(09-02) Digestive System IV (Innervation of the Digestive Tract and More!) Flashcards
(Innervation of the Digestive Tract)
- What coordinate activity of GI tract? What do fibers innervate?
- What fibers to these plexuses contain? (three types)
- Intramural nerve plexuses; smooth muscle and epithelial cells
- parasympathetic terminal ganglia and fibers (GVE), sympathetic fibers (GVE), sensory fibers (GVA)
(The intestinal Enterocyte has many diverse functions)
- What are entirely within the plexus and coordinate different segments of gut and different layers of wall?
- These must be intact for what to occur?
- This is what division of the parasympathetic nervous system?
- Can reflex arcs function without extrinsic input?
1. intrinsic interneurons
- peristalsis
- enteric division
- yes
(Innervation of the Digestive Tract)
- Submucosal Plexus (in T. submucosa)
contains which fibers that do what?
- GVA - sensory to epithelium
- GVE - motor to muscularis mucosae and blood vessels
(Innervation of the Digestive Tract)
Myenteric Plexus (between muscle layers of T. Muscularis)
- coordinates what?
- What are the fibers here?
- peristalsis
- GVA - stretch receptors
- GVE - motor to T. muscularis and blood vessels
(Innervation of the Digestive Tract)
(Extrinsic Innervation)
- what simulates smooth muscle activity?
- What depresses smooth muscle activity?
- parasympathetic
- sympathetic
(Innervation of the Digestive Tract)
(Summary of Some Important Points concerning the small intestine)
1-4. Digestive Enzymes Are produced by what 4 things?
- liver
- pancreas
- mucosal glands
- intestinal absorptive cells
(Innervation of the Digestive Tract)
1-3. Protective mucus comes from what three things?
(Summary of Some Important Points concerning the small intestine)
- goblet cells of epithelium
- intestinal mucosal glands
- submucosal glands of duodenum
(Innervation of the Digestive Tract)
1-3. Surface membrane area for absorption in increased by what 3 things?
(Summary of Some Important Points concerning the small intestine)
- plicae circularis
- villi
- microvilli
(Innervation of the Digestive Tract)
1-3. What are three protective features?
- together these constiture the what?
(Summary of Some Important Points concerning the small intestine)
- mucus which coats surface with unstirred layer
- bicarbonate to buffer acid stomach chyme
- apical junction complexes of epithelial cells which seal lumen
- intestinal mucosal barrier
(Innervation of the Digestive Tract)
- Cell division to replace the gland and surface epithelial cells occurs near where?
- Therefore, epithelial cells continually migrate towards what in the small and large?
(Summary of Some Important Points concerning the small intestine)
- the base of the intestinal glands (in contrast with gastric epithelium)
- the villi in the small intestine and luminal surface in large (where they are sloughed)
(Large Intestine)
- site of what action?
- Epithelium absorbs or secretes what? Secretes what? Absorbs products of what in non-ruminant herbivores?
- forms what mass?
- Are the colon, cecum, and rectum similar or different histologically?
- microbial action
- H2O and electrolytes; mucus; fermentation
- the fecal mass
- similar
(Large Intestine)
(T. mucosa)
- longitudinal folds in some areas
- have villi? What type of surface epithelium? What that open into luminal surface?
- Abundant goblet cells, also enterocytes and enteroendocrine cells
- l. propria has many free cells and numerous lymphtic nodules
- do large venous plexuses occur in rectum?
- no; “smooth” surface epithelium; deep mucosal glands
- yes
(Large Intestine)
(T. submucosa)
- may accumulate what?
- fat
(Large Intestine)
(T. muscularis)
- Outer longitudinal layer forms what in cecum and colon of what species?
- many elastic fibers
- bands (taenia); horse and pig
(Large Intestine)
(T. serosa)
- Covers large intestine except for most of rectum which has what?
- T. adventitia
(Large Intestine)
(other features)
- ruminants - longitudinal mucosal folds in rectum = ?
- alternate with what?
- dogs - many solitary lymphatic nodules with epithelial depressions over them called what?
- rectal columns
- rectal sinuses
- rectal pits
(Anus and Anal Canal)
- What marks the separation between the rectum and anal canal?
- At this point the epithelium changes from what to what?
- anorectal line
- simple columnar to stratifeid squamous
(Anus and Anal Canal)
- What is the short terminal segment of digestive tract which is lined by stratified squamous epithelium?
- It terminates at what - which is the opening to the exterior?
- anal canal
- anus
(Anus and Anal Canal)
- What are longitudinal folds which alternate with sinuses?
- These are continuous with what in ruminants? present in horse?
- anal columns
- rectal columns and sinuses in ruminants; no
(Anus and Anal Canal)
- What is the point at which stratifed squamous epithelium becomes keratinized
- What kind of junction is this?
- anocutaneous line
- mucocutaneous junction
(Anus and Anal Canal)
- What is skeletal muscle?
- What is a thickening of the circular layer of the smooth muscle of the T. muscularis?
- What do these surround?
- external anal sphincter
- internal anal sphincter
- the terminal portion of the anal canal
(Anus and Anal Canal)
- These are bilateral diverticula - are located on either side of the anal canal between the external and internal anal sphincters
- Ducts from the anal sacs open into the anal canal at the what?
- Anal sacs and ducts are lined by what?
- Anal sacs occur in what?
- anal sacs or perianal sinuses
- ancocutaneous line
- stratified squamous epithelium
- carnivors and many rodents
(Glands of the ANal Region)
- What are modified tubular sudoriferous glands (apocrine sweat) associated with the anal canal?
- Located in what layers? open directly into what?
- Secretion is what in carnivores? in pigs?
- Ruminants and horse?
- gland morphology is coiled tubular
- anal glands
- T. submucosa or in T. muscularis; anal canal
- lipid; mucus
- no anal glands
(Glands of the anal region)
- (Glands associated with the anal sac) secrete into neck of anal sac or directly into its duct? In the form of what?
- Which animal has modified tubular sudoriferous glands (apocrine sweat), similar to anal glands?
- Which are modified tubular sodiferous and modified sebaceous glands; what from sebaceous glands may reduce plugging?
- perisacular glands; coiled tubules
- dog
- cat; oil
(Glands of the anal region)
- these are located in the cutaneous area around anus
- Third most common site of what in dogs?
a) tubular sodiferous (apocrine sweat) glands (coiled tubular gland)
(b) Circumanal glands)
two types
- large sebaceous glands usually associated with hairs (holocrine secreting, simple alveolar gland)
- hepatoid (like liver) cell masses located deep to sebaceous glands, without ducts
- glands of the perianal zone
- tumors
- superficial
- deep
(Gall Bladder)
- absent in what?
- stores and concentrates what?
- resorbs what?
- water follows what?
- horse and rat
- bile
- Na
- osmotic gradient
(Gall Bladder)
- thin folded wall, highly distensible
- epithelium: tall columnar cells with what? folded into crypts and recesses that may look like what?
- Does it have muscularis mucosae?
- May contain glands in what? what types?
- T. mucsularis - generally what? organized?
- may contain what cell?
- microvilli; glands
- no
- propria-submucosa (ruminants); mucous and/or serous types
- circular; no
- goblet cell
(Bile Ducts - extrahepatic)
- connect what with what and what?
- structure similar to what?
- T. muscularis may be what?
- liver lobes with gall bladder and duodenum
- gall bladder
- discontinuous
it appears to be working again