Chapter 4 Flashcards
GI tract
Mouth, esophagus, stomach, small intestine, large intestine, rectum, anus
Actual flow of food through these organs/compartments
Involved in digestion and metabolism of foods and nutrients
Liver, pancreas, and gall bladder
Digestion
Process of breaking down foods into a form the body can use (like starch to sugar)
Absorption
Uptake of nutrients from the GI tract into the blood or lymph
4 layers of the GI tract
Mucosa
Submucosa
Muscle
Serosa
Mucosa
Innermost layer of GI tract
Lumen
hollow area where food travels
Submucosa
Contains blood vessels carrying nutrients
Muscle
Move food forward through contractions
Serosa
outside layer of GI tract protects it
Sphincters
Ring like muscles that control the flow of contents in the GI tract (prevent backflow)
Peristalsis
Contractions in the GI
Segmentation
Back and forth movement in the GI
Mass movements
peristalsis over widespread area in GI
Where is bile produced?
liver
Where is bile stored?
gallbladder
Function of enzymes
Catalyze chemical reactions including hydrolysis reactions that break down a product by adding H
3 components of saliva
Lysozyme
Mucus
Amylase
Lysozyme
breaks down bacteria
Mucus
Lubricate and hold bolus together
Amylase
Breaks down starch
Epiglottis
Prevents food from lodging in the trachea (windpipe)
stomach secretions
Hydrochloric acid Pepsinogen Gastric Lipase Gastrin Mucus (protects stomach from being digested)...regulated by prostaglandins
Hydrochloric acid
very acidic
inactivates proteins
destroys bacteria/viruses
aids in mineral absorption
Pepsinogen
protein digesting enzyme
Gastric Lipase
helps fat breakdown
Gastrin
hormone that controls release of HCl and pepsinogen
Where does most digestion and absorption occur?
Small intestine
Sections of small intestine
Duodenum ( 10 in )
Jejunum (4 ft )
Ileum (5 ft)
Villi
Folds in intestine that contain specialized epithelial cells called enterocytes
Microvilli
Located on enterocytes
Act to increase surface area
Function of Liver
Produces bile to help with fat absorption
Enterohepatic (recycling bile)
Function of gallbladder
Bile storage and release
Function of pancreas
Produces sodium bicarbonate (buffer), lipases, proteases and pancreatic amylase
Passive diffusion
nutrients in higher concentration in the lumen move to enterocytes that have lower concentrations
Facilitated diffusion
higher concentration to less plus a carrier protein or transport to help get them across (fructose)
Active absorption
In not dependent on concentration requires ATP and a transporter (amino acids and glucose)
Endocytosis
englufment, antibody absorption of colostrum
Cardiovascular System
Includes heart blood vessels and blood
Water-soluble nutrients transported via capillaries in villi to portal vein
Lymphatic System
Includes lymphs
Fat-soluble nutrients and large particles transported into the lymph vessels to thoracic duct (blood)
Parts of the Large intestine
cecum, colon, rectum and anus
Functions of large intestine
Some absorption especially water and electrolytes
Defecation feces
House bacteria
Bacterial Flora
Controls pathogenic bacteria
Synthesize vitamin K and biotin
aid lactose digestion
Pro-biotic
Live bacteria that provide health benefits
Pre-biotic
Non-digestible carbohydrates that promote the growth of bacteria
Heartburn and Gastroesphogeal reflux (GERD)
Reflux of stomach acid into esophagus
15% of US pop has heartburn daily, 3% GERD
Treatments: antacids and inhibitors of HCl production
Ulcers
Cause: H. pylori (bacteria) or aspirin (NSAID drugs)
Treatment: antibiotics or HCl inhibitors
Gallstones
Formation of hard stone-like structures in the gallbladder made mostly of cholesterol
Treatment: remove gallbladder
Causes of food intolerances
enzyme deficiency sensitivity to food component synthetic compounds added to foods medications toxins
Intestinal Gas
Flatulence caused by: bacterial fermentation of carbohydrates in large intestine, swallowed air
Treatment: enzyme preps that help break doown food
Constipation
Impaired ability to defecate
Treatments: fiber, fluid and exercise, laxative
Irritable Bowel Syndrome
abdominal pain, distension, diarrhea, constipation
15% of pop
Treatment: reduce stress and avoid food intolerances
Inflammatory Bowel Disease (IBD)
1 in 500 americans
Most common forms are ulcerative colitis and crohn’s
Hemorrhoids
swollen veins in the rectum and or anus
risk factors: preg, obesity, excess sitting
Celiac Disease (gluten intolerance)
inherited auto-immune disorder damage to villi
causes malabsorption
