Anatomy of Stomach & Small Intestine Flashcards
(136 cards)
1
Q
What does the dorsal mesentery form?
A
The greater omentum
Gastrosplenic ligament
Splenorenal ligament
2
Q
What is an omentum?
A
Peritoneal covering attached to the stomach
3
Q
What does the ventral mesentery form?
A
The lesser omentum
The capsule, and peritoneal covering of the liver
Falciform, coronary and triangular ligaments
4
Q
When and where does the lesser sac appear?
A
When the stomach rotates the first 90o, the lesser sac (space behind the stomach) appears
5
Q
What are the derivatives of the ventral mesogastrium?
A
Right and left triangular ligaments
Superior and inferior layers of coronary ligaments
Falciform ligament
Lesser omentum
6
Q
What are the derivatives of the dorsal mesogastrium?
A
Gastrophrenic ligament
Gastrosplenic ligament
Lienorenal ligament
Greater omentum
7
Q
What is the function of the dorsal mesogastrium?
A
To connect the esophagus to posterior stomach
8
Q
How and why does the stomach have a slight mobility?
A
The stomach is an intraperitoneal structure and is attached to ligaments which allow for slight mobility in order for the stomach to expand and empty out, and also take alternatives shapes
9
Q
Which of the 9 locations is the stomach located in (mainly)?
A
Epigastric region, part of it also in the left hypochondriac region
10
Q
What is the function of the stomach?
A
Mainly for storage, mechanical and chemical digestion
11
Q
What are the different regions of the stomach?
A
Cardia
Fundus
Body
Pylorus
12
Q
What does the cardia of the stomach connect to?
A
Connected part to esophagus
13
Q
What is the characteristic of the fundus of the stomach?
A
It is usually filled with gas
14
Q
Where does the digestion mechanism mainly take place (which region of the stomach)?
A
The body
15
Q
What is the function of the pyloric sphincter?
A
Both anatomic and physiologic
16
Q
What are the different surfaces of the stomach?
A
Anterior
Posterior
Medial
Lateral
17
Q
What is the main surface of the medial (stomach)?
A
Lesser curvature –> Lesser omentum
18
Q
What is the main surface of the lateral (stomach)?
A
Greater curvature –> Gastrosplenic omentum & Greater omentum
19
Q
What ligaments are associated with the lesser omentum?
A
Hepatoduodenal ligamnet
Hepatogastric ligament
20
Q
What is the location of the lesser sac?
A
Being the stomach, between the stomach and the pancreas
21
Q
Why is the free edge of the lesser omentum so important?
A
Entrance to lesser sac, important for surgeries regarding the gallbladder, so many structures contained
22
Q
What is free edge?
A
It is a layer surrounding the lesser omentum
23
Q
What are the divisions of the celiac trunk (stomach)?
A
Common hepatic artery
Left gastric artery
Splenic artery
24
Q
What are the further divisions of the the common hepatic artery?
A
Right gastric artery
Gastroduodenal artery –> Right gastroepiploic artery
25
What are the further divisions of the splenic artery?
Short gastric artery
Left gastroepiploic artery
26
What region does the right gastric artery supply?
The lower lesser curvature
27
What region does the right gastroepiploic artery supply?
Lower part of the greater curvature
28
What regions does the left gastric artery supply?
Lower part of esophagus and upper part of lesser curvature
29
What region does the gastric artery supply?
The fundus of the stomach
30
What region does the left gastroepiploic artery supply?
The upper part of the greater curvature
31
Splenic artery (path it follows)...
Splenorenal ligament enters the hilum of the spleen divides into the blood vessels that supply the stomach, and runs back to supply the stomach through the gastrophrenic ligament.
32
Where do all the veins of the stomach drain into?
Portal vein
33
What are the branches that directly drain into the portal vein?
Superior mesenteric vein
Right gastric vein
Left gastric vein
Splenic vein
34
What is the branch that drains into the superior mesenteric vein?
Right gastroepiploic vein
35
What are the branches that drain into the splenic vein?
The short gastric veins
Left gastroepiploic vein
36
Which vein drains the fundus of the stomach?
Short gastric veins
37
Which vein drains the upper greater curvature of the stomach?
Left gastroepiploic artery
38
Which vein drains the lower greater curvature of the stomach?
Right gastroepiploic vein
39
Which vein drains the upper lesser curvature of the stomach?
Left gastric vein
40
Which vein drains the lower lesser curvature of the stomach?
Right gastric vein
41
Which are the main nerves of the stomach?
Sympathetic and parasympathetic
42
What are the sympathetic nerves?
Pain transmitting nerve fibers
43
What are the parasympathetic nerves?
Secretomotor to gastric glands
Motor to the muscular wall
44
What is the specific sympathetic nerve that supplies the stomach?
Greater thoracic splanchnic nerves (T5 to T9)
&
Pyloric sphincter
45
What are the specific parasympathetic nerves that supply the stomach?
Left and right vagal nerves
46
Which path does the left vagal nerve follow?
Anterior vagal trunk --> Hepatic branch --> Pyloric branch --> Pyloric sphincter
47
What path does the right vagal nerve follow?
Right vagal nerve --> Posterior vagal trunk --> Celiac branch
48
What is the lymph drainage of the stomach like?
Superior two-thirds of the stomach drain to gastric nodes nearby
Otherwise they will follow the arteries
49
Where do all the lymph from the stomach end up?
Pass to the celiac nodes located around the root of the celiac artery on the posterior abdominal wall.
50
What are the layers of the stomach?
Mucous membrane
Muscular layer
Peritoneum
51
What does the mucous membrane of the stomach form?
Rugae
52
What kind of muscles does the muscular layer of the stomach form of?
Oblique
Circular
Longitudinal
53
What causes congenital hypertrophic pyloric stenosis?
If and when the circular muscles get hypertrophied
54
What is pyloric stenosis?
Narrowing of the stomach to the first part of the small intestine
55
What are the symptoms of pyloric stenosis?
Projectile vomiting without the presence of bile
56
What are the sublayers of the mucosa?
Simple columnar epithelium
Lamina propria
Lymphatic capillary, arteriole, venule
Muscularis mucosa
57
What are the sublayers of the submucosa?
Submucosal nerve plexus
58
What are the sublayers of muscularis external?
Oblique muscle
Circular muscle
Longitudinal muscle
59
Where are the different kinds of cells found in the stomach?
In the mucus membrane, in the rugae
60
What are the different cell types found in the rugae?
Surface mucus cells
Mucous neck cells
Parietal cells
Chief cells
G - cells
61
What is the function of surface mucus cells?
Secrete alkaline fluid mucin and balance HCl
62
What is the function of mucous neck cells?
Secrete acidic fluid mucin
63
What is the function of parietal cells?
Produce HCl and intrinsic factor
64
What is the function of the intrinsic factor?
Absorption of vitamin B12
65
What is the function of chief cells?
Secrete pepsinogen and gastric lipase
66
Why do chief cells secrete pepsinogen and not pepsin?
Pepsinogen is the inactivated form of pepsin, it has to be inactivated so that it does not damage the epithelial cells
67
When is pepsinogen activated and to what?
Pepsinogen gets activated when the pH is less than 3, so in the stomach
It gets converted to its activated form of pepsin
68
Whatis the function of G-cells?
To secrete gastrin
69
What is the function of gastrin?
Activate muscular layer
70
Are parietal cells eosinophilic basophilic or neutrophilic?
Eosinophilic
71
Are chief cells eosinophilic basophilic or neutrophilic?
Basophilic
72
What kind of cells are there in the pylorus?
Mainly mucin-producing cells for protection
G cells
73
What kind of cells are there in the body?
The main area of secretion so all kinds of cells will be present
74
What does the midgut give rise to?
Duodenum, distal to the opening of the common bile duct
Jejunum and ileum
Ceum and appendix
Ascending colon
Proximal part of transverse colon
75
Where does the distal part of the transverse colon derive from?
The hindgut
76
Which artery supplies the midgut?
Superior mesenteric artery
77
At what point does the superior mesenteric artery cross the midgut?
L1
78
At what point does the inferior mesenteric artery cross the hindgut?
L3
79
What are the nerve innovations of the midgut?
Lesser thoracic splanchnic nerves (T10, T11)
Vagus nerve
80
Where does the elongation and herniation of the midgut loop occur?
Midline into a space within the umbilical cord
81
Why does the herniation of the midgut loop occur?
The midgut elongates and can no longer fit into the embryonic sac, herniates into yolk sac
82
What is the result of the elongation and herniation of the midgut loop?
It creates the coils of the small intestine
83
What is the rotation of the loop like?
The first rotation is 90o clockwise toward the embryo's right
84
Where does the formation of the cecum take place?
In the initial segment of the distal limb of the midgut loop
85
What is the process of the return of the midgut?
The proximal part of the midgut begins to move back into the abdomen, rotates 90o clockwise.
This is then followed by the distal part
86
When is the final 90o rotation? What is its result?
A further 90o clockwise rotation as the return is underway --> the duodenojejunal junction is carried into the adult location
87
What is the initial position of the cecum? What happens to it?
It is initially sub-hepatic
As the distal part of the midgut elongates further, the ascending colon is formed, it moves the cecum into its position in the right iliac fossa
88
What does the vitelline duct connect?
The primitive gut to the remains of the yolk sac
The primitive gut at the area that will form the terminal ileum
89
When does the vitelline cord usually obliterate and disappear?
5th or 6th week
90
What are the remains of the vitelline cord usually associated with?
Typically associated with the terminal ileum
91
What is the name of the vitelline duct remains condition?
Meckel's diverticulum
92
Where is the Meckel's diverticulum found (population)?
2% of the population
2x more common in males than females
93
What are the complications associated with Meckel's syndrome?
Ulceration
Haemorrhage
Perforation
Intestinal obstruction
94
How many division s does the duodenum have?
4
95
Which organ is the duodenum quite similar to?
The stomach
96
Where does the 1st part of the duodenum lie?
In the lesser omentum (hepatoduodenal ligament)
97
Where do the rest of the duodenal parts lie?
Secondarily retroperitoneal
98
Where do the pancreas and gallbladder drain?
Into the 2nd part via the hepatopancreatic ampulla into duodenal papilla
99
What does the 4th part of the duodenum join?
Jujenum, form the duodenojejunal junction
100
What is the division between the foregut and midgut?
The duodenojejunal junction
101
How long do the jejunum and ileum measure?
About 6m long
102
Are there any major gross anatomical landmarks?
No, thus there is no distinct border between jejunum and ileum
103
What fraction of the small intestine does the jejunum make?
Proximal 2/3
104
What fraction the small intestine does the ileum make?
Distal 1/3
105
What are the histopathologies of the jejunum and ileum?
Jejunum is lined by simple columnar epithelium and it contains enterocytes and goblet cells
The ileum is also lined by simple columnar epithelium and contains goblet cells
Ileum is smoother compared to jejunum
106
Where is the mesentery of the small intestine located?
It is attached to the posterior abdominal wall and it is referred to as the root of the mesentery
107
Where does the mesentery of the small intestine extend to?
Duodenojejunal junction the left of L2 to the ileocecal junction at the right sacroiliac joint
108
What is the difference in colour between the jejunum and the ileum?
Jejunum: deeper red
Ileum: paler pink
109
What is the difference in caliber between the jejunum and the ileum?
Jejunum: 2 to 4 cm
Ileum: 2 to 3 cm
110
What is the difference in wall between the jejunum and the ileum?
Jejunum: thick and heavy
Ileum: tight and light
111
What is the difference in vascularity between the jejunum and the ileum?
Jejunum: greater
Ileum: less
112
What is the difference in vasa recta (capillary network) between the jejunum and the ileum?
Jejunum: long
Ileum: short
113
What is the difference in arcades between the jejunum and the ileum?
Jejunum: few large loops
Ileum: many short loops
114
What is the difference in fat in mesentery between the jejunum and the ileum?
Jejunum: less
Ileum: More
115
What is the difference in plicae circularis between the jejunum and the ileum?
jejunum: large, tall and packed
Ileum: low and sparse
116
What is the difference in lymphoid nodules between the jejunum and the ileum?
Jejunum: few
Ileum: many (Payer patches)
117
What are the arteries of the small intestine?
Celiac trunk
Superior mesentery
118
What is the path of the celiac trunk that actually supplies the small intestine?
Celiac trunk --> Common hepatic artery --> Gastroduodenal artery --> Superior pancreaticoduodenal artery
119
What does the superior pancreaticoduodenal artery supply?
The upper part of the duodenum and pancreas
120
What are the branches of the superior mesentery artery?
Inferior pancreaticoduodenal artery
Jejunal arteries
Ileac arteries
Ileocolic artery
121
What is the histological layers of the small intestine?
Mucosa
Submucosa
Muscularis externa
Serosa
122
What is the main function of the small intestine?
Absorption
123
What are plicae circulares?
Permanent, transverse fold of both mucosa & submucosa
124
What are intestinal villi?
Finger-like extensions of the mucosa only
125
What is the mucosa of the small intestine made of?
Epithelium
Lamina propria
126
What is the epithelium of the small intestine mucosa?
Simple columnar surface absorptive cels with microvilli, goblet cells
127
What does the lamina propria of the small intestine contain?
Capilaries, nerves and lacteals
128
What is the function of lacteals?
Carry larger lipid-protein complexes to the venous system
129
What is the purpose of the lamina propria?
Allows nutrient-rick blood in the capillaries to enter the hepatic portal system
130
What is the function of the glands of the small intestine?
Produce enzymes and hormones
131
What is the function of Paneth cells?
Produce lysozymes, help with innate immunity
132
What do enteroendocrine cells produce?
Cholecystokinin, motilin, sceretin
133
What are M cells?
Antigen presenting cells
134
Where are Brunner's glands found and what are they?
Duodenum, they are extra glands for protection
135
What is the function of the muscularis mucosa?
Motility
136
What are lacteals?
Lymphatic fat-dietary absorbing capillary in the villi of the small intestine
