Week #13 Flashcards
What are the two types of digestion?
Mechanical and Chemical
What is Mechanical Digestion?
Mastication: Mouth
Peristalsis: Esophagus
Maceration: Stomach
Segmentation: Small intestine
What is Chemical Digestion?
Enzymatic activity: Salivary amylase (Carbohydrates, starts in mouth)
What happens during swallowing?
Saliva:
- Helps prevent mouth from drying-out / lubricates mouth (oral cavity)
- Helps prevent cavities
- 1st line of defense against disease-causing microorganisms entering mouth
- Coats food
- With tongue, helps form bolus
Describe what happens with the muscles of stomach and what they are?
Longitudinal, Oblique, Circular; churn predigested food; about 1- 2 hours; mixes food with gastric juices creating chyme
What chemicals help digest in the stomach?
- HCL (Hydrochloric acid): activates pepsinogen into pepsin
- Pepsinogen: inactive form of pepsin
- Pepsin: active form of enzyme, breaks protein down into polypeptides (amino acids)
How much does the stomach absorb?
~10% absorption (caffeine, aspirin, tiny amount of water “if dehydrated”), 10% - 20% of alcohol
What is the pyloric sphincter?
Stomach to the small intestine (duodenum); controls the flow of chyme, from the stomach into the small intestine
How long is the small intestine?
~20 feet long
How much FOOD absorption does the small intestine?
90%
What are the three parts of the small intestine?
Duodenum, Jejunum, and Ileum (DJ Eye “I”)
What does the duodenum do?
Protein digestion; Fat breakdown - bile salts emulsify fat globule into tiny droplets, which increases surface area on which pancreatic lipase digest fatty acids (lipids) and glycerol
How much absorption does the jejunum do?
90%
How much absorption does the ileum do?
90%
What is the key absorption structure?
Microvilli (Brush border) !!
How long is the large intestine/colon?
~5 feet long (1.5 m)
How much WATER does the large intestine absorb?
90%
How much water is needed for digestion?
~1.8 gallons or ~7 liters
What is the ascending colon?
Cecum (“Dead end pouch” bacteria); Appendix (Vestigial organ but Duke says bacterial garden especially important w/ diarrhea)
What is the transverse colon?
Goes across
What is the descending colon?
Rectum
- ~4.7 inches to anal canal
- Defecation (removing waste material)
- Fecal matter/Feces/Stool (undigested material, 60% bacteria, mucus, cellulose “bulk flow”)
- Constipation (fecal impact)
- Diarrhea (loss of water/irritate intestinal lining leading to bacterial infection)
Where does digestion of carbohydrates start?
Starts in mouth w/ salivary amylase
Where does digestion of proteins to amino acids occur?
Starts in stomach w/ pepsin
Where does digestion of lipids start?
Small intestines w/ pancreatic lipase, bile salts (duodenum)
What does fiber help with?
Bulk flow
ex. Veggies, fruits, oats, wheat, corn, rice, and beans
What is bulk flow?
Movement of food particles through the digestive tract
What is the order of processing for nutrients?
Carbs –> Proteins –> Lipids
How long does it take food to move through the stomach and small intestines?
6 - 8 hours
How long does food remain in the large intestine?
1 - 2 days
What is Cirrhosis?
Disorder characterized by the gradual replacement of healthy liver tissue with scar tissue, leading to impaired liver function; liver does not function due to long-term damage
What is Cirrhosis most commonly caused by?
Alcohol, non-alcoholic fatty liver disease, hepatitis B, and hepatitis C
What is the primary cause of Type 2 Diabetes?
Insulin resistance resulting from lifestyle factors and obesity
