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GI system - intro
Terms in this set (52)
What are the parts of the GI tract?
what are the accessory structures?
name the organ to these roles
__ storage and concen of bile
__ bile secretion - lipid digestion, store nutrients
__ dehydration and compaction of indigestible materials in preparations for elimination
__ pharyngeal muscles propel materials -> esophagus
_ transport materials -> stomach
__exocrine cells -> buffers and digestive enzymes
__ secretion of lubricating fluids containing enzymes that break down carbs
__ enzymatic digestion and absorption of water, organic substrates, vit, ions
__ mech processing and mixing with salivary secretion
what are the basic digestive processes?
__ transport of digested end products -> blood and LN
__ taking in food thru mouth
__ digestion of carbs, proteins, and fats
what is propulsion?
peristalsis (esophagus, stomach, small intestine, large intestine)
nutrients and water of BV and lymph vessels happen in __
water to BV in __
chewing in mouth and churning, segmentation (happens in __) are types of __ digestion.
what are the layers of the wall of GI tract?
what is found in the mucosa layer of the GI tract?
muscular externa contains __
serosa contains __
instrinsic nerve plexuses include__
myenteric nerve plexus
submucosal nerve plexus
what epithelium is found in the mucosa?
strat squamous epithelial cells found in mouth, pharynx, esophagus = protective
columnar epithelial cells - stomach, small, large intestine -> secretion and absorption
mucosa is found in the __ and __.
it is highly folded to increase ___ for absorption and is freq invaginated to form the __ glands.
stomach - folded in rugae
small intestine - villi
tubular exocrine glands
in the mucosa, LP is formed by CT which contains the __.
___ aggregates of lymphoid tissue = immune cells -> __ first line of defense against pathogens
___ a thin of smooth muscle fibers - present in esophagus onwards
Peyer's patches (GALT)
Submucosa contains ___ (4)
elastic reticular fibers
blood and lymphatic vessels
submucosa (Meissener nerve plexus)
muscular layer consists of __ in stomach and __ in intestine.
inner oblique layer
inner circular layer
outer long layer
__ is found between circ and long muscle fibers.
Auerback nerve plexus (myenteric plexus)
___ is formed by CT and mesoepithelial cells
the oral cavity aka __ formed by cheeks, lip, and __ and encloses the __ (3).
Digestive juice present in mouth is __ which is secreted by salivary glands.
teeth, tongue, salivary glands
Fxn of mouth include (5)
food material ingestion
food chewing and mixing with saliva
appreciation of taste of food
food transfer (bolus) -> esophagus by swallowing
fxn of esophagus is to move ___ and keep it there
it connects pharynx thru __ and stomach via __ .
food and liquid to stomach
esophagus has __ fxnal zones known as __ .
upper zone - pharyngeal musc= skeletal
middle zone - longest -> smooth muscle
lower zone - smooth and LES (shortest)
___ prevents entry of air into esophagus and aspiration of esophageal contents -> airway
__ prevents reflux of gastric contents -> esophagus.
high UES tone
high LES tone
see slide 15
resting pressure are __ at UES and LES because both spincters -> cont resting smooth muscle tone.
In lumen of esophagus above diaphragm -> pressure is __ because esophagus is passing through intrathoracic space.
a different pattern of esophageal pressure observed upon swallowing:
1. UES briefly __ allowing food bolus -> esophagus -> transient EP is __
2. peristaltic wave sweeps down to esophagus -> transient EP is __
3. LES and prox stomach relax -> bolus enter stoach -> transient __ in EP
GERD occurs when ___ is incompetent allowing flow of gastric juices and contents back to esophagus.
presents clinically as ___ aka substernal chest pain and a __ taste in mouth
regions of stomach are __ (2)
___ generates much stronger contractions than orad region and is distal conatins stial portion of body and antrum -> thick walled
__ proximal, contains fundus + prox part of body - thin walled
what are the stomach fxns?
storage - holds food for 3-4 hrs
formation of chyme (converts food -> chyme)
- gastric juice
-pepsin (digestion of proteins)
-intrinsic factor (absorption of vit b12)
- gastric lipase (digestion of triglycerides)
glands of stomach are __ .
glands open into stomach cavity via __.
tubular structures made up of diff types of cells
mucuous neck cells secrete __ and __ and located in __.
parietal cells secrete __ and __ .
Chief cells secrete __ and __.
enterochromaffin like cells secrete __.
D cells secrete __
G cells secrete __ .
mucus - protects lining
histamine -> HCl
somatostain - inhibits acid
gastrin -> acid
see locations of all
intrinsic factor secreted in stomach by __ cells.
__ is part of GI tract -> extendng between __ sphincter of stomach and ileocecal valve -> large intestine.
What digestion takes place here ?
what is the important fxn .
wall of small intestine has all the __ layers as in stomach.
all chem and nutrient absorption
what are the 3 parts of the small intestine?
what are the following?
site of folic acid absorption __ aka __
aka __ and receives sotmach contents, pancreatic juice, and bile ; aka major site of Fe 2+ absorption and Ca 2+ abs.
__ site of folate and vit B12 absorption
what are the features of small intestine that amplify the SA for absorption?
__ fingerlike projection of mucosa which consist of __ cells
__ deep pits between villi; simmple tubular glands of intestine contains stem cells -> source of intestinal fluid secretion
__ transverse folds in mucosa
villi; enterocytes, goblet cells, endocrine cells, Paneth cells
mucous membrane of small intestine is covered by __.
villi are lined by __ cells called __ .
each __ gives rise to hair like projections called __.
__ and __ increase SA of mucous membrane by many folds.
villi + microvilli
what are the cells found in small intestines?
in small intestine
___ secrete hormones
__ transport substances
__ cytokines called defensins are secreted
__ mucus secreted
microvilli have dense __ at brush border protects cells from effects of digestive enzymes.
brush borders have brush border __.
most of the __ (microscopic paricle of TGs produced during digestion) -> diffuse into intestinal __ -> lymphatic vessels
large intestine or colon extends from __ valve to anus
what are the parts of large intestine?
cecum with appendix
sigmoidal colon or pelvi colon
what are the fxns of the large intestine?
absorptive (water, electrolytes, organic substances like glucose, alcohol, durgs like anesthetic agents, sedatives, steroids)
excretory - heavy metals like Hg
secretory - mucin + inorganic sub liek Cl-s and HCO3-'s
fecal continence is maintained by action of __ (3)
internal anal sphinc
external anal sphinc
___ is thickening of smooth muscle around anal canal controlled by __nerves.
__ composed of skeletal muscle around anal canal controlled by __ nerves.
internal anal sphincter
external anal sphincters
__ largest regional circ at rest and receives 30% of cardiac output.
The __ system is dominant effector that controls __ resistance.
__ causes vasoconstriction
__ is the largest circ at rest and receives about 30% of CO.
The __ is a dominant effector that controls splanchnic vasc. resistance.
__ stimulates GI secretion and motility -> __ splanchnic BF-> __ local metab
__ vasoconstriction __ splanchnic BF
inc PNS after meal
__ results from high levels of CCK and action of enteric nerves
period of splanchnic blood flow after a meal is called __.
an elderly woman comes in with unremitting ab pain that is out of proportion to physical finding with bloody diarrhea. What is the disease?
__ across injured bowel wall quickly results in potentially fatal peritonitis.
mortality rate in patients with mesenteric ___.
what is the most common cause of Mesenteric ischemia?
low BF to bowel
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