Test 2 Child Growth and Development Chapter 5 A Physical Growth First 2 Years 1 Changes in height and weight Average newborn weighs 7 5 lbs and measures 20 in Birth weight typically doubles by 5 months and triples by first birthday 2 Changes in body proportions Cephalocaudal Principle head to tail growth of the head and upper body precede growth in the lower body Proximodistal Principle near to far body grows from the center outward 3 Childproofing the Environment Childproofing precautions you must take such as covering light sockets stairs and dangerous objects stored 4 Nutrition in Infancy babies immune system does not become effective until middle of first year Colostrum think yellowish fluid secreted by breast for several days before milk is produced Provides immunological protection Sudden Infant Death Syndrome breastfeeding can reduce this by 36 It is recommended that mothers breastfeed their infants for first 6 months B Development of the Brain 1 Structure of the Brain Neurons conduct electrochemical impulses Transmits these from dendrites to cell body and from cell body to axon Synapse axon of one cell butts up against the dendrite of another impulses are transmitted across this by neurotransmitters Myelination At 28 weeks of gestation axons develop insulating fatty coating that improves efficiency of nerve impulse through transmission Synaptogensis Synapses develop in large numbers prenatally and continue through first 3 years of life Plasticity if one part of nervous system becomes damaged or unable to function other parts of system can take over Hemispherectomy surgical radical removeal of half of a child s brain in the treatment of extreme cases of brain seizures Use it or lose it principle results in a leveling off of the number of synapses from the end of the secon dyar through the tenth year Pruning synapses and cells that are not stimulated are eliminated through this destructive process C Perceptual Development 1 Methods of Study Sensation refers to the ability to passively receive and register info concerning internal and external events and to transmit that to CNS Perception infants active searching for info and processing of that sensory info by brain Visual preference method Researcher presents pairs of stimuli to the baby Researcher observes infant from hidden vantage point between two stimuli detects which stimulus infant is looking at Electroencephalography EEG measurement and interpretation of electrical activity in the brain Habituation dishabituation procedure researches take advantage of the fact infants react to changes in sound smell etc by changes in heart rate and respiration Habituate intensity of their response steadily decreases Dishabituates infant changes responses High amplitude sucking technique use a pacifier with an internal sensing device that indicates when infant s rate of sucking increases 2 Visual Development Structures of the eye Retina complex layered tissue on back surface of eye made up of nerve cells and light sensitive cells Fovea a densely packed set of highly sensitive cells at center of retina can discriminate the detail necessary to perceive objects Visual acuity sharpness of vision quite low at birth Visual Perception and the Brain Visual function in newborn appears to be regulated at subcortical levels of brain Cortical function is divided into distinct streams of cognitive processing One stream where object is located in space Second who or what the object is Third attempts to interact with objects in space Visual Evoked Potential Test VEP electrodes placed on head to record electrical impulses generated by infant brain in response to visual stimulation Tracking Moving Objects in Space By end of fourth month infants can locate objects in visual field focus on objects move from object to object and track motion through space Object Perception Separating the figure from the ground infant learns to explore external contours and internal contours of objects and differentiate them from the background Depth Perception Binocular information Each eye views nearby objects from slightly different angle and produce two slightly different retinal images than Kinetic information When infant s head moves from side to side image of near object moves more rapidly across retinal surface the distant Visual Cliff a laboratory task that places crawling infants on sheet of plate glass that creates illusion of a drop off Pictorial information photographs though flat give various pictorial cues that create the impression of three dimensionality Auditory Development Early detection and discrimination of sounds Ear is well developed several weeks before birth Begins as early as 28 weeks Locating Sound Sources Ability to hear declines after two months then by four months comes back Other Sensory Development Sensitivity to taste is present soon after birth By four months infants show interest in salty liquids Newborns can smell and develop it rapidly during neonatal period 3 Motor Control Reflexes involuntary stimulus response patterns Rooting turns head opens mouth and sucks when cheek is stroked Stepping Steps when feet contact surface Moro Sudden arching of back and grasping Babinski Toes fan our and foot curls when sole of foot is strokd Grasping grasp in response to pressure in palm Tonic Neck Head to one side and body in fencer position Sucking sucking to oral stimulation Eyeblink Rapid closing of eye to sudden light or air puff Reflexes controlled by clusters of cells in brain stem Spontaneous Movement Rhythmical movement stereotypies repetitious movement patterns that help infants to slowly learn to control their body parts Voluntary Movements Postural Control landmark ahievements holding head steady while moving 2 months Sitting without support 5 months Getting into sitting position 7 months Pulling to standing 7 8 months Locomotion the ability to move one s self from one place to another begins with rolling from supine to prone position Creeping pull with their arms and push with their legs to drag Crawling baby is up on all four limbs with stomach suspended Walking taking at least three steps without falling by 1st bodies forward above floor bday Manual Control Prehension manual control of objects By 3 4 months infants are capable of picking up cube Pincer grasp using the thumb and single finger by 9 10 months Visually initiated reaching primitive form of inaccurate swiping in general direction of objects Visually guided reaching
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