(胚胎學)授課綱要
授課節次:第__1__週上課
課程主題: Gametogenesis, Fertilization, and the First week
講授目的:
Outline: origin of the germ line; meiosis; gametogenesis in the male and female;
授課綱要:(請條列該堂課之授課大綱內容)
Origin of the germ line (during 2nd week)
Primordial germ cells (originate within primary ectoderm)  migrate into yolk sac
 wall of gut tube posterior body wall stimulate mesonephros  primitive sex cords
 genital ridges (primordial gonads)
male: medullary sex cord cells  Sertoli cells in testes
female: cortical sex cord cells  follicle cells in ovary
Meiosis -- halves the number of chromosome and DNA strands in sex cells
Meiosis I: DNA replication, recombination and homologous chromosome separate
 two haploid 2N cells
Meiosis II: no DNA replication, double-stranded chromosome division
 four haploid 1N cells
Gametogenesis
Primordial germ cells  gametogenesis (mitosis & meiosis)  gametes (sperm or oocyte)
The process of gametogenesis is called spermatogenesis (male) and oogenesis (female)
Spermatogenesis (one cycle about 64 days) begins at puberty (testosterone) in the male
Primordial germ cell  mitosis  spermatogonia
 DNA synthesis  primary spermatocyte  meiosis I  secondary spermatocytes
 meiosis II  spermatids  spermiogenesis  sperms (spermatozoa)
sperm: head (acrosome), midpiece (mitochondria), tail (microtubules)
Oogenesis is discontinuous and begins during fetal life in female
Primordial germ cell  mitosis  oogonia
 DNA synthesis  primary oocyte  meiosis I prophase arrest (before puberty)
primary oocyte + single-layered follicle cells  primordial follicle
Puberty: GnRH  FSH & LH  primordial follicle  primary follicle (zona pellucida)
 secondary follicle (antrum)  mature follicle
Day 13 or 14 of menstral cycle: FSH & LH  stimulate primary oocyte in mature follicle
 finish meiosis I  secondary oocyte + first polar body  meiosis II metaphase
 ovulation
(胚胎學)授課綱要
授課節次:第__2__週上課
課程主題: Ovulation to Implantation (1st Week)
講授目的:
Outlines: menstrual cycle; fertilization; cleavage
授課綱要:(請條列該堂課之授課大綱內容)
Ovarian cycle (FSH & LH)
Primordial follicle  primary follicle  secondary follicle  maturing follicle
 ovulation  corpus luteum  corpus albicans
Oocyte + zona pellucida + follicular cells (corona radiata cells)
Uterine cycle (estrogen & progesterone)
Menstrual phase  proliferative phase  secretary phase
Fertilization (day 0) – occurs in ampulla of oviduct
Sperm: capitation & acrosome reaction
oocyte: cortical (zona) reaction & 2nd meiotic division
Pronucleus stage  fusion of pronuclei  zygote
Cleavage (day 1-- day 4)
Zygote  two-cell stage  compaction (cell adhesion)
 morula (with zona pellucida)
Blastocyst formation (day 5) (hatching from zona pellucida)
Inner cell mass  embryoblast … embryo
Outer cell mass  trophoblast … placenta
Implantation (about day 6)
trophoblast  syncytiotrophoblast  human chorionic gonadotropin (hCG)
 corpus luteum – progesterone  maitain endometrium of uterus
(胚胎學)授課綱要
授課節次:第__3__週上課
課程主題: Bilaminar Germ Disc (2nd Week)& Uteroplacental Circulation
講授目的:
Outlines: 1. Development of Bilaminar Germ Disc
2. Establishment of the Uteroplacental Circulation
授課綱要:(請條列該堂課之授課大綱內容)
Bilaminar germ disc
Trophoblast  syncytiotrophoblast (outer layer) & cytotrophoblast (inner layer)
Embryoblast  epiblast & hypoblast (bilaminar germ disc)
Amniotic cavity = epiblast + amnioblast
Exocoelomic cavity (primitive yolk sac) = hypoblast + exocoelomic (Heuser’s) membrane
Fibrin coagulum (coagulation plug)
Extraembryonic reticulum (between Heuser’s membrane and cytotrophoblast)
Extraembryonic mesoderm
Chorionic cavity (extraembryonic coelom) & definitive yolk sac + exocoelomic cysts
Connecting stalk  umbilical cord
Uteroplacental Circulation
Syncytiotrophoblast  trophoblastic lacunae
Primary stem villus (11-13 days)  secondary stem villus (16 days)
 tertiary stem villus (21 days)
Syncytiotrophoblast + cytotrophoblast + extraembryonic mesoderm (blood vessels)
(胚胎學)授課綱要
授課節次:第__4__週上課
課程主題: Trilaminar Germ Disc (3rd Week) &
Somite and Neural Tube Development
講授目的:
Outlines: Gastrulation; Formation of Trilaminar Germ Disc;
Initial Development of the Somites and Neural Tube
授課綱要:(請條列該堂課之授課大綱內容)
Gastrulation : formation of embryonic mesoderm and endoderm
Primitive streak: primitive pit, node and groove
– epiblast migrate to form mesoderm and endoderm (some displace hypoblast)
Prechordal plate (buccopharyngeal membrane oral cavity) &
Cloacal memebrane  anus opening
= ectoderm + endoderm (no mesoderm)
Prenotochordal cells  notochordal plate  detach from endoderm to form notochord
Neurenteric canal – temporarily connect amniotic and yolk sac cavities
Trilaminar germ disc = ectoderm, mesoderm and endoderm
Mesoderm:
Paraxial mesoderm  axial skeleton, part of skeletal muscle and part of dermis of skin
Intermediate  urinary system and parts of genital system
Lateral plate mesoderm  split into splanchnopleuric mesoderm & somatopleuric mesoderm
splanchnopleuric mesoderm  smooth muscle of GI tract
somatopleuric mesoderm  inner lining of body wall, parts of limb and most of dermis
Paraxial mesoderm  somitomere (except 1-7 pairs)  somite (base of skull)
1-7 somitomeres  muscles of face, jaw, throat
8, 9, 10 … somitomeres  1, 2, 3 … somites
1,2,3,4 somites  occipital part of skull, bones around nose, eyes, inner ears
& muscles of eye ball and tongue
next eight (5-12) somites  8 cervical somites
next twelve (12-23) somites  12 thoracic somites
five lumbar, five sacral and three coccygeal somites
Ectoderm
Neural plate  neural fold  neural crest & groove
Endoderm
Yolk sac
(胚胎學)授課綱要
授課節次:第__5__週上課
課程主題: The Fourth Week
講授目的:
Outlines: Differentiation of Somite & Nervous System (the 3rd-8th Week)
Segmantal Development and Integration
授課綱要:(請條列該堂課之授課大綱內容)
Somites or somitomeres  dermo-myotome (dermatome + myotome), sclerotome
Dermatome  dermis
Myotome  skeletal muscles
Sclerotome  mesenchyme (embryonic connective tissue)  skeleton
Vertebral Column
Cells of sclerotome segment migrate to surround spinal cord and notochord
Caudal half of sclerotome + rostral half of next sclerotome  precartilaginous vertebral body
Center plate of sclerotome  annulus fibrosus
Notochord  vertebral body & nucleus pulposus
Intervertebral disc = annulus fibrosus + nucleus pulposus
Ribs and Sternum
Ribs from costal process of thoracic vertebra from sclerotome of paraxial mesoderm
Sternum fuse from two sides of somatic mesoderm in ventral body wall
Muscles of Trunk
Somites or somitomeres  dermo-myotome  dermatome + myotome
Myotome  epimere + hypomere
Epimere (dorsal primary ramus)  extensor
Hypomere (ventral primary ramus)  flexor
Cervical – geniohyoid, scalene & prevertebral muscles
Thoracic – split into 3 layers (external, internal, innermost intercostal muscles)
Abdominal – external, internal oblique & transversus abdominal muscles
Lumbar – quardratus lumborum
Sacral and coccygeal – pelvic diaphragm
Rectus column (from hypomere) – infrahyoid, sternalis, rectus abdominis
Ectoderm  nervous system
Neurulation (day 22): Neural plate  neural fold  neural crest & groove  neural tube
Cranial portion: prosencephalon, mesencephalon (mesencephalic flexure), rhombencephalon
Caudal portion: spinal cord
Closure of neural tube: cranial neuropore (day 24) and caudal neuropore (day 26)
Neural crest cells (originates in neural fold)  migrate  numerous structures
Cranial neural crest: cranial nerve ganglia,
connective tissue surrounding eye, papillary and ciliary muscles,
dermal bone of skull, pharyngeal arch cartilages, dermis and hypodermis of face and neck,
truncoconal septum, odontoblasts,
Cranial & spinal neural crest: glia cells, Schwann cells & enteric ganglia
arachnoid and pia mater, melanocytes
Spinal neural crest: dorsal root ganglia, chain ganglia, preaortic ganglia, adrenal medulla
Neuroepithelial cells surround neural tube  neurons, glia and ependymal cells of CNS
Ventricular layer (neuroblasts)  ependymal cells of ventricle & central canal
Mantle layer (neurons)  gray mater of CNS
Marginal layer (neuronal processes)  white mater of CNS
Mantal layer  dorsal (alar) columns & ventral (basal) columns
Sulcus limitans – between alar and basal column
dorsal (alar) columns  somatic motor neurons
ventral (basal) columns  association neurons
intermediolateral cell columns
(胚胎學)授課綱要
授課節次:第__6__週上課
課程主題: Embryonic Folding
講授目的:
Outlines: folding of the embryo; formation of body cavities and mesenteries
授課綱要:(請條列該堂課之授課大綱內容)
Folding – a flat trilaminar germ disc → a three dimentional embryo.
Grow faster in length than in width
Length: development of notochord, neural tube & somites
Width: growth of lateral plate mesoderm
Cephalic folding
Overgrowth and flexure of cephalic neural plate
Mesenchyme (a loose embryonic tissue)
Cardiogenic area (cranial to buccopharyngeal membrane) … heart
Septum transversum (day 22 – a thicken bar of mesoderm)
… part of diaphragm, ventral mesentery of stomach and duodenum
Caudal folding
Overgrowth and flexure of neural tube and somites
Cloacal membrane → ventral surface
Connecting stalk (connect caudal end of germ disc to placenta)
→ merges with the neck of yolk sac
Allantois: a endodermal hindgut diverticulum
Lateral folding
Overgrowth and flexure of lateral plate mesoderm
Lateral edges of germ disc fuse along ventral midline except umbilical region
Umbilical region: yolk sac + connecting stalk
Folding of endoderm → gut tube
Foregut, midgut, hindgut, allantois and vitelline duct (neck of yolk sac)
Intraembryonic coelom
lateral plate mesoderm splits into two layers:
Somato-pleuric (somatic) mesoderm (adheres to ectoderm)
→ serous membrane of inside of body wall
Splanchno-pleuric (visceral) mesoderm (adheres to endoderm)
→ serous membrane of visceral organs and gut tube
Mesenteries:
ventral mesentery: from septum transersum
dorsal mesentery: bilayered splanchno-pleuric mesoderm
intraperitoneal organs: suspended in peritoneal cavity
retroperitoneal organs: behind the peritoneum ex. kidneys and urinary bladder
secondarily retroperitoneal organs: initially suspended by mesentery → fused to body
wall ex. duodenum, pancreas, ascending colon and descending colon
Ventral body cavities
Septum transversum (4th week)
Primitive pericardial cavity (superior)
Peritoneal cavity (inferior)
Pericardio-peritoneal canals
Phrenic nerve (C3, C4, C5) elongation
Pleuro-pericardial folds (5th week) divide primitive pericardial cavity into
Difinitive pericardial cavity
Pleural cavities (two)
Pleuro-pericardial folds: three layer:
Outer somatic mesoderm → mediastinal pleura
Body wall mesenchyme → fibrous pericardium (with phrenic nerves)
Inner somatic mesoderm → parietal pericardium
Pleuro-peritoneal membranes – seal off pericardio-peritoneal canals (7th week)
Left canal is larger and close later than right canal
The diaphragm
(1) septum transversum → central tendon of diaphragm
(2) pleuro-peritoneal membranes → the bulk of diaphragm muscle
(3) body wall mesoderm → outer rim of diaphragm muscle
(4) esophageal mesoderm → right and left crura of diaphragm
(胚胎學)授課綱要
授課節次:第__7__週上課
課程主題: Development of skeletal system
講授目的: 了解中軸骨與附肢骨之發育情形
授課綱要:(請條列該堂課之授課大綱內容)
1. vertebral development
2. rib and sternum development
3. development of cranium
4. development of limbs
5. disease of skeletal develpoment
(胚胎學)授課綱要
授課節次:第__8__週上課
課程主題: Muscular System (embryology)
講授目的:
Outlines: differentiation of somitomeres or somites,
muscle development of the head, trunk and limbs
授課綱要:(請條列該堂課之授課大綱內容)
Develop from mesoderm (except iris – optic cup ectoderm)
Skeletal muscle – from paraxial mesoderm
Cardiac muscle – from splanchnic (visceral) mesoderm surrounding heart tube
Smooth muscle – from splanchnic (visceral) mesoderm surrounding GI tract
Muscles of Head
From paraxial mesoderm (except iris)
Somitomeres (1-7) + occipital somites (1-5); Origins of cranio-facial muscles (see table 10.1)
Muscles of Trunk
Somites or somitomeres  dermo-myotome  dermatome + myotome
Myotome  epimere + hypomere
Epimere (dorsal primary ramus)  extensor muscles
Hypomere (ventral primary ramus)  flexor muscles
Cervical – geniohyoid, scalene & prevertebral muscles
Thoracic – split into 3 layers (external, internal, innermost intercostal muscles)
Abdominal – external, internal oblique & transversus abdominal muscles
Lumbar – quardratus lumborum
Sacral and coccygeal – pelvic diaphragm
Rectus column (from hypomere) – infrahyoid, sternalis, rectus abdominis
Muscles of Limb
Mesenchymal condensation at base of limb bud
induce C4-C8 + T1-T2 myotomes  muscles of upper limb (brachial nerve plexus)
induce L1-L5 + S1-S2 myotomes  muscles of lower limb (lumbar nerve plexus)
Myotome of limb  dorsal and ventral muscle mass
Dorsal muscle mass  extensor & abductor of limb
Ventral muscle mass  flexor & adductor of limb
Limbs
Somatic layer of lateral plate mesoderm induced by apical ectodermal ridge (AER)
Upper limb buds  handplates  forearm, arm  finger rays  rotate 900 laterally
Lower limb buds  footplates  leg, thigh  toe rays  rotate 900 medially
(胚胎學)授課綱要
授課節次:第__9__週上課
課程主題: Development of nervous system
講授目的: 了解神經系統(中樞與周邊神經)之發育情形
授課綱要:(請條列該堂課之授課大綱內容)
1. neural plate, neural fold, neural groove & neural tube
2. development of spinal Cord
3. development of brain vesicles
4. development of brain stem
5. development of cerebellum
6. development of diencephalon
7. development of cerebrum
8. development of ganglion (PNS)
9. development of spinal nerves
10.development of cranial nerves
胚胎學(課程名稱)授課綱要
授課節次:第__10__週上課
課程主題: Development of heart
講授目的:
希望學生知道：Developmental processes of the heart
授課綱要:(請條列該堂課之授課大綱內容)
1.
2.
3.
4.
Formation of the heart tube
Formation of the cardiac septa
Formation of the conducting system of the heart
Structure of the heart
Endocardium
Myocardium
Epicardium
胚胎學(課程名稱)授課綱要
授課節次:第__11__週上課
課程主題: Development of vasculature
講授目的:
希望學生知道：Development of the vessels
授課綱要:(請條列該堂課之授課大綱內容)
Development of the arterial system
Development of the venous system
Circulatory changes at birth
胚胎學(課程名稱)授課綱要
授課節次:第__12__週上課
課程主題: Development of lung
講授目的:
希望學生知道：The embryological origin of the lung
授課綱要:(請條列該堂課之授課大綱內容)
1.
2.
Lung bud
Bronchial bud
3.
Bronchopulmonary segments
(胚胎學)授課綱要
授課節次:第__13__週上課
課程主題:
講授目的:
授課綱要:(請條列該堂課之授課大綱內容)
(胚胎學)授課綱要
授課節次:第__14__週上課
課程主題:
講授目的:
授課綱要:(請條列該堂課之授課大綱內容)
(胚胎學)授課綱要
授課節次:第__15__週上課
課程主題:
講授目的:
授課綱要:(請條列該堂課之授課大綱內容)
(胚胎學)授課綱要
授課節次:第__16__週上課
課程主題:
講授目的:
授課綱要:(請條列該堂課之授課大綱內容)
(胚胎學)授課綱要
授課節次:第__17__週上課
課程主題:
講授目的:
授課綱要:(請條列該堂課之授課大綱內容)