Exam 4 - Gastrointestinal Flashcards
What are the 5 functions of the GI system?
motility, digestion, absorption, excretion and circulation
GI tract is 5% of total body mass :)
3
Name the layers of GI system from outer to inner (5 layers)
(3 within layers in mucosa)
the serosa, longitudinal muscle, circular muscle, submucosa, mucosa
~Within mucosa is muscularis mucosae, lamina propia and epithelium
3
How do the longitutional muscle and circular muscle layers propagate gut motility?
- longitudinal muscle contracts to shorten the length
- circular muscle contracts to decrease the diameter
- They work together and propagate motility
4
What does the celiac plexus innervate?
the GI organs up to the proximal transverse colon
5
What does the inferior hypogastric plexus innervate?
descending colon and distal GI tract
5
Where do the submocosal plexus transmit information to?
What is the role of myenteric plexus?
submucosal plexus transmits info from epithelium to the enteric & CNS
-myenteric plexus lies btw smooth muscle layers and regulates smooth muscle
6
The mucosa is made up of muscularis mucosa, lamina propia and epithelium. What are their functions?
- muscularis mucosa -thin layer; moves the villi
-
lamina propria -contains blood vessels & nerve endings
immune and inflammatory cells - epithelium- senses GI contects, secretes enzymes,absorbs nutrients, exretes waste
7
The mucosa is made up of muscularis mucosa, lamina propia and epithelium. What are their functions?
- muscularis mucosa -thin layer; moves the villi
-
lamina propria -contains blood vessels & nerve endings
immune and inflammatory cells - epithelium- senses GI contects, secretes enzymes,absorbs nutrients, excretes waste
7
GI is innervated by ANS
The GI tract ANS consits of extrinsic and enteric nervous systems. What are their functions?
-
extrinsic nervous system
The extrinsic SNS -inhibitory and decreases GI motility
extrinsic PNS - excitatory and activates GI motility - enteric nervous system independent nervous system; controls motility, secretion, and blood flow
8
The enteric system is comprised of myenteric plexus and submucosal plexus. What are the functions of these?
- myenteric plexus controls motility-(carried out by enteric neurons,interstitial cells of Cajal, and smooth muscle cells)
- submucosal plexus controls absorption, secretion, and mucosal blood flow
Both these respond to sympathetic and parasympathetic stimualtion
9
Upper Gastrointestinal Endoscopy: may be diagnostic or therapeutic. Endoscope placed into what 4 structures
- esophagus
- pylorus
- stomach
- duodenum
10
High Resolution Manometry is a pressure catheter; measures pressures along _______?
Used to diagnose ______ _______
11
the entire esophageal lenght
motility disorder
11
GI series with ingested barium is a _______ assessment of _______ function and GI transit.
- radiologic
- swallowing
12
What is gastric empting study?
Pt fasts for 4 hours; then consumes a meal. There is continous imaging for 2 hours.
12
Lower GI Series involves the administration of a _____ enema to a patient. This outlines the ________ . This allows for the detection of ______ and _____ anatomical abnormalities.
- barium enema
- intestines
- colon
- rectal
12
Anatomical causes of Esophageal Disease include _______, ____ hernia, and changes associated with _____ acid reflux.
- diverticula
- Hiatal
- chronic
13
Mechanical causes of Esophageal Disease include achalasia, _______ spasm and a ______ LES
- Esophageal
- Hypertensive
13
Neurologic causes of Esophageal Disease may be stroke, ______ or hormone _________.
- vagotomy
- deficiencies
13
Oropharyngeal Dysphasia is most common after ______ and _______ surgeries.
- head
- neck
14
Esophageal Dysphasia is based on physiology. Includes Esophageal _______ and Mechanical ________ dysphasia.
- Esophageal Dysmotility (occurs w liquids and solids)
- Mechanical Esophageal (solids)
14
Gastroesphageal Reflux Disease is the effortless return of _____ contents into ________.
- gastric
- pharynx
14
What are (3) Classic symptoms of GERD
- Heatburn
- Lump in throat
- nausea
14
Achalasia is a ________ disorder of the _________ consisting of outflow obstuction d/t an inadequate _____ tone and _____ hypomobile esophagus.
- neuromuscular
- esophagus
- LES
- dilated
15
Achalsia is caused by loss of _______ cells of the esophagus ______ plexus.
Followed by an absence of ______ neurotransmitters of the LES.
Causing unopposed _________ LES stimulation (LES can’t RELAX)
- ganglionic
- myenteric
- inhibitory
- cholinergic
This disease was referred to as a symptom of several GI disorders later
15
Achalasia causes Esophageal ____ with food ______ to pass to the stomach.
- dilation
- unable
15
Achalsia symptoms include _______, regurgitation, ________ and chest pain. Long-term can increase risk of ________ cancer.
- dysphasia
- heart burn
- esophageal
15
Achalsia Type 1: __________ esophageal pressure, responds _______ to myotomy
- minimal
- well
15
Achalasia Type 2: _____ esophagus pressureized; responds well to treatment and has the ______ outcome.
- Entire
- Best
15
Achalasia Type 3: Esophageal ______ w/ premature contractions; has the ______ outcome.
- spasms
- worst
15
All treatments for Achalasia are __________.
- Palliative.
16
Medication treatments for Achalsia include nitrates and _____ to relax LES, and Endoscopic _____ injections.
- Calcium Channel Blockers (CCB)
- Botox
16
What is the most effective non surgical tx for achalasia?
Pneumatic dilation
16
What is the best surgical treatment for achalasia? hint laparascopic
- Laparascopic Hellar Myotomy
16
Surgical treatment for Achalasia can include Peri-oral Endoscopic Myotomy (POEM) which is the endoscopic division of the ____ muscle layers. 40% of the surgeries cause ________ or pneumoperitoneum.
- LES
- Pneumothroax
16
Esophagectomy for the treatment for Achalasia is only considered in the most _________ disease states.
- advanced.
high aspiration risk! RSI or awake intubation
16
What are diffuse esophageal spasms? Why do they occur?
Spasms that usually occur in distal esophagus; likely d/t autonomic dysfunction
Common in elderly
Tx: NTG, antidepressants, PD-I
17
What is esophageal diverticula?
outpouchings in the wall of the esophagus
17
What are the (3) types of esophagela diverticula?
What are they all at risk of?
Pharyngoesophagelal (zenker diverticulum)
Midesophageal
Epiphrenic (supradiaphragmatic)
All are aspiration risks. Removal of particles and RSI indicated.
17
What are the signs of Pharyngoesophageal (Zenker diverticulum)?
bad breath d/t food retention
17
What are the causes of Midesophageal diverticula?
old adhesions or inflamed lymph nodes
17
What does the pain from diffuse esophageal spasms mimic? What is the treatment of diffuse esophagela spasms?
Pain mimics angina.
TX: NTG, antidepressants, PD-I’s
17
What can Epiphrenic (supradiaphragmatic) pts experience?
achalasia
17
What is Hiatal Hernia? How does it occur? What is it associated with?
- Herniation of stomach into thoracic cavity, occurs through the esophageal hiatus in the diaphragm
- c/b weakening in anchors of gastroesophageal junction to the diaphragm
- May be asymptomatic; often associated with GERD
18
What type of cancer presents w/ progressive dysphagia and weight loss?
Esophageal cancer
5/100,000 ppl in US
poor survival rate :(
18
What is the most common type of esophageal cancer?
What 3 conditions does it relate to?
Most are adenocarcinomas, located in lower esophagus
These are r/t GERD, Barretts, Obesity
Squamous cell carcinoma accounts for the rest of esophageal cancers
18
Why does esophageal cancer have poor survival rate?
B/c abundant lymphatics lead to lymph node metastasis
18
What is the surgical intervention for esophageal cancer?
How is it performed?
Esophagectomy: May be curative or palliative
May be performed transthoracic, transhiatal, or minimally invasive.
19
What are pts at risk of when undergoing esophagectomy?
How do these pts usually present in pre-op?
If h/o of chemo and radiation, what 2 symptoms may occur?
High risk of recurrent laryngeal nerve injury; of which 40% resolve spontaneously.
Patients are often malnourished preop, & months after.
If h/o chemo/radiation -pancytopenia & dehydration may present
19
What are all patients post- esophagectomy at risk of?
High aspiration risk for life!
19
GERD
What do reflux contents include?
HCL, pepsin, pancreatic enzymes, bile
20
What is GERD? what are its s/s? How frequently does it occur in adults?
Incompetence of the gastro-esophageal junction, leading to reflux
Sx: heartburn, dysphagia & mucosal injury
Occurs in 15% of adults.
20
What diseases is bile reflux associated with?
Barrett metaplasia & adenocarcinoma
20
What are 3 mechanisms of GE incompetence?
- Transient LES relaxation, elicited by gastric distention
- LES hypotension (normal LES pressure-29mmHg, avg GERD pressure-13 mmHg)
- Autonomic dysfunction of GE junction
20
What is the treatment for GERD? (meds and surgery). What foods do you avoid?
- Meds: Antacids, H2 blockers, PPIs
- Surgery: Nissen Fundoplication, Toupet, LINX
- avoidance of trigger foods
21
What are the pre-op interventions for GERD patients?
- Cimetidine, Ranitidine-↓acid secretion & ↑pH
- PPI’s generally given night before and morning of surgery.
- Sodium Citrate- PO nonparticulate antacid
- Metoclopramide- gastrokinetic; often reserved for diabetics, obese, pregnant
Aspirations precautions –> RSI
21
What are the factors that increase intraop aspiration risk? (long list)
- Emergent surgery
- Full Stomach
- Difficult airway
- Inadequate anesthesia depth
- Lithotomy
- Autonomic Neuropathy
- Gastroparesis
- DM
- Pregnancy
- ↑ Intraabdominal pressure
- Severe Illness
- Morbid Obesity
22
The stomach is ____sac that serves as a ____ for large volumes of food, mixes and breaks down food to form ____, and slows emptying into the small intestine
J- shaped
reservoir
chyme
24
What does gastrin and motilin do?
What does gastric inhibitory peptide do ?
Gastrin & motilin increase the strength and frequency of contractions
Gastric inhibitory peptide inhibits contractions
These are controlled by neurohormonal
24
What is the effect of PNS and SNS on the motility of the stomach?
Parasympathetic stimulation to the vagus nerve increases the number and force of contractions
Sympathetic stimulation inhibits these contractions via the splanchnic nerve
24
What does the intrinsic nervous system do for motility?
Provides coordination
24
What controls the motility of the stomach?
intrinsic and extrinsic neural regulation
24
What are solids must be broken down into before entering duodenum?
1-2 mm particles
24
Peptic Ulcer Disease ::
- Most common cause of ____________________
- Prevalence= ___ women, ___ men
*____ death per year - may be associated with _______________
non-variceal upper GI bleeding
10% ,, 12%
15,000
Helicobacter Pylori
slide 25
Gastric Outlet Obstruction
What are 2 causes of acute obstructions
edema & inflammation in pyloric channel at beginning of duodenum
slide 26
Peptic Ulcer Disease ::
- Sx :: ______ epigastric pain exacerbated w/ ______ and improved w/ _______
- 10% risk of__________ in those who do not receive treatment
Mortalityis d/t (2 things)
BURNING epigastric pain exacerbated w/ FASTING and improved w/ MEALS
perforation
shock or perforation >48h
slide 25
PUD
Perforation is sudden/severe ______ pain from _____ secretions into ________
sudden/severe EPIGASTRIC pain c/b ACIDIC secretions into PERITONEUM
slide 25
What is the treatment for gastric outlet obstruction? (2)
Normally resolves in ___ hrs
Repetitive ______ & _____ may lead to fixed-stenosis and chronic obstruction
NGT + IV hydration
72 hrs
ulceration + scarring
slide 26
Gastric Ulcers ::
What is the treatment for H. Pylori
Triple therapy
2abx+ PPI x 14 days
What are 3 symptoms of pyloric obstruction?
Recurrent vomiting
dehydration
hyperchloremic alkalosis
Slide 26
What are 3 primary causes of gastric ulcers?
NSAIDs, alcohol, H. Pylori
27
What are the 5 types of gastric ulcers
Location – acid hyper secretion?
1 = Lesser curvature close of incisura – NO
2 = TWO ulcers : gastric body + duodenal - YES
3 = prepyloric - YES
4 = lesser curvature of gastroesophageal junction - NO
5 = anywhere - usually d/t NSAID use
27
Zollinger Ellison Syndrome ::
_________ tumor of the pancreas, causing ______ hypersecretion
Usually, gastrin stimulates gastric acid ________.
Gastric acid ________ further gastrin release (neg feedback)
This feedback loop is ________ in ZE syndrome
Non B cell islet
gastrin
secretion
inhibits
absent
28
Zollinger Ellison Syndrome ::
WHat are 2 treatments?
Pts have ↑ gastric fluid_______, ________imbalances, &________ abnormalities
Preop :: Correct ______, ↑ gastric ____ w/meds
Induction technique?
PPIs and surgical resection of gastrinoma
volume … electrolyte … endocrine
electrolytes … pH
RSI
28
Zollinger Ellison Syndrome ::
- 3 symptoms
- Occurs in ______ of PUD pts
- Gender affected?? Most commonly btw ages _____
Up to 50% of pts w/gastrinomas are______ at time of dx
peptic ulcer dz, erosive esophagitis, diarrhea
0.1-1%
Males > females agees 30-50
metastatic
28
Small Intestine ::
- motility mixes contents of the stomach with _____ ________, further reducing particle___ and increasing _____
- Major function :: _____ the contents and expose them to the ______ _____ to maximize absorption of ____, ______, and _______ before entering the large intestine
digestive enzymes … size …. solubility
circulate … mucosal wall …water, nutrients, vitamins
29
Small Intestine ::
The_____ and _________ muscle layers coordinate to achieve SEGMENTATION
Segmentation occurs when two areas _______ and thereby isolate a segment of intestine
Segmentation allows the contents to remain in the _______ long enough for the essential substances to be _______ into the circulation
It is controlled mainly by the ________ nervous system with modulation of motility by the _____ nervous system
circular … longitudinal
contract
intestine …. absorbed
Enteric ….EXtrinisic
29
Small bowel Dysmotility
5 Reversible Causes
2 types Nonreversible causes
- Mechanical Obstruction (hernias, adhesions)
- bacterial overgrowth
- ileus
- electrolyte abnormalities
- critical illness
Nonreversible: - Structural - scleroderma , IBD , connective tissue dx
- neuropathic - intrinsic + extrinsic NS altered + produce weak contractions»_space;> n/v, bloating, abd pain
29
Large Intestine ::
The colon also exhibits giant _______ complexes
These serve to produce mass _______ across the large intestine
In the healthy state, these complexes occur approximately ______x a day
Migrating
movements
6-10
31
Large Intestine ::
- Acts as a reservoir for _____ and ______ material before elimination
*extracts remaining ______ and water - _______ of the ileum will RELAX the _____ valve to allow intestinal contents to enter the colon
- Subsequent _____ distention will CONTRACT the ileocecal valve
waste .. indigestible
electrolytes
Distention … ileocecal
cecal
31
What are the most common diseases associated with Colonic dysmotility?
Large Intestine
- IBS (Inflammatory Bowel Syndrome)
- IBD (Inflammatory Bowel Disease)
32
Rome II criteria defines IBS as having abdominal discomfort along with 2 of the following features?
there are 3 features
- defecation relieves discomfort
- pain is assoc w/abnormal frequency (> 3x per day or < 3xper week)
- pain is associated with a change in the form of the stool
S32
In IBD, the contractions are suppressed due to colonic wall ____ by the inflamed mucosa, but the giant ____ complexes remain
In IBD, the contractions are suppressed due to colonic wall compression by the inflamed mucosa, but the giant migrating complexes remain
32
The ↑ frequency of the giant migrating complexes and their pressure effect = ↑ compression of inflamed mucosa which can lead to?
- hemorrhage
- thick mucus secretion
- significant erosions
S32
What is the 2nd most common inflammatory disorder (after RA)?
IBD
Incidence 18:100,000 ppl
33
What is a mucosal disease of rectum and part or all of the colon?
Ulcerative Colitis?
33
In severe cases of Ulcerative Colitis, what is the condition of the mucosa?
- hemorrhagic
- edematous
- ulcerated
S33
What are the s/s of Ulcerative Colitis?
- diarrhea
- rectal bleeding
- crampy abdominal pain
- N/V
- fever
- weight loss
33
What are the lab results of Ulcerative Colitis?
↑plts
↑erythrocyte sedimentation rate
↓H&H
↓albumin
33
What intervention to do after giving 6+ units of blood in 24-48 hours of hemorrhage of Ulcerative Colitis?
surgical colectomy
~ ½ cases resolve and ½ require colectomy
33
What are 2 primary symptoms that manifests with Colonic dysmotility?
altered bowel habits
and/or
intermittent cramping
S32
What is a complication of Ulcerative Colitis triggered by electrolyte disturbances?
Toxic megacolon
S33
What is a dangerous complication of toxic megacolon?
Colon perforation
S33
What is acute or chronic inflammatory process that may affect any/all of the bowel?
Crohn’s Disease
S34
Where is the most common site of Cronh’s disease?
Terminal ilium
34
What does presentation of Cronh’s disease?
w/ ileocolitis
w/ RLQ pain
& diarrhea
S34
What are 2 patterns of Cronh’s disease?
- penetrating-fistulous
- obstructing
S34
What are s/s of Cronh’s disease?
- weight loss
- fear of eating
- anorexia
- diarrhea
34
What does persistent inflammation of Crohn’s disease gradually progresses to?
- fibrous narrowing
- stricture formation
34
What replaces diarrhea with Cronh’s disease progression?
Chronic bowel obstruction
S34
Colonic disease may ____ into stomach/duodenum, causing fecal ____
Colonic disease may fistulize into stomach/duodenum, causing fecal vomitus
S34
What are additional symptoms of 1/3 Cronh’s patients?
- arthritis
- dermatitis
- kidney stones
S34
What are medical treatments of IBD?
- 5-Acetylsalicylic acid (5-ASA) - for antibacterial & anti-inflammatory
- PO/IV Glucorticoids - during flares
- Antibiotics - Rifaximin, Flagyl, Cipro
- Purine analogues
S35
What intervention should be the last resort for IBD?
Resection surgery
S35
What length should small intestestine resection be limited to?
< 1/2 length
Resected segment should be as conservative as possible
S35
What does > 2/3 of small intestine resection leads to? And what does it require?
“short bowel syndrome”
requiring TPN
S35
Where do most carcinoid tumors originate from? Where can they occur?
GI tract
occur in any GI tissue/segment
S36
What kind of products are secreted by Carcinoid tumors?
peptides & vasoactive substances
(gastrin, insulin, somatostatin, motilin, neurotensin, tachykinins, glucagon, serotonin, other biological actives)
S36
What occurs to 10% of patients with Carcinoid tumors where large amounts of serotonin and vasoactive substances reach systemic circulation?
Carcinoid syndrome
S36
What are s/s of Carcinoid syndrome?
- flushing
- diarrhea
- HTN/HoTN
- bronchoconstriction
S36
Effects of Carcinoid sydrome on CV:
May acquire right heart endocardial ____
Left heart generally more ____ as the lungs clear some of the vasoactive substances
May acquire right heart endocardial fibrosis
Left heart generally more protected as the lungs clear some of the vasoactive substances
S36
How to diagnose Carcinoid syndrome?
- urinary or plasma serotonin levels
- CT/MRI
S36
What are the treatments for Carcinoid syndrome?
- avoid serotonin-triggers
- control diarrhea
- serotonin antagonists
- somatostatin analogues
S36
What medication to give before surgery and prior to tumor manipulation of Carcinoid syndrome and why?
Ocreotide
to attenuate volatile hemodynamic change
S36
What are the secretory characteristics in the Foregut of Carcinoid tumors?
↓ Serotonin secretion
secreted ACTH, 5-HTP, GRF
Atypical Carcinoid syndrome
S38 table
What are the secretory characteristics in the Midgut of Carcinoid tumors?
↑ Serotonin secretion
secreted Tachykinins, rarely 5-HTP, ACTH
Typical Carcinoid syndrome
S38 table
What are the secretory characteristics in the Hindgut of Carcinoid tumors?
rare Serotonin secretion
rarely 5-HTP, ACTH, other peptides
rare Carcinoid syndrome
S38 table
What are the presentations of Carcinoid Tumors at the Small Intestines?
- Abdominal pain
- Intestinal obstruction
- tumor
- GI bleeding
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What are the presentations of Carcinoid Tumors at the Rectum?
- Bleeding
- constipation
- diarrhea
S38 table
What is the presentation of Carcinoid Tumors at the Bronchus?
Asymptomatic
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What is the presentation of Carcinoid Tumors at the Thymus?
Anterior mediastinal mass
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What is the presentation of Carcinoid Tumors at the Ovary and Testicle?
Mass discovered on physical examination or ultrasound
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Where do Carcinoid Tumors metastasize to and what is the presentation?
in the Liver
presents as Hepatomegaly
S38 table
How is autodigestion normally prevented to prevent trigger of Pancreatitis?
- Proteases packaged in precursor form
- Protease inhibitors
- Low intra-pancreatic calcium → decreases trypsin activity
S39
What are the most common causes of Pancreatitis?
- Gallstones - obstruch ampula of vater → pancreatic ductal HTN
- Alcohol abuse
S39
Pancreatitis is also seen in which 2 disorders?
immunodeficiency syndrome hyperparathyroidism (↑Ca++)
S39
What are s/s of Acute Pancreatitis?
- excruciating epigastric pain that radiates to back
- N/V
- abd distention
- steatorrhea
- ileus
- fever
- tachycardia
- HoTN
S40
What are the hallmark labs of Acute Pancreatitis?
↑serum amylase & lipase
S40
what are some imaging for acute pancreatitis?
contrast CT or MRI, endoscopic US (EUS)
s40
what are some complications of acute pancreatitis?
25% experience serious complications s/a shock, ARDS, renal failure, necrotic pancreatic abscess
s40
What are the treatments for Acute Pancreatitis?
- Aggressive IVF
- NPO (to rest pancreas)
- enteral feeding (preferred over TPN)
- opioids
TPN associated w/greater risk of infectious complications
S40
what is an ERCP? Interventions include what 4 things?
Fluoroscopic examination of biliary & pancreatic ducts
Interventions include
stone removal
stent placement
sphincterotomy
hemostasis
s40
which GI bleed is more common? (upper or lower?)
Upper GI bleed
s41
what vital sign changes will u see w/ >25% blood loss?
hypotension and tachycardia
s41
what does orthostatic hypotension normally indicate?
HCT <30%
s41
what does melena indicate?
GI Bleed that is above the cecum!!
(Cecum is where small intestine meets colon)
s41
why does the BUN go up >40 mg/dL during a GI bleed?
because absorption of nitrogen into bloodstream
s41
what is the therapeutic procedure of choice and also diagnostic for GI bleeds?
EGD (Esophagogastroduodenoscopy)
for endoscopic ulcer ligation and ligation of bleeding varices
s41
what is the last resort for uncontrolled variceal bleeding?
Mechanical balloon tamponade
s41
who usually has lower GI bleeds and what are some causes?
elderly
causes - diverticulosis, tumors, colitis
s42
What procedure can be performed for Lower GI bleeding as soon as HD stabilizes?
Unprepped sigmoidoscopy
S42
What procedure can be done for Lower GI bleeding if pt can tolerate prep?
Colonoscopy
S42
What 2 interventions are warranted if persistent bleeding occurs with Lower Gi bleed?
angiography and embolic therapy
S42
what is an adynamic ileus?
Colonic ileus characterized by massive dilation of the colon without mechanical obstruction
s43
what leads to distention of colon?
loss of peristalsis
s43
what is an adynamic ileus caused by?
electrolyte disorders, immobility, excessive narcotics, anticholinergics
s43
what could be the neural reason for adynamic ileus?
thought to be due to neural-input imbalance of excessive sympathetic stimulation along with inadequate parasympathetic input to the colon
s43
whats the tx for adynamic ileus?
- Restore e-lyte balance
- hydrate
- mobilize
- NG suction
- enemas
s43
what med and dose will u give for adynamic ileus?
and what do monitoring do u need if u give it?
neostigmine 2-2.5 mg over 5 min
- produces immediate results 80-90%
- CARDIAC MONITORING REQUIRED
s43
what happens if u leave an adynamic ileus untreated?
ischemia and perforation!
s43
what is inhibition GI activity directly proportional to?
amount of norepinephrine secreted from SNS stimulation, so the higher anxiety = higherinhibition
s44
what do volatiles do to the GI system?
depress the spontaneous, electrical, contractile, and propulsive activity in the stomach, small intestine, and colon
s44
whats the process of recovery of GI system?
- small intestine –> first part of GI tract to recover
- followed by stomach in approx 24 hrs
- then, colon 30-40 hours post-op
s44
what is important about nitrous oxide and gas containing cavities?
- N2O is 30x more soluble than nitrogen in blood
- will diffuse into gas-containing cavities from the blood faster than the nitrogen can diffuse out
s45
do NMBs affect GI motility?
No, NMBs only affect skeletal muscle, so GI motility remains intact
s45
when should N2O be avoided?
in lengthy abdominal surgeries or when the bowel is already distended
s45
what does gut distention correlate to?
- pre-existingamount of gas in the bowel
- duration of nitrous oxide administration
- concentration of nitrous oxideadministered
s45
what will neostigmine (AChE-I) cause w/ GI system?
what will offsets the cholinergic activity of neostigmine?
increase PNS activity and bowel peristalsis by increasing the frequency & intensity of contractions
- concurrent admin of anticholinergics (glycopyrrolate or atropine)
s46
What is sugammadex’s effects on motility?
NONE, Sugammadex does not appear to have any effect on motility
s46
What is known to cause reduced GI motility and constipation?
How?
Opioids
by exerting their function on both central & peripheralmu, delta, and kappa receptors
- and there’s a high density of peripheral mu-opioid receptors in the myenteric and submucosal plexuses!!!
- Activation of the mu-receptors causes delayed gastric emptying and slowertransit through the intestine!!!
s47
what are some adverse events w/ opioids and the GI system?
- nausea
- anorexia
- delayed digestion
- abdominal pain
- excessive straining during bowel movements
- incomplete evacuation
s47
what are the 5 main functions of the GI tract?
- motility
- digestion
- absorption
- excretion
- circulation
s48
name the layers of GI tract wall from outermost to innermost
outermost to innermost
1. serosa
2. longitudinal muscle
3. circular muscle
4. submucosa
5. mucosa
s48
name the layers of the mucosa from outer to inner
- muscularis mucosae
- lamina propria
- epithelium
s48
how do the SNS and PNS act on the GI motility?
The extrinsic nervous system consists of:
SNS –> primarily inhibitory
PNS –> primarily excitatory on GI tract motility
s48
what does the enteric nervous system control?
motility, secretion, and blood flow
s48
what are the 2 primary movements w/in and along the GI tract?
mixing and propulsive movements
s49
What can hemodynamic changes, bowel manipulation and open abdominal surgeries induce?
ileus, inflammatory states, mesenteric ischemia, and partial or total disruption of myogenic continuity
s49
