Lecture On Early Human Embryology: Implantation, Bilaminar Germinal Disc & Yolk Sac Formation | MBBS

Описание: This video provides a deep, step-by-step analysis of early human development, focusing on Week 2 Embryology, including Implantation, the formation of the Bilaminar Germinal Disc, and the initiation of Uteroplacental Circulation. This is foundational material for all first-year medical students.

LECTURE BREAKDOWN (TIMESTAMPS):

[00:00] Blastocyst Differentiation: Inner Cell Mass (Embryoblast) and Outer Cell Mass (Trophoblast)

[02:17] Naming Conventions and the Protective Role of the Zona Pellucida

[04:40] Blastocyst Hatching (Disappearance of Zona Pellucida) and Early Day 6 Changes

[07:00] Formation of Cytotrophoblast and the highly invasive Syncytiotrophoblast

[09:54] Detailed process of Implantation into the uterine wall (Stratum Compactum)

[12:38] The maternal contribution: Decidua Formation and its components (glands, spiral arteries)

[15:59] Differentiation of the Embryoblast into Epiblast and Hypoblast

[18:42] Formation of the Amniotic Cavity and Amniotic Cells

[22:38] Hypoblast Forms Heuser's Membrane and the Primary Yolk Sac

[25:01] The Structure of the Bilaminar Germinal Disc (Day 8-9)

[27:19] The origin and appearance of the Extra-embryonic Mesoderm

[29:58] Splitting of the Mesoderm by the Extra-embryonic Coelom (Chorionic Cavity)

[33:59] The Connecting Stalk (Unsplit Mesoderm) - The future Umbilical Cord

[35:38] Formation of Lacunae and the crucial initiation of Uteroplacental Circulation

[39:25] Formation of the smaller Secondary Yolk Sac

Key Learning Objectives:

Define and describe the function of the Trophoblast layers.

Understand the timeline and site of normal Implantation and the associated maternal changes (Decidua).

Identify the components and importance of the Bilaminar Germinal Disc (Epiblast & Hypoblast).

Trace the development of the Amniotic Cavity and the Yolk Sac.

Explain the formation of the Extra-embryonic Coelom and the Connecting Stalk.

Describe the initiation of blood flow between mother and conceptus.

This lecture is a crucial aid for students preparing for MBBS, USMLE Step 1, NEET PG, and other medical licensing exams.


SANTINIKETAN MEDICAL COLLEGE & HOSPITAL
Real Classroom Demonstration/Lecture
On: ANATOMY by Prof. (Dr.) Abhijit Roy
(MBBS Batch: 2025-26)
Conducted on: 25-11-25