Chapter 23Chapter 23Development of digestive and respiraDevelopment of digestive and respira

tory systemtory system

ⅠⅠ.Primitive gut and its derivetives.Primitive gut and its derivetives

ForegutForegut

MidgutMidgut

HindgutHindgut

Oropharyngeal membrane Cloacal membrane Vitelline duct

ⅡⅡ.Development of the digestive system.Development of the digestive system

1.Evolution of foregut1.Evolution of foregut– Esophagus and stomachEsophagus and stomach– Liver and gallbladderLiver and gallbladder– Pancreas Pancreas

(1) Development of the esophagus(1) Development of the esophagus

esophagus

Epithelium simple to stratified recanalization incomplete recanalization esophageal stenosis esophageal atresia

(2) Development of the stomach(2) Development of the stomach

dorsal mesenterydorsal mesenteryMesentery Mesentery

ventral mesenteryventral mesentery

Dorsal border: greater curvature, fundusDorsal border: greater curvature, fundus

Ventral border: lesser curvatureVentral border: lesser curvature

Dorsal mesogastrium: omental bursaDorsal mesogastrium: omental bursa

(3) Development of liver and gallbladder(3) Development of liver and gallbladderHepatic diverticulumHepatic diverticulum

Cephalic limb: liverCephalic limb: liver

Caudal limb:Caudal limb:

gallbladder cystic ductgallbladder cystic duct

Septum transversumSeptum transversum肝憩室肝憩室

Common bile duct

原始横隔

原始横隔

原始横隔

Congenital obstructive jaundice

(4) Development of pancreas(4) Development of pancreas

Ventral pancreatic Ventral pancreatic budbudDorsal pancreatic Dorsal pancreatic budbudVentral pancreatic Ventral pancreatic ductductDorsal pancreatic Dorsal pancreatic ductductCommon Common pancreatic ductpancreatic ductAccessory Accessory pancreatic ductpancreatic duct

Annular pancreas

2. Evolution of midgut and hindgut2. Evolution of midgut and hindgut(development of intestine)(development of intestine)

(1)Midgut loop(1)Midgut loopCephalic limbCephalic limbCaudal limbCaudal limbCaecal swellingCaecal swelling (bud)(bud)

CaecumCaecumAppendixAppendix

Superior mesenteric artery

Physiological Physiological umbilical herumbilical herniationniation

rotate counterotate counter clockwiser clockwise

(2) Evolution of hindgut (2) Evolution of hindgut (Separation of the cloac(Separation of the cloaca)a)

urorectal septumurorectal septum

Cloaca Cloaca Urogenital sinusUrogenital sinus

Urinary bladder, urethraUrinary bladder, urethra

Anorectal canalAnorectal canalRectum Rectum Upper part of anal canalUpper part of anal canal

Cloacal membraneCloacal membrane– Urogenital membraneUrogenital membrane– Anal membraneAnal membrane

Anal pitAnal pit

Separation of the cloacaSeparation of the cloaca

Pectinate linePectinate line

3.Congenital malformation of the intestine3.Congenital malformation of the intestine

(1)Stenosis, atresia and duplication

(2) Umbilical fistula and Meckel’s diverticulum(2) Umbilical fistula and Meckel’s diverticulum vitelline fistula vitelline fistula Vitelline cystVitelline cyst(3) Congenital umbilical hernia (3) Congenital umbilical hernia

Vitelline ligamentVitelline ligament

(4)Congenital Aganglionic Megacolon

due to absence of parasympathetic ganglia in the bowel wall

(5) Imperforate anus(5) Imperforate anusrectovaginal fistula

rectourethral fistula

Rectourethral fistulaRectovesical fistula

(6) Abnormal midgut rotation(6) Abnormal midgut rotation

nonrotation of the midgut

reversed rotation of the midgut

situs inversus viscerum

left side colon

ⅢⅢ.Development of the respiratory system.Development of the respiratory system

1. 1. Development of Development of

the Larynx and the Larynx and

tracheatrachea– LaryngotrachealLaryngotracheal

groovegroove– Laryngotracheal diveLaryngotracheal dive

rticulumrticulum– Tracheoesophageal Tracheoesophageal

septumseptum– Diverticulum: larynx, Diverticulum: larynx,

trachea, lung budstrachea, lung buds

喉气管憩室喉气管憩室

2. Development of bronchi and lungs2. Development of bronchi and lungs

Lung buds Lung buds Bronchi, bronchial tree, alveoliBronchi, bronchial tree, alveoli– Surfactant: lowering the surface tensionSurfactant: lowering the surface tension

Mesenchyme: CT, cartilage, smooth muscles, blood vesselsMesenchyme: CT, cartilage, smooth muscles, blood vessels

3. Malformation3. Malformation Stenosis or atresia of larynx and tracheaStenosis or atresia of larynx and tracheaEsophagotracheal fistulaEsophagotracheal fistulahyaline membrane diseasehyaline membrane disease

respiratory distress syndromerespiratory distress syndrome