4. State the source, substrate, products and optimum pH of one amylase, one protease and one lipase.
5. Explain how the structure of both the small and large intestine make them suitable for the absorption of nutrients and water from food.
Small Intestine: completes digestion of food molecules.
Process: Chyme enters the deuodenum. Bile from the gallbladder and liver is emptied into the duodenum, neutralizing the acid and emulsifying fats. Pancreatic enzymes then are released into the jejenum. The ileum is the last stage of the small intestine where the absorption of digested food molecules takes place. Villi increase the surface area for absorption and have a rich blood supply. (Through its outer layer of columnar epitheliam cells containing microvilli). At last, a wave of muscle contractions keeps the mixture of digested and undigested food moving through the intestine.
Large Intestine: absorbs water from the remaining indigestible food matter and transmit the useless waste material from the body.
Process: As large intestine must absorb as much water and nutrients as possible before egesting of feces, they are folded for increased surface area and lined with mucus for movement of food.
It is full of bacteria, which are obligate anaerobes, and the bacteria’s break down non-digestible material and produce both vitamins and minerals to be absorbed.
5. Describe how the stomach is utilized for both mechanical and chemical digestion.
Both mechanical and chemical digestions are processes of the digestive system that enable the digestion, absorption and the excretion of the ingested food.
- The function of the stomach is best described as a good processing unit and a storage cistern.
- Chemical: Various chemicals in the stomach like the digestive enzymes pepsin, rennin, and lipase interact to break down the food. In addition, hydrochloric acid creates suitable environment for the enzymes and assists in the digestion. Water mucus also provide a protective lining for the muscular walls of the stomach so it will not be digested by the acid or enzymes.
- Mechanical: The mechanical action of the muscles in the stomach constrict and relax in a continuous motion blending, whipping, and stirring the stomach’s contents in the chyme, a pulpy substance that can be handled by the small intestine.
6. What is the significance of HCl in the stomach (Hint: there are 2 roles!)
HCl is a vital component in digestive health as it is produced by the stomach to aid in the digestion of food. When the stomach produces too much HCl, the condition is known as Hyperchlorhydria. On the other hand, when the stomach does not produce enough HCl, the condition is known as hypochlorhydra.
- HCl allows for the digestion an absorption of the trace minerals zinc, iron, copper, and magnesium, calcium, selenium, and vitamins B12 and B3.
- It triggers the pancrease to produce the bile and digestive enzymes needed to digest and absorb proteins, carbohydrates, and fats.
- It serves to sterilize the stomach. This kills off pathogens found in food and prevents the overgrwoth of yeast, fungus, and bacteria.
7. Within the small intestine, where specifically are nutrient molecules absorbed and taken to either the circulatory or lymphatic systems?
-Lymphatic Systems: A network of vessels that transports nutrients to the cells and collects their waste products. It is consists of lymph capillaries and lymph vessels that are somewhat similar to blood capillaries and blood vessels. It includes lymph ducts and lymph nodes.
- Circulatory Systems: Blood flows from the heart, through the arteries, and into capillaries that surround all cells. When blood reaches the capillaries, a portion of blood plasma seeps out of the capillaries and into the space surrounding cells. That plasma is the tissue flud that consists of water and dissolved molecules that are small enough to fit through the small openings in capillaries.
8. Find out what Peyer’s patches are!
Peyer’s patches are lymphoid follicles located in the wall of the small intestine.
- They destroy bacteria, preventing them from breaching the wall of the small intestine and entering the bloodstream
- They generate memory lypgocytes for long term immunity. They are a part of the collection of lymphoid tissues called MALT, mucosa-associated lymphatic tissue.
9. What is the difference in structure and function between the small intestine and the large intestine?
10. What, specifically, exits the anus after processing by the digestive tract? What is it composed of?
Food enters the mouth, passes through a long tube, exists as feces through the anus.
- During the process of absorption, nutrients that come from the food (including carbohydrates, proteins, fats, vitamins, and minerals) pass through channels in the intestinal wall and into the bloodstream. The blood works to distribute these nutrients to the rest of the body. The waste parts of food that the body can't use are passed out of the body as feces.
- Feces are ¾ water and ¼ non digestible solids such as bacteria, fiber and others. Bacteria produce sulfur-rich organic compounds such as indole, skatole, and mercaptans, and the in organic gas hydrogen sulfide.
