Fertilization Takes place in the fallopian tube. Head of the sperm cell(23) penetrates the egg cell (23).This forms a single cell called a zygote(46). Following fertilization, the embryo implants itself into the lining of the uterus and develop its own support system. Fertilization

Oocyte (egg) The egg is viable for 12 -24 hours after ovulation. Sperm are viable in the reproductive tract for 12 – 72 hours after ejaculation. Pregnancy is considered the period from conception to birth. Pregnancy Test: The hCG hormone tells the ovary to continue producing hormones to keep the endometrium thick if fertilization has occurred. This is what is detected in the urine of a pregnancy test.

Uterus The uterus consists of a body and a cervix. The cervix protrudes into the vagina.   The uterus maintains an environment for accepting a fertilized egg. Endometrium remains thick. The fertilized ovum becomes an embryo(stays an embryo for the 1st 8weeks of pregnancy), attaches to a wall of the uterus, creates a placenta, and develops into a fetus (gestates) until childbirth.  If no fertilized egg reaches the uterus, the lining is shed monthly in a process known as menstruation

Implantation of the zygote occurs in the uterus. FERTILIZATION occurs in the Fallopian Tubes Implantation of the zygote occurs in the uterus.

FERTILIZATION & PREGNANCY Sperm must travel to the egg and penetrate to combine the DNA from both parents -- this creates the first cell after fertilization: the zygote

SEX DETERMINATION

If the zygote has the incorrect number of chromosomes, it may never start growing.  An extra chromosome #21 will result in the baby having Down Syndrome.

Embryonic Development 1. Zygote-fertilized egg divides and cleaves. 2. Morula- after 3-4 days following fertilization the cluster of cells leaves the fallopian tube and enters uterus. 3. Blastocyst- 6 days after fertilization cluster forms a hollow cavity and lands on the endometrium and implants. Cells continue to develop. 4. Embryonic Disk- amnionic cavity forms and 3 germ layers form. Endoderm- digestive, respiratory and glands Ectoderm- epidermis, skin, hair , nails, tooth enamel & eyes Mesoderm- bones, muscle, and heart

At the 8th week, the embryo is called a FETUS At 8 weeks Embryo, approximately 8 weeks from conception http://www.flickr.com/photos/lunarcaustic/3385925240/

Fetal Development 8 weeks after fertilization the embryo becomes a fetus. After 8 weeks: neural tube becomes spinal cord 4 chambered heart can be seen Face and neck take shape Fingers and toes form Embryo can move 2.5- 3.0 cm After 12 weeks-1st trimester head is large compared to rest of body Features are distinctly human All major organs are developed External genetalia is visible Hair grows

Fetal Tests     Ultrasound - sound waves are used to get an image of the baby You can tell the sex of the baby and its position

Fetal Development

Fetal Development

Placenta Placenta: The embryo develops an organ called the placenta. The placenta produces hormones crucial to continuation of pregnancy. It acts as an endocrine organ. The main function of the placenta is to supply the fetus with oxygen and nutrients and rid waste products via diffusion. The placenta acts as a barrier against harmful substances that could enter the body of the fetus.

Other Structures Umbilical Cord: Structure that connects the placenta and the fetus. Linked to the mother Amniotic Fluid: shock absorbing liquid in which the fetus floats.

CHILDBIRTH- Position

Pregnancy Changes: 38-40 weeks 1st Trimester (3 months) Breast become tender and larger. Frequent urination Nausea and vomiting 2nd Trimester Enlarging Uterus Intestines become compressed Heart rate increases Skin may darken (pregnancy mask) 3rd Trimester skin stretches fatigue back pain heart burn

Changes Usually the size of a fist, the uterus enlarges and go all the way to the tip of the sternum. Pregnant Women need about 300 additional calories a day Urinary system have increase function as they filter waste from baby. Morning Sickness: due to elevated levels of hormones (estrogen and progesterone) women’s bodies react with nausea. Heartburn: esophagus is displaced, constipation occurs.

Amniocentesis  &  Chorionic Villi Sampling Tests fetal cells for abnormalities, such as chromosome numbers

Stages of Labor Hormone oxytocin stimulates rhythmic contractions Dilation stage: full dilation of cervix is 10 cm amnion ruptures releasing amniotic fluid longest part of labor (6-12 hours) contractions occur Expulsion Stage: full dilation until delivery of infant infant passes through cervix and then the vagina 20-50 minutes At this point a C-section may be performed Placental Stage: delivery of the placenta-afterbirth Most common fetal positin is head down facing mothers back. But 1/30 are breech

Position of Fetus

Labor Contractions of muscles occur and become faster and faster, this timing can be used to predict the progression of the labor. Braxton Hicks contractions can occur throughout pregnancy, but probably more frequent at the end Dilation of the cervix allows for baby to pass through, the amount of dilation also is a good clue for how close baby is.

Epidural An epidural can be used to manage pain of labor.  A shot in the spine will temporarily eliminate any feeling below that point.  Mom is awake for the birth, but doesn't have the pain of it. Unfortunately, an epidural must be timed exactly right.  Too soon and it will wear off.  Too late, and they cannot do the procedure.

Complications During Birth Placenta Previa placenta is not attached to the top of the uterus, partially or fully blocks the cervix, this can cause bleeding during pregnancy Solution:  C-Section

What Is An Episiotomy? It is a surgical incision to open the perineum - the tissue between the anus and vagina. It is performed during the second stage of labor when the baby is being pushed through the vagina. The purpose of the procedure is to avoid tearing the delicate perineal tissue.

BREECH BIRTH (Footling) If the baby is rear or feet first, it is called a BREECH BIRTH.  Doctors will attempt to turn the baby or even do an emergency C section.  Breech births are dangerous for baby because the head can get stuck or umbilical cord gets tangled.   Solution:  turning the baby before delivery, C-section, or footling birth 

Ectopic Pregnancy Fertilized egg attaches (or implants) someplace other than the uterus, most often in the fallopian tube. (sometimes called a tubal pregnancy.)    The pregnancy cannot continue to term, usually embryo is removed. Can be very dangerous for woman.

Gestational Diabetes Pregnancy hormones can block insulin from doing its job. When this happens, glucose levels may increase in a pregnant woman's blood.

Problems with Getting Pregnant Fertility clinics can assist with family planning. There are many reasons for infertility. In Vitro Fertilization  (IVF) involves the removal of egg and fertilization in a petri dish, then transferring one or more fertilized eggs back into the uterus (once called test-tube babies)