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Physiological Development in Infants

by Karen Hellesvig-Gaskell

The term "miracle of life" to describe the birth and development of a newborn is far from an overstatement. An infant's physical development starts at the head and spreads to other areas of the body, explains MedlinePlus, a website published by the National Institutes of Health. Sucking and smiling comes before sitting and crawling, which takes places before walking with support and then independently. By their first birthday, most babies are three times heavier than their birth weight and have gained about 12 inches in length.

Vision and Hearing

Your baby had the ability to hear before she was born. At birth her hearing is fully mature and she is partial to the human voice, according to Medline Plus. You'll know your baby's hearing is normal when she is surprised or frightened by loud noises. She may also blink her eyes or frown at certain noises. Your baby may turn a deaf ear to loud sounds after hearing them repeatedly. A newborn's vision is limited; he's able to see things up to 12 inches away. His little eyes are less than half the size of an adult's eyes, notes Boston Children's Hospital. A 2-month-old can follow a moving object from side to side. He's able to distinguish dark from light; it will take four to six months before he'll start to see in "living" color.

Taste and Smell

Your infant's taste buds started forming in the early stages of pregnancy. She has a sweet tooth long before her first tooth appears. Babies naturally like sweet tastes much better than bitter or sour tastes. Your infant will grow to love the taste of breast milk or formula during the first few months of life. The brain's smell center -- or olfactory -- also develops in the early stages of fetal development. A newborn has such a strong sense of smell that she quickly displays a fondness for the scent of her mother, according to the MayoClinic.com website.

Motor Development

Your newborn has no control over her bodily movements due to her immature nervous system. If you happen to catch your baby twitching or kicking, it's an unintentional reflex. Babies develop a modest amount of control over their muscles and nervous system by around 4 months. Within a few weeks your baby will have the strength to raise his head while lying on his stomach, push up with his arms and raise his chest off the floor. Crawling typically comes between 7 and 10 months. You'll probably witness the first tentative step by 12 months, explains HealthyChildren.org, a website published by the American Academy of Pediatrics.

Fine Motor Progress

Around 3 to 4 months, your infant may begin to use both hands to accomplish tasks. Although he has yet to develop the coordination to grasp an object, he can take swipes at them to bring them closer. Your Infant begins to grasp blocks or cubes by pressing the block into palm of hand while flexing or bending wrist inward but does not yet use his thumb. A 7- to 9-month-old is usually able to move objects from one hand to the next. The raking motion of the hands will gradually become more fine-tuned. For example, your baby will be able to pick up objects using his thumb and forefinger, notes MayoClinic.com. Improved fine motor skills will help your little one use a spoon and cup and eat soft finger foods without assistance.

About the Author

Karen Hellesvig-Gaskell is a broadcast journalist who began writing professionally in 1980. Her writing focuses on parenting and health, and has appeared in “Spirituality & Health Magazine" and “Essential Wellness.” Hellesvig-Gaskell has worked with autistic children at the Fraser School in Minneapolis and as a child care assistant for toddlers and preschoolers at the International School of Minnesota, Eden Prairie.

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