GIT Physiology Overview Lectures and Cases Flashcards
If an epigastric pain is related to meals, what does that tell us?
Indigestion or GERD
What is Zollinger-Ellison syndrome? How does this affect the G-cells of the stomach?
Gastrinoma (usually pancreatic) causing excess gastrin secretion => ulcerations + pancreatic enzymes cannot work due to acidification of duodenum and early jejunum + bile precipitates => steatorrhea and excess bile salts in feces
=> G-cells of the stomach are inhibited by pancreatic and intestinal hormones attempting to decrease HCl gastric secretion
How does low pH affect bile?
Bile is ineffective and clumps
What is being stuperous indicative of?
Shock
Normal Na+ plasma level?
140 mEq/L
Normal hematocrit?
35 to 50%
Normal BP?
120/80
What are high hematocrit and blood proteins indicative of?
Low BV
How is plasma Na+ affected by low BV?
Should be elevated
What does it mean if the BV is low but the Na+ is normal?
Na+ was lost with the water
What happens if you remove isotonic fluid from the ECF?
No change in osmolarity, no change in the volume of ICF, and a decrease in ECF volume
Effect of cholera infection? What do we call this?
Bacteria enters the enterocytes => makes a toxin that increases intracellular cAMP => increased activity of the CFTR => excess Cl- secreted into lumen => Na+/H2O follows to maintain electroneutrality inside the enterocytes = extreme diarrhea
Hallmark type of secretory diarrhea
Treatment of cholera infection to make the diarrhea stop?
Oral rehydration therapy and once the patient is stabilized the cholera resolves because the enterocytes slough off (that is where the cholera is) but need to be very careful with sanitation
You can also use antibiotics: tetracyclin
Normal basal plasma glucose level?
70-90 mg% (mg/dL)
2 GIT issues associated with alcoholism? What to note?
- Pancreatitis
- Liver cirrhosis
You usually do not see these together
Why does alcoholism cause pancreatitis?
Alcohol inhibits the trypsin inhibitor
Can the pancreas regenerate?
NOPE
Does pancreatitis affect the exocrine or endocrine cells of the pancreas more?
Exocrine because they represent 90% of the pancreas
If a patient has pancreatitis can you assume that administering CCK will not cause a normal pancreas secretion?
YUP
Treatment for pancreatitis?
Diet low in fat and synthetic pancreatic enzymes
What % of digestion happens pre-duodenally?
25% for all types
What are feces of steatorrhea so smelly?
Bacteria feed off of the lipids and make gases like putrescine
Why does steatorrhea caused by pancreatitis not involve diarrhea?
Because the lipids are bulky and block osmosis of undigested compounds like undigested proteins and carbs
Does glucose absorption depend on adequate pancreatic function?
NOPE
What happens if a patient lacks the SGLT1 glucose transporter?
DEATH, not a real thing
What would cause the basolateral Na+/K+ ATP-ase to not work? aka glucose cannot be absorbed…
Ouabain
Does the vagus nerve stimulate bile secretion?
YUP
Can some lipids cross the unstirred water layer without bile/micelle?
VERY little
When does vagus innervation to the GIT turn off?
Once chyme has left the stomach! Vagus only active when chyme is present in the upper GIT (up to lower jeju)
Is the MMC similar to a mass movement in that both extend for a considerable distance?
YUP
What is the primary factor in determining the rate of bile acid and bile salt formation by hepatocytes?
Amount of bile salts absorbed by the ileum
What is the MOST important factor affecting water movement through GIT?
Na+/K+-ATPase on basolateral membrane
When does the composition of saliva most closely resembles that of plasma?
When parasympathetic NS is stimulated
Are salivary secretions dependent on parasympathetic innervation? Are they almost entirely under neural control?
YUP
YUP
Why does removal of the gallbladder cause diarrhea? Treatment?
This is because of increased bile salts in the intestines acting as osmotic agents
Treatment: drug that makes the bile non-osmotic = cholestyramine
Does inflammation of the gallbladder necessarily mean there are stones?
NOPE
Usual number of bile cycles per meal?
3
How does increased bile excretion affect absorption in the SI?
Decreases ability of colon to absorb Na+/H2O => diarrhea
Where does bilirubin excretion mainly occur?
FECES
