Mod 3: Lecture 1 Flashcards
Exam 1
Divisions of the GI system
Upper
Lower
Hepatobilliary system
Divisions of the GI system: Upper
Esophagus
Stomach
Small intestine
Divisions of the GI system: Lower
Large intestine (colon)
Appendix
Rectum
Divisions of the GI system: Hepatobilliary system
Liver, gallbladder, pancreas
Neural controls: Sympathetic nervous system- what does it decrease?
Decreases secretion and peristalsis
Neural controls: Parasympathetic nervous system- what nerve
Vagus nerve
Neural controls: Parasympathetic nervous system- does what?
Increases secretion and peristalsis
Tasting food
Neural controls: Sympathetic nervous system- what does it stimulate?
Stimulates vasoconstriction in the mucosa
What stomach enzyme digests proteins?
Pepsin
What does HCI do in the stomach?
HCl acid activates enzymes, breaks up food, kills germs
What protects the stomach walls?
Mucus protects stomach wall
What is an issue with the stomach?
limited absorption
Lower esophageal (cardiac) sphincter is where:
between esophagus and stomach
Pyloric sphincter is where:
between the stomach and duodenum
What protects gut wall of small intestine?
Mucus
What does small intestine do?
Absorbs nutrients and most water
What in small intestine digests proteins, what digests sugars? What digests nucleotides?
Peptidase digests protein
Sucrases digest sugar
Nucleotidases and phosphatases digest nucleotides
What does large intestine do?
Reabsorbs some water and ions
Forms and stores feces
What does rectum do?
Stores feces prior to elimination through anus
What organ completes digestion?
small intestine
Chyme
acid fluid passes partially digested food from stomach to small intestine
What are the digestive juices stomach makes:
Hydrochloric acid ~
Pepsin ~
Gastric lipase ~
Intrinsic factor ~
Mucus ~
How does HCI work?
is secreted by parietal cells,
protein digestion, kills bacteria
What does gastric lipase do?
Gastric lipase ~ fat digestion
What does intrinsic factor do?
Intrinsic factor ~ B12 absorption in small intestine
What is mucus stimulated by?
Mucus ~ Protects stomach lining,
stimulated by prostaglandins,
mucosal barrier, gastric mucosal blood flow
Stomach absorption of nutrient? What is absorbed in the stomach?
No nutrients, only prepares for absorption.
ETOH
Pyloric sphincter- what does it prevent?
Prevents reflux of bile from the small intestines
Pyloric sphincter
a muscular valve at the bottom of the stomach that controls the flow of food from the stomach into the small intestine
What is the initial part of the small intestine?
Duodenum
Emesis- what kind of action?
Involuntary or voluntary
How is emesis protective?
Drug OD
Infection
What is emesis associated with? What are examples?
Association with severe pain
ex;
Migraines
Renal calculi
What does emesis involve coordination with?
Coordination via medulla oblongata
Coordination via medulla oblongata for emesis include what two groups?
- Vomiting center (VC) activation
- Chemoreceptor Trigger Zone (CTZ)
What is needed for Vomiting center (VC) activation?
Direct acting stimuli
What are examples of direct acting stimuli in VC activation?
Fear ~ cerebral cortex
Smell/sight or pain ~ sensory organs
Motion sickness ~ vestibular apparatus of inner ear (cranial nerve VIII)
Fear is involved with what part of the brain?
Fear ~ cerebral cortex
Smell/sight or pain is involved with what part of the brain?
Smell/sight or pain ~ sensory organs
Motion sickness is involved with what part of the brain?
Motion sickness ~ vestibular apparatus of inner ear (cranial nerve VIII)
The Chemoreceptor Trigger Zone (CTZ) requires what kind of stimuli?
Indirect stimuli
Indirect stimuli for the CTZ include what?
Gut activation
Drugs, toxins, chemicals in the blood
Vomitus; What is it and does it aid with?
Contents vomited
Aids w/ ID of underlying cause
Hematemesis:
vomitus with blood
What kind of appearance does vomit with blood have? Why?
Brown, granular appearance ~ coffee grounds
It is Partially digested protein
Why does hematemesis occur?
Blood irritation to GI mucosa –> attempts to expel
Diagnosis is capable of causing upper GI bleed include
Gastric ulcers
Esophageal varices
GIB gastro intestinal bleeding
Bile containing vomitus is what color?
Yellow- or green-colored
Bile containing vomitus
Why does it occur?
Can occur from GI tract obstruction
Liver biliary
Fecal containing vomitus (throwing up poop); how does it appear? Why?
Deep brown color of
May indicate content from lower intestine, possibly fecal
Fecal containing vomitus (throwing up poop) diagnosis include:
Intestinal obstruction
Impacted feces
cancer
Undigested food in vomitus occur because:
Impaired gastric emptying
Pyloric stenosis
Projectile Emesis
Vomitus exits with force
What are qualities of projectile emesis?
Often sudden
Subsequent excessive vomitus with each attack
Are not preceded by nausea
Associated conditions of projectile vomitting? what is the main one?
Intestinal obstructions
Delayed gastric emptying
↑ ICP/Head injury
Poisoning
Overeating
Neurologic lesions – tumors, aneurysms- involving brainstem
Pyloric stenosis
Complications of Emesis include:
Exhaustion
Fluid imbalances
Electrolyte imbalances
Acid–Base imbalances -?
Aspiration
What kind of acid base imbalance from vomitting?
metabolic alkalosis
acidosis for diarrhea
Procedures for management of Emesis may include?
PMH
PE
Blood chem
What are treatment goals for management of emesis?
Cessation of vomiting
Maintaining hydration (PO/IVF)
Restoring acid–base balance
Correcting electrolyte alterations
For cessation of vomiting, what can be given?
Antiemetics
Antiemetics include
5HT antagonists
Metoclopramide
Antihistamines: Dimenhydrinate, Meclizine, Diphenhydramine
Muscarinic antagonist: scopolamine
Best management of motion sickness
Most effective to treat prophylactically
Scopolamine is what kind of drug?
Muscarinic antagonist
How does Scopolamine patch work?
TD patch behind the ear
Apply 4h prior to travel
What are examples of Antihistamines for motion sickness?
Dimenhydrinate & meclizine
Which is most effective for managing motion sickness?
Scopolamine
Receptors & Agents Involved in Emesis
What classes of drugs are involved in emesis control?
- Serotonin antagonists
- Anticholinergics
- Antihistamines
5HT3 receptor Antagonists (serotonin receptor antagonists)- What is the prototype?
Ondansetron (Zofran)
What class in Ondansetron (Zofran)?
Class: Serotonin antagonists
What is the mode of action of Ondansetron (Zofran)?
Blocks type 5HT-3 serotonin receptors in the CTZ & on afferent vagal nerves upper GIT
What is Ondansetron (Zofran) used for?
CINV
Radiation
Anesthesia
How is Ondansetron (Zofran) administered?
PO, IM or IV, ODT
What is Ondansetron (Zofran) augmented with?
Augmentation with GCs
How should Ondansetron (Zofran) for a procedure (chemo)?
Give before to prevent:
CINV 30min prior
Anesthesia 1h prior
Radiation TID
Postop N/V
COmmon adverse effects of Ondansetron (Zofran)?
HA, diarrhea, dizziness
What is a serious adverse effect of Ondansetron (Zofran)?
QT prolongation
↑ risk of torsades de pointes
Avoid in long QT syndrome
When should Ondansetron (Zofran) be avoided?
Avoid in long QT syndrome
What does Ondansetron (Zofran) not cause?
⍉ DA blockade = ⍉ EPS
Precautions to take for Ondansetron (Zofran)?
Electrolyte imbalances
HF
Brady dysrhythmias
QT prolonging drugs
Metoclopramide (Reglan) is what class of drug?
Prokinetic agent/Dopamine antagonist
Since Metoclopramide (Reglan) is a Prokinetic agent/Dopamine antagonist, what does that mean?
Increase GI tone & motility
What is the mode of action of Metoclopramide (Reglan) ?
Blockade of Dopamine & serotonin receptors in CTZ
Increases Ach actions = increase in upper GI motility
Metoclopramide (Reglan) causes Blockade of Dopamine & serotonin receptors in CTZ, what can this be used for?
CINV & post-op N/V
chemotherapy-induced nausea and vomiting
Since Metoclopramide (Reglan) increases acetylcholine actions and increases upper GI motilitywhat does that mean?
Stimulates motility of UGI tract & accelerates gastric emptying (rest & digest)
Metoclopramide (Reglan) Stimulates motility of UGI tract & accelerates gastric emptying (rest & digest); What does this mean it can be used for?
Diabetic gastroparesis
Suppression of gastroesophageal reflux
How is Metoclopramide (Reglan) administered?
PO
IV
When should Metoclopramide (Reglan) be administered for Diabetic gastroparesis ? How?
PO
Diabetic gastroparesis (10mg PO 30 min before meals & HS x 2-8 wks)
When should Metoclopramide (Reglan) be administered for gastroesophageal reflux? How?
PO
Suppression of gastroesophageal reflux (10-15mg PO 30 min before meals & HS for max 12 wks)
What is Metoclopramide (Reglan) given IV for?When?
CINV & post-op N/V ~ 30min prior
Adverse effects of Metoclopramide (Reglan)
Sedation & diarrhea- Common in High Dose therapy
Irreversibletardive dyskinesia
Since Metoclopramide (Reglan) causes tardive dyskinesia, what does this?
Keep TX brief!!!
What is Metoclopramide (Reglan) contraindicated in?
GI obstruction, perforation, or hemorrhage
as per ↑ GI motility
Key Nursing Responsibilities with Metoclopramide Administration:
Assess for Parkinsonian sx – diff speaking, swallowing, loss of balance, pill rolling, rigidity, tremors, dystonia and tardive dyskinesia – uncontrolled rhythmic movements of mouth, face, exts, lip smacking, puffing cheeks
What is the mode of action of scopolamine?
Suppressing nerve communication in neuronal pathway that connects the vestibular apparatus of inner ear to the vomiting center
What is released during vestibular system activation?
Acetylcholine
Vestibular apparatus –> XX inner ear XX –> VC
Scopolamine is used for what?
Most effective drug for preventing motion sickness
End Of Life
Scopolamine > antihistamines
How is Scopolamine administered?
Oral, Sq, transdermal
TD patch applied behind ear
Q72h
Common Adverse effects of Scopolamine?
Dry mouth, blurred vision, drowsiness
What are more severe but less common effects of scopolamine?
Urinary retention, constipation, disorientation
Antihistamine drugs include?
Dimenhydrinate (Dramamine)
Meclizine (Antivert)
Why are antihistamines classified as anticholingerics?
Classified as anticholinergic because block receptors for acetylcholine (muscarinic cholinergic)
Why are antihistamines mode of action?
Blockade of histamine (H1) & muscarinic receptors in the neuro pathway connecting inner ear to VC
What can antihistamines be used for?
Use: motion sickness
What are adverse effects of antihistamines?
H1 blockade
Muscarinic blockade
Adverse effects of antihistamines: H1 blockade means it leads to what symptoms?
Sedation
Adverse effects of antihistamines: muscarinic blockade means it leads to what symptoms??
Dry mouth, confusion, hallucinations
Blurry vision, urinary retention, constipation
Gastritis
Inflammatory disorder of the gastric mucosa lining
What does gastritic do to stomach lining?
Gastric lining red, edematous
What occurs when the stomach lining is damaged?
Ulceration and bleeding when the mucosal barrier is damaged, or circulation compromised
What are common causes of gastritis?
Drugs: *NSAIDs, Glucocorticoids
*H. pylori, physiologic stress-related mucosal changes
Alcohol, metabolic disorders (eg renal failure – uremia)
Symptoms of acute gastritis include?
Sx: vague abd pain, epigastric tenderness, bleeding
Who does Chronic gastritis tend to occur in?
Tends to occur in older adults
What does Chronic gastritis cause?
Causes gastric mucosal atrophy, epithelial changes
What are two types of chronic gastritis?
2 types: immune (T-cell toleranace, auto Abs) vs
non-immune (same causes as acute)
What is immune cause of chronic gastritis?
T-cell toleranace, auto Abs)