Infancy Development The first year of life marks rapid physical and cognitive development. Babies typically triple their birth weight, develop motor skills from rolling to walking, and begin forming basic language abilities. Brain development occurs rapidly, with infants learning through sensory experiences and interactions. This period establis

Tooth Layers Teeth consist of multiple specialized layers. The outer enamel, the hardest substance in the body, protects against decay and damage. Beneath lies dentin, a bone-like tissue containing microscopic tubes that transmit sensations. The innermost pulp contains blood vessels, nerves, and connective tissue providing nutrients and sensatio

Signal Transmission The spinal cord serves as the main communication highway between brain and body, carrying electrical signals through bundles of nerve fibers. Ascending pathways transmit sensory information to the brain, while descending pathways carry motor commands to muscles and organs. This two-way communication system enables rapid respo

Structural Design Joints form where bones meet, providing various movement types based on their structure. Ball-and-socket joints like the hip allow movement in multiple directions, while hinge joints like the elbow permit movement in one plane. Each joint contains specific components: cartilage covers bone surfaces to reduce friction, ligaments