Anatomy - Midgut and Hindgut Flashcards
1
Q
what parts of the pancreas are retroperitoneal vs intraperitoneal
A
everything is retroperitoneal except for the tail
2
Q
what does the pancreas produce
A
exocrine secretions (digestive)
endocrine secretions (hormones)
3
Q
what is lateral to the head of the pancreas
A
2nd portion of the duodenum
4
Q
what is posterior to the head of the pancreas
A
IVC
Common bile duct
right renal artery & vein
5
Q
what is inferior to the uncinate process of the pancreas
A
3rd portion of the duodenum
6
Q
what is anterior to the uncinate process of the pancreas
A
SMA
SMV
7
Q
what is anterior to the neck of the pancreas
A
pylorus of stomach
8
Q
what is posterior to the neck of the pancreas
A
SMA
SMV
formation of hepatic portal vein
9
Q
what is superior/posterosuperior to the body of the pancreas
A
splenic artery and vein
10
Q
what is anterior to the body of the pancreas
A
omental bursa
11
Q
what is posterior to the body of the pancreas
A
aorta
origin of SMA
left adrenal gland
left kidney and renal vessels
12
Q
what is lateral to the tail of the pancreas
A
hilum of spleen
13
Q
what is anterior to the tail of the pancreas
A
left colic flexure
14
Q
what is posterior to the tail of the pancreas
A
left kidney
15
Q
what is the shortest, widest, and most fixed part of the SI
A
duodenum
16
Q
where does the duodenum begin and extend to
A
the pylorus and extends to the duodenojejunal junction
17
Q
the duodenum is the major site of
A
chemical digestion
18
Q
what does the duodenum mark the transition of
A
the foregut to midgut
19
Q
the duodenum receives blood supply and innervation from both
A
foregut and midgut structures
20
Q
what is another name for the suspensory muscle of the duodenum
A
ligament of treitz
21
Q
what is the ligament of treitz
A
Slip of skeletal muscle from diaphragm and fibromuscular band of smooth muscle from duodenum
22
Q
Contraction of muscle widens angle of ?
A
duodenojejunal flexure
23
Q
Contraction of muscle widens angle of duodenojejunal flexure and facilitates movement of
A
intestinal contents
24
Q
Portions and Levels of the duodenum
A
1st portion (superior) - L1
2nd portion (descending) - L2-3
3rd portion (horizontal) - L3
4th portion (ascending) - L3 to L2
25
what is anterior to the 1st portion of the duodenum
body of gallbladder
peritoneum
26
what is posterior to the 1st portion of the duodenum
bile duct
gastroduodenal artery
hepatic portal vein
IVC
27
what is superior to the 1st portion of the duodenum
neck of gallbladder
28
what is anterior to the 2nd portion of the duodenum
transverse colon
transverse mesocolon
29
what is posterior to the 2nd portion of the duodenum
right kidney hilum
renal vessels
right ureter
30
what is medial to the 2nd portion of the duodenum
head of pancreas
pancreatic duct
bile duct
31
what is anterior to the 3rd portion of the duodenum
SMA
SMV
32
what is posterior to the 3rd portion of the duodenum
IVC
abdominal aorta
right ureter
33
what is superior to the 3rd portion of the duodenum
head and uncinate process of pancreas
34
what is anterior to the 4th portion of the duodenum
beginning of root of mesentery proper
jejunum
35
what is posterior to the 4th portion of the duodenum
left edge of abdominal aorta
36
what is superior to the 4th portion of the duodenum
body of pancreas
37
where is a duodenal ulcer most often to occur
posterior wall of the superior part of duodenum
38
what parts of the pancreas/duodenum are supplied by branches of the gastroduodenal artery?
superior portion of head
1st and superior portion of 2nd part of duodenum
39
what parts of the pancreas are supplied by the splenic artery
neck
body
tail
40
what parts of the pancreas are supplied by branches of the SMA?
inferior portion of head and uncinate process
inferior portion of 2nd part of the duodenum, 3rd part, 4th part
41
the hepatic portal vein collects blood from
superior portion of head of pancreas
1st and superior portion of 2nd part of duodenum
42
the splenic vein collects blood from which parts of the pancreas
neck
body
tail
43
superior mesenteric vein collects blood from
inferior portion of head and uncinate process
inferior portion of 2nd part of the duodenum, 3rd part, 4th part
44
lymphatic nodes of the pancreas and duodenum
celiac nodes
pyloric nodes
pancreatico-splenico nodes
45
innveration of pancreas and duodenum proximal to entrance of common bile duct
duodenum (1st part and superior portion of 2nd part)
pancreas: neck, body, tail, and superior portion of head
46
parasympathetic innervation of pancreas and duodenum proximal to entrance of common bile duct
vagus nerve to peri-arterial plexus to viscera
47
sympathetic innervation of pancreas and duodenum proximal to entrance of common bile duct
Greater thoracic splanchnic N (T5-T9)
Synapse at celiac ganglion
Peri-arterial plexus to viscera
48
Sensory REFLEX innervation of pancreas and duodenum proximal to entrance of common bile duct
travels back with parasympathetics
49
Sensory PAIN innervation of pancreas and duodenum proximal to entrance of common bile duct
travels back with sympathetics
50
innveration of pancreas and duodenum DISTAL to entrance of common bile duct
inferior portion of 2nd part of duodenum then all of 3rd and 4th part
51
parasympathetic innervation of pancreas and duodenum distal to entrance of common bile duct
vagus nerve to peri-arterial plexus to viscera
52
sympathetic innervation of pancreas and duodenum distal to entrance of common bile duct
Lesser thoracic splanchnic N
Synapse at superior mesenteric ganglion
Peri-arterial plexus to viscera
53
Sensory REFLEX innervation of pancreas and duodenum proximal to entrance of common bile duct
travels back with parasympathetics
54
Sensory PAIN innervation of pancreas and duodenum proximal to entrance of common bile duct
travels back with sympathetics
55
jejunum and ileum handle the majority of
nutrient absorption
56
the jejunum and ileum are continuous with the duodenum at the
duodenojejunal junction
57
the jejunum and ileum are continuous with the cecum (large intestine) at the
ileocecal junction
58
the jejunum and ileum are anchored to the posterior wall by the
mesentery proper
59
the root of mesentery spans
obliquely, inferiorly, and to the right
60
what runs between layers of mesentery
SMA
intestinal arcades
vasa recta
61
The jejunum primarily occupies upper quadrants, especially the
left epigastric region
62
The jejunum is related primarily to the
left colic flexure
transverse colon
63
The ileum primarily occupies the lower quadrants, especially the
right hypogastric region
64
the ileum is related to the
cecum
inferior ascending colon
inferior descending colon
65
arterial supply of the jejunum and ileum
SMA --> intestinal arteries (15-18 total), arcades, vasa recta
66
what does the large intestine do
absorb water, storage, compaction of wastes
67
large intestine is divided into
cecum
appendix (vermiform)
colon
rectum
anal canal
68
what is the first part of the large intestine
cecum
69
what does the cecum receive
the ileum (small intestine)
70
where does the cecum lie
in the iliac fossa in the right lower quadrant
71
where are appendicitis visceral sensory pain fibers
T10 level
72
colon is further divided into
ascending
transverse
descending
sigmoid
73
longitudinal muscles are reduced to 3 bands of
taenia coli muscle (not on appendix or rectum)
74
tone in the large intestine creates pouches called
haustra
75
incomplete rings in the large intestine
plicae semilunares
76
where does the rectum begin and end
begins: rectosigmoidal junction at S3
ends: anorectal junction
77
at the level of the rectum, Tania coli muscles spread out and form a
continuous layer of longitudinal muscle
78
the terminal portion of the rectum is dilated and supported by
pelvic diaphragm
79
the perineal flexure angle at resting bonus helps to maintain
fecal continence
80
during defectation, the puborectalis and anorectal canal do what
puborectalis RELAXES
anorectal canal STRAIGHTENS
81
where does the anal canal being and end
perineal flexure/anorectal junction and ends at the anus
82
where are anal columns located
in the superior portion of anal canal
83
anal columns secrete
mucus that aids in defectation
84
Blood supply and drainage, lymphatics, innervation of the anal canal ABOVE the pectinate line
Superior rectal arteries (from IMA)
Superior rectal veins (drains into IMV)
Internal iliac lymph nodes
Autonomic innervation
85
Blood supply and drainage, lymphatics, innervation of the anal canal BELOW the pectinate line
Inferior rectal arteries (from internal pudendal A)
Inferior rectal veins
Superficial inguinal nodes
Somatic innervation (pudendal n)
86
internal and external anal sphincter must do what for defecation to occur
relax
87
internal anal sphincter
- voluntary or involuntary?
- what does it surround
involuntary (smooth muscle)
surrounds upper 2/3 anal canal
88
sympathetic innervation of internal anal sphincter
lumbar SN (L1-L2)
****stimulates contraction****
tonically contracted most of the time to prevent leakage
89
parasympathetic innervation of internal anal sphincter
Pelvic SNs (S2-S4)
****inhibits contraction****
90
external anal sphincter
- voluntary or involuntary?
- what does it surround
voluntary (skeletal muscle)
surrounds lower 2/3 of anal canal
91
Somatic innervation of external anal sphincter
pudendal nerve
92
the defecation reflex is initiated when
the rectum is distended (sensory fibers relay)
93
when the rectum is distended, what happens to the internal anal sphincter
it relaxes it
94
if defecation is appropriate, what will happen
Relaxation of external anal sphincter
Relaxation of the puborectalis M
Contraction of abdominal wall muscles
95
Large Intestine SMA supply
Ileocolic A
- appendicular A
- marginal A
- vasa recta
Right colic A
- marginal A
- vasa recta
Middle colic A
- marginal A
- vasa recta
96
Large Intestine - SMV drainage
Veins course retrograde to arteries
Venous return enters SMV
SMV flows into hepatic portal vein
97
Midgut lymphatics pathway starting with the superior mesenteric LNs
lymph around intestinal wall/arterial arcades/proximal portions of the SMA --> Superior mesenteric LNs --> cisterna chyli --> thoracic duct
98
sympathetic innervation of the midgut does what?
Reduces motility and glandular secretion
vasoconstricts GI blood supply
99
Sympathetic Innervation of the Midgut
Preganglionic sympathetic cell bodies in IML of T10-T11
Preganglionic sympathetic fibers travel through ventral root to white ramus to sympathetic trunk
Pass through paravertebral ganglion
(NO synapsing)
Leave sympathetic trunk as preganglionic sympathetic fibers via lesser thoracic splanchnic nerve
Synapse on the postganglionic sympathetic cell bodies within the superior mesenteric ganglion (a prevertebral ganglion)
Postganglionic sympathetic fibers wrap around the major arteries as a peri-arterial plexus to travel to viscera
100
parasympathetic innervation of the midgut does what?
Stimulates and restores smooth muscle contractions for peristalsis and glandular secretions, vasodilates GI supply
101
parasympathetic Innervation of the Midgut
Preganglionic parasympathetic cell bodies located in brainstem
Preganglionic parasympathetic fibers carried on the vagus N (CN X)
Pass through neck and thorax to abdomen, passing through diaphragm with the esophagus
Join the peri-arterial plexuses that wrap around the major arteries traveling to midgut viscera
Synapse on postganglionic parasympathetic cell bodies (intramural ganglia) on midgut viscera
102
visceral sensory pain sympathetics for midgut
Travels back on nerves that carried sympathetics to midgut =
Lesser thoracic splanchnic NN (T10-T11)
103
Large Intestine - IMA supply
Left colic A
- marginal A
- vasa recta
Sigmoid AA
- marginal A
- vasa recta
Superior rectal A
104
sympathetic innervation of the hindgut does what
Reduces motility and glandular secretion, vasoconstricts GI blood supply
105
sympathetic innervation pathway of the hindgut
Preganglionic sympathetic cell bodies in IML of LI-L2
Preganglionic sympathetic fibers travel through ventral root to white ramus to sympathetic trunk
Pass through paravertebral ganglion
(NO synapsing)
Leave sympathetic trunk as preganglionic sympathetic fibers via lumbar splanchnic nerves
Synapse on the postganglionic sympathetic cell bodies within the inferior mesenteric ganglion (a prevertebral ganglion)
Postganglionic sympathetic fibers wrap around the major arteries traveling to hindgut viscera as a peri-arterial plexus
106
parasympathetic innervation of the hindgut does what
Stimulates and restores smooth muscle contractions for peristalsis and glandular secretions, vasodilates GI supply
107
parasympathetic innervation pathway of the hindgut
Preganglionic parasympathetic cell bodies located in sacral portion of spinal cord
Preganglionic parasympathetic fibers carried on pelvic splanchnic NN (S2-S4)
Pass through inferior hypogastric plexus in pelvis (no synapsing)
Emerge as ascending parasympathetic fibers that travel to hindgut viscera
Synapse on postganglionic parasympathetic cell bodies (intramural ganglia) on viscera
108
Hindgut parasympathetic innervation
Pelvic SNs (S2-S4)
Inferior hypogastric plexus
Ascending parasympathetic fibers
109
Innervation of Hindgut - pelvic pain line corresponds to
the inferior limit of the peritoneum and mid-sigmoid colon
110
Innervation of Hindgut - Superior to Pelvic Pain Line
pain fibers travel back on the sympathetic pathway for that structure
- lumbar SNs (L1-L2)
111
Innervation of Hindgut - Inferior to Pelvic Pain Line
pain fibers travel back on the parasympathetic pathway for that structure
- pelvic SNs (S2-S4)
112
Depending on the portion of the GI tract involved, nociceptive (pain) fibers travel on different pathways
Innervation and Pathway for the proximal sigmoid colon (more superior portion)?
Autonomic innervation
Pain fibers follow the sympathetic pathway (superior to the pelvic pain line)
Lumbar splanchnics (L1-L2)
113
Depending on the portion of the GI tract involved, nociceptive (pain) fibers travel on different pathways
Innervation and Pathway for the distal sigmoid colon (more inferior portion), rectum, and superior anal canal?
Autonomic innervation
Pain fibers follow the parasympathetic pathway (inferior to the pelvic pain line)
Pelvic splanchnics (S2-S4)
114
Depending on the portion of the GI tract involved, nociceptive (pain) fibers travel on different pathways
Innervation and Pathway for the inferior anal canal (inferior to pectinate line)
Somatic innervation
Pudendal nerve (S2-S4)
