DIGESTIVE SYSTEMUnit 2: Cells & Systems

CRACKER DIGESTION OBSERVATION

Write down your observations:

1) What does it feel like initially (at the beginning)?

2) What does it feel like after 1 minutes in your mouth? 3) What does it feel like after 1.5 minutes in your mouth? 4) What was the main texture (feeling) difference in your mouth between chewing right away and waiting 1.5 minutes before chowing down?

TYPES OF DIGESTION

Types of digestion:

1) mechanical: physical breakdown to small pieces

2) chemical: digestion by enzymes happen in different places

EXIT SLIP QUESTIONS

1) Why are wastes, oxygen and nutrients exchanged in capillaries instead of in veins or arteries?

2) Create a Venn diagram of the similarities and differences between mechanical & chemical digestion.

MOUTH

➤ M: chewing, saliva moistens

➤ C: enzymes in saliva

STOMACH

➤ M: Churns food

➤ C: gastric juice

➤ HCl

➤ mucus

➤ enzymes

➤ H2O

PANCREAS

➤ C: Pancreatic enzymes

➤ digest protein and starch

LIVER

➤ secretes bile

➤ C: bile enzymes digest fat

SMALL INTESTINE

➤ vili

➤ microvili

➤ increases surface area for absorption

LARGE INTESTINE

➤ mechanical and chemical digestion is now complete

➤ absorbs H20, vitamins, minerals

DIGESTION DEEPER

DIGESTION DEEPER

DIGESTION EXPLAINED

Types of digestion:

➤ 1) mechanical (physical breakdown to small pieces);

➤ mouth mechanical (chewing)

➤ salivary glands moisten food and ease swallowing

➤ salivary amylase digest starch.

➤ 2) chemical (digestion by enzymes happen in different places);

➤ mouth & stomach

➤ chemical digestion continues in small intestine from:

➤ pancreas enzymes (ptn and starches);

➤ liver + bile from gall bladder: big globs of lipid -> small particles;

➤ vili (small finger like projections) absorb macronutrients into vessels just below epithelial tissue + microvilli increase surface area

DISEASES OF THE DIGESTIVE SYSTEMApplicability Reading – Disorders of the Digestive System

Instructions: Read the following information article and answer the associated questions found below in the Applicability Reading section of your passport.

Disorders of the digestive system can have a significant impact on the health and well being of both children and adults. Many of the symptoms are extremely uncomfortable and can include such things as diarrhea, gas, constipation, nausea, vomiting, and cramps. Because of how common many of these symptoms are with other general illnesses, it often takes a significant amount of time to properly diagnose and pinpoint the underlying disorder. The 3 most common digestive disorders are as follows: celiac disease, inflammatory bowel disease (IBD), and irritable bowel syndrome (IBS).

In cases where celiac disease is present, the small intestine in the body is hypersensitive to gluten. This can ultimately lead to significant problems in the digestion of food. For example, if a person eats gluten, then the immune system reacts by fighting what it sees as a foreign host. This leads to the gradual damage and deterioration of the wall in the small intestine. Ultimately, this damage can result in significant health problems for individuals, as the small intestine is no longer able to properly absorb vitamins, minerals, and other nutrients from food. Gluten is mainly found in such foods as rye, barley, and all types of wheat, including: durum, semolina, spelt, kamut, einkorn and faro. Although there is no cure for celiac disease, it can be treated by following a strict gluten-free diet.

Regular inflammation of the small or large intestine results in what is known as inflammatory bowel disease (IBD). Inflammation can lead to significant pain and swelling and will ultimately produce such symptoms as diarrhea, bloating, cramps in the stomach, and even general weight loss. There are two main type of IBD: crohn’s disease and ulcerative colitis.

Crohn’s disease can have its impact anywhere in the digestive tract. The usual progression is through a substantial thickening of the inner walls of the affected areas. These walls become bumpy and rough, like a cobblestone surface. Although the specific symptoms of crohn’s depend primarily on where in the digestive system the affected area is located, the most common systems are: stomach pain, vomiting, loss of appetite, bloody diarrhea, poor growth, and mouth ulcers.

Although similar to crohn’s, ulcerative colitis only affects the large intestine. This disorder can result in tears and ulcers, and ultimately lead to stomach pain, bloody diarrhea, bleeding, weight loss, and decreased appetite.

There are a number of treatments for IBD and these include: medicine to reduce the infection and limit the response of the immune system, and nutritional supplements to compensate for the body’s inability to properly absorb these from food. However, in many cases the only solution is to have surgery where the affected area is removed in order to control the disease from further progression.

Irritable bowel syndrome (IBS) can be classified as a chronic disorder; that is, it affects the small and large intestine of digestive system over the long term. This disorder results from the fact that the colon is unable to properly regulate the movement of food (it’s either too slow or too fast). In turn, this results in the inability of the individual to properly absorb an appropriate amount of water from food. This can lead to either diarrhea or constipation. IBS can present itself at different points in a person’s life and treatment options available include: reducing stress, and changing your diet to reduce potential triggering factors.

Applicability Reading – Disorders of the Digestive System Questions 1. What are the three common disorders of the digestive system?

2. What component in food should people with celiac disease avoid eating?

3. Is there a cure for celiac disease?

4. What are the two main types of irritable bowel disease?

5. What is one of the main factors contributing to irritable bowel syndrome?

6. What parts of the digestive system do crohn’s disease and ulcerative colitis affect?

DIGESTION SUMMARY

➤ epiglottis moves across windpipe into esophagus +peristalsis (wave like movement by contractions of muscle lining esophagus).

➤ stomach: responds to food by (1) churning, (2) secretions of gastric juice ( mucus, HCL, digestive enzymes). chemical digestion. stomach slowly releases food to small intestine.

➤ large intestine: mechanical and chemical digestion are complete: absorbs water, vitamins and minerals - feces - stored in rectum.