Lecture Five.

StudyBlue printing of Lecture Five. html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, abbr, acronym, address, big, cite, code, del, dfn, em, font, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, b, u, i, center, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td { margin: 0; padding: 0; border: 0; outline: 0; font-size: 100%; background: transparent; } body { line-height: 1; } blockquote, q { quotes: none; } blockquote:before, blockquote:after, q:before, q:after { content: ''; content: none; } /* remember to define focus styles! */ :focus { outline: 0; } /* remember to highlight inserts somehow! */ ins { text-decoration: none; } del { text-decoration: line-through; } /* tables still need 'cellspacing="0"' in the markup */ table { border-collapse: collapse; border-spacing: 0; } /* end RESET */ .header { min-width:800px; } .logo { padding:6px 20px 2px 20px; margin:0; font-size:25px; font-weight:bold; color:#808285; position:relative; border-bottom: 1px solid #c5c5c5; } .logo-blue { color:#70adc4; } .logo-desc { font-weight:normal; font-size:19px; color:#cccccc; margin-top:50px; position:absolute; display: none; } .back-button { position:absolute; top:20px; right:20px; font-size:13px; line-height:25px; color:rgb(0,175,225); font-weight:normal; } .back-button a { color:rgb(0,175,225); } .instructions { padding:0; margin:0; width:100%; position:relative; color:rgb(100,100,100); } .step-holder { border-left:1px solid #ededed; margin-left:20px; } .steps { padding:15px 0; float:left; width:24%; border-right:1px solid #ededed; text-align:center; } .steps-01 { } .steps-02 { } .steps-03 { } .steps-04 { } .label { padding:5px 10px; } .print-button { } .print-button a { background-color:rgb(0,175,225); color:white; line-height: 19px; padding:9px 8px 5px 30px; font-size:14px; text-decoration:none; background-image: url(images/printer.png); background-repeat: no-repeat; background-position: 7px 50%; -moz-border-radius: 5px; -webkit-border-radius: 5px; } .print-button a:hover { background-color:black; } .theNote .content { width: 8.0in !important; margin: 5px auto; padding:20px; background-color:white; } .theNote .header { border-bottom: 1px dashed #C8C8C8; font-size: 17px; padding: 0 0 10px; line-height: 19px; color: #00ADE1; min-width:500px; } .theNote .body { font-size: 14px; line-height: 19px; padding: 10px 0; } .theNote{ padding:6px 0; clear:both; background-color: rgb(200,200,200); } .theNote h3{ color: rgb(100,100,100); } .theNote h1, .theNote h3{ background-color:white; padding:2px 20px; width:8.0in !important; margin: 0 auto; font-size: 15px; } .theNote h1{ padding-top: 10px; font-size: 15px; } .theNote h1:first-child{ font-size: 20px; } .theNote h3 { font-size: 14px; font-weight: normal; } #options { border: 3px double #ccc; padding: 5px 12px; margin: 10px 50px 10px 20px; float: left; } #info { border-top: 1px solid #ccc; padding-top: 5px; font-style: italic; } li { margin: 5px 10px 5px 25px; } ul li { list-style: disc; } ol li { list-style: decimal; } img { border: 0; } table { clear: both; width: 100%; border: 1px solid #c5c5c5; border-width: 1px 0; margin: 0; page-break-after: always; } table#page { page-break-after: auto; } td { text-align: center; font-size: 12px; border-bottom: 1px dashed #c5c5c5; height: 1.75in; width: 50%; padding-left: 15px; } .leftside { border-right: 1px solid #cccccc; padding: 0 15px 0 0; } .bottom td { border-bottom: none; } .clearfix { clear:both; line-height:1px; height:1px; } img { max-width:80%; max-height:150px; margin:20px; } @media print {.header { display: none; } .content .header{ display:inherit; } table { border: 1px dashed #bbb; border-width: 1px 0; } .theNote{ background-color:white; } } Chapter 3- Prenatal Development at Birth Basics of Prenatal Development Prenatal development: approximately 38- 40 weeks from fertilization to birth 3 periods: germinal, embryonic, fetal The Germinal Period up until 2 weeks after conception includes the creation of the zygote (fertilized egg), cell division, and attachment of zygote to the uterine wall rapid division of zygote (mitosis) blastocyst- consists of an inner mass of cells that will eventually develop into the embryo trophoblast- outer layer that provides support and nutrition for the embryo 10-14 days after conception to uterine wall The Embryonic Period 2-8 weeks after conception cell differentiation (specialization) increases and organs form This period begins with blastocyst attaching to the uterine wall 3 embryonic layer Endoderm- (inner layer) will develop the digestive and respiratory systems; internal parts Mesoderm- (middle layer) circulatory system, bones, muscles, excretory system, and reproductive system surround internal parts Ectoderm- (outermost layer)- nervous system and brain, sensory receptors, skin parts (hair, nails); surface parts Life Support Systems- Embryo Amnion- a bad containing clear fluid where the embryo floats, provides an environment that it temperature and humidity controlled and shock proof. Placenta- consists of disk-shaped tissue groups in which small blood vessels from the mother intertwine but do not join; provides the baby with oxygen and food Umbilical Cord- two arteries and one vein connects the baby to the placenta Organ Formation a.k.a. organogenesis occurs in the first 2 months Can environmental factors influence organ formation so early? YES After Conception (timeline) 21 days spinal cord forms eyes appear 24 days cells for heart differentiate 4th week arm and legs four heart chambers begin blood vessels 5-8 weeks face starts to form; intestinal tract (PAGE 84) The Fetal Period 2-9 months (lasts 7 months 3 months 3 inches long 1 ounce moving body parts facial features are distinguishable sex can be identified 4 months 6 inches 4-7 ounces 5 months 12 inches long 1 pound 6 months 14 inches long 1.5-2 pounds eyes and eyelids complete hair grasping reflex 7 to 9 months viable for life fatty tissue organ systems finish developing weight and length grow The Brain neurons (nerve cells) handle information processing during prenatal development neurons begin moving to their locations and begin forming connections the basic architecture is developed within the first two trimesters (6 months) last trimester- connectivity and functioning of neurons occur neural tube (the beginnings of the nervous system) closes at the top and bottom after 24 days Birth defects related to neural tubes not closing anencephaly- highest regions of the brain don't develop and fetus dies in the womb during childbirth or immediately after spina bifida- varying degrees of paralysis in lower limbs and vertebra does not close; baby has to use crutches and wheelchairs; mothers take vitamin B and folic acid during pregnancy to help the vertebra close When neural tube closes --> massive proliferation of neurons (neurogenesis) --> and migrates to its location and further develops (neuronal migration)