-
Mvmt of food particles into circulation
Absorption
-
Mvmt of nutrients into body cells
Transport
-
Layers of GI tract starting from outside inward
- Connective tissue
- Smooth muscle layers
- Connective tissue
- Mucosa
- Lumen
-
-
Stores, concentrates, releases bile
Gallbladder
-
Releases bicarbonate & dig enzymes
Pancreas
-
Location of 3 diff muscle layers & what are they
- Stomach;
- circular, longitudinal, diagonal
-
Muscle mvmt in the small intestine; back & forth mvmt which mixes chyme
Segmentation
-
1st phase of digestion
cephalic phase (senses)
-
2nd phase digestion
- Gastric phase (stomach)
- 3-4 hrs
-
3rd phase digestion
- Intestinal phase (most chem digestion)
- starts when food enters duodenum
-
In mouth, starch broken down into:
dextrin + maltose
-
In mouth, lingual lipase breaks triglyceride into:
Diglyceride + FA
-
Enzyme secreted in mouth which kills bacteria
Lysozyme
-
____ controls entry of food into stomach
Esophageal (cardiac) sphincter
-
Hormone secreted by stomach wall which stimulates gastric secretion, pepsin production, mvmt, & stimulates stomach glands
Gastrin
-
HCL secretion in stomach has 4 purposes
- Denature protein
- Activate pepsin (protein digesting enzyme)
- Turns off salivary amylase
- Kills bacteria
-
Enzymes secreted into stomach:
-
Enzyme which has a higher affinity for TG with short/med chain FA
Gastric lipase
-
Inactive form of pepsin which is activated by HCL in stomach & brks protein into smaller pep chains
Pepsinogen
-
___ controls flow of chyme into small int
Pyloric sphincter
-
3 parts of small int
- Duodenum (beginning)
- Jejunum
- Ileum (end-nearest lrg int)
-
Hormone released by duodenal mucosa which stimulates pancreas to secrete bicarbonate which neutralizes acid chyme & inhibits gastrin release
Secretin
-
Hormone released by int wall which stimulates pancreas to secrete enzymes, GB to release bile, & slows GI mvmt
Cholecystokinin (CCK)
-
Hormone released by int wall which stimulates insulin secretion & has receptors on pancreatic beta-cells
Gastric Inhibitory Peptide (GIP)
-
2 Pancreatic Proteases (inactive & active forms) which brk proteins into small peps & AAs
- Trypsinogen, trypsin
- Chymotrypsinogen, chymotrypsin
-
Enzymes produced by intestinal mucosal cells & finish brkdown of proteins into AAs, di- & tripeptides
Peptidases
-
Enzyme which is primary for starch digestion into maltose
Pancreatic amylase
-
Enzymes which are produced by int mucosal cells & brkdown disaccs to monosaccs
Disaccharidases
-
Sucrase enzyme brks __ into __
Sucrose==> glucose + fructose
-
Lactase brks __ into __
Lactose==> glucose + galactose
-
Maltase brks __ into __
Maltose==> glucose + glucose
-
Primary enzyme for TG digestion
Pancreatic Lipase
-
Pancreatic lipase brks __ into __
TG==> monoglyceride + 2 FA
(some free glycerol also)
-
Microflora in large int produce gases & ____ provide ____. Also provide us with ___. Also help digest __.
- Acids (like short chain FAs)
- energy for colonocytes (cells which line int)
- vit K & B12
- Fiber
-
Location of absorption of most nutrients into blood
Villus of small int which has capillaries throughout
-
Location of absorption of lipids & fat sol vitamins into lymph
Lacteal of each villus of small int
-
Particles which require active transport (energy + carrier)
Minerals, some sugars, most AAs
-
Monosaccs which require active transport:
Monosaccs which pass by facilitated diffusion:
- Glucose, galactose
- Fructose
-
Carbs & proteins steps of absorption into circulation:
- Lumen
- Mucosal cell
- Capillaries
- Portal vein
- Liver
-
Glycerol & short-chain FA steps of absorption into circ
- Diffuse into mucosal cells
- Capillaries
- Portal Vein
- Liver
-
Mono-, diglycerides, long-chain FAs, cholesterol, phospholipds steps of absorption into circ
- 1) Micelles form in lumen (bile surrounding lipid)
- 2) Lipids diffuse in mucosal cells
- ----TG reassemble
- ----Bile recycled bk to lumen
- ----Chylomicron forms (TG+chol+phosphlip+protein)
- 3) To circ
- ----Chylomicron enter lacteal (lymph vessel) then go to blood & remnants taken up by liver
- ----TG released to cells
-
Fate of bile:
- Reabsorbed & recycled by liver OR
- Trapped by fiber & excreted in feces
-
2 types ulcers & cause
- Duodenal
- Peptide
- Anti-inflammatory meds, lots acid production
-
Infection which causes swelling & inflammation of a pouch in lrg int wall
Diverticulitis
-
Presence of inflammed pouches of lrg int
Diverticulosis
-
GALT (__) includes:
- Gut Associated Lymphoid Tissues
- Peyer's patches (accumulation of immune cells)
-
__ to __ species of bacteria in colon
300-500
-
Delivery system of nutrients into body via cardiovascular system: (3)
- Blood circ
- Hepatic portal circ
- Lymphatics- lipid soluble molecs
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