1000ft view GI Flashcards
What are the layers of the GI tract
Mucosa
Submucosa
Muscularis
Serosa
What type of tissue is in the GI mucosa and what do they secrete
Epithelium and Glands
GLP-1
CCK
What is the lamina propria and where is it found
Contains blood and lymphoid tissue (MALT) within the mucosa
What tissue makes up the submucosa in GI tract
connective tissue
meissners plexus (autonomic nerves)
Peyers patches (lymph nodes)
What makes up the muscular layer in the GI tract
Skeletal muscle from the mouth to anal sphincter
rest: smooth muscle in the inner circular layer and outer longitudinal layer
Myentric plexus
What is the serosa in the GI tract
Connective tissue that lines the surface of the organ
What is the omentum
large fat pad that overlies the organist protect them
What makes up proteins in the GI tract
Amino acids
DiPeptides
Tripeptides
What makes up lipids in the GI tract
fatty acids
monoglycerides
cholesterol
What makes up carbohydrates in the Gi tract
Glucose
galactose
fructose
What is the three step process that makes up swallowing
Oral phase
pharyngeal phase
Esophageal phase
What begins the initial chemical breakdown of carbs
how about fat?
amylase
Lingual lipase
What are teeth needed for
needed for clear speech and mastication
How much saliva does an adult make a day
1L
*mostly water
What is contained within saliva and what is the pH
Na+, Mucus, Bicarb, chloride, K+, amylase
*7.4
What does your tongue do during mastication
Push food bolus against hard palate to break food up
How long is the esophagus
25cm
What initiates peristalsis in the esophagus
stimulation of the stretch receptors
What occurs when the UES closes
LES opens
What muscles helps the UES close
cricopharyngeal
Where is the Z-line
The change in cells between the stomach and esophagus
What is the other name for the submucosal plexus
miessner
What is the other name for the myenteric plexus
Auerbach
What are the three plexus for nerve innervation in the GI tract
Submucosal
Myenteric
Subserosal
What does the stomach do to the food that enters it
liquifies it into Chyme
*absorbs NSAIDs and ETOH
Where is the pacemaker of the stomach located
near the body
How much gastric acid is released during the cephalic phase of digestion
30%
What is involved with the cephalic phase of digestion
Seeing, smelling, anticipating food
How much gastric acid is secreted in the gastric phase of digestion (food hitting stomach)
60*
What happens to pH when food hits stomach
increase it
What enzyme will be secreted to signal fullness and when is it secreted
Cholecystokinin (decrease motility and emptying)
Somatostatin (slow gastric juice release)
Intestinal phase
Where is the primary area of gastric juice secretion
Gastric pits
What is the pH of pepsin
2
What protects the stomach lining from acidic environments
mucus
What cells secrete gastric acid
parietal
What do the chief cells do
secrete pepsinogen
What do the D cells secrete
somatostatin
What cells secrete gastrin
G cells
Besides secreting gastric acid, what do parietal cells in the stomach do
make intrinsic factor for B12 absorption
How much HCl is made by the body a day
3-4L
How much food can your stomach hold
1.5L
How long does food typically stay in the stomach
3hrs
What sphincter does Bile get secreted through
sphincter of Oddi
What stimulates bile secretion
secretin which is released by the duodenum
What does Bile do
emulsifies fats into droplets, which increases its surface area for further breakdown
What cells make up the bulk of the pancreas and what do they do
Acini cells that will secrete enzymes into the GI tract
What does secretin do
promotes ductal cells to release aqueous secretion
buffers acidic material coming from stomach by stimulating bicarb to be released by pancreas
What does amylase breakdown
starches and glycogen
What does a high lipase indicate on labs
pancreatitis
What makes up the small intestine and how long is it
Duodenum, jejunum, ileum
*20ft long
What is the primary site of chemical digestion and nutrient absorption
small intestine
What is the purpose of the brush border
increase surface area of small intestine
What separates the duodenum and the jejunum
Ligament of Treitz
What is the longest section of the small intestine
ileum
What is Haustral segmentation
mechanical digestion stimulated by distention
What two movements occur in the small intestine to help with digestion
segmentation
peristalsis (slow)
Where does absorption occur in the small intestine
within the villi
Where does most of nutrient absorption occur
small intestine
What is the basic cell of the small intestine and what do they do
Enterocytes
-mucus secretion
-absorption
Where is magnesium absorbed
Magnesium
phosphate
Where is iron absorbed
proximal duodenum
*transported via ferritin
What causes the ileocecal valve to open
pressure in the ileum
What is the first part of the large intestine
cecum
*appendix is attached here
