting the food.

Pharynx

The pharynx is the throat, the function of the muscular walls helps as a pathway for the movement of food to the oesophagus from the mouth. The respiratory and digestive system consists of the pharynx. the pharynx is connected by two small tubes and the middle ears, this enables air pressure on the eardrum to be stable. Chewed food is rolled by the tongue into a ball-like (bolus) shape, this is pushed against the roof of the mouth to the pharynx where the process of swallowing occurs.

Oesophagus

The oesophagus is a muscular tube will a wall made of four layers. The mucous membrane helps secrete mucus, resulting in a smooth pathway for food. Submucosa hols the mucous membrane in place. This consists of a moderately thick layer containing smooth and long muscle fibres. This tube connects the throat to the stomach for the food/drink to travel down. When finished eating and drinking, the sphincters close from the oesophagus so that stomach acid and food doesn’t not flow back up the oesophagus, and during eating and drink the sphincters.

Stomach

The role of the stomach is to secrete enzymes and acids that digest food. The muscles of the stomach are contracted to mix food and enable digestion. The stomach is lined with muscle tissue called rugae. The secretion of gastric juices helps to coat the lining of the muscle tissue. Gastric juices are mixed with food in the stomach to enable digestion. The muscle valve, pyloric sphincter, opens to enable food to pass from the stomach to the small intestine. The food in the stomach is mixed with enzymes from the pancreas and bile, then from the gall bladder. These enzymes function is then to break down the food.

Small intestine - Duodenum/Jejunum/Ileum

The role of the small intestine is to absorb nutrients and minerals from food in the stomach. The stomach consists of three regions; jejunum, duodenum and ileum. The duodenum is fixed to the dorsal abdominal wall, this contains layers of smooth muscle cells that is line with epithelium. This is the shortest part of the intestine and where absorption initiates.  The duodenum roles are to receive pancreatic juice and bile through the pancreatic duct to complete the first stage of digestion. The role of the jejunum is to also absorb nutrients from digesting food then allows this into the bloodstream. Villi (finger-like projections) is lined in the jejunum; this enables the jejunum to absorb the nutrients. The nutrients that are absorbed are amino acids, fatty acids and sugars. The function of the ileum is to also absorb nutrients, however, to absorb the ones that may have not got absorbed buy the duodenum and jejunum, important nutrients for example, bile salts and vitamin B12. The wall of the ileum folds up, these have tiny villi on its surface. This increases the surface area for absorption. The ileum absorbs the nutrients and water from food in the stomach so they can be used by the body. The ileum is supported on a mesentery, this is a membrane. The jejunum is also supported on a membrane.

Large intestine – rectum/colon/appendix/caecum/anal canal

The role of the large intestine is to absorb water from the remaining food that has been digested and transmit the useless waste material from the body. The caecum is the sac of the large intestine. The appendix contains a lot of lymphoid tissue. The appendix is a part of the gastrointestinal tract. The appendix acts a storage place for good bacteria, “restarting” the digestive system later after diarrheal illnesses. This allows the body to release stool and cleans out the intestines allowing the digestive system to be healthy. The appendix stores good bacteria in the intestines. It is located in the lower right side of the abdomen. The function of the colon is to reabsorb fluids and process waste products from the body. The role of the cecum is the absorption of fluids and salts that are remained after accomplishment of intestinal digestion. The role of the rectum is to stores faces only temporarily, until you are needed to go. The anal sphincter relaxes in the anal canal resulting it that the blood in the cushions drains away, enabling a smooth passage of the stool to travel through the anal canal.

Anus

The anus is the last region of the digestive tract. The anus detects rectal contents by the lining of the upper anus. This also gives away if the contents are solid, liquid or gas. As faeces are forced into the anal canal, a voluntary response is given from impulses to the brain as to decide to open the external anal sphincter. The stretchy wall from the anus enables the defaecation reflex. The anus ends at the last region of the colon, this is the larger intestine, and start at the bottom region of the rectum. The anus and rectum are separated from the anorectal line.

Pancreas

The pancreas is located in the abdomen and converts food into fuel for the body’s cells. The pancreas releases juices right from the bloodstream. It has both an endocrine and exocrine function as it releases juices into ducts. The exocrine function is to help digestion and the endocrine regulates blood sugar. Enzymes are secreted by the pancreas which is within the small intestine. It then continues to breaks down food. Beta cells in the islets of the pancreas secret insulin, which is a hormone, in response to the increased blood glucose level. This insulin helps muscle and liver, including many different cells, takes up more glucose, in so doing lowering blood glucose level. The glucose is transformed into glycogen in muscle and liver cells. Alpha cells secret glycogen, in doing so this decreases blood glucose level. This causes deposited glycogen in the liver to be broken down to glucose then released into the blood.

Liver

The role of the liver is to filter blood coming from the digestive tract. The liver secretes bile that after ends up back in the intestines. In addition to this, the lover purifies chemicals and metabolizes drugs. The liver if found in the abdomen, front of the stomach, and is a large gland.  The liver sores glycogen, this helps regulate blood glucose level and makes plasma proteins. Furthermore, this also metabolises alcohol, drugs and other toxins and stores fat-soluble vitamins. The glycogen breaks down excess amino acids to make urea for removal at the kidneys. Oxygenated blood enters the liver from the hepatic artery. Deoxygenated blood leaves the liver in the hepatic vein.

Gall bladder

The gall bladder is found under the liver on the abdomens right side. This is to store and concentrate bile (digestive enzyme) that is produced by the liver. The gall bladder is a region of the biliary tract. Bile helps to break down the fat and absorb them. When the liver produces bile, the gall bladder then stores this extra bile to break down and absorb fat. bile continues to travel to reach the small intestine. The gall bladder releases the bile by the bile duct, then into the duodenum at the sphincter at the Oddi, when the food enters the duodenum of the stomach.

Irritable bowel syndrome (IBS)

Irritable bowel syndrome is a chronic condition that affects the large intestine. However, it doesn’t cause any changes in the bowel tissue. This condition affects the digestive system, and cause symptoms such as abdominal pain, and either constipation and diarrhoea, bloating, and stomach cramps. The symptoms of this tend to come and go; couple of days to a couple of months at a time. IBS can be a lifelong problem however, there are treatments that can control the symptoms, as there is no cure for irritable bowel syndrome. The cause of this condition is related to food that passes through your system either too slowly or too quickly. Family history, stress and nerves in the gut also are factors that is linked causes. Twice as many women are affected by bowel syndrome then men (nhs.uk, 2019). As there is no cure, there are several ways to help the diet and lifestyle you are living to reduce and manage the symptoms. Vitamin D deficiency occurs in irritable bowel syndrome. This can ease and help the condition. To reduce the symptoms, increasing the level of vitamin can help. Irritable bowel syndrome is caused by the decreased levels of vitamin D in the body. Vitamin D is important for the bones, as this helps the body custom calcium from the diet as this is an important role nerve cell communication the function of the immune system.  An inflammatory response occurs in the gut when vitamin D levels are low.

Symptoms of irritable bowel syndrome

The symptoms of IBS are; constipation, diarrhoea, abdominal pain, and stanch cramps.  Vitamin D deficiency symptoms can be unclear and can lead to not knowing of what the condition is.

• Diarrhoea – this is one of the common symptoms of IBS. This is caused by abdominal pain and the is related with the consistency of stool. Suffers of IBS also endure constipation along with the diarrhoea.

• Constipation – this is also caused by abdominal pain. The pain is related with the consistency of bowel habit. Constipation can mean infrequent stools, difficult to empty during bowel movement and straining feeling when want to go. Bloating is also a symptom that causes constipation.

• Abdominal pain – this occurs in the lower abdomen and is a feeling that is caused in the gut. Abdominal pain is caused by excessive gut muscle contractions and this can also lead to stomach cramps in the lower abdomen.

Symptoms of vitamin D deficiency related to irritable bowel syndrome

• Depression - vitamin D deficiency can cause depression conflicting of irritable bowel syndrome. Suffers with depression have shown to have high prevalence of vitamin D deficiency. Vitamin D is safe in the body, and depression is very dangerous to the body. Physicla depression symptoms are feeling sick or muscle aches, and even flu. Depression link to IBS as when the feeling of pain becomes to much, suffers become fed up and feeling useless, this can cause depression.

• Hair loss – this is associated with stress and can be severe when resulting in a nutrient deficiency.  Low vitamin D levels are linked to IBS in in the way that the causing of abdominal pain, constipation affects sufferers’ lives and a cause stress leading to hair loss.

• Muscle pain - vitamin D deficiency is a cause of muscle pain. The receptor in vitamin D is current in nerve cells, this is named nociceptors, they sense pain. The abdominal pain that is caused by IBS, cause muscle pain as constipation and straining went trying to go can tear and damage muscle tissue.

Corrective for treatments of vitamin D deficiency

The treatment for vitamin D deficiency in irritable bowel syndrome is used to alleviate the symptoms; constipation, abdominal pain and diarrhoea. vitamin D supplements is used to manage the nutrient deficiency in IBS. These supplements should be taken with a meal that consist of fat. There are supplements that can be taken on a daily, weekly, or monthly basis and taken orally by the mouth. The treatment regimes are different for every type of person. For children, aged 1-18 should for at least six weeks, once a week accomplish the maintenance of vitamin D. adults who are vitamin D deficient should be treated once a week, for eight weeks, daily to maintain the vitamin D storage in the body. To treat deficiency, vitamin D can be administered orally.

Bibliography

• Annets.F, Hartley.J, Hocking.S, Llewellyn.R, Menunier.C, Parmar.C, Peers.A (2016) Pearson BTEC National Applied Science. Student book 1. London: Pearson Educated Limited.
• Diagram Link. (2019). Diagram of the Digestive System. [online] Available at: https://www.diagramlink.com/diagram-of-the-digestive-system/ [Accessed 12 Jun. 2019].
• https://www.healthline.com/health-news/vitamin-d-may-ease-ibs
• https://www.nhs.uk/news/food-and-diet/vitamin-d-deficiency-linked-to-irritable-bowel-syndrome/
• https://www.mayoclinic.org/diseases-conditions/irritable-bowel-syndrome/symptoms-causes/syc-20360016
• https://www.medicalnewstoday.com/articles/324259.php