Sclera Sclera The sclera, also known as the white of the eye, is the opaque, fibrous, protective, outer layer of the human eye containing mainly collagen and some elastic fiber. In humans, the whole sclera is white, contrasting with the coloured iris, but in other mammals the visible part of the sclera matches the colour of the iris, so the white part does not normally show. In the development of the embryo, the sclera is derived from the neural crest. In children, it is thinner and shows some of the underlying pigment, appearing slightly blue. In the elderly, fatty deposits on
Development of the human body Development of the human body Human development is the process of growth to maturity. The process begins with fertilisation, where an egg released from the ovary of a female is penetrated by a sperm cell from a male. The egg then lodges in the uterus, where an embryo and later fetus develop until birth. Further growth and development continues after birth, and includes both physical and psychological development, influenced by genetic, hormonal, environmental and other factors. This continues throughout life, through childhood, and adolescence into adulthood. Development before birth, or prenatal development () is the process in which an embryo