Esophagus, Stomach, Small intestine and Large intestine Flashcards
Structure of esophagus
- muscular tube
- 25cm long and 2 cm diameter
- cervical part: cricoid cartilage to thoracic inlet
- thoracic part: thoracic inlet to diaphragm
- abdominal part: diaphragm to cardiac opening in stomach
- upper 1/3- striated muscle
- middle 1/3- mixed skeletal and smooth
- lower 1/3 - smooth muscle
Constrictors of esophagus
- Cervical constrictor:
- at pharyngo-esophageal junction
- caused by cricoid cartilage
- lower constrictor of pharynx form Upper Esophageal sphincter - Thoracic constrictor:
- crossed by aortic arch and left main bronchus - Diaphragmatic constrictor:
- at esophageal hiatus
- Lower esophageal sphincter- by right crus
Laimer trigone
- triangular V-shaped area on posterior side of esophagus
- area of weakness due to absence of outer longitudinal muscle layer
- potential site of herniation or Zener Diverticulum
Z-line
where the mucosa abruptly changes from esophageal (stratified non-keratinized squamous) to gastric (simple columnar, glandular) at the cardia
Arterial supply of Esophagus
- Esophageal branch of Inferior Thyroid artery
- Esophageal branch of Left and Right bronchial a
- Esophageal branches of Thoracic aorta
- Left Gastric artery
- Left Inferior Phrenic artery
Venous drainage of Esophagus
- Left Gastric vein of stomach into Portal system
- Esophageal veins to Azygos and hemiazygos veins
Lymphatic drainage of Esophagus
- Left gastric lymph nodes
- Inferior Deep cervical lymph nodes
- Para-tracheal lymoh nodes
- Posterior mediastinal and intercosal lymph nodes
Innervation of Esophagus
Vagal nerves
sympathetic: cervical and thoracic sympathetic chain
Muscular layer of Stomach
innermost oblique
inner circular
outer longitudinal
Ligaments of stomach
- Hepatogastric ligament: from liver into lesser curvature, part of lesser omentum, contains left and right gastric artery and vein
- Gastrocholic ligament: greater omentum to transverse mesocolon, 6 layers, contains left and right gastroepiploic arteries
- Gastrosplenic ligament: continuation of gastrocolic
- Gastrophrenic ligament
Arterial supply of stomach
- Left gastric a. (celiac trunk)
- Right gastric a. (proper hepatic a.)
- Posterior gastric a. (splenic a.)
- Short gastric a. (splenic a.)
- Left Gastro-omental a. (splenic a.)
- Right Gastro-omental a. (gastro-duodenal a.)
Vanous drainage of Stomach
- Left gastric vein (⇒portal vein)
- Right gastric vein (⇒portal vein)
- Left Gastroepiploic vein (⇒splenic vein)
- Right gastroepiploic vein (⇒sup. mesenteric vein)
- Prepyloric vein
Lymphatic drainage of Stomach
- sup 1/3: gastric lymph node ⇒ cisterna chyli
- fundus, corpus: pancreatico-splenic lymph nodes
- right inf: pyloric and gastroomental lymph nodes
- left inf: pancreatico-duodenal lymph nodes
Innervation of Stomach
parasymp: Anterior /Posterior Vagal trunks + celiac plexus
symp: Th6-Th9⇒ celiac plexus through greater splanchnic nerves
Duodenojejunal junction
- level of L2
- duodenojejunal flexure
- fixed by Suspensory ligament of Treitz
Superior Horizontal part of Duodenum
- 5cm long
- anterolateral to L1
- has ampulla - hepatoduodenal ligament attaches
- intraperitoneal
Descending part of Duodenum
- 7-10 cm long
- right side of L1-L3
- Vater’s papilla + sphincter of Oddi
- minor duodenal papilla + sphincter of Santorini
- retroperitoneal
Inferior Horizontal part of Duodenum
- 6-8 cm long, crosses L3
- retroperitoneal
Ascending part of Duodenum
- 5cm long, left side of L3-L2
- retroperitoneal
Arterial supply of Duodenum
- Superior Pancreaticoduodenal a (gastroduodenal)
- Gastroduodenal a (common hepatic a)
- Inferior Pancreaticoduodenal a (SMA)
VEINS:
Pancreaticoduodenal veins ⇒ SMV
Lymphatic drainage of Duodenum
- anterior lymph vessels ⇒ pancreaticoduodenal + pyloric lymph nodes
- posterior lymph vessels ⇒ SMLN
Innervation of Duodenum
parasymp: Vagus
symp: Lesser/greater Splanchnic nerves
Jejunum
- intraperitoneal
- wider, emptier, thicker walled
- less fat, less prominent arterial arcades, longer vasa recta
Ileum
- longer than jejunum
- darker, more vertical loops
- contains Payer’s patches
- shorter plica circularis, shorter vasa recta, more mesenteric fat, more prominent arcades
Meckel’s diverticulum
remains of yolk stalk of embryo, which when persistent abnormally as sac or pouch, located 60-90cm orally from ileocecal junction; may be free or attached to umbilicus
Blood supply of Jejunum and Ileum
ARTERY:
- superior mesenteric artery
VEIN:
- superior mesenteric vein ⇒ splenic vein ⇒ portal vein
Lymphatic drainage of Jejunum and Ileum
- Juxta-intestinal lymph nodes
- mesenteric lymph nodes
- superior central nodes
Innervation of Jejunum and Ileum
symp: Th8-Th10 ⇒ lesser/greater splanchnic nerves
parasymp: vagal trunks
Teniae coli
three bands in which the longitudinal muscular fibers of large intestine, except rectum and anal canal, are collected
- mesocholic: transverse + sigmoidal mesocolons attach ⇒ posteromedial tenia
- omental: greater omentum attach to transverse colon ⇒ posterolateral tenia
- libera: opposite to mesocolic, no attachment ⇒ anterior tenia
Cecum
- 7,5 cm
- semi-intraperitoneal
- ileocecal junction + ileocecal valve of Bauhin
Vermiform Appendix
- blind intestinal diverticulum
- contain lymphoid tissue
- has mesoapendix
- clinically found with McBurney point
- found where all tenia join
Blood supply of Cecum and Appendix
ARTERY:
- Ileocolic artery (SME)
VEIN:
- Ileocecal vein (⇒SMV)
LYMPH:
- Ileocecal lymph nodes ⇒ SMLN
Ascending colon
- semi-intraperitoneal
- cecum ⇒ right colic flexure
- right paracolic gutter ⇒ recess continuous with sub hepatic recess and Morrison’s pouch⇒ infection spread
- Jackson’s membrane ⇒ thin vascular membrane on anterior surface, may cause obstruction by kinking the bowel
Blood supply of Ascending colon
ARTERY:
- ileocecal, right colic + middle colic arteries (SMA)
VEIN:
- ileocolic, right colic veins ⇒SMV
LYMPH:
- epicolic, paracolic, right colic lymph nodes ⇒ SMLN
Transverse colon
- right colic flexure ⇒ left colic flexure
- phrenicocolic ligament attached
- transverse mesocolon: mesentery of transverse colon. forms inferior border of omental bursa, fuses with greater omentum forming 6 layered gastrocolic ligament
- L3 vertebral level
Blood supply of transverse colon
ARTERY: - middle colic artery (SMA - left colic artery (IMA) ⇒ 2nd Riolan anastomosis VEIN: - middle colic vein ⇒ SMV LYMPH: - middle colic lymph nodes ⇒ SMLN
Descending colon
- semi-intraperitoneal
- left paracolic gutter- closed upward by phrenicocolic ligament
- thinner than ascending
Blood supply of Descending colon
ARTERY: - left colic artery (IMA) ⇒ Marginal artery of Drummond together with right colic artery VEIN: - left colic vein ⇒ IMV LYMPH: - left colic lymph nodes ⇒ IMLN
Sigmoid colon
- S-shaped loop, 40cm
- iliac fossa ⇒ S3 vertebra
- Rectosigmoidal junction: termination of teniae
- Mesosigmoidum: freely moving
Blood supply of Sigmoid colon
ARTERY: - sigmoidal artery (IMA) ⇒ Sudeck point: anastomosis with superior rectal a VEIN: - sigmoidal vein ⇒ IMV
Innervation of Colon
parasymp: vagus nerve (until 2/3 of transverse colon), sacral plexus (1/3 of transverse colon ⇒ anus)
symp: superior hypogastric plexus
Cannon-Böhm point
point were innervation changes from vagus to sacral plexus in colon
Rectum
- 15-20 cm long, has no omental appendices or haustra
- sacral flexure + perineal flexure
- 3 lateral flexures: 2 on left side, 1 right- Kohlrausch’s fold
- superior 1/3⇒ semi-intraperitoneal, middle 1/3⇒retroperitoneal, inferior 1/3⇒ infra peritoneal
Blood supply of Rectum
ARTERY:
- superior rectal artery (IMA)
- middle rectal artery (internal iliac artery)
- inferior rectal artery (internal pudendal artery)
VEIN:
- superior rectal vein ⇒ IMV
- middle, inferior rectal veins ⇒ internal iliac vein
- submucosal rectal plexus
Innervation of Rectum
symp: lumbar part of sympathetic trunk + superior hypogastric plexus
parasymp: pelvic splanchnic nerves
Anal canal
- 4cm long, pelvic diaphragm ⇒ anus
- internal anal sphincter: involuntary, innervated by parasympathetic nerves
- external anal sphincter: voluntary striated muscle, 3 components⇒ subcutaneous, superficial and deep part
- anal columns of Morgagni
- anal valves of Morgagni
- anal sinuses: pocket like recesses above valves
Pectinate line
limit of anal valves that indicates the junction of the superior part of anal canal (hindgut) and the inferior part (proctodeum)
Zones of mucosa in anal canal
- Zona columnaris: anorectal junction⇒ pectinate line, simple columnar epith.
- Zona Hemorrhagica: pectinate line ⇒ hilton white line, stratified squamous non-keratinized epithelium
- Zona cutanea: stratified squamous keratinized non-hairy epithelium
Blood supply of Anal canal
ARTERY: - superior rectal artery - 2 inferior rectal arteries - middle rectal artery VEIN: - superior rectal vein - inferior rectal vein - middle rectal vein
Innervation of Anal canal
superior to pectinate line: inferior hypogastric plexus
inferior to pectinate line: inferior anal nerves (pudendal nerve)
