Presentation on theme: "C HAPTER 19 P RENATAL D EVELOPMENT AND B IRTH L ESSON 1- T HE BEGINNING OF THE LIFE C YCLE In this Chapter we will discuss events from fertilization."— Presentation transcript:
C HAPTER 19 P RENATAL D EVELOPMENT AND B IRTH L ESSON 1- T HE BEGINNING OF THE LIFE C YCLE In this Chapter we will discuss events from fertilization to birth Describe Prenatal care Indentify Prenatal risks
P RENATAL D EVELOPMENT We begin life from a single cell During the 9-month period, the cell will divide millions of times It will form tissues, organs, body systems, & characteristics of the person it will become
C ONCEPTION AND I MPLANTATION Fertilization: Union of egg cell(female) and the sperm cell (male) Also known as conception Zygote: Fertilized egg cell Takes about 4 days to reach the uterus Once formed, a protective membrane surrounds it to prevent more sperm from entering the ovum Divides many times ( mitosis -cell division) to form a cluster of cells with a hollow space in the middle After 5 days, the zygote reaches the uterus & is called Blastocyst Implantation: the zygote attaches to the uterine wall Takes about 10 days to implant The endometrium tissue protects & nourish the egg
E MBRYONIC G ROWTH Embryo: A cluster of cells following implantation Called an embryo for about 8 weeks 3 layers of tissue formed as cell continues dividing: Respiratory & digestive system Muscles, bones, blood vessels, & skin Nervous system, sense organs, mouth
E MBRYONIC G ROWTH Amniotic Sac: Thin membrane formed to surround the developing embryo Amniotic Fluid: Fluid in the amniotic sac Acts as a shock absorber Insulates from temperature changes Allows fetal movement Permits proper lung development Constantly circulated by the baby swallowing & inhaling existing fluid & replacing it through exhalation & urination.
E MBRYONIC G ROWTH Placenta: Provides nutrition, excretion, & immunity Blood rich tissue made by embryonic cells & the tissue from the mother Umbilical Cord: Tube which nutrients & oxygen pass from the mother’s blood to the embryo Carries waste products from embryo to diffuse into the mother’s blood
F ETAL D EVELOPMENT Conception to birth is usually about 9 months Divided into (3) 3-month periods called Trimesters First Trimester: 0-14 weeks Second Trimester: 15-28 weeks Third Trimester: 29 weeks to birth Let’s look at pages 488-489 to see what’s going on in these stages of fetal development!
S TAGES OF BIRTH The last few weeks of pregnancy, the baby’s head moves to the lower part of the uterus 95% of the time it rests on the cervix Dilation: Cervix stretches because of mild contractions (Labor) Contractions break the amniotic sac (water breaks) Cervix dilated about 3 cm Contractions are about 5-20 minutes apart
S TAGES OF BIRTH Birth: Contractions are 1-3 minutes apart (active labor) Cervix 8 to 10 cm Stage lasts minutes to hours Baby passes through the birth canal Cries to clear lungs and amniotic fluid Umbilical cord cut Apgar Test: Routine diagnostic test to determine the physical condition of the baby Appearance Reflex Activity Pulse and respiration
A FTERBIRTH C ONTRACTIONS CONTINUE TO PUSH OUT THE PLACENTA 15-30 MINUTES LATER Umbilical CordPlacenta
H OW ARE TWINS B ORN ? Single egg fertilized by single sperm that divides to form 2 embryos Same genetic info Same gender Ovaries release 2 eggs Separate sperm fertilize each egg Different genetic makeup May or may not be the same gender IdenticalFraternal
1 OUT OF 87 BIRTHS RESULT IN TWINS (1/3 BEING IDENTICAL ) 1 OUT OF 7570 ARE TRIPLETS 1 OUT OF 658,00 ARE QUADRUPLETS 1 OUT OF 57, 290, 000 ARE Q UINTUPLETS 1 IN 50,000 ARE BORN CONJOINED
P AIN RELIEF D URING P REGNANCY Anesthetic: Local-numbs the vagina Regional-eases the pain of contractions Spinal: Injection into the spine (works immediately) Epidural: Tube inserted into the back for medicine to be released throughout labor General: Puts patient to sleep (used mainly in C-sections) Birthing Tube: Warm soakPromotes deep relaxation Reduces anxietyRelieves pain Lamaze: Used since the 1950’s Started mainly with breathing exercises Goal is to increase the mother’s confidence in their ability to give birth
C OMPLICATIONS DURING PREGNANCY Miscarriage: Spontaneous expulsion of the fetus before the 20 th week Still Birth: Death of a fetus after week 20 of pregnancy Ectopic Pregnancy: Zygote implants in the fallopian tube, abdomen, ovary, or cervix Egg cannot get to the uterus because of inflammation or scar tissue resulting from a STD Stone baby Preclampsia: Toxemia prevents the placenta from getting enough blood High Blood pressure and high protein in the urine Bed rest, meds, or hospitilization
P ROBLEMS WITH PREGNANCIES Ectopic pregnancyBreech position