The digestive tract plays a role of bringing life sustaining elements into the body and taking waste...
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Transcript of The digestive tract plays a role of bringing life sustaining elements into the body and taking waste...
The digestive tract plays a role of bringing life sustaining elements into the body and
taking waste products out of it.
Flow of material occurs by peristalsis. A wavelike motion
of longitudinal and circular muscle fibers. Another process
is segmentation..periodic repeating intestinal constrictions
http://www.youtube.com/watch?v=o18UycWRsaA
Peristalsis
Regulation of the actions is controlled by the autonomic
nervous system. This consists of the
Sympathetic branch
Parasympathetic branch
Parasympathetic stimulation increases intestinal motility,
increases secretions and relaxes sphincters
Cholinergic drugs stimulate these actions
Anticholinergic drugs inhibit these actions
Gastrointestinal drugshelp maintain the unobstructed and regulated flow of food into the body and waste products out
of the body
Types of Gastrointestinal drugs
Saliva Stopping : Antisialogues
These drugs can be administered I.V, I.M or SQ, and are often given secondary to anesthetic
use.These anticholinergic drugs
block the effects of acetylcholine (a neuro transmitter) at
parasympathetic nerve endings
These drugs are used to control:* hypersalivation
*vomiting*diarrhea
*excessive gastric secretions
Glycopyrrolate (Robinul)
Atropine
Diarrhea Stopping Drugs:Diarrhea is not a disease, but a sign of an underlying problem and can cause excessive fluid
loss and a decrease in the uptake of nutrients.
Antidiarrheals decrease peristalsis allowing fluid
absorption from the intestinal contents. These include:
*anticholinergics*protectants*adsorbents
*narcotic analgesics
Anticholinergics*used to treat tenesmus
these drugs should be used with caution as motility may already
be decreased.
Protectants/Adsorbents*coat the inflamed intestinal tract with a protective layer*binding bacteria, digestive
enzymes and or toxins to protect the mucosa
Narcotic (Opiate related drugs)*decrease intestinal secretions and flow of feces, increasing
segmental contractions resulting in increased intestinal
absorption
Probiotics
*seed the gastrointestinal tract with beneficial bacteria. Some forms of diarrhea are caused by
the disruption of normal bacteria flora
Metronidazole is an antibiotic that is effective against
anaerobic bacteria and may be used to regulate intestinal
bacteria and help return the stool to normal consistency
Stool Loosening
laxative: loosens bowel contents and encourages evacuation of
stoolcathartic: harsher laxative
resulting in watery stool and abdominal cramping
purgative: harsher cathartic.
Types of laxatives:*osmotic
*stimulant*bulk forming
*emollients (stool softener)
Osmotic:Include salts or saline, lactulose
and glycerin.These salts pull water into the colon and increase the water
content in the feces.
Stimulant laxatives increase peristalsis by chemically
irritating sensory nerve endingsBulk forming laxatives consists
of natural fibrous substances that absorb water into intestinal
tract, increase fecal bulk stimulate peristalsis resulting in
large soft stool production
Emollients are stool softeners, lubricants, and fecal wetting agents. These drugs are not
absorbed systemically and have few side effects
Antiemetic Drugs
The act of vomiting is controlled by the vomiting center in the medulla of the
brain. Acetylcholine is the neurotransmitter for the vomiting center.
This center gets input from pathways including*equilibrium changes
*pain*fear
*intracranial pressure changes*vagus nerve stimulation
*activity in chemoreceptor trigger zone (CRTZ)
Dopamine is the neurotransmitter for the CRTZ and stimulation of the CRTZ
results in dopamine release and stimulation of the vomiting
center.
Types of antiemetics*Phenothiazine derivatives: inhibit dopamine in CRTZ.
Antihistamines: block input from the vestibular system to the
CRTZ
Anticholinergics block acetylcholine which decreases
intestinal motility. HOWEVER these drugs also decrease gastric
emptying and may in fact increase the tendency to vomit
Procainamide derivatives block the CRTZ and speed gastric
emptying. Do not use in obstructed animals due to the stimulation of gastric motility
Vomit Producing Drugs: Emetics
used in the tx of poisonings and drug overdoses.
Check with poison control prior to administering emetics
Remember…horses, cattle sheep and goats are
unable to vomit
Apomorphinestimulates dopamine receptors in
the CRTZ. Given SQ, IM or topically in the conjunctival sac
Xylazine (Rompun)induces vomiting in cats as a side
effect of its use as a sedative
=
Ipecac syrup, salt and hydrogen peroxide are also commonly
used to induce vomiting.
Activated charcoal may be given to reduce absorption of
toxins when vomiting is contraindicated
Ulcer stopping Drugs
Antiulcer drugs: prevent the formation of ulcers
Antiactids: promote ulcer healing
Histamine-2: prevent acid reflux by reducing gastric acid
secretion.
Antifoaming Drugs.Used in ruminants who are
subject to acute frothy bloat. The rumen distends with gas
that mixes with fluid to form a froth which can asphyxiate the
animal
Motility Enhancing Drugsused for treating constipation, chronic hairballs or used after surgery to increase GI motility
Enzyme Supplementing Drugsused in cases of Pancreatic Enzyme Insufficiency (PEI)
Care should be taken when handling this drug, it can be irritating to skin and to nasal passages
Dental Prophylaxisattention should be given to the
oral cavity in any gastrointestinal condition.