Gastrointestinal Pancreas Flashcards
Name 4 different secretions of the exocrine Pancrease?
Bicarb
Amylase
Lipase
Proteolyic enzyems (trypsogen, chymotrypsogen)
What are the stimulators and inhibitors of the cephalic phase?
Stim: Sight, smell, taste- stimulate cerebral cortex and vagus nerve
Inhibits: SNS— decreases HCL and pepsin
What are the stimulators and inhibitors of the gastric phase
Stim: Stretch receptor, stimulates locally as well vago-vago reflex.
Inhibits: SNS, Stomatostatin
When food enters the stomach what is stimulated
Stimulate enteroendocrine G-Cells in the gastric glands to release gastrin. It is also the partial digested protiens
What are the actions of gastrin
Parietal cells: Bind to CCK2 receptors; increase intracellular calcium; then pump out H+ and in K+
Chief cells: Binds to CCK2, increases Ca release; leads to vesiclues of pepsinogen excocytosis- activated by H+ in the lumen
How is pepsinogen activated
It is activated to pepsin at a pH of 1.8-3.5
What is somatostatin and where is it released
Antrum D- cells. Released due to really low pH and will act on receptor of G cells to stop gastrin release and at parietal cells
What are the stimulators and inhibitors of parietal cells
Stim: ACh through M3— increse Ca levels; Gatsrin; Histamines through H2 receptors
Inhibit: Somatostatin, Prostaglandin E2
What are the stimulators and inhibitors of chief cells
Stim: Gastrin, Histamine H2 receptors;
Inhibit: Secretin
What do mucous cells do
Secrete to form mucosal barrier to protect cells from acid.
Electrolytes, phospholipdis, mucin protiens, and HCO3-
95% water
What are the function of duodenal G cells
Stimulated by increase protien
Secrete intestinal gastrin which acts on parietal and chief cells
What are the function of duodenal S cells
Stimulated with incrased protons and FA
Release Secretin
inhibits antrial G celles and Cheif cells
Liver stimulate hepatocytes to convert cholesterol to bile
Pancrease to epithlealial cells to make HCO3-
What are the function of enteroendocrine I cells
Stimulated by increase protiens, glucose, and fats
CCK- cholecystokin
Pariteal cells- inhibit proton pump
Liver potientates acteions of secretin
What are the effects of CCK
Gall bladder- stimulate to contract
Sphincter of Odi (bile/pancreas) relaxes at duodenum
Pancrease acini for trypsinogyn, lypase, amylase, chylotrypsinogen
What doe K cells do
Simulated by increased fats and glucose
Rleases gastric inhibiting peptide
Decreased parietal cell H/K antiporter
Stimulates inusulin release
Who doe chemoreceptors act in the face of extreme H+ concentration
Inhibit the Vagus nerve
What is the muscle of the esophagus.
Dogs: Striated the entire length
Cats Distal portion (1/3~) smooth muscle
What are the stretch mechanism in the stomach
Cephalic phase- receptive relaxation via vagus nerve stimulation
Gastric- bolus stretches in stomach and get local VIP/NO to get adaptive stretch (myenteric reflex)
What is gastric accommodation
Increase in gastric volume has a constant gastric pressure to a certain limit.
How does gastrin act on gastric motility
Allows more relaxation/stretch
Stimulate pump motility
How does intestinal resivor affect the stomach
Stimulate CCK, Secretin, and GIP and will cause relaxation of stomach and decrease gastric motility to allow the duodenum more time.
How does the mixing/emptying function of the stomach work
Pacemaker cells in the body stimulate contraction from body to antrum becoming more intense.
In pylorus have three regions that lead to the mixing effect as only the middle with pulpose through where the distal will contract the pylorus to close.
What is the enteric-gastric reflex
Distension of the duodenum leads to SNS stimulation of the pylorus to contract.
Low pH, high osmolality and prescence of fat
What is a migrating motor complex and where does it occur
Occurs in a fasting state: in the stomach and intestines
Motilin released resultiing in parastatlic wave that goes from body to pylorus.
Used to move larger particles
Cats don’t have MMC, rather less vigorous spikes
What is the vomit reflex
Coordinated by the brainstem
Relaxation of the stomach and LES. Closing of the pylorus
Contraction of intraabdominal muscles increase intra ab pressure
Chest cavity expands decreasing intrathoracic pressure and that of the esophagus.
Oppening of the upper esophageal sphencter
Glottis closes to prevent aspiration
Where is and what acts on the vomiting center
Medulla
Ach, dopamine, 5HT3, histamine
Stimulated by both the CTZ, and nucleus tracts solitaris
Where is and what acts on the chemoreceptor trigger zone
Floor of the fourth ventricle- incomplete bbb
dopamine, Ach, 5HT3, histamine opiods, neurokin 1
Were is and what acts on the nucleus tracts solitaris
Vestibular
Ach, Histamine, dopamine, 5HT3, Neurokin 1
What is the MOA of chlorpmazine
A1, D2, M1 antagonists
Works at the CTZ and emetic center
What is the MOA for ondansetron
5HT3 Anatagonist
CTZ, vagus afferent
What is the MOA for maropitant
NK1 anatagonist- blocks substance P
CTz, emetic center
What is the MOA of metoclopramide
D2 antagonist, 5Ht3 Anatagonist, 5HT4 agonist
CTZ
Where does metoclopramide have its effect
increases LES, increases frequency and amplituded of antril contractions, inhibits releacin
Side effects are CNS stimulation- excitation, tremors, aggression SSRI
What are the mechanisms of movement in the small intestine
Propulsive- digesitve phase moves food forwards. Also has MMC
Non propulses- interdigestive period. Contract titghtly in alternating segments, Contents move back and forth
What is intestinointestinal inhibition
Enteric nervous system reflex
grossly distended bowel leads to contractile activity in the rest of the bowel to be inhibited.
How does the ileocolic sphincter work
Prevents retrograde movement from colon
Primarily constricted.
Peristalsis results in relaxation and closes with increased colonic pressure
What is the gastric colic reflex
Distension in stomach leads to increased motility and mass movements in teh colon.
Afferent limb is stomach distension
efferent limb is mediated by CCK and gastrin
What is the MOA for cisapride
Sertonergic 5HT4 agonist
Increases LES pressure, and distal esophageal motility in cats.
Stomach increased gastric emptying at 0.5-1 mg/kg
Jejunal pike burst migration and increase in propulsive motility
What is the MOA for ranitidine
Ach inhibitor
Increase gastric antral contractions
Dogs propication of colonic on tractions
How does erythromycin have gastric motility effects
Macrolides positively stimulate motilin to work directly on smooth muscle
What is regurgitation
Passive ejection of material from upper gastrointestinal tract.
No reflex arc so airway is not able to be protected
What is granulamotous colitis in boxers
Associated with E.COli
also reported in french bulldogs and border collies
What is the MOA for NSAID/Steroid ulcers in the stomach
Prostaglandin inhibititoin via cycloxengenase 1 & 2
Decrases epithelial mucous production and decrease bicarb secretion
Decrease mucosal blood flow.
It also decreases negative feedback on parietal cells
What is the MOA of hepatic induced ulcers
Increased gastrin secretion and mucosal blood flow alterations
What is the MOA of uremic induced ulcers
Decreased gastric excretion through teh kidneys due to decreased renal clearance
What is the MOA of Misoprostol
Prostoglandin E1 analogue
What is the MOA of sucralfate
Dissociated to sucrose octassulfate and alumunim hydroxide (ALOH)
Bind ulcerated mucosa to prevent diffusion of hydrogen ions and inactiving pepsin
May reduce efficacy of other medications due to chelation by alumnium
More effective as suspension
What is the phys of pancreatitis
Mechanisms in place to prevent early activitation of trypsin become overwhelmed.
Trypsin activates other pancreatic enzymes leading to autodigestion
What are the three categories of acute pancreatitis
Mild- no organ failure, resolves in 1 week
Mod: Transient organ failure of co morbidities; may resolve without treatment or require speciality care
Severe: persistant organ failure > 48 hours, increased mortality
What is the anatomical difference in the pancreatic ducts of dogs and cats
Dogs have two pancreatic ducts which do not combine generally with the CBD
Cats have 1 duct that hoins the CBD prior to entering the duodenum
What electrolyte abnormality is associated with a poor outcome.
Decreased calcium
Why does Kaluresis not occur despite aldosterone stimulation in GI obstruction
RAAS activationd due to hypovolemia,
Angiotensin II inhibits, decrased GFR, and PCT/DCT increased Na reabsorption
Called aldosterone paradox
What are the indications for septic abdomen or bile peritonitis.
Lactate fluid: peripheral > 2.5 mmol/L
Glucose peripheral: Fluid > 20 mg/dl
Bile: Bilirubin Fluid: Serum > 2
When can you not use lactate and glucose for abdominal fluid
DPL- diagnostic peritoneal lavage
Post surgical abdomens/ abdomens with drains
What increases the survival of GDV
Lacated < 4 mmol/L, lactate clearance 40% reduction after rescitation
> 6 mmol/L increase cost of care and gastric wall necrosis more likely
Where is decompression for GDV generally performed
Area of tympamy in the dorsolateral region 1-3 cm caudal to the right 13 th rib
What is the gastric pressure thought to occlude venous return via azogus
Intragastric pressure of > 20 mmHg
What is the MOA of Apomorphine
Central acting non selective Dopamine (D2) agonist
Vomiting by stimulating D2 receptors in the medullary CTZ
How is intrabdominal hypertension defined in dogs
Normal 0 - 7.4 mmHg Mild 7.4-14.7 mmHg Mod 14.7-25.7 Severe > 25.7 Sustained
How is intraabdominal hypertension measured in dogs
Via intravesicular pressure generally U-bladder
Sterilely placed foley catheter. Urine is emptied
Instill 1 ml/kg of 0.9% Na CL
Connect to pressure transducer zeroed at the level of the pubic symphysis
Obtain while dog is standing
How does IAH lead to decreased CO, GFR, and UO
Increase in afterolad (mechanical compression of vessels)
Decrease in preload from caudal vena cava
List the complications of esophageal foreign bodies
esophagitis, aspiration pneumonia, esophageal perforation, stricture
Pneumothorax, pneumomediastinum, bronchoesophageal fistula
CPA, Death
Compare H2RA vs. PPI
PPI: More effective at increasing gastric PH over time
takes several days to be effective
Availability of pantropazole
H2RA: effective on first day of tx, can give with a meal, prolonged administration may decreased effectiveness overtime
Famotidine may increase mucous and bicarbonate secretion in stomach
What are differentials for rbc microcytosis
GI bleeding Copper deficency Chronic liver disease- PSS Lead poisioning Breed: Shiba Inu, Akita
What are negative prognostic factors in PLE
medium body weight
Altered BUN (both increase/decrease)
Decreased serum albumin
How does octeotide work
Somatostatin analogue
decreased GI motility
Hormone alterations in intestines, pancrease, pituitary
How does xylazine induce vomiting in cats
Centrally mediated alpha 2 adrenergic agonist
Stimulus in CTZ
Blocked/reversed by yohimbe
What is the assessment of radiographs for intestinal dilation in dogs.
SI: L5 mid body 2.5-2.4 times
variable
What is the MOA for lidocaines other than arrhythmic properties
Na channel blockade, inhibition of G-coupled protien, and inhibition of NMDA Recptors
CRI: Decrease Opiod doses, Reduce MAC
What are unique characiteristics of BIPS
The smaller BIPS have a constent gastric emptying rate with 75% leaving
Larger BIPS do not empty as well
