Coelom formation in protostomes and deuterostomes and types of coelom

FOR SYBSC ZOOLOGY STUDENTS OF SMT CHM COLLEGE , UlHAS NAGAR THANE MAHARASHTRA

1. S.Y.B.Sc Zoology Semester IV: Course X : Unit 1 Comparative Embryology Date : 14/01/2022

2. Coelom : Formation & Types Extra-Embryonic Membranes Yolk Sac, Allantois , Amnion , Chorion Types of Placenta (Based on Morphology, Implantation and Histology)

3. Gastrulation In mammals

4. COELOM Fluid filled body cavity Formed in triploblastic animals Internally lined by Mesoderm Function : Protection against accidental shocks & Allows organs to grow and move internally Formed from mesodermal layer In Lower triploblastic animals ( Protostomes) Mesoderm Splits into Inner & outer layer to form cavity = Schizocoely (protostomes) Deuterostomes: Enterocoely

5. Somatopleure & Splanchnopleure Formation of Lateral & ventral walls of embryo Extra embryonic membranes Protostomes ( Schizocoely ) Somatopleure = Mesoderm+ectoderm Splanchnopleure = Mesoderm + endoderm Deuterostomes Somatopleure = Mesoderm+ Endoderm Splanchnopleure = Mesoderm+Ectoderm Extra Embryonic membranes Developed from germ layers of embryo but not incorporated within embryo Functions: Protection of developing embryo from : Dessication , Infection, Shock etc Amnion : Protection Allantois : Waste & gas exchange Chorion : Gas Exchange Yolk sac : Food reserve

6. Extra embryonic membranes