Symptoms include: 1  excessive fatigue and exhaustion. 2  non-refreshing sleep (you get sufficient hours of sleep, but wake fatigued) 3  overwhelmed by or unable to cope with stressors. 4  feeling rundown or overwhelmed. 5  craving salty and sweet foods. 6  you feel most energetic in the evening.
The blastocyst is the second major stage of development, after the morula, for a newly fertilized individual once cell division has begun. Cells begin to differentiate, or become specialized, and have moved on to an outer/inner arrangement: the outer cells are called the trophoblast which will give rise to the placenta, and the inner are called the embryoblast (or inner cell mass) as they will give rise to the embryo.
In mammals, the blastula forms the blastocyst in the next stage of development. Here the cells in the blastula arrange themselves in two layers: the inner cell mass and an outer layer called the trophoblast . The inner cell mass is also known as the embryoblast; this mass of cells will go on to form the embryo.