GI Tract Part 3 Flashcards
Proteins are initially denatured by —, then hydrolyzed by —
HCl from parietal cells
pepsin into polypeptide fragments
Continued by pancreatic enzymes (4)
trypsin, chymotrypsin, elastase, & carboxypeptidase
Continued by pancreatic enzymes—trypsin, chymotrypsin, elastase, & carboxypeptidase results in formation of
small peptide fragments, AA’s
absorbed by — via active transport by carrier proteins
enterocytes
Carbohydrates include (3)
1’ starches; poly-, oligo-, & disaccharides
Salivary & pancreatic amylase hydrolyze starch to
disaccharides (sucrose, lactose,maltose, & isomaltose)
Further broken down into
monosaccharides (glucose, galactose, & fructose), absorbed by facilitated diffusion
AA’s & monosaccharides absorbed by enterocytes lining villi, transported across epithelium, enter
capillaries within lamina propria
portal V to liver for —
storage
Lipids are 1’
triglycerides from diet
lipids are emulsified by action of
bile acids
Further broken down into monoglycerides & FA’s by
— —-, to form extracellular —
pancreatic lipase
micelles
Micelles are absorbed by —, then re-synthesized
into — within enterocytes & coated with proteins
& phospholipids to form intracellular —
enterocytes
triglycerides
chylomicrons
These are transported across enterocytes to
lacteals
lacteals
blind-ended lymph vessels within lamina propria of villi
Eventually carried to (2)
thoracic duct & general circulation
what does the large intestine include? (7)
cecum apppendix ascending transverse descending sigmoid colon rectum
Large intestine lacks (2)
villi & plicae circulares
Appendix
small, blind-ended sac, 2-13 cm in length distal to ileo-cecal junction
— cecum; used for — — in herbivores
Vestigial
bacterial digestion
appendix contains large amounts of submucosal —, active in —
MALT
children
inflamed appendix
appendicitis
treatment of appendicitis
surgical removal
appendectomy
colon 1’ function
H2O & electrolyte
resorption
colon also produces mucous for
elimination of undigested food & waste
what is included within the colon? (2)
large #’s of goblet cells in epithelium & colonic glands in submucosa—but no Brunner’s glands
colon does not contain — for nutrient absorption
villi
colon does not contain — —
place circulares
mucosal folds contain core of lamina propria
Mucosal epithelium similar to — —, but — cells generally
absent in adults
small intestine
Paneth
MALT in large intestine does notform domed
Peyer’s patches
No — present in lamina propria of colon
lacteals
Epithelial cell replacement q 5 days from — — located at base of glandular crypts
stem cells
Large #’s of — present in large intestine
commensal bacteria (“coliforms”)
Outer longitudinal M layer in muscularis externa is reduced or incomplete—forms 3 longitudinal strips, — —
taenia coli
taenia coli are responsible for formation of
haustra
haustra
sacculations of large intestine
Polyps are also known as
adenoma
adenoma
any mass arising from the wall of the colon that protrudes into the
lumen
polyps are generally —; most common sign is
asymptomatic
rectal bleeding
treatment of polyps/adenoma
surgical removal
Colon cancer is also known as
adenocarcinoma
increase (2) in diet decrease colon cancer by decrease — — & increase — —
roughage & fiber
transit time
GI motility
treatment of colon cancer
surgical removal; if extensive, may require resection of portion of
colon
New test kits for early detection; detect tumor Ab; also colonoscopy
screening over 50
rectum
short, dilated, terminal portion of large intestine
rectum contains (2)
transverse rectal folds and large #’s of mucus glands
Transition of mucosa from simple columnar epithelium to stratified squamous epithelium at
anal canal
Anal canal contains longitudinal folds called
anal columns (=columns of Morgani)
Within anal canal, anal glands extend into (2)
submucosa & muscularis externa
anal glands
branched, straight, tubular glands
anal glands secrete
mucous
Surrounding Mm forms (2)
internal & external anal sphincters
external—voluntary, skeletal Mm; internal—involuntary, smooth Mm
Occasional enlargement & irritation of submucosal Vv ~anal canal results in
hemorrhoids (like varicose Vv)
Anus (2)
external opening and exit of GI tract