Do Now – On your slip of paper, write what you know about the image in front of you.

Fertilization and Development EQ: What happens during each trimester of human development?

Path of an Egg- Review Where is the egg produced? Ovary Where is the egg fertilized? Fallopian Tube Where does the fetus develop? Uterus

Fertilization An egg is fertilized when a single sperm penetrates the membrane of the egg cell. Occurs in the upper 1/3 of the Fallopian Tube. Fertilized Egg = Zygote Once a sperm has entered the egg cell, the membrane of the egg changes and prevents any other sperm from entering. Twins?

Cleavage Occurs after fertilization and zygote is formed. Repeated mitotic divisions of zygote. 1st step to becoming multicellular. Zygote Blastula different cells receive different portions of egg cytoplasm & therefore different regulatory signals

Implantation Blastocyst are implanted into thick walls of uterus. Chorion membranes dig into uterus to form placenta. Fertilization  Zygote  Blastocyst  Implantation in Uterus

Amniotic Sac & Placenta Amniotic Sac: fluid filled sac that protects the developing embryo. Placenta: organ that allows nutrients and oxygen to pass from mother to embryo. Placenta Umbilical Cord Amniotic Sac Umbilical Cord: connects the placenta to the fetus and allows air and nutrients to pass through.

Fetal Development: Trimesters & the Mother Gestation (gestational period) – the 9 month period of development (in humans) from fertilization to childbirth Pregnancy = 3 stages called trimesters (3 months each) The baby is ready to be born starting at about 38 weeks 40 weeks is considered full term A fetus typically won’t survive if born much before midway through the third trimester The mother affects the fetus, and the fetus affects the mother Nutrition of the mother affects the development of the fetus

First Trimester: Weeks 1-12 Fetus Embryo Week 3-8 Balstocyst Zygote Weeks 1-2 When the zygote begins to divide, a blastocyst is formed (a hollow ball of cells) which then implants into the wall of the uterus The blastocyst is considered an embryo once the major body structures begin to form

First Trimester: weeks 1-12 Period of rapid growth Zygote becomes an Embryo when: (week 3-8) Major body structures start to form (brain, spinal cord, heart, external organs) embryo produces own blood and starts to move Embryo becomes a Fetus: (weeks 8-12) Cartilage turns into bone limbs move Toenails and fingernails start to form External genitals form Camping- First trimester- need to build the tent first and to do so you need all the parts/pieces Second trimester- need to be protected but able to survive (sleeping bag, pillow, food, water, flashlight) Third trimester- now you are going to enjoy your campsite

Second Trimester: Weeks 13-24 Fetus grows rapidly Movement is felt by mother Fetal heartbeat can be heard Internal organs start maturing (working) Hiccup and swallow Soft hair grows (lanugo) Wake and sleep cycles are regular Fetus can hear mother’s sounds.

Third Trimester: Weeks 25-40 Growth continues and all organ systems mature in preparation for birth. eyes are open when awake and closed when asleep Brain and nerve connections increase Fetus turns to head-down position

There are 3 stages of labor-birth Birth: Begins with contractions (labor) and continues until the baby and placenta emerge. There are 3 stages of labor-birth STAGE 1: Strong contractions occur, the cervix dilates and baby is head down. STAGE 2: Baby pushes through cervix and out of the vaginal canal. STAGE 3: Contractions continue to expel the placenta

Write on bottom of notes… Which of the following is true of fetal development in the first trimester of a pregnancy? The fetus is mostly a cluster of cells without form during the first trimester. It takes the full first trimester for the fetus to develop its hair and body fat. The major body structures develop in their basic form during the first trimester. The fetus depends on the mother's blood flowing through the umbilical cord only in the first trimester.

What is the relationship? Left Side Activity What is the relationship? Compare, contrast or identify the relationship between the two words. Fetus / Embryo Fertilization / Implantation Amniotic Sac / Placenta Trimester / Gestation Zygote / Embryo 1st trimester / 2nd trimester 2nd trimester / 3rd trimester

Baby Book/Comic Project Task: Create a baby book with pictures and descriptions from conception to birth. The book must be hand written but may include digital pictures. The goal is to take more of a creative approach to explaining the key points of development occurring at each stage. The could be a creative story about your personal development or a fictional baby. Each section in the book (listed on the rubric) should be its own page. Descriptions should be scientifically accurate and not explicit. You must pass in your rubric with the project or you will lose 10 points. The rubric has EVERYTHING on there that you need to do. The project will be worth 50 points.

Exit ticket Clear your desk!!!

Which of the following describes part of a baby's development in the second trimester of pregnancy? The fetus turns into a head-down position in the uterus. The fetus develops fat under the skin and practices breathing movements. The fetus is in the embryonic stage, and the amniotic sac forms. The fetus grows soft hair called lanugo over its skin and can swallow and hiccup.

The drinking of alcoholic beverages by a pregnant woman is harmful to the development of her fetus. This is most damaging early in a pregnancy because during this time A. the lungs of the fetus become functional. B. alcohol can easily enter the mouth of the fetus. C. many of the essential organs of the fetus are forming. D. the fetus cannot excrete wastes.

Which of the following describes fertilization. A Which of the following describes fertilization? A. cell differentiation to form a blastula B. formation of germ layers in a deuterostome C. a sperm joining an egg to form a zygote D. sperm and egg production

Abnormalities present in the cells that line the uterus may prevent the production of offspring by directly interfering with which process?  A. the development of the embryo B. the differentiation of gametes into zygotes C. the secretion of estrogen by the ovary D. the production and release of egg cells