Human body blood to produce urine, which carries a variety of waste molecules and excess ions and water out of the body. Human anatomy is the study of the shape and form of the human body. The human body has four limbs (two arms and two legs), a head and a neck which connect to the torso. The body's shape is determined by a strong skeleton made of bone and cartilage, surrounded by fat, muscle, connective tissue, organs, and other structures. The spine at the back of the skeleton contains the flexible vertebral column which surrounds the spinal cord, which is a
Development of the human body and temporal changes in gene expression, cell growth and cellular differentiation. A nearly identical process occurs in other species, especially among chordates. A fetus is a stage in the human development considered to begin nine weeks after fertilization. In biological terms, however, prenatal development is a continuum, with many defining feature distinguishing an embryo from a fetus. A fetus is also characterized by the presence of all the major body organs, though they will not yet be fully developed and functional and some not yet situated in their final location. The fetus and embryo develop within the uterus, an organ