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143 Cards in this Set
- Front
- Back
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5 general components of GI
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1. oral cavity
2. stomach 3. intestine 4. transit 5. reabsorption |
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oral cavity main component
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salivary glands
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2 digestive enzymes in oral cavity
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amylase and lipase
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immunoglobulin A purpose
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immune function
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what does saliva act as
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a buffer. pH 6.8
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in horses: what does eating roughage trigger?
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saliva secretions.
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what problem can be triggered if horses are fed more grain in comparison to roughage?
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large grain concentrations= less saliva secretions stimulated
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gastric digestion refers to what organ?
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stomach
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describe gastric juice
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clear, pale yellow fluid
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what is gastric juice composed of 6 things
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mostly water - 99%
HCl - .2% digestive enzymes hormones inorganic salts mucin |
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what is HCl? basic or acidic
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brings pH down
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what is the purpose of HCl in gastric juice?
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low pH facilitiates nutrient (protein) breakdown
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what is mucin?
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component of mucous
a gycoprotein secreted by GI tract protects the stomach and small intestin lining |
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what does luminal refer to?
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small intestine
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what 2 types of secretions are directly involved with luminal digestion?
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pancreatic and hepatic secretions
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what are pancreatic secretions composed of? 3
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h20
endopeptidases inorganic cmpds |
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what are hepatic secretions composed of? 4
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water
bile acids mucin pigments |
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what is the order of hepatic secretions?
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liver, gall bladder, intestines
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what is a characteristic of animals without a gall bladder?
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need to forage/ constantly eat
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what animal doesnt have a gall bladder?
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horses
pigeons rats |
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difference btwn hepatic bile and gall bladder bile
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same components-different amounts
gall bladder bile = more concentrated less inorganic salts |
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why is bile pH higher than gastric juice pH?
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so that digestive enzymes in small intestine can become active
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order of events: gastric juice, bile, digestion..
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-gastric juice directly enters duodenum
-bile comes to duodenum and neutralizes pH -now luminal digestion can occur |
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2 facts about GI tract motor function
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-requires energy
-under neuroendocrine control |
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purpose of transit
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max exposure to epithelial cell surface
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what are 2 main digestive secretions?
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water
electrolyte must be reabsorbed! |
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where does reabsorbtion occur?
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lg intestine
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what is the purpose of reabsor.
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prevents dehydration
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what % of fecal matter is dry?
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50%
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when does diarrhea occur?
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when absorbtion doesnt occur quick enough
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obligate carnivore digestion is mainly?
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hydrolytic or enzymatic
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what does hydrolytic mean?
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water breaking
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what does obligate carnivore mean?
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will only eat meat/ has to eat meat
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examples of obligate carnivores
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felids
mink polar bears |
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what occurs in ruminant herbivores prior to enzymatic digestion?
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extensice microbial fermentation
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what occurs in non ruminant herbivores prior to microbial fermentation in the hind gut?
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some hydrolytic digestion
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examples of non ruminant herbs
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horse
guinea pig elephant kangaroo |
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characteristics of cat dig system
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large stomach (can handle large meals)
not really a cecum lg intestine is just a tube |
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what composes a hindgut?
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cecum and lg intestine
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dog dig system characterstics?
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presence of small cecum
seculation in lg intestine |
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characteristics of pig dig system
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-long, thin small intestine (what passes through has less mass)
-more time for reabsor. -well developed lg intestine |
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omnivore digestion characteristics
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mainly hydrolytic with some fermentative digestion in hindgut
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how many flexures in the equine lg intestine?
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3
sternal pelvic diaphragmatic |
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what do the 3 lg intestine flexures in horses connect?
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sternal: R and L ventral colon
Pelvic: L ventral and L dorsal colon diaphragmatic: L dorsal and R dorsal |
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what do the flexures make a horse suceptable to?
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feed impaction and digesta
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the small intestine of the horse increases in length until what age?
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4 weeks
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the large intestine of the horse grows until what age?
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20 yrs
reflects reliance on roughage for older horses |
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how big can a horse's cecum be?
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up to 1m long
25-35L volumic capacity |
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describe a horses stomach
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has a powerful cardiac sphincter
emesis (vomitting) is rare in horses |
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fish digestive tracts
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simple: trout, a carnivore
complex: milkfish- a planktivore |
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avian dig tracts: simple to complex
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simplest: necarivores
most complex: herbivores |
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order of complexity of dig tracts
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nectarivores, carnivores, omnivores, herbivores
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characteristics of animal that eats meat
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large stomach, short small int, no cecum
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characteristics of animals that eat plants
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larger and sacculated cecum
smaller stomach |
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for carnivores: gluconeogenesis is used by which substrate?
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alanine
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what is the form of glucose in meat?
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glycogen but not a lot of it
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describe chicken dig tract
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2 cecum
no lg intestine usually referred to s rectum |
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ostrich dig tract characteristics
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lg colon
seculation= indicates forager |
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red tailed hawk dig characteristics
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very simple
kinda like a cats |
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dove dig syst characteristics
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crop
proventriculus gizzard pancrease clse to small int because it provides enzymes for digestion |
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what 2 parts serve as short-term food storage
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esophagus and crop
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short term storage is important in which 2 types of animals?
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piscivores and carnivores
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how is storage function enhanced in some birds?
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by widening of the esoph prior to enterint the thoracic cavity-referred to as crop
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what piscivores do
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eat fish. dive and grab fish
sometimes have to fly a distance before eating and digesting |
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which birds secrete crop milk?
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dove and pigeon
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explain brooding
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period of covering eggs. this stimulates prolactin secretion
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what does prolactin stimulate?
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differentiation of the crop epithelium and increased synth of fats and proteins
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what are 2 functional regions of stomach
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proventriculus/glandular stomach
gizzard/muscular stomach |
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characteristics of proventric/glandular stomach
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large in carns and pisc
serves as storage for some species has secretory function: HCl and pepsin |
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gizzard/muscular stomach/ventriculus characteristics
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muscular contractions
grinding and mixing |
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small intestine in herbivores and grain eaters
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longer
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small intestine in carnivores
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villi of intestinal cells are more developed. finger like. have shorter SI, but increased surface area because of longer villi
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is ceca present in all avian species?
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no
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functions of ceca
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water and electrolyte reabs.
fiber digestion (in ostrich) immunity: ceca contain lymphatic tissue positioned to monitor and control gut microflora |
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where does water and electrolyte reabs. happen in mammals?
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large intestine
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describe microbial fermentation
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microbes do the fiber digestions
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do penguins have ceca?
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yes
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what is an important barrier for pathogens?
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gi tract
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colon can also be called what in avian species?
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rectum
except in ostrich |
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describe rectum in avian species
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more than 50% of the total intestinal length
is sacculated |
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name the 2 regions of the stomach
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proximal and distal
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where is the fundus located?
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in the proximal region of the stomach
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what happens to the proximal region as food remains?
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enlarges and increases the intragastric pressuere
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what does proximal mean?
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close to the oral cavity
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what does distal mean?
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away from the oral cavity
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what is difference btwn pepsinogen and pepsin?
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pepsin is active and pepsinogen is inactive form
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pressure and relaxation in the stomach. why does this occur?
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allows more storage without an increase in pressure and prevents stomach from inflating
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what is the corpus?
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transition, main body of stomach.
midregion |
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what is the purpose of the distal region of the stomach?
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for mixing and emptying
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what orchestrates the distal part of the stomach?
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nervous and endocrine system
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where is the pyloric antrum?
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in distal region of the stomach
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what is muscularis externa?
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external muscular coats of the stomach
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what is the external muscular coat of the stomach composed of?
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all smooth muscle fibers
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what are the 3 layers of the external muscular coat of the stomach?
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middle circular
outer longitudinal inner oblique |
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2 facts about the middle circular
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present in most areas of the stomach and strongest
thickens as pylorus approaches and forms muscular ring of pyloric sphincter |
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another name for gastroduodenual junction?
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pyloric sphincter
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2 facts about outer longitudinal muscles
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absent on anterior and posterior surfaces of the stomach
located on inner and outer curvatures |
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where is the inner oblique muscle?
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lies on anterior and posterior surfaces
not on curvatures |
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what does innervation mean?
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supplying body part with nerves
or to stimulate something to action |
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innervation-where does it occur?
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via gastric branches of the vagal nerve (vagus)
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anterior nerve branch is responsible for what?
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signaling different functions of the upper GI- stomach, gall bladder, duod
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what region of the small intestine do anterior branches innervate?
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duodenal region
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what do the posterior nerve branches signal?
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signal distal parts of GI. starts at ileum to hingut and some pancreatic funtion
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describe muscularis mucosae
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anterior part. not considered part that directly interacts with injesta
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CCK? what is it
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hormone. acts as a signaler. from organ to the brain stem
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another name for gastroduodenual junction?
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pyloric sphincter
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2 facts about outer longitudinal muscles
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absent on anterior and posterior surfaces of the stomach
located on inner and outer curvatures |
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where is the inner oblique muscle?
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lies on anterior and posterior surfaces
not on curvatures |
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what does innervation mean?
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supplying body part with nerves
or to stimulate something to action |
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innervation-where does it occur?
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via gastric branches of the vagal nerve (vagus)
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where is the pyloric antrum?
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in distal region of the stomach
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what is muscularis externa?
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external muscular coats of the stomach
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what is the external muscular coat of the stomach composed of?
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all smooth muscle fibers
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what are the 3 layers of the external muscular coat of the stomach?
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middle circular
outer longitudinal inner oblique |
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2 facts about the middle circular
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present in most areas of the stomach and strongest
thickens as pylorus approaches and forms muscular ring of pyloric sphincter |
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start and end for vagus nerve
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starts at brain stem and goes to GI
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what is vagal shock?
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empty stomach. you feel dizzy and can faint
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what occurs in the nervous system when u eat
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stomach stretches
vagal nerve is activated you dont experience symptoms |
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what composes the cns?
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brain and spinal cord
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what makes up the peripheral system?
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afferent and efferent
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efferent- describe
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brain to organ
composed of somatic and autonomic cell bodies located in brain or spinal cord |
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somatic- which tissues are under control?
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skeletal muscle.
neurons are motor neurons- lead to contraction of innervated skel muscle |
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autonomic- what is innervated?
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smooth muscle, cardiac and glands
divided into sympathetic and parasympathetic |
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where is sympathetic division located?
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in thoracic and lumbar regions of spinal cord
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where is parasympathetic division located?
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in cervical and sacral portion of spinal cord
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what is gastric emptying a combination of?
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peristaltic waves and slow waves
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what does rate gastric emptying prevent?
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small intestine from becoming overwhelmed
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why cant large particles pass into duod?
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due to pyloric canal
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once chyme has been discharged into the duod, how does the pyloric muscle prevent regurgitation?
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it remains in a contracted state
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contraction/peristaltic waves in duod occur as gastic content enters and before _____?
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the pyloric canal relaxes
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2 types of factors regulating emptying
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gastric and duodenal factors
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what influences emptying in regards to gastric
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composition and amount of gastric content
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when will vomitting occur in regards to particle size
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if particles are not small enough to remain in suspension (chewed correclty)
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what is gastric emptying a functin of? 3 things
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meal volume
dry matter caloric value |
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why do liquids pass faster from stomach to small intest?
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all liq particles are already in suspension
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name 2 duodenal factors when it comes to emptying processes
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enterogastric nervous reflexes
endocrine mechanisms |
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where is the enterogastric nervous reflex located?
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in duodenal mucosa
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what does the enterogastric nervous reflex sense?
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senses tonicity and pH of gastric content
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what are endocrine mechanisms under control of?
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enterogastrones
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name 4 hormones involved with emptying
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cck
secretin gip vip |
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what does cck stand for
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cholecystokinin-
chole=bile cysto=bladder kinen=movement |
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what does gip stand for?
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gastric inhibitory peptide
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what does vip stand for?
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vasoactive inhibitory peptide
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