Anatomy and Cell Biology 3319 Lecture : Anatomy Notes

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purplejackal117

1 May 2012

School

Western University

Department

Anatomy and Cell Biology

Course

Anatomy and Cell Biology 3319

Professor

Peter Merrifield

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Document Summary

The gi tract is also called the alimentary canal. The upper digestive (gi) tract consists of the mouth, pharynx, esophagus, and stomach, and these structures are involved in ingestion and digestion. The lower digestive (gi) tract consists of the small intestine, large intestine, and rectum/anus, and these structures are involved in absorption and defecation. Ingestion is the taking of food into the mouth. Digestion is the breaking down of food and it can be mechanical (chewing) or chemical (enzymes). Absorption occurs mainly in the small intestine and it is the transportation of nutrients from food into the blood. Defecation is the removal of indigestible substances from the body as feces. The oral stage involves the movement of food from the mouth to the oropharynx (which is located right behind the oral cavity). The pharyngeal stage moves food from the oropharynx to the esophagus.

Related Questions

Explain how the structure and function are linked together for the following organs of the digestive system:

1) Mouth

2) Oesophagus

3) Stomach

4) Small intestine

5)Large intestine

6)Rectum

7) Anuss

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2. General questions about the digestive tract A. Mechanical digestion of all foods begins in the oral cavity. Describe how food is digested mechanically in the oral cavity. B. What is the scientific name for swallowing? Which portions of the pharynx does food pass through when swallowing? What is the function of the esophagus? C. Cells lining the stomach release hydrochloric acid (HCl). How does HCl assist in food digestion? How are the cells lining the stomach protected from being auto-digested by HCl? D. Carbohydrates, fats, and proteins must be broken down into their smallest subunits (AKA building blocks) in order to be absorbed through the epithelial lining of the small intestine. Name the building blocks of each of the major classes of nutrients: complex carbohydrates (AKA polysaccharides), fats, and proteins. E. About 99% of all nutrients are absorbed in the small intestine. Name the 3 portions of the small intestine. In which of these 3 portions does the greatest amount of nutrient absorption occur (think about the location and length of each segment)? Which type(s) of nutrient(s) is/are absorbed into blood capillaries? Which type(s) of nutrient(s) is/are absorbed into lymphatic capillaries? F. The last portions of the digestive tract are the rectum, anal canal and anus. Name the 2 muscular sphincters located at the anus. When the rectum fills, the defecation reflex is initiated. Describe the events that occur during the defecation reflex. Name the 2 sphincters located at the anus. Which sphincter undergoes involuntary relaxation during the defecation reflex? Which division of the autonomic nervous system causes this sphincter to relax and open? Name the sphincter that you control consciously to stop or initiate defecation.