Alimentary System 解剖學科徐淑媛

Alimentary System 解剖學科徐淑媛

本堂重點 1. Structures derived from primitive guts 2. Specific events

Alimentary System endoderm of primordial gut epithelium & glands of digestive tract ectoderm of stomodeum epithelium of mouth ectoderm of proctodeum epithelium of anus splanchnic mesenchyme muscle, connective tissue & other tissues Fig. 11-1

Alimentary System @ recanalization & rotation Fig. 11-6 Fig. 11-12

Alimentary System Foregut Midgut Hindgut Fig. 11-1

Foregut -- primordial pharynx : oral cavity, tongue, tonsils, salivary glands -- lower respiratory system -- esophagus, stomach, proximal duodenum, liver, gallbladder, pancreas, spleen -- supplied by celiac trunk Fig. 11-1

Foregut Esophagus -- superior 1/3 striated muscles are derived from mesenchyme of lower pharyngeal arches -- inferior 1/3 smooth muscles are derived from splanchnic mesenchyme -- innervated by vagus nerve Fig. 11-1

Foregut Stomach -- the dorsal border grows faster than the ventral border -- rotate 90 degrees in a clockwise direction -- ventral border (lesser curvature) to the right, dorsal border (greater curvature) to the left -- left vagus innervate anterior wall, right vagus supply posterior wall Fig. 11-5 Fig. 11-2

Foregut Stomach -- the dorsal border grows faster than the ventral border -- rotate 90 degrees in a clockwise direction -- ventral border (lesser curvature) to the right, dorsal border (greater curvature) to the left -- left vagus innervate anterior wall, right vagus supply posterior wall From Moore: Clinical Oriented Anatomy Fig. 11-2

Foregut Stomach -- mesentery -- ventral mesogastrium lesser omentum + falciform lig. -- dorsal mesogastrium greater omentum + gastrosplenic lig. + splenorenal lig. ventral mesogastrium dorsal mesogastrium dorsal mesogastrium ventral mesogastrium Fig. 11-5 Fig. 11-2

Foregut Stomach -- mesentery -- ventral mesogastrium lesser omentum + falciform lig. -- dorsal mesogastrium greater omentum + gastrosplenic lig. + splenorenal lig. dorsal mesogastrium ventral mesogastrium Fig. 11-12 Fig. 11-2

Foregut Stomach -- omental bursa, omental foramen Fig. 11-2 Fig. 11-3

Foregut Duodenum -- caudal part of foregut + cranial part of midgut -- junction : distal to origin of bile duct -- blood supply : celiac trunk & superior mesenteric artery -- rotate to the right Fig. 11-2 Fig. 11-5

Liver & Gallbladder Foregut -- hepatic diverticulum -- primordium of liver -- small caudal part Fig. Fig. 11-5

Liver & Gallbladder -- hepatic diverticulum -- primordium of liver -- hepatocytes (hepatic cords) & epithelia of intrahepatic biliary ducts come from endoderm -- connective tissue, hepatic sinusoids & Kuppfer cells are derived from mesenchyme -- small caudal part -- gallbladder, cystic duct & bile duct Foregut Fig. 11-12

Liver & Gallbladder -- ventral mesentery -- lesser omentum & falciform ligament -- umbilical vein : pass through inferior border of faciform ligament Foregut Fig. 11-12

Foregut Pancreas -- dorsal & ventral pancreatic buds -- fused & lies retroperitoneally because of the rotation of duodenum -- parenchyma is derived from the endoderm -- pancreatic islets develop from group of cells separated from tubules -- connective tissue sheath develop from the surrounding splanchnic mesenchyme http://bio.sunyorange.edu/updated2/ev.html/9.%20embryological%20evidence%203_files/ima ge041.jpg Fig. 11-10

Foregut Pancreas -- dorsal & ventral pancreatic buds -- fused & lies retroperitoneally because of the rotation of duodenum https://embryology.med.unsw.edu.au/embryology/images/4/4b/ Pancreas_rotation.jpg Fig. 11-12

Foregut Spleen -- derived from mesenchymal cells in dorsal mesogastrium Fig. 11-12 Fig. 11-2

Midgut -- small intestine, cecum, appendix, ascending colon, right 2/3 of transverse colon -- supplied by superior mesenteric artery -- midgut loop Fig. 11-9

Midgut midgut loop -- physiological umbilical herniation -- no space of abdomen (large liver & two sets of kidneys) -- cranial limb : small intestinal loops -- caudal limb : parts of small & large intestine; cecum & appendix (cecal swelling) Fig. 11-14

Midgut midgut loop -- rotation : 90 degrees counterclockwise -- cranial limb to the right, caudal limb to the left -- return -- small intestine first : central part -- large intestine return & rotate further 180 degrees counterclockwise Fig. 11-16 From Moore: Clinical Oriented Anatomy

Midgut midgut loop -- rotation : 90 degrees counterclockwise -- cranial limb to the right, caudal limb to the left -- return -- small intestine first : central part -- large intestine return & rotate further 180 degrees counterclockwise Fig. 11-13

From Moore: Clinical Oriented Anatomy Midgut

Midgut -- fixation : fusion of mesentery & peritoneum Fig. 11-13 Fig. 11-15

Hindgut -- left 1/3 of transverse colon, descending & sigmoid colon, rectum, superior anal canal -- epithelium of urinary bladder & most of urethra -- supplied by inferior mesenteric artery Fig. 11-1

Hindgut -- left 1/3 of transverse colon, descending & sigmoid colon, rectum, superior anal canal -- epithelium of urinary bladder & most of urethra -- supplied by inferior mesenteric artery Fig. 11-13

Hindgut -- cloaca -- cloacal membrane = endoderm of cloaca + ectoderm of proctodeum (anal pit) -- urorectal septum (mesenchyme) -- dorsal : rectum & superior part of anal canal -- ventral : urogenital sinus Fig. 11-25

Anal Canal upper 2/3 (25 mm) lower 1/3 (13 mm) Hindgut origin vessel innervation epithelium carcinoma hindgut proctodeum superior rectal (inferior mesenteric) inferior rectal (internal pudendal) ANS columnar painless inferior rectal n. (keratinized) stratified squamous painful From Gray s Anatomy for Students Fig. 11-26

Alimentary system 1. Structures derived from primitive guts 2. Specific events