Health Sciences 2700A/B Lecture Notes - Lecture 4: Synaptic Pruning, Somatosensory System, Oral Stage
13 Oct 2020
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Document Summary
In the rst year, infants grow 25-30cm and triple their body weight. Two year olds have proportionally larger heads, as they need hold their nearly full-sized brain. We see many changes in the rapidly developing brain at this age. This is followed by a period of synaptic pruning to make the nervous system more ef cient. The brain"s ability to reorganize neural pathways and connections. Myelin gradually covers individual axons and electrically insulates them from one another. Sucking, for example, helps newborns to survive by being able to latch and feed. These are controlled by primitive parts of the brain. These re exes disappear by about 6 months of age. A soft touch on the cheek will cause an infant to turn toward the touch and open the mouth (they are looking for food) Stroking the sole of the foot causes the infants toes to fan out and up. This demonstrates normality or abnormality in the nervous system.
