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USMLE (S1) Gastrointestinal > Gastro - Anatomy > Flashcards

Flashcards in Gastro - Anatomy Deck (170)
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1
Q

What two blood vessels and one nerve run anterior to the spine at the level of the umbilicus?

A

The aorta, inferior vena cava, and sympathetic trunk run together along the spine.

2
Q

Identify the branch of the abdominal aorta that supplies the foregut.

A

(A) celiac trunk

3
Q

What is the most superficial muscle group making up the lateral abdominal wall?

A

External oblique

4
Q

What is the deepest muscle group making up the lateral abdominal wall?

A

Transversus abdominis

5
Q

What is the name of the connective tissue that lies between the rectus muscles at the midline?

A

Linea alba

6
Q

What individual layers of fascia join to make the rectus sheath?

A

Fascia of the external oblique, internal oblique, and transversus abdominus

7
Q

Which parts of the duodenum are retroperitoneal?

A

The second, third, and fourth parts of the duodenum

8
Q

Name two major organs that lie completely in the retroperitoneal space.

A

The kidneys and adrenal glands

9
Q

What part of the pancreas is not found in the retroperitoneal space?

A

The tail of the pancreas

10
Q

Which two parts of the urinary system are retroperitoneal?

A

The kidney and ureters

11
Q

Which portion of the colon is not retroperitoneal?

A

Transverse colon

12
Q

In the gastrointestinal tract, the falciform ligament connects which two structures?

A

The liver and the abdominal wall

13
Q

In the gastrointestinal tract, the gastrohepatic ligament connects which two structures?

A

The liver and the lesser curvature of the stomach

14
Q

In the gastrointestinal tract, the gastrocolic ligament connects which two structures?

A

The transverse colon and the greater curvature of the stomach

15
Q

In the gastrointestinal tract, the gastrosplenic ligament connects which two structures?

A

The spleen and the greater curvature of the stomach

16
Q

In the gastrointestinal tract, the splenorenal ligament connects which two structures?

A

The spleen and the posterior abdominal wall

17
Q

The _____ ligament connects the liver and the duodenum.

A

Hepatoduodenal

18
Q

The falciform ligament contains what structure?

A

The ligamentum teres

19
Q

The hepatoduodenal ligament contains what structures?

A

The portal triad (the portal vein, the portal artery, and the common bile duct)

20
Q

The gastrohepatic ligament contains what structures?

A

The gastric arteries

21
Q

The gastrocolic ligament contains what structures?

A

The gastroepiploic arteries

22
Q

The splenorenal ligament contains what structures?

A

The splenic artery and the splenic vein

23
Q

From what fetal structure is the falciform ligament derived?

A

Fetal umbilical vein

24
Q

The portal triad can be compressed through what opening to control bleeding?

A

The omental foramen (also known as the epiploic foramen of Winslow)

25
Q

What gastrointestinal ligament can be cut to access the lesser sac during surgery?

A

The gastrohepatic ligament

26
Q

What ligament is part of the greater omentum?

A

Gastrocolic ligament

27
Q

What ligament separates the greater and lesser sacs?

A

Gastrosplenic ligament

28
Q

Which layer of the muscularis externa is closer to the lumen: the circular layer or the longitudinal layer?

A

The circular layer

29
Q

List three components of the gut wall mucosa.

A

Epithelium, lamina propria, and muscularis mucosa

30
Q

What is the primary function of the epithelium of the gut wall mucosa?

A

Absorption

31
Q

What is the primary function of the lamina propria of the gut wall mucosa?

A

Support

32
Q

What is the primary function of the muscularis mucosa of the gut wall mucosa?

A

Mucosal motility

33
Q

What structure is found within the submucosa of the gut wall?

A

The submucosal nerve plexus (Meissner's plexus)

34
Q

Meissner's plexus controls what three functions of the submucosal gut wall?

A

Secretions, blood flow, and absorption

35
Q

What lies between the inner circular and outer longitudinal layers of the muscularis externa?

A

The myenteric nerve plexus (Auerbach's plexus)

36
Q

List the four main layers of the gut wall, starting from the inside and going out.

A

Mucosa, submucosa, muscularis externa, and serosa

37
Q

What is the rate of basal electrical rhythm in the stomach?

A

3 waves/min

38
Q

What is the rate of basal electrical rhythm in the duodenum?

A

12 waves/min

39
Q

What is the rate of basal electrical rhythm in the ileum?

A

8-9 waves/min

40
Q

Villi are found in which section of the digestive tract?

A

Small intestine

41
Q

Describe the epithelium of the esophagus in histological terms.

A

Nonkeratinized stratified squamous cell epithelium

42
Q

A patient presents with intractable diarrhea and is found to have celiac disease. What microstructure is damaged and where is it located?

A

The villi and the microvilli of the small intestine are likely damaged resulting in decreased absorptive capacity and diarrhea

43
Q

What part of the small intestine has the highest concentration of villi and microvilli?

A

Duodenum; villi increase the surface area of the epithelium to maximize absorption

44
Q

Name a submucosal structure that is unique to the duodenum.

A

Brunner's glands

45
Q

These epithelial glands are found throughout the small intestine.

A

Crypts of Lieberkühn

46
Q

Goblet cells are highly concentrated in this area of the small intestine.

A

Jejunum

47
Q

Which immunologic structures are unique to the Ileum?

A

Peyer's patches

48
Q

Name a major histological difference between the duodenum and the colon.

A

The duodenum has villi whereas the colon only has crypts

49
Q

The primary function of the myenteric plexus is to coordinate what function?

A

Motility along the entire gut wall

50
Q

The myenteric plexus is located between what two smooth muscle layers?

A

The inner circular layer and the outer longitudinal layer (remember: AUerbach's is on the Autside)

51
Q

The submucosal plexus is located between what two layers?

A

The mucosa and the inner layer of smooth muscle

52
Q

What are the functions of the submucosal nerve plexus?

A

Regulation of secretions, blood flow, and absorption

53
Q

The upper one-third of the esophagus is composed of _____ muscle.

A

Striated

54
Q

The lower one-third of the esophagus is composed of ______ muscle.

A

Smooth

55
Q

What type of muscle fibers make up the middle one third of the esophagus?

A

Both striated and smooth muscle

56
Q

This branch of the aorta supplies the foregut.

A

Celiac trunk

57
Q

Which branch of the aorta comes off at the level of L1?

A

The superior mesenteric artery

58
Q

Which paired arteries come off the aorta at the level of L2?

A

The ovarian or testicular arteries

59
Q

Which paired arteries come off the aorta at the level of L1?

A

The renal arteries

60
Q

At what level does the abdominal aorta bifurcate?

A

L4

61
Q

Which two arteries does the aorta become after the bifurcation?

A

Left and right common iliac arteries

62
Q

An elderly patient presents with bright red bleeding per rectum and is found to be hypotensive. On colonoscopy, she is found to have necrotic mucosa at the splenic flexure. What is the blood supply to this region?

A

Inferior and superior mesenteric arteries

63
Q

What are the three embryologic divisions of the gastrointestinal tract?

A

The foregut, midgut, and hindgut

64
Q

Which artery supplies the foregut?

A

Celiac artery

65
Q

Which artery supplies the midgut?

A

The superior mesenteric artery

66
Q

Which artery supplies the hindgut?

A

Inferior mesenteric artery

67
Q

What are the main gastrointestinal structures derived from the embryonic foregut?

A

The stomach, proximal duodenum, liver, gallbladder, and pancreas

68
Q

What portion of the gastrointestinal tract is derived from the embryonic midgut?

A

From the distal duodenum to the proximal two-thirds of the transverse colon

69
Q

What portion of the gastrointestinal tract is derived from the embryonic hindgut?

A

From the distal one-third of the transverse colon to the upper rectum

70
Q

What organ supplied by the celiac trunk is not an embryonic gut derivative?

A

Spleen

71
Q

Which segments of the gastrointestinal tract receive parasympathetic innervation from the vagus?

A

Foregut (stomach to proximal duodenum, liver, gallbladder, pancreas, spleen) and midgut (distal duodenum to proximal 2/3 of transverse colon)

72
Q

The stomach receives its main blood supply from branches of what structure?

A

The celiac trunk

73
Q

Name the three main branches of the celiac trunk.

A

Common hepatic artery, splenic artery, and left gastric artery

74
Q

From what artery does the cystic artery arise?

A

The right hepatic artery, a branch of the common hepatic artery; the cystic artery supplies the gallbladder

75
Q

What are the main branches of the common hepatic artery?

A

The right gastric artery, gastroduodenal artery, and hepatic artery proper

76
Q

What are the two branches of the gastroduodenal artery?

A

Superior pancreaticoduodenal and right gastroepiploic arteries

77
Q

What arteries feed the greater curvature of the stomach?

A

The right and left gastroepiploic arteries

78
Q

What arteries feed the lesser curvature of the stomach?

A

The right and left gastric arteries

79
Q

The short gastric arteries have poor anastomoses if the _____ artery is blocked.

A

Splenic

80
Q

Strong anastomoses exist between what two sets of arteries of the celiac trunk?

A

Left and right gastroepiploics and left and right gastrics

81
Q

What are the branches of the splenic artery?

A

The short gastrics and left gastroepiploic artery

82
Q

If the abdominal aorta is blocked, blood can travel through the subclavian artery into the internal thoracic artery and then through an anastomosis to which artery?

A

Superior epigastric (internal thoracic)

83
Q

If the abdominal aorta is blocked, the superior pancreaticoduodenal artery of the celiac trunk can anastamose with what vessel?

A

Inferior pancreaticoduodenal artery (of the superior mesenteric artery)

84
Q

If the abdominal aorta is blocked, which artery can anastamose with the left colic artery (of the inferior mesenteric artery)?

A

Middle colic artery (of the superior mesenteric artery)

85
Q

The superior rectal artery (of the inferior mesenteric artery) can anastamose with what artery?

A

Middle rectal artery (of the internal iliac)

86
Q

If the abdominal aorta is blocked, there are several anastomoses that will provide collateral flow. Complete this one: _____ _____ (from the subclavian) to the superior epigastric (internal thoracic) to the inferior epigastric (normally fed by the external iliac).

A

Internal mammary

87
Q

If the abdominal aorta is blocked, there are several anastomoses that will provide collateral flow. Complete this one: internal mammary (from the subclavian) to the _____ _____ (internal thoracic) to the inferior epigastric (normally fed by the external iliac).

A

Superior epigastric

88
Q

If the abdominal aorta is blocked, there are several anastomoses that will provide collateral flow. Complete this one: internal mammary (from the subclavian) to the superior epigastric (internal thoracic) to the _____ _____ (normally fed by the external iliac).

A

Inferior epigastric

89
Q

If the abdominal aorta is blocked, there are several anastomoses that will provide collateral flow. Complete this one: _____ _____ (from the celiac trunk) to the inferior pancreaticoduodenal (normally fed by the superior mesenteric artery).

A

Superior pancreaticoduodenal

90
Q

If the abdominal aorta is blocked, there are several anastomoses that will provide collateral flow. Complete this one: superior pancreaticoduodenal (from the celiac trunk) to the _____ _____ (normally fed by the superior mesenteric artery).

A

Inferior pancreaticoduodenal

91
Q

If the abdominal aorta is blocked, there are several anastomoses that will provide collateral flow. Complete this one: _____ _____ (from the inferior mesenteric artery) to the middle rectal (normally fed by the internal iliac).

A

Superior rectal

92
Q

If the abdominal aorta is blocked, there are several anastomoses that will provide collateral flow. Complete this one: superior rectal (from the inferior mesenteric artery) to the _____ _____ (normally fed by the internal iliac).

A

Middle rectal

93
Q

If the abdominal aorta is blocked, there are several anastomoses that will provide collateral flow. Complete this one: _____ _____ (from the superior mesenteric artery) to the left colic (normally fed by the inferior mesenteric artery).

A

Middle colic

94
Q

If the abdominal aorta is blocked, there are several anastomoses that will provide collateral flow. Complete this one: middle colic (from the superior mesenteric artery) to the _____ _____ (normally fed by the inferior mesenteric artery).

A

Left colic

95
Q

Give three examples of clinical manifestations of portosystemic anastomoses seen in patients with portal hypertension.

A

Esophageal varices, internal hemorrhoids, and caput medusae (remember: gut, butt, and caput

96
Q

A chronic alcoholic patient presents with mental status change, tense ascites, and hematemesis. What is a likely cause of his hematemesis?

A

Portal hypertension from his cirrhosis (as evidenced by his ascites) created esophageal varices that ruptured, causing hematemesis

97
Q

A patient with portal hypertension presents with discomfort on defecation and bright red blood per rectum. Physical examination shows prolapsed dilated veins around the anus that are not tender. What is the explanation of these findings?

A

A portosystemic anastomoses between the superior and middle rectal arteries created internal hemorrhoids, which are painless

98
Q

Portal-systemic anastomoses from the paraumbilical vein to the inferior epigastric and superior epigastric veins can manifest as what?

A

Caput medusae at the navel

99
Q

What condition causes portal-systemic anastomoses?

A

Portal hypertension

100
Q

What is the underlying principle in surgical treatment of portal hypertension?

A

Creation of anastomoses to shunt blood from portal circulation into systemic circulation, thereby bypassing the liver

101
Q

Name two potential shunts that can be created surgically to relieve portal hypertension.

A

Splenic vein to left renal vein; portal vein to inferior vena cava

102
Q

The pectinate line is formed where the embryonic _____ derivatives meet the _____ derivatives.

A

Hindgut; ectodermal

103
Q

What type of hemorrhoids occur above the pectinate line? Below the pectinate line?

A

Internal; external

104
Q

True or False? Internal hemorrhoids are painful.

A

False; internal hemorrhoids are not painful whereas external hemorrhoids are painful

105
Q

What type of cancer occurs above the pectinate line in the rectum? Below the pectinate line?

A

Adenocarcinoma; squamous cell carcinoma

106
Q

Above the pectinate line, there is what type of innervation: visceral or somatic?

A

Visceral innervation

107
Q

Above the pectinate line, the arterial supply comes from what artery?

A

The superior rectal artery

108
Q

The superior rectal artery is a branch of what artery?

A

The inferior mesenteric artery

109
Q

Below the pectinate line, there is what type of innervation, somatic or visceral?

A

Somatic innervation

110
Q

Below the pectinate line, the arterial supply is from what artery?

A

The inferior rectal artery

111
Q

The inferior rectal artery is a branch of what artery?

A

The internal pudendal artery

112
Q

_____ hemorrhoids receive somatic innervation and are therefore _____.

A

External; painful

113
Q

A patient with hepatocellular carcinoma and tense ascites presents with mental status change and bright red blood per rectum. On physical exam, you see dilated veins but cannot deduce if they are painful given the patient's mental status. What is the likely diagnosis of the rectal exam findings?

A

Internal hemorrhoids, which can result from portal hypertension

114
Q

The apical surface of hepatocytes face which space?

A

The bile canaliculi

115
Q

The basolateral surface of hepatocytes face what space?

A

The sinusoids

116
Q

Describe the venous blood flow of the liver in order.

A

Portal circulation, portal vein, liver sinusoids, central vein, inferior vena cava

117
Q

What fluid drains through the space of Disse in the liver?

A

Lymph (in the liver)

118
Q

Describe bile flow through the liver.

A

Hepatocytes secrete bile via their apical surfaces into the bile canaliculi, which then drain into the bile ductule

119
Q

Zone I of the liver is also known as the _______ zone.

A

Periportal

120
Q

What structures are found in Zone I of the liver?

A

The portal triad (the portal vein, the portal artery, and the common bile duct)

121
Q

Zone III of the liver is also known as what?

A

Pericentral vein zone (centrilobular zone)

122
Q

What major structure is found in Zone III of the liver?

A

Branches of the central vein

123
Q

Which zone of the liver contains the P450 enzyme system?

A

Zone III (pericentral vein/centrilobular zone)

124
Q

Which zone is affected most by viral hepatitis?

A

Zone I

125
Q

A patient presents with elevated alanine aminotransferase and aspartate aminotransferase levels with an alanine aminotransferase to aspartate aminotransferase ratio > 2.0. What zone of his liver is likely affected?

A

Zone III; alcoholic hepatitis usually affects Zone III

126
Q

A patient presents with jaundice, encephalopathy, and oliguria. He has elevated liver enzymes. What zone of his liver is likely affected?

A

Zone III

127
Q

Why is Zone II of the liver most affected by ischemia?

A

It is furthest away from the hepatic artery

128
Q

Whereas portal veins drain from ____, the central vein drains to ____.

A

Splanchnic (gut) circulation; hepatic vein and systemic circulation

129
Q

Liver sinusoids are lined with what kind of endothelium?

A

Fenestrated

130
Q

Notably, the sinusoids of the liver are lacking what structure that most capillaries have?

A

Basement membrane

131
Q

Why is it advantageous to have fenestrated capillaries in the liver sinusoids?

A

They allow macromolecules to have access to the hepatocytes, thereby facilitating appropriate metabolism of these macromolecules

132
Q

En route from the liver sinusoids to the hepatocytes, plasma macromolecules must pass through what space?

A

The perisinusoidal space (the space of Disse)

133
Q

A patient presents with right upper quadrant abdominal pain. Further work-up reveals a gallstone obstructing the common bile duct. Which two biliary ducts drain directly into the common bile duct?

A

The cystic duct and common hepatic duct

134
Q

What is the name of the structure formed by the common bile duct and the pancreatic duct as they empty into the duodenum?

A

The ampulla of Vater

135
Q

What is the name of the sphincter through which bile passes to enter the duodenum?

A

The sphincter of Oddi

136
Q

Blockage of which biliary structure would cause a dilated gallbladder but no other blockage?

A

The cystic duct

137
Q

A gallstone in what location would lead to elevated amylase and lipase as well as serum bilirubin and alkaline phosphatase?

A

Ampulla of Vater

138
Q

A patient presents with right upper quadrant pain, fever, and jaundice. She has elevated liver enzymes but normal pancreatic enzymes. If a gallstone is the cause of these findings, where is it likely to be located?

A

In the common bile duct

139
Q

What structure forms the superior border of the femoral triangle?

A

The inguinal ligament

140
Q

What structure forms the lateral border of the femoral triangle?

A

The sartorius muscle

141
Q

What structure forms the medial border of the femoral triangle?

A

The adductor longus muscle

142
Q

What three main structures are contained within the femoral sheath?

A

Femoral artery, femoral vein, and femoral canal

143
Q

What femoral triangle structure lies outside of the femoral sheath?

A

The femoral nerve

144
Q

Going from lateral to medial, list the components that are found within the femoral triangle.

A

Nerve, artery, vein, empty space, lymphatics (remember: the contents lateral to medial are NAVEL as well as venous near the penis)

145
Q

What is the site of protrusion of an indirect hernia into the inguinal canal?

A

The internal inguinal ring

146
Q

Name the layers that compose the spermatic cord, from the most superficial to the deepest layer.

A

External spermatic fascia, cremasteric muscle and fascia, and internal spermatic fascia

147
Q

From the most superficial layer to deep, what are the three muscles that cover the internal (deep) inguinal ring?

A

External oblique, internal oblique, and transversus abdominis

148
Q

Between which two structures would you find a direct inguinal hernia?

A

The inferior epigastric vessels and the rectus abdominus

149
Q

Diaphragmatic hernias in infants are often a result of the defective development of what membrane?

A

The pleuroperitoneal membrane

150
Q

What type of inguinal hernia is seen in infants?

A

Indirect, especially in males

151
Q

What is the difference between sliding and paraesophageal hernias?

A

Sliding hernias result in a displaced gastroesophageal junction, resulting in increased risk for gastroesophageal reflux disease, whereas paraesophageal hernias lead to displacement of the gastric cardia increasing risk of gastric incarceration

152
Q

Which type of hiatal hernia is associated with gastroesophageal reflux disease refractory to medical treatment?

A

Sliding hernias result in a displaced gastroesophageal junction, resulting in increased risk for gastroesophageal reflux disease

153
Q

What structures are displaced in a paraesophageal hernia?

A

The cardia of the stomach is displaced into the thorax whereas the gastroesophageal junction is unaffected

154
Q

Trace the path of an indirect inguinal hernia.

A

Internal (deep) inguinal ring, through external (superficial) ring, into scrotum

155
Q

What structure do both direct and indirect inguinal hernias pass through?

A

The external (superficial) inguinal ring

156
Q

What structure is useful for spatially differentiating direct inguinal hernias from indirect inguinal hernias?

A

The inferior epigastric artery (remember: MDs don't LIe: Medial to inferior epigastric artery = Direct hernia and Lateral to inferior epigastric artery = Indirect hernia to recall locations

157
Q

An indirect inguinal hernia enters the internal inguinal ring _____ to the inferior epigastric artery.

A

Lateral

158
Q

Indirect hernias occur in infants as a result of the failure of the _____ _____ to close.

A

Processus vaginalis

159
Q

Which type of hernia is much more common among males?

A

The indirect inguinal hernia

160
Q

A direct inguinal hernia bulges directly through the abdominal wall _____ to the inferior epigastric artery.

A

Medial

161
Q

Which type of hernia usually occurs among older men?

A

The direct inguinal hernia

162
Q

Hesselbach's triangle is defined by what structures?

A

The inguinal ligament, rectus abdominus muscle, inferior epigastric artery

163
Q

Relative to the pubic tubercle, where is a femoral hernia typically located?

A

Below and lateral to the pubic tubercle (through the femoral canal)

164
Q

Are femoral hernias more common in men or women?

A

Women

165
Q

What type of hernia is most likely to become incarcerated?

A

Femoral

166
Q

How many layers of the spermatic cord cover the sac of an indirect hernia? A direct hernia?

A

Only the superficial layer; all layers

167
Q

The G cells of the antrum produce which hormone?

A

Gastrin

168
Q

From what fetal structure is structure (A) derived?

A

Fetal umbilical vein

169
Q

Arrow (A) indicates the flow of what material?
Arrow (B)?

A

Blood; bile

170
Q

From lateral to medial, list the five structures in the image that are found in the femoral triangle.

A

Nerve, Artery, Vein, Empty space, Lymphatics (the contents lateral to medial are NAVEL )