Implantation

Introduction

The term used to describe process of attachment and invasion of the uterus endometrium by the blastocyst (conceptus) in placental animals. Abnormal implantation is where this process does not occur in the body of the uterus (ectopic) or where the placenta forms incorrectly.

--Mark Hill 19:10, 5 August 2009 (EST) Page under development - notice removed when completed.

Week 1 and 2 Human Development Overview

Movie - Implantation

The second week of human development is concerned with the process of implantation and the differentiation of the blastocyst into early embryonic and placental forming structures.

implantation commences about day 6 to 7
Adplantation - begins with initial adhesion to the uterine epithelium
- blastocyst then slows in motility, "rolls" on surface, aligns with the inner cell mass closest to the epithelium and stops
Implantation - migration of the blastocyst into the uterine epithelium, process complete by about day 9
coagulation plug - left where the blastocyst has entered the uterine wall day 12

Normal Implantation Sites - in uterine wall superior, posterior, lateral

Abnormal Implantation

Ectopic tubal pregnancy

Abnormal implantation sites or Ectopic Pregnancy occurs if implantation is in uterine tube or outside the uterus.

sites - external surface of uterus, ovary, bowel, gastrointestinal tract, mesentry, peritoneal wall
If not spontaneous then, embryo has to be removed surgically

Tubal pregnancy - 94% of ectopic pregnancies

if uterine epithelium is damaged (scarring, pelvic inflammatory disease)
if zona pellucida is lost too early, allows premature tubal implantation
embryo may develop through early stages, can erode through the uterine horn and reattach within the peritoneal cavity

Links: Ectopic Pregnancy | Movie - Ectopic pregnancy ultrasound

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Cite this page: Hill, M.A. (2024, June 2) Embryology Implantation. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Implantation

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