Class 3 Flashcards
Where is the oesophagus constricted?
- Cervical
- Thoracic
- Diaphragmatic (Oesophageal hiatus at T10)
What structures go through the oesophageal hiatus?
- Oesophagus
- Vagus nerve
- Left inf. phrenic vessels
- Small oesophageal arteries (branches of the left gastric artery)
Explain the arteries, veins and lymphatics of the abdominal oesophagus?
Art = Branches of Left Gastric Artery Veins = Left Gastric vein -> Portal Vein Lymphatics = follows Left gastric artery to gastric & coeliac nodes
What happens around the lower end of the oesophagus when theres portal hypertension?
The portosystemic anastomoses become dilated, their rupture can cause severe & dangerous haematemesis.
These are called oesophageal varices
What are the orifices, curvatures & surfaces of the stomach?
- Cardiac orifice (+ sphincter) & Pyloric orifice (+ sphincter)
- Greater & Lesser curvature
- Anterior & Posterior surfaces
Define the pyloric sphincter?
Band of smooth muscle between stomach pylorus & Duodenum.
It functions by controlling gastric outflow
Formed from the thickening of the circular (inner) layer of muscularis externa
Describe the greater/lesser omenta?
Greater omentum - Greater curvature of the stomach to transverse colon
Lesser Omentum - Lesser curvature of the stomach to the liver
Where does the epiploic foramen pass?
Behind the lesser omentum over the stomach from greater to lesser sac.
What layers of the stomach from the gastric rugae?
Mucosa submucosa
(Mi casa et tu casa)
They are most apparent in the pylorus and body of the stomach
What forms the stomach bed?
The structures on which the stomach lies:
- Pancreas
- Left Kidney
- Spleen
- Left Suprarenal gland
- Transverse and mesocolon
- Splenic artery
- Left dome of diaphragm
Explain the arterial supply of the stomach? Probably easier just to look at the diagram in the workbook
Coeliac Trunk splits into common hepatic artery, left gastric artery and splenic artery.
- The left gastric artery supplies the top and gastroesophageal junction
The common hepatic then splits into the right gastric, true hepatic and gastroduodenal arteries.
- The right gastric supplies the lesser curvature
- The gastroduodenal artery gives off the right gastroepiploic artery which supplies the distal section of the greater curvature
The splenic artery gives off the short gastric arteries suppling the fundus and the Left Gastroepiploic artery which supplies the proximal half of the greater curvature
Explain the arterial supply of the colon:
Abdominal aorta gives off the superior (L1/L2) and inferior mesenteric (L3) arteries.
Superior mesenteric:
- Ileocolic = supplies caecum and ileocaecal junction
- Right Colic = Often absent but otherwise Supplies Asc. colon
- Middle Colic = Supplies hepatic flexure and proximal transverse colon and Asc. Colon if right absent.
Inferior Mesenteric:
- Left colic = supplies Desc. Colon
- Sigmoid = Sigmoid Colon
- Superior Rectal = Main supply of rectum
(Also the internal iliac branches to form inferior/middle rectal arteries, the middle is often absent)
All the branches of the Sup & Inf Mesenterics described above are connected round the border of the colon by the marginal artery
Explain the lymphatics of the colon?
Follows the arterial supply and has to be removed when removing a cancer.
- Epicolic (on wall of colon)
- Paracolic (Next to colon)
- Intermidiate (Along main arteries of colon)
- Central or principle (Along large vessels e.g. sup. mesenteric)
Drains to the superior and inferior mesenteric lymph nodes based on location
Explain the veins of the colon?
Same as the arteries except:
Inferior mesenteric feeds into splenic.
Then splenic and superior mesenteric combine to form the portal vein going into liver.
Explain the lymphatic drainage of the stomach?
Split into four groups:
Pyloric - Around pylorus
Superior Gastric - Around upper end of lesser curvature and gastroesophageal junction
Pancreaticosplenic - Along splenic artery and posterior of stomach
Inferior Gastric - on greater curvature
All drain into the ceoliac nodes
{Gastric carcinoma most often occurs along the greater curvature}
How does vagal stimulation affect the pylorus and gastric secretion?
Vagal stimulation causes pylorus to relax and gastric secretion to increase
Describe “highly selective vagotomy of the stomach”
Cutting specific vagal branches to the fundus and body decreases gastric secretion to treat overactive gastric acid secretion
While the antrum remains unaffected so gastric motility is preserved.
Where is the boundary of fore/midgut?
Half way along duodenum, just after major duodenal papilla
Which part of the small intestine is the most short, wide and fixed?
Duodenum
Differences between ileum and jejunum?
Jejunum:
Deep red - Thick/heavy wall - Very Vascular - Long Vasa Recta - Few Large loops of arcades - Little fat in mesentery - Large, tall closely packed plicae circulares
Ileum:
Pale Pink - Thin/light wall - Less vasculature - Short vasa recta - many shrt loops of arcades - Fatty Mesentery - Smaller/less plicae ciculares
What nervous system reduces secretion/motility and vasconstricts the intestine?
Sympathetic Autonomic NS
How do we tell large intestine from small?
The large had teniae Coli, Haustr and is broader.
Histologically the large:
- Lacks Villi
- Lacks Plicae Ciruclares
- Very few peyer’s patches
How is the colon peritonised?
Asc/Desc and caecum are retroperitoneal
The rest is intraperitoneal.
Acronym of Intraperitoneal organs
SALTD SPRSS
- Stomach
- Appendix
- Liver
- Transverse Colon
- Duodenum (1st part)
- Small Intestine
- Pancreas (tail)
- Rectum (lower 2/3rds are retroperitoneal)
- Sigmoid Colon
- Spleen
Acronym of retroperitoneal structures?
SAD PUCKER
- Supradrenal Gland
- Aorta & IVC
- Duodenum
- Pancreas
- Ureter + Bladder
- Colon (Asc/Desc)
- Kidneys
- Esophagus
- Rectum
Where is the midgut/hindgut boundary?
2/3rds of the way along the transverse colon
How do the haustra form on the colon?
The longitudinal muscle of the gut tube forms three strips called tenia coli which sacculate the colon into haustra and reform at the rectum into a continuous longitudnial sheet.
What is McBurney’s Point?
1/3rd distance from anterior superior iliac spine to umbilicus
Its the most common location for the base of the appendix
explain the arterial supply, venous drainage and peritonisation of the rectum
Superior 1/3rd:
- Sup. Rectal Artery (Inf. mesenteric artery)
- Superior Rectal Vein
- Intraperitoneal
Middle 1/3rd:
- Middle Rectal Artery if present (Internal Iliac artery)
- Middle Rectal Vein
- Retroperitoneal
Inferior 1/3rd:
- Inferior Rectal Artery (Internal iliac artery)
- Inferior Rectal Vein
- Subperitoneal
How does the pevlic floor maintain faecal continence?
- Contracts to prevent soilage
Internal/external anal sphincters also involved.
At what point does pain begin in the rectum?
Below the dentate (Pectinate) line the innervation becomes somatic not visceral so you can feel pain.
What ligaments are part of the lesser omentum?
Hepatoduodenal
Hepatogastric
Whats the functoin of the falciform ligament and whats in its free border?
IT binds the liver to the anterior body wall
The ligamentum teres and paraumbilical veins are found in its free border
Ligamentum teres?
Round ligament of the liver
Remnant of the foetal umbilical vein
How many layers of peritoneum are in the greater omentum?
4
Why do we call the greater omentum the abdominal policeman?
Abdominal infection releases inflammatory exudate which causes the omentum to wrap around the infected viscera and adhere to it, containing the infection.
Clinical significance of the paracolic gutters?
Important to know the adjacent structures from which fluid or particles could have leaked to end up in the gutters and where they will drain to
What kind of epithelium is found in the oesophagus?
Stratified Squamous
What secretory cells are found in the gastric pits?
Parietal - HCl & Intrinsic Factor Chief - Pepsinogen Mucous neck - Mucins ECL - Histamine G - Gastrin D - Somatostatin
What kind of epithelium is found in the intestine?
Simple Columnar
In what section of the gut tube are there submucosal glands?
- Duodenum
- Oesophagus
Whats the predominant cell in the surface epithelium of the small intestine?
Enterocyte
Also present are goblet cells, paneth cells etc.
What is the transpyloric plane
Transverse plane halfway between jugular notch & upper border of the pubic symphysis
Locate it by roughly a hands breadth below the xiphoid process
What structures does the transpyloric plane pass through?
- Pylorus
- L1/L2 vertebrae
- Tip of 9th costal cartilage
- Neck of pancreas
- Sphincter of Oddi
- Origin of sup. mesenteric art. & Portal vein
- Hilum of kidney
- Fundus of gall bladder
- Duodenojejunal flexure
- 2nd part of duodenum
