GIT Physiology Overview Lectures and Cases

Question 1

If an epigastric pain is related to meals, what does that tell us?

Answer 1

Indigestion or GERD

Question 2

What is Zollinger-Ellison syndrome? How does this affect the G-cells of the stomach?

Answer 2

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

Question 3

How does low pH affect bile?

Answer 3

Bile is ineffective and clumps

Question 4

What is being stuperous indicative of?

Answer 4

Shock

Question 5

Normal Na+ plasma level?

Answer 5

140 mEq/L

Question 6

Normal hematocrit?

Answer 6

35 to 50%

Question 7

Normal BP?

Answer 7

120/80

Question 8

What are high hematocrit and blood proteins indicative of?

Answer 8

Low BV

Question 9

How is plasma Na+ affected by low BV?

Answer 9

Should be elevated

Question 10

What does it mean if the BV is low but the Na+ is normal?

Answer 10

Na+ was lost with the water

Question 11

What happens if you remove isotonic fluid from the ECF?

Answer 11

No change in osmolarity, no change in the volume of ICF, and a decrease in ECF volume

Question 12

Effect of cholera infection? What do we call this?

Answer 12

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

Question 13

Treatment of cholera infection to make the diarrhea stop?

Answer 13

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

Question 14

Normal basal plasma glucose level?

Answer 14

70-90 mg% (mg/dL)

Question 15

2 GIT issues associated with alcoholism? What to note?

Answer 15

1. Pancreatitis
2. Liver cirrhosis

You usually do not see these together

Question 16

Why does alcoholism cause pancreatitis?

Answer 16

Alcohol inhibits the trypsin inhibitor

Question 17

Can the pancreas regenerate?

Answer 17

NOPE

Question 18

Does pancreatitis affect the exocrine or endocrine cells of the pancreas more?

Answer 18

Exocrine because they represent 90% of the pancreas

Question 19

If a patient has pancreatitis can you assume that administering CCK will not cause a normal pancreas secretion?

Answer 19

YUP

Question 20

Treatment for pancreatitis?

Answer 20

Diet low in fat and synthetic pancreatic enzymes

Question 21

What % of digestion happens pre-duodenally?

Answer 21

25% for all types

Question 22

What are feces of steatorrhea so smelly?

Answer 22

Bacteria feed off of the lipids and make gases like putrescine

Question 23

Why does steatorrhea caused by pancreatitis not involve diarrhea?

Answer 23

Because the lipids are bulky and block osmosis of undigested compounds like undigested proteins and carbs

Question 24

Does glucose absorption depend on adequate pancreatic function?

Answer 24

NOPE

Question 25

What happens if a patient lacks the SGLT1 glucose transporter?

Answer 25

DEATH, not a real thing

Question 26

What would cause the basolateral Na+/K+ ATP-ase to not work? aka glucose cannot be absorbed...

Answer 26

Ouabain

Question 27

Does the vagus nerve stimulate bile secretion?

Answer 27

YUP

Question 28

Can some lipids cross the unstirred water layer without bile/micelle?

Answer 28

VERY little

Question 29

When does vagus innervation to the GIT turn off?

Answer 29

Once chyme has left the stomach! Vagus only active when chyme is present in the upper GIT (up to lower jeju)

Question 30

Is the MMC similar to a mass movement in that both extend for a considerable distance?

Answer 30

YUP

Question 31

What is the primary factor in determining the rate of bile acid and bile salt formation by hepatocytes?

Answer 31

Amount of bile salts absorbed by the ileum

Question 32

What is the MOST important factor affecting water movement through GIT?

Answer 32

Na+/K+-ATPase on basolateral membrane

Question 33

When does the composition of saliva most closely resembles that of plasma?

Answer 33

When parasympathetic NS is stimulated

Question 34

Are salivary secretions dependent on parasympathetic innervation? Are they almost entirely under neural control?

Answer 34

YUP YUP

Question 35

Why does removal of the gallbladder cause diarrhea? Treatment?

Answer 35

This is because of increased bile salts in the intestines acting as osmotic agents Treatment: drug that makes the bile non-osmotic = cholestyramine

Question 36

Does inflammation of the gallbladder necessarily mean there are stones?

Answer 36

NOPE

Question 37

Usual number of bile cycles per meal?

Answer 37

3

Question 38

How does increased bile excretion affect absorption in the SI?

Answer 38

Decreases ability of colon to absorb Na+/H2O => diarrhea

Question 39

Where does bilirubin excretion mainly occur?

Answer 39

FECES