Pronunciation: [jˈə͡ʊk spˈe͡ɪs] (IPA) 
The correct spelling of the empty area within an egg yolk is not "yoke space", but rather "yolk space". The first part of the word, "yolk", is pronounced as [joʊk], with a long "o" sound followed by a hard "k". The second part, "space", is pronounced as [speɪs], with a long "a" sound and a soft "s". The word refers to the space where the egg white has been separated from the yolk, leaving a hollow center in the yolk.
Yolk space, also known as the blastocoel or blastocoele, is a term used in embryology to describe the fluid-filled cavity that forms within the developing embryo, specifically in the early stages of animal development. The yolk space develops during the process of blastulation, the second stage of embryogenesis, following fertilization.
During blastulation, the zygote, or fertilized egg, undergoes multiple cell divisions and rearrangements. As these cellular divisions occur, a fluid-filled cavity begins to form within the developing embryo, creating the yolk space. This fluid-filled cavity provides an essential environment for the movement and differentiation of cells during embryonic development.
The yolk space plays a vital role in embryo nourishment, as it is connected to the yolk sac, which stores the nutrients required for the early development of the organism. The yolk sac is responsible for supplying vital nutrients to the developing embryo until it can establish its own means of nourishment.
The size and shape of the yolk space can vary depending on the species and developmental stage of the embryo. In earlier stage embryos, the yolk space tends to be relatively large compared to the size of the developing organism. However, as the embryo continues to mature, the yolk space gradually becomes smaller in proportion to the growing embryo.
Understanding the development of the yolk space is crucial in developmental biology, as it provides insights into the growth and nourishment of the embryo during its early stages and sets the foundation for further developmental processes.
An interval in the impregnated ovum between the zona pellucida and the vitellus.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "yolk" originated from the Old English word "geolc" or "geoloca", which referred to the yellow part of an egg. It is related to the Old High German word "gelouga" and Old Norse word "gulka". "Space", on the other hand, comes from the Latin word "spatium", meaning "room" or "area". When these two words are combined, "yolk space" refers to the area or region occupied by the yolk within an egg.
