Science Fair Project Encyclopedia
Yolk sac
The yolk sac is the first element seen in the gestational sac during pregnancy, usually at 5 weeks gestation. It is a critical landmark, identifying a true gestation sac. It is quite echogenic (light) to ultrasound, and reliably seen early. In the mouse, the yolk sac is the first site of blood formation, generating primitive macrophages and erythrocytes.
10-26-2009 08:16:03
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details