Compendium Review CH 8

Digestive System

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Chapter 8- Digestive System and Nutrition
8.1 Overview of Digestion
A. Ingestion
· Occurs when the mouth takes in food.
B. Digestion
· Can mechanical or chemical.

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· Stomach http://www.becomehealthynow.com/images/organs/digestive/sm_intestine_bh.jpg
· Small intestine
C. Movement
· Through the GI tract is important to fulfill digestion
· EX: food must be passed along from one organ to the next
D. Absorption
· Nutrients pass through the walls of the GI tract
· Then enter the blood stream entering the body
E. Elimination
· Unused food turns into waste
· Then its expelled through the anus
1. Walls of the Digestive Tract
A. The digestive tract has 4 layers
1. The first layer, Mucosa, is next to the lumen. It produces mucus to protect the wall from digestive enzymes.
a. Diverticulosis- is a disorder with the first layer that has pushed its way through the other layers creating pouches.
2. The second layer, sub mucosa. Its loose connective tissues and carry nutrients absorbed by the mucosa layer.
a. Inflammatory bowel disease- is one of the disorders of this layer and has fever, weight loss, and chronic diarrhea associated with it.
3. The third layer, Muscularis. This contains 2 smooth muscle layers the inner layer, encircles the tract. The longitudinal layer lies in the same direction as the tract. This controls the movement of the tract.
a. IBS (irritable bowel syndrome)- stress being an underlying cause of this and abdominal pain, constipation, and diarrhea are associated with it.
4. The fourth layer, serosa. Secretes serous fluid. The appendix is with this.
a. appendicitis
8.2 First part of the digestive tract
1. The Mouth
A. This begins the digestion process.
B. Three pairs of salivary glands.
C. Salivary amylase beings the process of digesting starch.
D. the tongue pushes the food towards the Pharynx.
2. The pharynx and esophagus
A. The pharynx is at the end of the nasal and mouth openings.
B. The esophagus is located at the end of the pharynx and is long and narrow. Leads the food to the stomach
1. Swallowing:
a. The soft plate moves back to close off the nasal passages
b. The trachea moves up under the esophagus to cover the glottis
c. The glottis is opening the to the larynx (the airway)
d. a rhythmic contraction called peristalsis pushes the food along the esophagus and continues to the rest of the digestive tract.
e. sphincters are muscles that encircle tubes and act as valves
f. the entrance to the esophagus to the stomach is marked by constriction (lower gastroesophageal sphincter)
8.3 The stomach and small intestine
1.The stomach
A. The stomach is a thick walled, j-shaped organ that lies on the left side of the body beneath the diaphragm.
B. The esophagus and the small intestine are on each side of the stomach.
C. Stores food
D. initiates digestion of protein
E. controls the movement of Chyme into the small intestine
F. does not absorb nutrients
G. Has four layers
H. can hold about a liter
I. Gastric Juice- pepsin
J. empties in about 2-6 hours
2. The small intestine
A. is named for its small diameter and is about 18 ft long
B. the small intestine has enzymes to digest all types of foods, carbs, proteins, and fat.
C. These enzymes are secreted by the pancreas and enter the via a duct at the duodenum (the first 25 cm of the small intestine)
D. Bile- emulsifies the fats
E. The small intestine absorbs nutrients
3. Lactose intolerance
A. Primarily in milk and sugar
B. the Brush Border Enzyme is what keeps people from being able to tolerate lactose
C. Can have it as long as the lactose enzyme has already been broken down
D. When it is eaten diarrhea can be present along with gas and cramps
4. Obesity: diabetes type 2 and cardiovascular disease
A. Consuming to much of one thing can cause weight gain
B. To much sugar and fat in system
C. Foods such as breads, pies, cookies, and fatty foods such as fried foods are the main cause for the epidemic in the US
8.4 Three Accessory Organs and Regulation of Secretions

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1. Three Accessory Organs
A. Pancreas
· Pancreatic Juice which contains Sodium Bicarbonate
· Digestive enzymes for all types of foods
· Neutralizes acid from the stomach

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B. Liver
· Produces Bile
· Destroys old blood cells
· Detoxifies the blood
· Stores iron
· Makes plasma proteins
· Stores glucose
· Produces urea
· Helps regulate the blood cholesterol levels
C. gallbladder
· Stores Bile
2. Liver Disorders
A. Jaundice
B. Hepatitis
C. Cirrhosis
3. Regulation of digestive secretions
A. Controlled by the nervous system and by hormones

Large Intestine

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8.5 The Large Intestine and defecation
A. The large intestine include the cerum, the colon, and the rectum, and anal canal
B. about 4 and half ft long
C. The Cecum lies below the junction of the small intestine and is at the blind end of the large intestine (worm like appearance)
D. Colon includes the ascending colon
E. The rectum is the last 20 cm of the large intestine
F. The opening is the anus
1. Functions of the large intestine
A. absorbs water
B. absorbs vitamins
C. forms feces
D. Removes indigestible substances (fiber and bacteria)
2. Disorders of the colon and rectum
A. Diarrhea
B. Constipation
C. Hemorrhoids
D. Diverticulosis
E. IBS
F. IBD
G. Polyps and cancer
8.6 Nutrition and weight control
A. Obesity is considered grossly overweight
B. nearly 1/3 of adults is obese
1. How obesity is defined
A. Body Mass Index (BMI)
B. if is equal to 26.5 to 40 this considered mildly obese to morbidly obese

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2. Class of nutrients
A. Carbohydrates
B. Proteins
C. Lipids
D. Minerals
E. Calcium
F. Vitamins
1. Antioxidants
2. Vitamin D
3. How to plan a nutritious meal
A. Eat a variety of foods
B. Eat more: Fruit, Veggies, Whole Grains, Fat-free or Low-fat Milks
C. eat less foods at night
D. Be active everyday
4. Eating disorders

Anorexia

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A. Anorexia Nervosa
· Fear of getting fat
· Self-imposed starvation
B. Bulimia Nervosa
· Binge eating then purging
C. Binge eating
· Over eating in episodes with out purging

Muscle Dysmorphia

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D. Muscle dysmorphia
· When the body is thought to be underdeveloped
· May spend hours in the gym to reach perfection