{"id":245,"date":"2014-09-25T21:35:05","date_gmt":"2014-09-25T21:35:05","guid":{"rendered":"https:\/\/courses.candelalearning.com\/lifespandevelopment1x1\/?post_type=chapter&#038;p=245"},"modified":"2024-04-30T19:10:30","modified_gmt":"2024-04-30T19:10:30","slug":"physical-development","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/wm-lifespandevelopment\/chapter\/physical-development\/","title":{"raw":"Physical Growth and Brain Development in Infancy","rendered":"Physical Growth and Brain Development in Infancy"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Summarize overall physical growth patterns during infancy<\/li>\r\n \t<li>Describe the growth of the brain during infancy<\/li>\r\n<\/ul>\r\n<\/div>\r\n<h2>Overall Physical Growth<\/h2>\r\nThe average newborn weighs approximately 7.5 pounds, although a healthy birth weight for a full-term baby is considered to be between 5 pounds, 8 ounces (2,500 grams) and 8 pounds, 13 ounces (4,000 grams).[footnote]Iannelli, V. (2018). What Parents Need to Know About Baby Weight Trends and Newborn Gaining. Retrieved from <a href=\"https:\/\/www.verywellfamily.com\/baby-birth-weight-statistics-2633630\" target=\"_blank\" rel=\"noopener\">https:\/\/www.verywellfamily.com\/baby-birth-weight-statistics-2633630<\/a>[\/footnote] The average length of a newborn is 19.5 inches, increasing to 29.5 inches by 12 months and 34.4 inches by 2 years old (WHO Multicentre Growth Reference Study Group, 2006).\r\n\r\nFor the first few days of life, infants typically lose about 5 percent of their body weight as they eliminate waste and get used to feeding.\u00a0This often goes unnoticed by most parents, but can be cause for concern for those who have a smaller infant.\u00a0This weight loss is temporary, however, and is followed by a rapid period of growth.\u00a0By the time an infant is 4 months old, it usually doubles in weight, and by one year has tripled its birth weight.\u00a0By age 2, the weight has quadrupled.\u00a0The average length at 12 months (one year old) typically ranges from 28.5-30.5 inches.\u00a0The average length at 24 months (two years old) is around 33.2-35.4 inches (CDC, 2010).\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"975\"]<img src=\"https:\/\/textimgs.s3.amazonaws.com\/ospsych\/m49112\/CNX_Psych_09_04_Growth.jpg#fixme\" alt=\"A collage of four photographs depicting babies. On the far left is a bundled up sleeping newborn. Then a picture of a toddler next to a toy giraffe. Then a baby blowing out a single candle on a birthday cake. Then a child on a swing set.\" width=\"975\" height=\"244\" \/> <strong>Figure 1<\/strong>. Children experience rapid physical changes through infancy and early childhood. (credit \"left\": modification of work by Kerry Ceszyk; credit \"middle-left\": modification of work by Kristi Fausel; credit \"middle-right\": modification of work by \"devinf\"\/Flickr; credit \"right\": modification of work by Rose Spielman)[\/caption]\r\n<h3>Monitoring Physical Growth<\/h3>\r\nAs mentioned earlier,\u00a0growth is so rapid in infancy that the consequences of neglect can be severe. For this reason, gains are closely monitored. At each well-baby check-up, a baby's growth is compared to that baby's previous numbers. Often, measurements are expressed as a <strong>percentile\u00a0<\/strong>from 0 to 100, which compares each baby to other babies the same age. For example, weight at the 40th percentile means that 40 percent of all babies weigh less, and 60 percent weight more. For any baby, pediatricians and parents can be alerted early just by watching percentile changes. If an average baby moves from the 50th percentile to the 20th, this could be a sign of <strong>failure to thrive,<\/strong> which could be caused by various medical conditions or factors in the child's environment. The earlier the concern is detected, the earlier intervention and support can be provided for the infant and caregiver.\r\n\r\n<strong style=\"font-size: 1em; color: #6c64ad;\">Body Proportions<\/strong>\r\n\r\nAnother dramatic physical change that takes place in the first several years of life is a change in body proportions.\u00a0The head initially makes up about 50 percent of a person's entire length when developing in the womb.\u00a0At birth, the head makes up about 25 percent of a person's length (just imagine how big your head would be if the proportions remained the same throughout your life!). In adulthood, the head comprises about 15 percent of a person's length.[footnote]Huelke D. F. (1998). An Overview of Anatomical Considerations of Infants and Children in the Adult World of Automobile Safety Design. Annual Proceedings \/ Association for the Advancement of Automotive Medicine, 42, 93\u2013113.[\/footnote] Imagine how difficult it must be to raise one\u2019s head during the first year of life!\u00a0And indeed, if you have ever seen a 2- to 4-month-old infant lying on their stomach trying to raise the head, you know how much of a challenge this is.\r\n<div class=\"textbox tryit\">\r\n<h3>Try It<\/h3>\r\nhttps:\/\/assess.lumenlearning.com\/practice\/255f9750-6387-4593-a116-37cc637d3635\r\n\r\n<\/div>\r\n<h2>The Brain in the First Two Years<\/h2>\r\nSome of the most dramatic physical change that occurs during this period is in the brain.\u00a0At birth, the brain is about 25 percent of its adult weight, and this is not true for any other part of the body.\u00a0By age 2, it is at 75 percent of its adult weight, at 95 percent by age 6, and at 100 percent by age 7 years.\r\n\r\n[caption id=\"attachment_4158\" align=\"aligncenter\" width=\"615\"]<img class=\"wp-image-4158 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3707\/2014\/09\/02120906\/Babybrains_615.png\" alt=\"Brain MRIs that show similar regions activated by adult brains and infant brains while looking at either scenes or faces.\" width=\"615\" height=\"266\" \/> <strong>Figure 2<\/strong>. Research shows that as early at 4-6 months, infants utilize similar areas of the brain as adults to process information. Image from research article conducted by Ben Deen, Hilary Richardson, Daniel D. Dilks, Atsushi Takahashi, Boris Keil, Lawrence L. Wald, Nancy Kanwisher &amp; Rebecca Saxe.\"Article\u00a0<span class=\"pl6 pr6 text-gray-extra-light\">|\u00a0<\/span><abbr class=\"text-orange upper\" title=\"Open Access\">OPEN<\/abbr>\u00a0<span class=\"pl6 pr6 text-gray-extra-light\">|\u00a0<\/span>Published:\u00a010 January 2017<br \/>Organization of high-level visual cortex in human infants\". Image retrieved from\u00a0https:\/\/www.quantamagazine.org\/infant-brains-reveal-how-the-mind-gets-built-20170110\/.[\/caption]\r\n\r\n<span style=\"color: #333333;\">Communication within the central nervous system (CNS), which consists of the brain and spinal cord, begins with nerve cells called <strong>neurons<\/strong>. Neurons connect to other neurons via networks of nerve fibers called <strong>axons<\/strong> and <strong>dendrites<\/strong>. Each neuron typically has a single axon and numerous dendrites which are spread out like branches of a tree (some will say it looks like a hand with fingers). The axon of each neuron reaches toward the dendrites of other neurons at intersections called <strong>synapses<\/strong>, which are critical communication links within the brain. Axons and dendrites do not touch, instead, electrical impulses in the axons cause the release of chemicals called <strong>neurotransmitters<\/strong> which carry information from the axon of the sending neuron to the dendrites of the receiving neuron.\u00a0<\/span>\r\n\r\n<span style=\"color: #333333;\">While most of the brain\u2019s 100 to 200 billion neurons are present at birth, they are not fully mature.\u00a0Each neural pathway forms thousands of new connections during infancy and toddlerhood. During the next several years,\u00a0dendrites<strong>,<\/strong> or connections between neurons, will undergo a period of <strong>transient exuberance<\/strong> or temporary dramatic growth (<em>exuberant\u00a0<\/em>because it\u00a0is\u00a0so rapid and\u00a0<em>transient<\/em>\u00a0because some of it is\u00a0temporary). There is a proliferation of these dendrites during the first two years so that by age 2, a single neuron might have thousands of dendrites.\u00a0After this dramatic increase, the neural pathways that are not used will be eliminated through a process called <strong>pruning<\/strong>, thereby making those that are used much stronger. It is thought that pruning causes the brain to function more efficiently, allowing for mastery of more complex skills (Hutchinson, 2011).\u00a0Transient exuberance\u00a0occurs during the first few years of life, and pruning continues through childhood and into adolescence in various areas of the brain. This activity is occurring primarily in the <strong>cortex<\/strong> or the thin outer covering of the brain involved in voluntary activity and thinking.\u00a0<\/span>\r\n<div class=\"textbox examples\">\r\n<h3>Watch It<\/h3>\r\nThis brief video describes some of the remarkable brain development that takes places in the first few years of life.\r\n\r\n<iframe src=\"\/\/plugin.3playmedia.com\/show?mf=3935259&amp;p3sdk_version=1.10.1&amp;p=20361&amp;pt=375&amp;video_id=R0fiu2S0_3M&amp;video_target=tpm-plugin-iufrcs9o-R0fiu2S0_3M\" width=\"800px\" height=\"520px\" frameborder=\"0\" marginwidth=\"0px\" marginheight=\"0px\"><\/iframe>\r\n\r\nYou can <a href=\"https:\/\/oerfiles.s3-us-west-2.amazonaws.com\/Lifespan+Development\/Transcriptions\/HowBabyBrainsDevelop_transcript.txt\" target=\"_blank\" rel=\"noopener\">view the transcript for \"How baby brains develop\" here (opens in new window)<\/a>.\r\n\r\n<\/div>\r\n\r\n[caption id=\"attachment_4160\" align=\"aligncenter\" width=\"534\"]<img class=\"wp-image-4160\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3707\/2014\/09\/02122048\/1206_The_Neuron-1.jpg\" alt=\"Parts of a neuron, showing the cell body with extended branches called dendrites, then a long extended axon which is covered by myelin sheath that extends to the synapses. The gap between the myelin sheaths is called the Node of Ranvier and the Oligodendrocyte is attached to the myelin sheaths.\" width=\"534\" height=\"358\" \/> <strong>Figure 3<\/strong>. Parts of a neuron.[\/caption]\r\n\r\n<span style=\"color: #333333;\">The <strong>prefrontal cortex,<\/strong>\u00a0located behind the forehead, continues to grow and mature throughout childhood and experiences an addition growth spurt during adolescence.\u00a0It is the last part of t<\/span>he brain to mature and will eventually comprise 85 percent of the brain\u2019s weight.\u00a0Experience will shape which of these connections are maintained and which of these are lost.\u00a0Ultimately, about 40 percent of these connections will be lost (Webb, Monk, &amp; Nelson, 2001).\u00a0As the prefrontal cortex matures, the child is increasingly able to regulate or control emotions, to plan activity, to strategize, and have better judgment.\u00a0Of course, this is not fully accomplished in infancy and toddlerhood but continues throughout childhood and adolescence.\r\n\r\nAnother major change occurring in the central nervous system is the development of <strong>myelin<\/strong>, a coating of fatty tissues around the axon of the neuron.\u00a0Myelin helps insulate the nerve cell and speed the rate of transmission of impulses from one cell to another.\u00a0This enhances the building of neural pathways and improves coordination and control of movement and thought processes.\u00a0The development of myelin continues into adolescence but is most dramatic during the first several years of life.\r\n<div class=\"textbox examples\">\r\n<h3>Watch it<\/h3>\r\nHow does all of this brain growth translate into cognitive abilities? We will discuss this later on in the module, but this video provides a nice overview of new research and some of the impressive abilities of newborns.\r\n\r\nhttps:\/\/www.youtube.com\/watch?v=nM-GhFzX8yQ\r\n\r\nYou can <a href=\"https:\/\/oerfiles.s3-us-west-2.amazonaws.com\/Lifespan+Development\/Transcriptions\/BabiesAreSurprisinglySmart_transcript.txt\" target=\"_blank\" rel=\"noopener\">view the transcript for \"Babies are Surprisingly Smart\" here (opens in new window)<\/a>.\r\n\r\n<\/div>\r\n<div class=\"textbox tryit\">\r\n<h3>Try It<\/h3>\r\nhttps:\/\/assess.lumenlearning.com\/practice\/b6b9c621-ae49-4177-8285-69ad0786266c\r\n\r\n<\/div>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Glossary<\/h3>\r\n[glossary-page]\r\n[glossary-term]axons:[\/glossary-term]\r\n[glossary-definition]fibers that extend from the neurons and transmit electrochemical impulses from that neuron to the dendrites of other neurons[\/glossary-definition]\r\n\r\n[glossary-term]cortex:[\/glossary-term]\r\n[glossary-definition]the outer layers of the brain in humans and other mammals. Most thinking, feeling, and sensing involves the cortex[\/glossary-definition]\r\n\r\n[glossary-term]dendrites:[\/glossary-term]\r\n[glossary-definition]fibers that extend from neurons and receive electrochemical impulses transmitted from other neurons via their axons[\/glossary-definition]\r\n\r\n[glossary-term]failure to thrive:[\/glossary-term]\r\n[glossary-definition]decelerated or arrested physical growth (height and weight measurements fall below the third or fifth percentile or a downward change in growth across two major growth percentiles) and is associated with abnormal growth and development[\/glossary-definition]\r\n\r\n[glossary-term]myelin:[\/glossary-term]\r\n[glossary-definition]a coating of fatty tissues around the axon of the neuron[\/glossary-definition]\r\n\r\n[glossary-term]neurons:[\/glossary-term]\r\n[glossary-definition]nerve cells in the central nervous system, especially in the brain[\/glossary-definition]\r\n\r\n[glossary-term]neurotransmitters:[\/glossary-term]\r\n[glossary-definition]brain chemicals that carry information from the axon of a sending neuron to the dendrites of a receiving neuron[\/glossary-definition]\r\n\r\n[glossary-term]percentile:[\/glossary-term]\r\n[glossary-definition]a point on a ranking scale of 0 to 100. The 50th percentile is the midpoint; half of the infants in the population being studied rank higher and half rank lower[\/glossary-definition]\r\n\r\n[glossary-term]prefrontal cortex:[\/glossary-term]\r\n[glossary-definition]the area of the cortex at the very front of the brain that specializes in anticipation, planning, and impulse control[\/glossary-definition]\r\n\r\n[glossary-term]pruning:[\/glossary-term]\r\n[glossary-definition]the process by which unused connections in the brain atrophy and die[\/glossary-definition]\r\n\r\n[glossary-term]synapses:[\/glossary-term]\r\n[glossary-definition]the intersection between the axon of one neuron to the dendrites of another neuron[\/glossary-definition]\r\n\r\n[glossary-term]transient exuberance:[\/glossary-term]\r\n[glossary-definition]the great, but temporary increase in the number of dendrites that develop in an infant's brain during the first two years of life[\/glossary-definition]\r\n[\/glossary-page]\r\n\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Summarize overall physical growth patterns during infancy<\/li>\n<li>Describe the growth of the brain during infancy<\/li>\n<\/ul>\n<\/div>\n<h2>Overall Physical Growth<\/h2>\n<p>The average newborn weighs approximately 7.5 pounds, although a healthy birth weight for a full-term baby is considered to be between 5 pounds, 8 ounces (2,500 grams) and 8 pounds, 13 ounces (4,000 grams).<a class=\"footnote\" title=\"Iannelli, V. (2018). What Parents Need to Know About Baby Weight Trends and Newborn Gaining. Retrieved from https:\/\/www.verywellfamily.com\/baby-birth-weight-statistics-2633630\" id=\"return-footnote-245-1\" href=\"#footnote-245-1\" aria-label=\"Footnote 1\"><sup class=\"footnote\">[1]<\/sup><\/a> The average length of a newborn is 19.5 inches, increasing to 29.5 inches by 12 months and 34.4 inches by 2 years old (WHO Multicentre Growth Reference Study Group, 2006).<\/p>\n<p>For the first few days of life, infants typically lose about 5 percent of their body weight as they eliminate waste and get used to feeding.\u00a0This often goes unnoticed by most parents, but can be cause for concern for those who have a smaller infant.\u00a0This weight loss is temporary, however, and is followed by a rapid period of growth.\u00a0By the time an infant is 4 months old, it usually doubles in weight, and by one year has tripled its birth weight.\u00a0By age 2, the weight has quadrupled.\u00a0The average length at 12 months (one year old) typically ranges from 28.5-30.5 inches.\u00a0The average length at 24 months (two years old) is around 33.2-35.4 inches (CDC, 2010).<\/p>\n<div style=\"width: 985px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/textimgs.s3.amazonaws.com\/ospsych\/m49112\/CNX_Psych_09_04_Growth.jpg#fixme\" alt=\"A collage of four photographs depicting babies. On the far left is a bundled up sleeping newborn. Then a picture of a toddler next to a toy giraffe. Then a baby blowing out a single candle on a birthday cake. Then a child on a swing set.\" width=\"975\" height=\"244\" \/><\/p>\n<p class=\"wp-caption-text\"><strong>Figure 1<\/strong>. Children experience rapid physical changes through infancy and early childhood. (credit &#8220;left&#8221;: modification of work by Kerry Ceszyk; credit &#8220;middle-left&#8221;: modification of work by Kristi Fausel; credit &#8220;middle-right&#8221;: modification of work by &#8220;devinf&#8221;\/Flickr; credit &#8220;right&#8221;: modification of work by Rose Spielman)<\/p>\n<\/div>\n<h3>Monitoring Physical Growth<\/h3>\n<p>As mentioned earlier,\u00a0growth is so rapid in infancy that the consequences of neglect can be severe. For this reason, gains are closely monitored. At each well-baby check-up, a baby&#8217;s growth is compared to that baby&#8217;s previous numbers. Often, measurements are expressed as a <strong>percentile\u00a0<\/strong>from 0 to 100, which compares each baby to other babies the same age. For example, weight at the 40th percentile means that 40 percent of all babies weigh less, and 60 percent weight more. For any baby, pediatricians and parents can be alerted early just by watching percentile changes. If an average baby moves from the 50th percentile to the 20th, this could be a sign of <strong>failure to thrive,<\/strong> which could be caused by various medical conditions or factors in the child&#8217;s environment. The earlier the concern is detected, the earlier intervention and support can be provided for the infant and caregiver.<\/p>\n<p><strong style=\"font-size: 1em; color: #6c64ad;\">Body Proportions<\/strong><\/p>\n<p>Another dramatic physical change that takes place in the first several years of life is a change in body proportions.\u00a0The head initially makes up about 50 percent of a person&#8217;s entire length when developing in the womb.\u00a0At birth, the head makes up about 25 percent of a person&#8217;s length (just imagine how big your head would be if the proportions remained the same throughout your life!). In adulthood, the head comprises about 15 percent of a person&#8217;s length.<a class=\"footnote\" title=\"Huelke D. F. (1998). An Overview of Anatomical Considerations of Infants and Children in the Adult World of Automobile Safety Design. Annual Proceedings \/ Association for the Advancement of Automotive Medicine, 42, 93\u2013113.\" id=\"return-footnote-245-2\" href=\"#footnote-245-2\" aria-label=\"Footnote 2\"><sup class=\"footnote\">[2]<\/sup><\/a> Imagine how difficult it must be to raise one\u2019s head during the first year of life!\u00a0And indeed, if you have ever seen a 2- to 4-month-old infant lying on their stomach trying to raise the head, you know how much of a challenge this is.<\/p>\n<div class=\"textbox tryit\">\n<h3>Try It<\/h3>\n<p>\t<iframe id=\"assessment_practice_255f9750-6387-4593-a116-37cc637d3635\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/255f9750-6387-4593-a116-37cc637d3635?iframe_resize_id=assessment_practice_id_255f9750-6387-4593-a116-37cc637d3635\" frameborder=\"0\" style=\"border:none;width:100%;height:100%;min-height:300px;\"><br \/>\n\t<\/iframe><\/p>\n<\/div>\n<h2>The Brain in the First Two Years<\/h2>\n<p>Some of the most dramatic physical change that occurs during this period is in the brain.\u00a0At birth, the brain is about 25 percent of its adult weight, and this is not true for any other part of the body.\u00a0By age 2, it is at 75 percent of its adult weight, at 95 percent by age 6, and at 100 percent by age 7 years.<\/p>\n<div id=\"attachment_4158\" style=\"width: 625px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-4158\" class=\"wp-image-4158 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3707\/2014\/09\/02120906\/Babybrains_615.png\" alt=\"Brain MRIs that show similar regions activated by adult brains and infant brains while looking at either scenes or faces.\" width=\"615\" height=\"266\" \/><\/p>\n<p id=\"caption-attachment-4158\" class=\"wp-caption-text\"><strong>Figure 2<\/strong>. Research shows that as early at 4-6 months, infants utilize similar areas of the brain as adults to process information. Image from research article conducted by Ben Deen, Hilary Richardson, Daniel D. Dilks, Atsushi Takahashi, Boris Keil, Lawrence L. Wald, Nancy Kanwisher &amp; Rebecca Saxe.&#8221;Article\u00a0<span class=\"pl6 pr6 text-gray-extra-light\">|\u00a0<\/span><abbr class=\"text-orange upper\" title=\"Open Access\">OPEN<\/abbr>\u00a0<span class=\"pl6 pr6 text-gray-extra-light\">|\u00a0<\/span>Published:\u00a010 January 2017<br \/>Organization of high-level visual cortex in human infants&#8221;. Image retrieved from\u00a0https:\/\/www.quantamagazine.org\/infant-brains-reveal-how-the-mind-gets-built-20170110\/.<\/p>\n<\/div>\n<p><span style=\"color: #333333;\">Communication within the central nervous system (CNS), which consists of the brain and spinal cord, begins with nerve cells called <strong>neurons<\/strong>. Neurons connect to other neurons via networks of nerve fibers called <strong>axons<\/strong> and <strong>dendrites<\/strong>. Each neuron typically has a single axon and numerous dendrites which are spread out like branches of a tree (some will say it looks like a hand with fingers). The axon of each neuron reaches toward the dendrites of other neurons at intersections called <strong>synapses<\/strong>, which are critical communication links within the brain. Axons and dendrites do not touch, instead, electrical impulses in the axons cause the release of chemicals called <strong>neurotransmitters<\/strong> which carry information from the axon of the sending neuron to the dendrites of the receiving neuron.\u00a0<\/span><\/p>\n<p><span style=\"color: #333333;\">While most of the brain\u2019s 100 to 200 billion neurons are present at birth, they are not fully mature.\u00a0Each neural pathway forms thousands of new connections during infancy and toddlerhood. During the next several years,\u00a0dendrites<strong>,<\/strong> or connections between neurons, will undergo a period of <strong>transient exuberance<\/strong> or temporary dramatic growth (<em>exuberant\u00a0<\/em>because it\u00a0is\u00a0so rapid and\u00a0<em>transient<\/em>\u00a0because some of it is\u00a0temporary). There is a proliferation of these dendrites during the first two years so that by age 2, a single neuron might have thousands of dendrites.\u00a0After this dramatic increase, the neural pathways that are not used will be eliminated through a process called <strong>pruning<\/strong>, thereby making those that are used much stronger. It is thought that pruning causes the brain to function more efficiently, allowing for mastery of more complex skills (Hutchinson, 2011).\u00a0Transient exuberance\u00a0occurs during the first few years of life, and pruning continues through childhood and into adolescence in various areas of the brain. This activity is occurring primarily in the <strong>cortex<\/strong> or the thin outer covering of the brain involved in voluntary activity and thinking.\u00a0<\/span><\/p>\n<div class=\"textbox examples\">\n<h3>Watch It<\/h3>\n<p>This brief video describes some of the remarkable brain development that takes places in the first few years of life.<\/p>\n<p><iframe loading=\"lazy\" src=\"\/\/plugin.3playmedia.com\/show?mf=3935259&amp;p3sdk_version=1.10.1&amp;p=20361&amp;pt=375&amp;video_id=R0fiu2S0_3M&amp;video_target=tpm-plugin-iufrcs9o-R0fiu2S0_3M\" width=\"800px\" height=\"520px\" frameborder=\"0\" marginwidth=\"0px\" marginheight=\"0px\"><\/iframe><\/p>\n<p>You can <a href=\"https:\/\/oerfiles.s3-us-west-2.amazonaws.com\/Lifespan+Development\/Transcriptions\/HowBabyBrainsDevelop_transcript.txt\" target=\"_blank\" rel=\"noopener\">view the transcript for &#8220;How baby brains develop&#8221; here (opens in new window)<\/a>.<\/p>\n<\/div>\n<div id=\"attachment_4160\" style=\"width: 544px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-4160\" class=\"wp-image-4160\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3707\/2014\/09\/02122048\/1206_The_Neuron-1.jpg\" alt=\"Parts of a neuron, showing the cell body with extended branches called dendrites, then a long extended axon which is covered by myelin sheath that extends to the synapses. The gap between the myelin sheaths is called the Node of Ranvier and the Oligodendrocyte is attached to the myelin sheaths.\" width=\"534\" height=\"358\" \/><\/p>\n<p id=\"caption-attachment-4160\" class=\"wp-caption-text\"><strong>Figure 3<\/strong>. Parts of a neuron.<\/p>\n<\/div>\n<p><span style=\"color: #333333;\">The <strong>prefrontal cortex,<\/strong>\u00a0located behind the forehead, continues to grow and mature throughout childhood and experiences an addition growth spurt during adolescence.\u00a0It is the last part of t<\/span>he brain to mature and will eventually comprise 85 percent of the brain\u2019s weight.\u00a0Experience will shape which of these connections are maintained and which of these are lost.\u00a0Ultimately, about 40 percent of these connections will be lost (Webb, Monk, &amp; Nelson, 2001).\u00a0As the prefrontal cortex matures, the child is increasingly able to regulate or control emotions, to plan activity, to strategize, and have better judgment.\u00a0Of course, this is not fully accomplished in infancy and toddlerhood but continues throughout childhood and adolescence.<\/p>\n<p>Another major change occurring in the central nervous system is the development of <strong>myelin<\/strong>, a coating of fatty tissues around the axon of the neuron.\u00a0Myelin helps insulate the nerve cell and speed the rate of transmission of impulses from one cell to another.\u00a0This enhances the building of neural pathways and improves coordination and control of movement and thought processes.\u00a0The development of myelin continues into adolescence but is most dramatic during the first several years of life.<\/p>\n<div class=\"textbox examples\">\n<h3>Watch it<\/h3>\n<p>How does all of this brain growth translate into cognitive abilities? We will discuss this later on in the module, but this video provides a nice overview of new research and some of the impressive abilities of newborns.<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-1\" title=\"Babies are Surprisingly Smart\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/nM-GhFzX8yQ?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p>You can <a href=\"https:\/\/oerfiles.s3-us-west-2.amazonaws.com\/Lifespan+Development\/Transcriptions\/BabiesAreSurprisinglySmart_transcript.txt\" target=\"_blank\" rel=\"noopener\">view the transcript for &#8220;Babies are Surprisingly Smart&#8221; here (opens in new window)<\/a>.<\/p>\n<\/div>\n<div class=\"textbox tryit\">\n<h3>Try It<\/h3>\n<p>\t<iframe id=\"assessment_practice_b6b9c621-ae49-4177-8285-69ad0786266c\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/b6b9c621-ae49-4177-8285-69ad0786266c?iframe_resize_id=assessment_practice_id_b6b9c621-ae49-4177-8285-69ad0786266c\" frameborder=\"0\" style=\"border:none;width:100%;height:100%;min-height:300px;\"><br \/>\n\t<\/iframe><\/p>\n<\/div>\n<div class=\"textbox key-takeaways\">\n<h3>Glossary<\/h3>\n<div class=\"titlepage\">\n<dl>\n<dt>axons:<\/dt>\n<dd>fibers that extend from the neurons and transmit electrochemical impulses from that neuron to the dendrites of other neurons<\/dd>\n<dt>cortex:<\/dt>\n<dd>the outer layers of the brain in humans and other mammals. Most thinking, feeling, and sensing involves the cortex<\/dd>\n<dt>dendrites:<\/dt>\n<dd>fibers that extend from neurons and receive electrochemical impulses transmitted from other neurons via their axons<\/dd>\n<dt>failure to thrive:<\/dt>\n<dd>decelerated or arrested physical growth (height and weight measurements fall below the third or fifth percentile or a downward change in growth across two major growth percentiles) and is associated with abnormal growth and development<\/dd>\n<dt>myelin:<\/dt>\n<dd>a coating of fatty tissues around the axon of the neuron<\/dd>\n<dt>neurons:<\/dt>\n<dd>nerve cells in the central nervous system, especially in the brain<\/dd>\n<dt>neurotransmitters:<\/dt>\n<dd>brain chemicals that carry information from the axon of a sending neuron to the dendrites of a receiving neuron<\/dd>\n<dt>percentile:<\/dt>\n<dd>a point on a ranking scale of 0 to 100. The 50th percentile is the midpoint; half of the infants in the population being studied rank higher and half rank lower<\/dd>\n<dt>prefrontal cortex:<\/dt>\n<dd>the area of the cortex at the very front of the brain that specializes in anticipation, planning, and impulse control<\/dd>\n<dt>pruning:<\/dt>\n<dd>the process by which unused connections in the brain atrophy and die<\/dd>\n<dt>synapses:<\/dt>\n<dd>the intersection between the axon of one neuron to the dendrites of another neuron<\/dd>\n<dt>transient exuberance:<\/dt>\n<dd>the great, but temporary increase in the number of dendrites that develop in an infant&#8217;s brain during the first two years of life<\/dd>\n<\/dl>\n<\/div>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-245\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Original<\/div><ul class=\"citation-list\"><li>Modification, adaptation, and original content. <strong>Authored by<\/strong>: Tera Jones for Lumen Learning. <strong>Provided by<\/strong>: Lumen Learning. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><\/ul><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Psyc 200 Lifespan Psychology. <strong>Authored by<\/strong>: Laura Overstreet. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/opencourselibrary.org\/econ-201\/\">http:\/\/opencourselibrary.org\/econ-201\/<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><li>Childhood: Physical and Cognitive Development image and supportive text. <strong>Provided by<\/strong>: Lumen Learning. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/courses.lumenlearning.com\/waymaker-psychology\/chapter\/reading-childhood\/\">https:\/\/courses.lumenlearning.com\/waymaker-psychology\/chapter\/reading-childhood\/<\/a>. <strong>Project<\/strong>: Introduction to Psychology. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><li>The neuron. <strong>Provided by<\/strong>: Wikimedia. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/commons.wikimedia.org\/wiki\/File:1206_The_Neuron.jpg\">https:\/\/commons.wikimedia.org\/wiki\/File:1206_The_Neuron.jpg<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by-sa\/4.0\/\">CC BY-SA: Attribution-ShareAlike<\/a><\/em><\/li><\/ul><div class=\"license-attribution-dropdown-subheading\">All rights reserved content<\/div><ul class=\"citation-list\"><li>How Baby Brains Develop. <strong>Provided by<\/strong>: CNN. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/www.youtube.com\/watch?v=R0fiu2S0_3M\">https:\/\/www.youtube.com\/watch?v=R0fiu2S0_3M<\/a>. <strong>License<\/strong>: <em>Other<\/em>. <strong>License Terms<\/strong>: Standard YouTube License<\/li><li>Baby MRI image. <strong>Provided by<\/strong>: Quanta Magazine. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/www.quantamagazine.org\/infant-brains-reveal-how-the-mind-gets-built-20170110\/\">https:\/\/www.quantamagazine.org\/infant-brains-reveal-how-the-mind-gets-built-20170110\/<\/a>. <strong>License<\/strong>: <em>All Rights Reserved<\/em><\/li><li>Babies are surprisingly smart. <strong>Authored by<\/strong>: SciShow Psych. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/www.youtube.com\/watch?v=nM-GhFzX8yQ\">https:\/\/www.youtube.com\/watch?v=nM-GhFzX8yQ<\/a>. <strong>License<\/strong>: <em>Other<\/em>. <strong>License Terms<\/strong>: Standard YouTube License<\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section><hr class=\"before-footnotes clear\" \/><div class=\"footnotes\"><ol><li id=\"footnote-245-1\">Iannelli, V. (2018). What Parents Need to Know About Baby Weight Trends and Newborn Gaining. Retrieved from <a href=\"https:\/\/www.verywellfamily.com\/baby-birth-weight-statistics-2633630\" target=\"_blank\" rel=\"noopener\">https:\/\/www.verywellfamily.com\/baby-birth-weight-statistics-2633630<\/a> <a href=\"#return-footnote-245-1\" class=\"return-footnote\" aria-label=\"Return to footnote 1\">&crarr;<\/a><\/li><li id=\"footnote-245-2\">Huelke D. F. (1998). An Overview of Anatomical Considerations of Infants and Children in the Adult World of Automobile Safety Design. Annual Proceedings \/ Association for the Advancement of Automotive Medicine, 42, 93\u2013113. <a href=\"#return-footnote-245-2\" class=\"return-footnote\" aria-label=\"Return to footnote 2\">&crarr;<\/a><\/li><\/ol><\/div>","protected":false},"author":74,"menu_order":3,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Psyc 200 Lifespan Psychology\",\"author\":\"Laura Overstreet\",\"organization\":\"\",\"url\":\"http:\/\/opencourselibrary.org\/econ-201\/\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"},{\"type\":\"cc\",\"description\":\"Childhood: Physical and Cognitive Development image and supportive text\",\"author\":\"\",\"organization\":\"Lumen Learning\",\"url\":\"https:\/\/courses.lumenlearning.com\/waymaker-psychology\/chapter\/reading-childhood\/\",\"project\":\"Introduction to Psychology\",\"license\":\"cc-by\",\"license_terms\":\"\"},{\"type\":\"original\",\"description\":\"Modification, adaptation, and original content\",\"author\":\"Tera Jones for Lumen Learning\",\"organization\":\"Lumen Learning\",\"url\":\"\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"},{\"type\":\"copyrighted_video\",\"description\":\"How Baby Brains Develop\",\"author\":\"\",\"organization\":\"CNN\",\"url\":\"https:\/\/www.youtube.com\/watch?v=R0fiu2S0_3M\",\"project\":\"\",\"license\":\"other\",\"license_terms\":\"Standard YouTube License\"},{\"type\":\"copyrighted_video\",\"description\":\"Baby MRI image\",\"author\":\"\",\"organization\":\"Quanta Magazine\",\"url\":\"https:\/\/www.quantamagazine.org\/infant-brains-reveal-how-the-mind-gets-built-20170110\/\",\"project\":\"\",\"license\":\"arr\",\"license_terms\":\"\"},{\"type\":\"cc\",\"description\":\"The neuron\",\"author\":\"\",\"organization\":\"Wikimedia\",\"url\":\"https:\/\/commons.wikimedia.org\/wiki\/File:1206_The_Neuron.jpg\",\"project\":\"\",\"license\":\"cc-by-sa\",\"license_terms\":\"\"},{\"type\":\"copyrighted_video\",\"description\":\"Babies are surprisingly smart\",\"author\":\"SciShow Psych\",\"organization\":\"\",\"url\":\"https:\/\/www.youtube.com\/watch?v=nM-GhFzX8yQ\",\"project\":\"\",\"license\":\"other\",\"license_terms\":\"Standard YouTube License\"}]","CANDELA_OUTCOMES_GUID":"2697bd6e-bea1-4f64-81ea-c79ffad7bcf2, 39fff0a5-c622-4ed3-99ff-6e1022087f5a, dd42257c-1fdb-4a00-aec1-987b6c6cd755","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-245","chapter","type-chapter","status-publish","hentry"],"part":212,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/wm-lifespandevelopment\/wp-json\/pressbooks\/v2\/chapters\/245","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/wm-lifespandevelopment\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/wm-lifespandevelopment\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-lifespandevelopment\/wp-json\/wp\/v2\/users\/74"}],"version-history":[{"count":46,"href":"https:\/\/courses.lumenlearning.com\/wm-lifespandevelopment\/wp-json\/pressbooks\/v2\/chapters\/245\/revisions"}],"predecessor-version":[{"id":7759,"href":"https:\/\/courses.lumenlearning.com\/wm-lifespandevelopment\/wp-json\/pressbooks\/v2\/chapters\/245\/revisions\/7759"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/wm-lifespandevelopment\/wp-json\/pressbooks\/v2\/parts\/212"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/wm-lifespandevelopment\/wp-json\/pressbooks\/v2\/chapters\/245\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/wm-lifespandevelopment\/wp-json\/wp\/v2\/media?parent=245"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-lifespandevelopment\/wp-json\/pressbooks\/v2\/chapter-type?post=245"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-lifespandevelopment\/wp-json\/wp\/v2\/contributor?post=245"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-lifespandevelopment\/wp-json\/wp\/v2\/license?post=245"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}