1. Small and Large Intestines

2. Parts of the Small Intestines

4. How do the parts of Small intestines Vary?
Duodenum: secretes mucous enzymes and hormones and is a site of entry for bile and pancreatic juices
Jejunum: nutrient absorption
ileum: central portion of the abdominal cavity; pH 7-8; absorbs B12 and bile salts

5. Intestinal Wall Mucosa contain: absorptive cells aka: enterocytes
2 layers of smooth muscle
Circular and longitudinal aid in intestinal mobility
Serosa: supportive CT

6. Function of villi and microvilli
Specialized absorptive units
Microscopic units with layers of epithelial cells
200m2 for nutrient absorption
desmosomes and tight junctions prevent microbes b/t cells

7. Regulator of absorptive units
Absorption occurs by active transport, facilitated diffusion, Na/K pump
Actin (protein)
Filaments regulated by autonomic nerve fibers
Fats and water soluble nutrients take different paths

8. Movement Patterns Segmentation: circular muscle contraction
Peristalsis: movements by circular and longitudinal muscles

11. Large Intestines
Colon
6 cm wide and 1.5 meets long (6 feet)

12. Movement of chyme Chyme enters the colon thru ileocecal valve
Located b/t ileum and colon
Gastroileal reflex regulates ileocecal valve by the peristaltic waves

14. Major segments of Lg intestines
Transverse
Ascending
Sites of water and Na absorption and mucus secretions
Descending
Sigmoid
Storage of fecal matter

16. Process that allows for water absorption
Osmosis
…following the Na/K pump which is what type of cellular transport??

17. Important to replenish electrolyte balance
Homeostasis
K is secreted into large intestines

18. Stool mass What’s in your Poo?
Dietary fiber (pectin and cellulose)
Fruits and vegetables
Indigestible substances

19. Movements of colon Segmentation: circular muscle contraction
Peristalsis: movements by circular and longitudinal muscles
Mass movement: force of feces along the colon through the anal canal

20. Mass movements Defecation
Rectal distention triggers defecation reflex, which then forces feces out of anal canal
Control? Other mechanisms
Internal and external valves (sphincters)
Pressure from abdominal cavity

21. Diseases/Disorders Diverticulitis
Fever, pain in abdomin, diareherra
Possibly caused from increase in intraluminal pressure.
Indiv. With low dietary fiber intake at high risk

23. Crohn’s Disease
autoimmune disease: caused by the immune system attacking the gastrointestinal tract and producing inflammation in the gastrointestinal tract
may affect any part of the gastrointestinal tract from mouth to anus,
Symptoms: abdominal pain, diarrhea (which may be bloody), vomiting, or weight loss
Type of inflammatory bowel disease (IBD)
appears to be a genetic link
Mutations in the CARD15 gene