Lecture 25- Intestines Flashcards
Small intestine
Major site for digestion and absorption
Has threes divisions: duodenum, jujenum and ileum
What do villi and microvilli do in small intestine?
They increase surface area
Cells in small intestine mucosa
Goblet cells- produce mucous
Enteroendocrine cells- produce hormones
Enterocytes (absorptive cells)
Planets cells- anti microbial compounds that can destroy invasive bacteria
Chemotherapy
Targets rapidly dividing cells (cancer cells)
Also targets rapidly dividing GI tract epithelium, which is th reason many patients have symptoms of nausea, vomiting and diarrhea
Intestinal juice
Secreted in response to acidic chyme, contains mostly water and mucous
After a meal what mixes chyme and propels it through intestine?
Segmentation (mixing) and peristalsis (actively moving food forward) work together
Migrating motor complexes
Move remenents toward large intestine in waves
Ileocecal valve
One way valve from small intestine to large intestine that relaxes to allow chyme to enter cecum
Large intestine
Absurd water from indigestible food residues and eliminates latter as feces
Three unique features large intestine exhibits
Teniae coil- three bands of longitudinal smooth muscle in muscularis
Haustra- pocket like sacs caused by partial contraction of teniae coli
Epiplocic appendices- fat filled pouches of visceral peitoneum, unknown function
Parts of large intestine
Cecum- first part of large intestine
Appendix
Colon includes: ascending colon, transverse colon, descending colon and sigmoid colon
Rectum
Anal canal
Haustral contractions
Slow segmenting movements
Mass movements
Slow powerful waves of peristalsis
What initiates defecation reflex?
When rectal wall is stretched from feces being pushed into rectum by mass movements
Diarrhea
Watery stool
Large intestine does not have sufficient time to absorb remaining water
