Lets follow the path of a delicious ham and cheese sandwich

Let’s follow the path of a delicious ham and cheese sandwich with lettuce and pickles as it is eaten and digested! Start at the beginning and discuss the anatomical parts as well as the biochemical roles that contribute to this sandwich being turned into chemical energy. Be sure to include mechanical and chemical mechanisms, along with how they are metabolized in the body!

What happens if one part does not function? For example, what happens to digestion if the person is missing many teeth but can\'t afford dentures or perhaps has a digestive disorder?

What stress factors may cause issues in the digestive tract for some people?

How can a regular exercise program aid in the development of a healthy digestive tract?

How might digestion and metabolism be different over the life span?

Please answer it as a discussion post and make sure you answer each question.

Solution

1. The process by which large insoluble food substances converted to soluble molecules which can be absorbed into blood is called as digestion. Digestion initiates from ingestion of food into the mouth. The morsel of food is chewed by teeth which breaks food into small pieces. The saliva secreted by salivary gland is mixed with the food, saliva contains enzyme salivary amylase which breakdown complex carbohydrate starch into maltose sugar. Bread of the sandwich has carbohydrates which are likely to get altered chemically. The bolus of food is propelled by peristalsis and passes through the oesophagus into the stomach. The gastric juice secreted by gastric gland is mixed with the bolus. Gastric juice is primarily composed of pepsinogen and hydrochloric acid. The mixture of gastric juice and bolus gets churned and is converted to chyme (partially digested food). Pepsinogen is converted to pepsin via hydrochloric acid and pepsin breakdown proteins into peptides. Ham is a good source of proteins which breakdown at this stage. The food becomes acidic here.

From stomach chyme passes to small intestine by peristaltic movement. Cheese is good source of fats and fatty substances. Breakdown of lipids occurs in small intestine. Bile which is secreted by the liver breakdown fatty substances. Pancreatic juice secreted by pancreas consist if lipase which breakdown fat into fatty acid and glycerol. The simple nutrients then get absorbed by the small intestine except water and minerals. Undigested food and waste product then passed to the large intestine. Large intestine absorbs water and minerals. The waste product (feces) is reached to the rectum and later excreted through the anus.

2. If the person is missing many teeth then that person won\'t be able to chew food such as ham. He will look for soft food. Though his mouth has saliva which can digest carbohydrates from soft food such as bread. In case of digestive disorder such as gastroesophageal reflux disease, celiac disease, Crohn\'s disease etc. one or more of the digestive steps is altered.

3. Stress factors adversely affect digestion in some people. Stress might cause hypothyroidism in some people (especially women) means under functioning of thyroid gland. Due to inadequate thyroid hormones, there is slow down of metabolism which can lead to weight gain and also constipation. Stress might increase acidity. Digestion slows down due to stress hence may cause bloating and gas.

4. Exercise improves the blood flow of entire body including digestive system. Improved circulation positively affects functioning of digestive system. There is increase of peristaltic movement. Exercise helps in digestive problem such as bloating, gas, heartburn etc. It also helps bacterial flora for digestion. It also improves elimination of waste products.

5. As the age progresses the body functions slows down, hence digestion and metabolism of elder person is slow and impaired. Also the physical inactivity increases with the progressive age. The elderly person does not able to digest the food as he used to do it when he was young. And also there are various diseases which tend to follow increasing age. Most elderly person takes many medicines. Medicines can affects digestion, also there can drug - food interactions involved.