Gastrointestinal Physiology Flashcards
What is the percentage of the foregut?
37%
What organs are included in the foregut?
Stomach and Small Intestine
What is the percentage of the hindgut?
63%
What organs are included in the hindgut?
cecum, large colon, and small colon
what is the purpose of the ENS?
constantly monitors GIT function; brain of the gut
what processes are occurring in the ENS?
synaptic transmission, paracrine signaling, hormonal signaling
what are the 3 main salivary glands?
parotid, mandibular, and sublingual
saliva is what percent water?
99%
how much saliva do horses secrete daily?
10-12 L with. a 8.6-9.1 pH
saliva secretion is stimulated by what?
mastication and intake
do horses have digestive enzymes such as amylase?
not really
do horses chew thoroughly compared to ruminants?
no
what are the 3 phases of the chewing cycle?
opening, closing, and power stroke
chewing increases the surface area which allows for what to occur?
more digestive access
what are the 2 portions of the esophagus and their fractions?
proximal is 2/3 striated and distal is 1/3 smooth
swallowing is induced by the presence of what?
food!
what is the transit time of the esophagus
4-10 seconds
why can’t horses vomit
no proven reason; oblique angle of connection between esophagus and stomach; esophagus structure; poor retching action, etc.
is the stomach small or large comparitive to the size of the horse?
small and fixed
what are the 2 main mucosal divisions of the stomach? and what divides them?
glandular and nonglandular; marco plicatus divides
the glandular region of the stomach is also known as what?
fundic
what cells are located in the fundic (glandular) region of the stomach? what do they do?
parietal (HCl)
zymogen/chief (pepsin, lipase)
ECL- histamine
D-somatostatin
what cells are present in the pyloric region of the stomach and what do they do?enzy
G- gastrin
D- somatostatin
goblet- mucus
enzymatic activity occurs where?
glandular fundus
where does fermentative action occur in the stomach?
saccus caecus due to lactic acid bacteria that produces VFAs that go through the tract and get digested
what likes to sit in the saccus caecus?
low density fiber mat
what occurs in the saccus caecus?
fermentation!!
what are the 3 major regions of the small intestine (in order)
duodenum, ileum, jujenum
what is the meeting point of the bile duct and the pancreatic duct in the small intestine?
duodenal diverticulum
what is in the small intestine that aids in the tract (tell what it aids in?)
surface epithelium (absorption)
goblet (mucus)
endteroendocrine (communicates with the ENS)
paneth (immunity)
undifferentiated (?)
what organs do horses not have?
gallbladder
where do liver and pancreas secretions flow w/o the gallbladder?
sphincter oddi (continuous)
bile salts help to emulsify what in horses?
fat
compare the pancreatic activity of horses to other species?
lower
the brush border in the small intestines contains what?
dissaccharides
explain protein digestion/absorption in the small intestine?
11-30% of whole tract apparent N digestion
explain fat digestion/absorption in the small intestine?
90% digested, can easily overwhelm the system
explain carb digestion/absorption in the small intestine?
readily increases in transporter expression but less than other types of species (cats, dogs, etc.)
what are the 3 parts of the cecum?
base, body, apex
does the cecum contain enzymes or villi?
no
where is the cecum located?
upper right flank
the colon direction!
right ventral (sternal flexure) left ventral (pelvic flexure) left dorsal (diaphragmatic flexure) right dorsal
what occurs in the small/descending colon
fecal ball formation
what to think of when you think of cecum and colon?
fermentation!
what is the product of the cecum and colon fermentation?
VFAs
is there a more diverse bacterial and microorganism population in the cecum or colon?
colon
what are the commonly seen microbial population?
fungal zoospores, protozoa, and bacteria
stomach is what percent?
9%
small intestine is what percent?
28%
cecum is what percent?
17%
large colon is what percent?
35%
small colon is what percent?
11%
