دارای بالاترین آمار بازدیدها در بین وبلاگهای علمی در ایران
پنجشنبه 14 خرداد 1388 :: نویسنده : حمیده شیخ زین الدین

The Amnion

Early Embryonic Development

Ectoderm and somatic mesoderm surrounding the embryo, form a protective covering over the embryo called the amnion. The inner layer of cells secretes amniotic fluid in which the embryo floats. This fluid keeps the embryo from drying out and helps protect it when the egg is jarred.

The Chorio-Allantoic Membrane

Ectoderm and somatic mesoderm form the chorion which lines the eggshell and performs gas exchange and waste elimination. The allantois is the embryo's connection to the chorion. It appears as a balloon-like structure coming off the hindgut at about day 4 or 5. It is made up of endoderm and splanchnic mesoderm and carries with it the allantoic vessels coming off the heart. The allantois grows larger as the chick grows, wraps around above the chick, and fuses with the chorion. It works together with the chorion to exchange gasses between the embryo and the outside environment. The egg shell is porous and thus allows oxygen and carbon dioxide to pass freely back and forth from the environment to the inside of the egg. The chorio-allantoic membrane is also responsible for drawing calcium from the egg shell and carrying it back to the chick. Calcium is needed to carry on general metabolism and make bone. For the first ten days the chick can absorb a sufficient amount of calcium from the yolk. But at around day 10, the formation of bones begins to accelerate and the embryo must draw calcium from the egg shell. The allantois also stores wastes (urine) once the embryonic kidneys begin to function. When the chick hatches, the chorio- allantoic membrane remains attached to the egg shell and is therefore discarded with it.

نوع مطلب : محصولات کشاورزی، عمومی، 
برچسب ها :
لینک های مرتبط :
پنجشنبه 14 خرداد 1388 09:09 بعد از ظهر
با سلام.
دوست عزیز وب زیبای شما را دیدم.اگر به سایت ما هم سر بزنید خوشحال میشیم.
ما آماده تبادل لینك با شما هستیم.
اگر مایل هستید با ما تبادل لینك كنید،مارو با نام:
.:: تفریح و سرگرمی در اینجا ::.
لینك كنید و به ما اطلاع بدهید تا ما نیز شمارو لینك كنیم.
منتظر نظرات سازنده شما هستیم.
با تشكر

آمار وبلاگ
  • کل بازدید :
  • بازدید امروز :
  • بازدید دیروز :
  • بازدید این ماه :
  • بازدید ماه قبل :
  • تعداد نویسندگان :
  • تعداد کل پست ها :
  • آخرین بازدید :
  • آخرین بروز رسانی :