PRegnancy

Essential Question What are the stages of a pregnancy from fertilization to birth?

Conception Egg & Sperm Cells Egg Cell: Same as “ovum”… the cell from a girl or woman that can start pregnancy. Sperm Cell: The cell from a boy or man that can start pregnancy when joined with an ovum. Each cell has 23 chromosomes.

Egg & Sperm Cells http://www.saburchill.com/images02/020107032.jpg http://www.saburchill.com/images02/020107031.jpg

Fertilization Fertilization: the joining of a sperm and an ovum. Fertilized egg: What an ovum is called after the chromosomes from a sperm have mixed with the ovum’s chromosomes. http://worms.zoology.wisc.edu/dd2/echino/fert/files/page19_2.gif

Implantation: The ball of cells (that used to be a single fertilized egg) nesting in the wall of the uterus. Fertilization & Implantation = Conception Conception: The beginning of a pregnancy. Implantation http://2.bp.blogspot.com/_UdOhpj0rJJo/THcSyYF3gsI/AAAAAAAAAi8/Zmk3xBOTV2I/s1600/getty_rm_illustration_of_egg_implanting_in_uterus.jpg

Pregnancy Amniotic Sac: The thin membrane (like the skin inside the shell of a chicken egg) that surrounds the amniotic fluid and fetus. http://www.camberwellultrasound.com.au/photos/amn.jpg

Pregnancy Fetus: The developing baby from about 10 weeks to birth. Before that, it is called an “embryo”. http://leaveofabsinthe.files.wordpress.com/2010/01/15week-fetus1.jpg

Pregnancy Placenta: An organ that grows inside the uterus http://www.aurorahealthcare.org/yourhealth/healthgate/images/si55550962.jpg Pregnancy Placenta: An organ that grows inside the uterus during pregnancy to carry food and oxygen from the mother and waste from the embryo or fetus. It produces many hormones that affect both the mother and the baby. It develops from the original ball of cells that implanted in the uterus.

Pregnancy Umbilical Cord: the tube leading from the navel of the embryo or fetus to the placenta. It carries food and oxygen to the developing baby and waste from the developing baby. http://themomblog.ocregister.com/files/2009/03/umbilicalcordatbirth.jpg

First Trimester – Month 1 The placenta is beginning to form. Primitive face begins to form. Large dark circles for eyes Mouth, lower jaw & throat are developing. Blood cells are developing. Circulation will soon begin. Baby is 1/4 inch long. About the size of a grain of rice. Picture: www.webmd.com

First Trimester – Month 2 Facial features continue to develop. Ears begin as a little fold of skin. Tiny buds are forming for arms and legs. Fingers, toes & eyes are forming. Brain, spinal cord is well formed. Digestive tract & sensory organs begins to develop. Bone starts to replace cartilage.

First Trimester – Month 2 Embryo begins to move, but mom can’t feel it yet. Fetus is now 1 inch long. 1/3 of the baby is its head.

First Trimester – Month 3 By the end of this month, baby is fully formed. Has arms, hands, fingers, feet & toes. Can open & close mouth, hands & feet. Nails are beginning to form. External ears are formed. Beginning of teeth are forming. Can hear heartbeat through a Doppler.

First Trimester – Month 3 Reproductive organs start developing. Though you can’t tell gender yet. Circulatory & urinary systems are working. Baby is 3-4 inches long & weighs 1 ounce. Chance of miscarriage drops considerably after this month.

Second Trimester – Month 4 Eyelids, eyebrows, eyelashes, nails & hair are formed. Teeth & bones are becoming more dense. Baby can suck their thumb, yawn, stretch & make faces. Nervous system is starting to FUNCTION.

Second Trimester – Month 4 Reproductive organs & genitalia are fully developed. Can now tell gender. Baby is 6 inches long and weighs about 4oz.

Gender Determined by two sex chromosomes. Girl - XX Boy – XY Each parent gives one chromosome. One is always X because moms only have X’s. The dad can give either X or Y. This determines whether a boy or girl.

Second Trimester – Month 5 Hair is beginning to grow & lanugo. Lanugo: a soft fine hair that covers their shoulders, back and temples. It protects baby & is usually shed the first week after they are born. Lanugo --> Picture: http://health-7.com/Atlas%20of%20Pediatric%20Physical%20Diagnosis/Assessment%20of%20Gestational%20Age/3

Second Trimester – Month 5 Baby’s skin is covered with Vernix. Vernix: whitish coating. “Cheesy” substance protects baby’s long exposure to amniotic fluid. It is usually shed just before birth. Mother may start to feel baby move. First movement felt is called: Quickening Baby is 10 inches & weighs 0.5-1lb. Picture: http://drugline.org/medic/term/vernix/

Second Trimester – Month 6 Skin is reddish in color, wrinkled. Veins are visible through the translucent skin. Has finger and toe prints. Eyelids begin to part & eyes open. Baby can respond to sound. Baby can get hiccups.

Second Trimester – Month 6 If born prematurely, baby can survive after 23 weeks of pregnancy with intensive care. Baby is 12 inches long, & weighs about 2 lbs.

Third Trimester – Month 7 Fat begins to be deposited. Baby’s hearing is fully developed. Changes position frequently. Responds to stimuli: sound, pain, & light. If born prematurely, it would survive after this month. Baby is 14 inches long, & weighs 2-4 lbs.

Third Trimester – Month 8 Baby continues to mature and develop fat reserves. Baby may be kicking more. Baby’s brain is rapidly developing. Baby can see & hear. Most internal systems are developed. Baby is 18 inches long, & weighs about 5 lbs.

Third Trimester – Month 9 Baby continues to grow and mature. Lungs are nearly fully developed. Reflexes are coordinated: blinking. Baby changes position to prepare for delivery. Drops down into moms pelvis, with head down in the birth canal. Baby is 18-20inches, & weighs about 7lbs.

Multiple Births Identical Twins: Twins that grow from one egg, fertilized by one sperm, that split into two balls of cells before it implanted in the uterus. They have the same genes, so they look exactly alike. http://www.dptips-central.com/image-files/diane_arbus_identical_twins_1967.jpg http://upload.wikimedia.org/wikipedia/en/7/7e/Identical-fraternal-sperm-egg.png

Multiple Births Fraternal Twins: Twins that grew from two eggs, each fertilized by a different sperm. They don’t look any more alike that any brothers and sisters because they have different genes. http://upload.wikimedia.org/wikipedia/en/7/7e/Identical-fraternal-sperm-egg.png