stem cell

alveolar anatomy biological biology biotechnology blastocyst blood body bone cardiac cardiomyocytes cell cells collagen diagram ectoderm education egg elastic embryo embryonic endoderm epithelial fiber fibroblasts genetic germ graphic health human intestinal lab laboratory liver medical medicine melanocyte mesoderm microbiology muscle nerve neuron osteocyte pancreas red research science scientific stem structure therapy tissue totipotent vector zygote