337 - 339 - GI Anatomy Flashcards
What are the 4 main layers of the gut wall?
inside → outside:
1. Mucosa
2. Submucosa
3. Muscularis externa
4. Serosa
mnemonic: MSMS
What are the 3 main structures within the gut mucosa, and what are their main functions?
- Epithleium - absorption
- Lamina propria - support
- Muscularis mucosa - motility
What important structure is contained within the submucosa?
Submucosal nerve plexus (Meissner)
What are the 3 main components and corresponding functions of the muscularis externa?
- Inner circular muscle layer - motility
- Myenteric nerve plexus (Auerbach) - control mm. contractions
- Outer longitudinal muscle layer - motility
What is the function of the serosa? What is its name when it becomes retroperitoneal?
Function: support
Becomes the adventitia when retroperitoneal
Differentiate between an ulcer and an erosion of the gut wall?
Erosions are in the mucosa only while ulcers can extend into the submucosa, inner or outer muscular layer (of the muscularis externa).
What are the frequencies of basal electrical rhythm (slow waves) in the:
- Stomach?
- Duodenum?
- Ileum?
- Stomach: 3 waves/min
- Duodenum: 12 waves/min
- Ileum: 8-9 waves/min
Histological appearance of the esophagus:
Nonkeratinized stratified squamous epithelium
Histological appearance of the stomach:
gastric glands
Histological appearance of the duodenum:
- Villi and microvilla ↑ absorptive surface
- Brunner glands (submucosa)
- Crypts of Lieberkühn
Histological appearance of the jejunum:
- Plicae circularis
2. Crypts of Lieberkühn
Histological appearance of the ileum:
- Peyer patches (lamina propria, submucosa)
- Plicae circulares (proximal ileum)
- Crypts of Lieberkühn
- Lots of goblet cells (largest # in the sm. intestine)
Histological appearance of the colon:
- Crypts of Lieberkün but no villi
2. Numerous goblet cells
Give the vertebral levels for the following structures:
- Celiac trunk
- SMA
- L renal artery
- IMA
- Bifurcation of abd. aorta
- Celiac trunk - T12
- SMA - L1
- L renal artery - L1
- IMA - L3
- Bifurcation of abd. aorta - L4 (“bifourcation”)
What artery comes off the abdominal aorta between the two branches of the common iliacs?
Median sacral artery
Does the right or left testicular (ovarian) artery branch from the aorta first?
Left
Which arteries come off the aorta on either side of the celiac trunk?
inferior phrenic arteries
What artery comes off the aorta laterally to the SMA?
left middle suprarenal artery
Arteries supplying GI structures branch from the aorta _______ (anteriorly/laterally) while those supplying non-GI structures branch ______ (anteriorly/laterally).
GI: anteriorly
non-GI: laterally
What is the SMA syndrome?
When the transverse portion (third segment) of the duodenum is entrapped b/w the SMA and aorta → intestinal obstruction
For the foregut, name the following:
- Artery:
- Parasympathetic innervation:
- Vertebral level:
- Artery: Celiac
- Parasympathetic innervation: Vagus
- Vertebral level: T12/L1
For the midgut, name the following:
- Artery:
- Parasympathetic innervation:
- Vertebral level:
- Artery: SMA
- Parasympathetic innervation: Vagus
- Vertebral level: L1
For the hindgut, name the following:
- Artery:
- Parasympathetic innervation:
- Vertebral level:
- Artery: IMA
- Parasympathetic innervation: Pelvic
- Vertebral level: L3
What structures are supplied by the artery and nerves that supply the foregut?
Pharynx to proximal duodenum Liver Gallbladder Pancreas Spleen (mesoderm)
What structures are supplied by the artery and nerves that supply the midgut?
Distal duodenum to proximal 2/3 of transverse colon
What structures are supplied by the artery and nerves that supply the hindgut?
Distal 1/3 of transverse colon to upper portion of rectum (splenic flexure is a watershed region)
What are the branches of the celiac trunk? What structure do these arteries supply?
- common hepatic a.
- splenic a.
- left gastric a.
- main blood supply of the stomach
From what artery do the short gastric arteries arise?
Splenic artery
In addition to the spleen, what structure would you be concerned about if the splenic artery were blocked?
the stomach: the short gastrics that arise from the splenic artery have poor anastomoses
Which arteries travel along the greater curvature of the stomach? Describe the strength of their anastomoses.
Left and right gastroepiploic arteries; strong anastomoses
From what main arteries do the gastroepiploic arteries arise?
Left: splenic artery
Right: gastroduodenal artery
What are the branches of the common hepatic artery?
hepatic artery proper
gastroduodenal artery
What are the branches of the gastroduodenal artery?
- anterior superior pancreaticoduodenal artery
- posterior superior pancreaticoduodenal artery
- right gastroepiploic artery
Where do the left and right gastric arteries arise? Describe their anastomoses in terms of strength.
Left: celiac trunk
Right: hepatic artery proper (less commonly from the common hepatic artery)
Strong anastomoses
What artery compensates through anastomoses when the superior gastric a. (from interal thoracic/mammary) is blocked (and vice-versa)?
inferior epigastric a. (from external iliac)
What artery compensates through anastomoses when the superior pancreaticoduodenal a. (from celiac trunk) is blocked (and vice-versa)?
inferior pancreaticoduodenal a. (from SMA)
What artery compensates through anastomoses when the middle colic a. (from SMA) is blocked (and vice-versa)?
left colic a. (from IMA)
What artery compensates through anastomoses when the superior rectal a. (from IMA) is blocked (and vice-versa)?
middle and inferior rectal a. (from internal iliac)
