The embryo has grown to about 10mm long from head to bottom (crown-rump length), roughly the size of a grape. The brain is growing rapidly, causing the head to grow faster than the rest of the body, resulting in a large forehead. About 100 new brain cells are generated every minute. Eyes and ears continue to develop. Small dimples appear where the nose and ears will be. The inner ears start developing, but outer ears won't appear for a couple more weeks. Eyelids are beginning to grow and cover the eyes. Even the tiny tongue is forming. Limb buds start forming cartilage, which will become arm and leg bones. Arm buds lengthen, and the ends flatten out, beginning to form hands. Arm and leg joints, including elbows and knees, are now forming. Nerve cells multiply as the brain and spinal cord (nervous system) take shape. A delicate network of nerves spreads through the body, allowing for constant small motions as the brain sends signals. The heart, intestines, and permanent set of kidneys are developing.