Intro to GI Tract Diseases Flashcards
Digestion
process of breaking down complex nutrients into simple molecules (so they can be absorbed)
Absorption
process of transporting simple molecules across intestinal epithelium into bloodstream
Where does digestion begin?
in the mouth
Digestion in the mouth:
teeth grind food (chewing) and cover it in saliva
Saliva
-lubricates food so it can pass through the esophagus
-buffers the stomach
-starts digesting starches (but not much)
When do horses produce saliva?
only when chewing
Choke
food is stuck (not chewed or lubricated enough) in the esophagus
-can lead to aspiration pneumonia
-EMERGENCY
Esophagus
tube connecting the mouth to the stomach
-no secretion
-just peristalsis (pushing food forward)
Stomach
-gastric juices
-stomach acid secreted all the time (unlike humans-only when we eat)
What does the stomach digest?
protein
What is the role of the cardiac valve?
closes off food from going from the stomach back to the esophagus (horses cannot vomit or eructate)
What does the small intestine digest?
enzymatic digestion
Bile
-produced by the liver
-digests fat in the SI
Pancrease
helps in the digestion of protein, fat, and starch
Where are the majority of sugars absorbed?
small intestine (leads to increase in blood glucose 30 min after a meal)
What is absorbed in the small intestine?
-vitamins
-minerals
-sugars
What is secreted into the small intestine?
bile and large volumes of water
What are the three sections of the small intestine?
-duodenum
-jejunum
-ileum
What raises risk of choke?
-bad teeth
-coarse hay
-dry hay
What valve separates the small intestine from the large intestine?
ileocecal valve
What are the sections of the large intestine?
-cecum
-large colon
-small colon
What is absorbed in the large intestine?
water and water-soluble proteins
Large intestine
microbial fermentation of material that was not digested in the small intestine (fiber)
Water moves via…
osmosis
Hypoosmotic
sends water to areas with less solutes
Hyperosmotic
sends water to areas with more solutes
Everything we eat is considered hyper or hypoosmotic?
hyperosmotic
What causes gastric ulcers?
if horses do not have food in their stomachs, gastric juices can splash up
How long does food stay in the stomach
not long (feed/concentrates stay longer)
How long can it take for digestion to complete?
up to 2 days
Pyloric sphiincter
the valve from the stomach to the small intestine
Glandular region of the stomach
contains glands that secrete mucus, gastric juices, and digestive enzymes
-the mucus protects the stomach lining (prostaglandins)
Aglandular region of the stomach
Rougher lining, no secretions, can be harmed by stomach acid
What are the 3 types of plant carbohydrates?
-fiber
-sugars
-starches
Fiber
structural part of plants and an important energy source for herbivores
-cannot be digested by mammalian enzymes (needs to be broken down by microbes through fermentation)
When does grass have the most fiber/water?
when it is young
What does eating young grass cause?
-cowpie/loose feces
-causes bloat
-usually in the spring
What influences water movement?
water moves in whatever direction necessary to keep ingesta iso-osmotic
-entering the gut when ingesta is hyperosmotic
-leaving the gut when ingesta is hypo-osmotic
What is water absorption dependent on?
nutrient absorption
Diarrhea
-increase in frequency of defecation or fecal volume
-volume is an increase in water content
-mismatch between secretion and absorption
What is water in the GI tract a sum of?
-ingested water
-water secreted in intestines
Water absorbed is ____ than the _____ of water ingested and water secreted leaving water for the passage of feces
less; sum
What can happen if ingesta is too dry?
it can cause impaction colic
When does diarrhea occur?
when absorption is inadequate to recover secreted water
-generally because of loss of GI epithelium (bacterial, viral, or protozoal infection)
How does infection lead to diarrhea?
it destroys villi, which impedes nutrient absorption, leading to impaired water absorption
What sometimes happens to horses that have diarrhea at a young age?
they often don’t return to normal
What happens to horses when they get diarrhea?
they get dehydrated quickly
Where does the majority of gastric ulcers occur?
in the aglandular part of the stomach
What type of horse is more prone to pyloric ulcers?
warmbloods
Pyloric ulcer is ______ to treat
hard
Concentrates increase or decrease the pH of the gut?
decrease
What is needed to buffer the stomach?
calcium
