Function of Six Organs

a. Liver: The liver has numerous functions; however, its specific digestive function is the production of the fat emulsifier, bile (Marieb, p755). The catabolic process leads to fats that are easily accessible to digestive enzymes (Marieb, p756). The liver metabolizes the nutrient-laden blood from other organs.

b. Gallbladder: The gallbladder’s chief function is to store bile and augment its properties with ions and water (Marieb, p752).

c. Pancreas: The pancreas is essential to the creation of a broad spectrum of enzymes that are necessary for the breakdown of various food particles. The exocrine pancreatic juice through the main pancreatic duct amylase, lipases, and nucleases are secreted and join the bile in the small intestine to optimal activity (Marieb, p753) .

d. Large Intestine: The main function of the large intestine is to absorb the water from indigestible foods and eliminate them in semisolid feces (Marieb, p766).

e. Small Intestine:  The small intestine has the most significant contribution to the digestive process. Within its twisted confines, the ileum, duodenum, and jejunum have the surface area capable of maximal nutrient absorption (Marieb, p754).

f. Stomach: The stomach is a storage area for food in which the proteins in the food are turned into chyme (Marieb, p754).

Summary of Mechanical and Chemical Digestion

Mechanical Digestion

Mechanical digestion is the process in which food is physically prepared before the next stage of chemical digestion. The physical grinding and churning that occurs in the form of mastication, churning in the stomach and segmentation, which occurs in the intestine (Marieb, p740).

Chemical Digestion

Chemical digestion consists of catabolism of the most basic chemical constituents. Enzymes are released into the lumen of the alimentary canal (Marieb, p740). This process begins in the mouth cavity and reaches its completion in the small intestine.

Six Examples of Enzymes

1. Lysozyme: Lysozyme is a bacterial enzyme that inhibits bacterial growth in the mouth cavity.

2. Acetyl – CoA: Acetyl CoA is used in the Kreb’s Cycle and is pertinent to the process of  aerobic respiration.

3. Pepsin: Chief cells are activated by the pepsinogen, which is activated by HCl before aiding in the digestion of proteins.

4. Rennin: A chief enzyme that works in the conversion of the milk protein, casein, converting it to the curded substance.

5. Lipases: Lipases break down fats.

6. Urease: An enzyme that breaks down urea into carbon dioxide (CO₂) and ammonia (NH₄).

Two Experiments

1. An experiment  was completed regarding supplemental enzymes and the effects that were seen in individuals who took the supplements.  By using a computerized  gastrointestinal model (TIM), it was found that supplemental enzymes increased the availability of glucose to the whole body in the study entitled “Enzyme Supplements Could Improve Digestive Processes, New Research” (2004).

2. The simulation of the various enzymes that were isolated using polymerase chain reactions were  added to a experiment participant’s diet. The health effects were apparent and all beneficial in the study entitled “Digestive Enzymes and Their Importance” (2009).

Part B: Design Plan for the Experiment

Independent and Dependent Variables

This experiment will recreate the experiment completed by the Neo/Sci Digestion Kit. By adding larger amount of an enzyme to a experiment food, the effect can be recorded. The independent variable is the untreated food. The dependent variable is the food treated with the enzyme.

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