GI- physiology and anatomy

Question 1

What is the foregut?

Answer 1

pharynx to duodenum

Question 2

What is the midgut?

Answer 2

duodenum to proxima 2/3 of transverse colon

Question 3

What is the hidngut?

Answer 3

distal 1/3 of transverse colon to anal canal above pectinate line

Question 4

When does the midgut herniate through the umbilical ring?

Answer 4

6th week

Question 5

What does the midgut return to the abdominal cavity and rotate around the SMA?

Answer 5

10th week

Question 6

Compare gastroschisis to omphalocele. What fold is defective in both?

Answer 6

Lateral fold
Gastroschisis- not covered by peritoneum (defect in abd wall)
omphalocle- covered by peritoneum (persistent herniation)

Question 7

What chromosomal abnormality is duodenal atresia associated with?

Answer 7

Trisomy 21

Question 8

What congenital abnormality presents as an olive mass and nonbilious projectile vomiting at 2-6 weeks?

Answer 8

congenital pyloric stenosis

Question 9

What is the uncinate process formed from?

Answer 9

ventral pancreatic bud only

Question 10

What is an annular pancreas

Answer 10

ventral pancreatic bud encircles 2nd part of duodenum- duodenal narrowing

Question 11

what is a pancreas divisum

Answer 11

ventral and dorsal parts fail to fuse

Question 12

What parts of the colon and rectum are intraperitoneal and retroperitoneal?

Answer 12

ascending, descending, upper rectum- secondarily retropertioneal
transverse colon, sigmoid colon- intraperitoneal
lower rectum, anal canal- primary retropartineum

Question 13

What ligament is the portal triad contained in?

Answer 13

hepatoduodenal

Question 14

What vessels are contained in the gastrohepatic ligament?

Answer 14

gastric arteries

Question 15

What vessels are contained in the gastrocolic ligament?

Answer 15

gastroepiploic arteries

Question 16

What vessels are contained in the gastrosplenic ligament?

Answer 16

short gastrics, left gastroepiploic

Question 17

What vessels are contained in the splenorenal ligament?

Answer 17

splenic artery and vein, tail of pancrease

Question 18

What directions do the inner and outer muscle layers of the digestive tract face?

Answer 18

Inner- circular

outer- longitudinal

Question 19

Where is the myenteric/auerbach plexus located? What does it do?

Answer 19

in muscularis externa, controls muscle contractions

Question 20

Where is the Meissner plexus located? What does it do?

Answer 20

submucosa, controls secretory activity

Question 21

Where are brunner glands located?

Answer 21

duodenum

Question 22

What are the levels of the celiac trunk, SMA, IMA, Renal arteries

Answer 22

Celiac: T12
SMA/renal: L1
IMA: L3

Question 23

What is the parasympathetic innervation of the foregut, midgut, and hindgut?

Answer 23

foregut, midgut- vagus

hindgut- pelvic

Question 24

What area of the colon is particularly susceptible to ischemia?

Answer 24

splenic flexure (jxn midgut + hindgut)

Question 25

What are the 3 branches of the celiac trunk?

Answer 25

common hepatic, splenic, left gastric

Question 26

What arteries supply the greater vs lesser curvature of the stomach?

Answer 26

lesser curvature- gastric | greater curvature- gastroepiploic

Question 27

What is the embryologic and circulatory significance of the pectinate line?

Answer 27

above pectinate- endoderm, portal venous | below- ectoderm, systemic circ

Question 28

How does an external vs internal hemorrhage differ?

Answer 28

internal- not painful, drain deep nodes | external- painful, drain superficial inguinal

Question 29

Describe blood flow and bile flow of the liver

Answer 29

Glood flows from portal ven to central vein | bile flows towards portal triad

Question 30

What area of the liver is most likely to be damaged by viral hepatitis?

Answer 30

Periportal zone (zone I)

Question 31

What area of the liver is most likely to be damaged by ingested toxins?

Answer 31

Periportal zone (zone I)

Question 32

What area of the liver is most likely to be damaged by ischemia?

Answer 32

centrilobular zone (zone III)

Question 33

What area of the liver is most likely to be damaged by alcohol hepatitis?

Answer 33

centrilobular zone (zone III)

Question 34

What area of the liver contains the cytochrome P450 system?

Answer 34

centrilobular zone (zone III)

Question 35

Describe the locations of the medial and median umbilical ligaments

Answer 35

Medial lig- located just lateral to the rectus abdominus | median lig- located just medial to the rectus abdominus

Question 36

Where would the inferior epigastric artery be in relation to a direct and indirect hernia?

Answer 36

Medial to- direct hernia | lateral to- indirect hernia

Question 37

Which inguinal ring(s) does an indirect hernia pass through?

Answer 37

deep and superficail rings

Question 38

What is the underlying defect for an indirect hernia?

Answer 38

failure of processus vaginalis to close

Question 39

Which inguinal ring(s) does a direct hernia pass through?

Answer 39

superficial ring only

Question 40

What hernia is most common in women? Where is it located?

Answer 40

femoral hernia | below femoral canal and lateral to pubic tubercle

Question 41

What cells produce cholecystokinin?

Answer 41

I cells (duodenum, jejunum)

Question 42

What stimulates CCK?

Answer 42

fatty acids, amino acids

Question 43

What cells produce gastrin?

Answer 43

G cells (antrum of stomach)

Question 44

What stimulates gastrin?

Answer 44

stomach distention, alkalinization, vagal stim, amino acids

Question 45

What does motilin do?

Answer 45

produces migrating motor complexes, increased in fasting state

Question 46

What cells produce GIP

Answer 46

K cells (duodenum, jejunum)

Question 47

What are the symptoms of a VIPoma

Answer 47

watery diahrrhea, hypokalemia, achlorhydria

Question 48

What cells produce VIP?

Answer 48

parasympathetic ganglia in sphincters, gallbladder, SI

Question 49

What cells produce secretin?

Answer 49

S cells (duodenum)

Question 50

What stimulates secretin?

Answer 50

acid, fatty acids in lumen of duodenum

Question 51

What cells secrete somatostatin?

Answer 51

D cells (pancreatic islets, GI mucosa)

Question 52

What stimulates somatostatin?

Answer 52

incr acid, decr vagal stim

Question 53

What intestinal hormones affect insulin and glucagon secretion?

Answer 53

GIP- increases insulin | somatostatin- decreases insulin and glucagon

Question 54

What intestinal hormones affect gastric acid secretion?

Answer 54

Gastrin (+ histamine, vagal stim)- incr H+ secr | GIP, Secretin, somastostatin- decr acid secr

Question 55

What GI hormones affect pancreatic secretion?

Answer 55

CCK- incr secr secretin- incr HCO3 secr somatostatin- decreases

Question 56

What two amino acids are potent stimulators of gastrin?

Answer 56

phenylalanine, tryptophan

Question 57

What do parietal cells produce (2)

Answer 57

intrinsic factor, gastric acid

Question 58

What cells produce pepsin?

Answer 58

chief cells of stomach

Question 59

How does is gastrin stimulation of acid secretion mediated?

Answer 59

act directly on ECL cells which produce histamine

Question 60

How do pancreatic secretions compare with high and low flow?

Answer 60

low flow- high Cl | high flow- high HCO3

Question 61

What is the purpose of the D-xylose absorption test?

Answer 61

distinguishes GI mucosal damage from other types of malabsorption

Question 62

How are glucose, galactose, and fructose absorbed? transported to blood?

Answer 62

glucose, galactose- taken up by SGLT1 froctuse- by GLUT-5 all taken to blood- GLUT-2

Question 63

Where are iron, folate and B12 absorbed?

Answer 63

Iron- duodenum floate- jejunum and ileum Bqw- terminal ileum

Question 64

What enzyme catalyzes the rate-limiting step of bile synthesis?

Answer 64

cholesterol 7a-hydroxylase

Question 65

Compare direct to indirect bilirubin?

Answer 65

direct- conjugated with glucoronic acid, water sol | indirect- unconjugated, water insol