1. P & A

2.  A. Def: condition resulting in union of sperm and egg and a fetus developing in the uterus  B. How occur?  1. semen containing sperm is deposited in vagina  2. sperm travels up through uterus & uterine tubes A. able to move b/c of tails and sugary energy B. estrogen is high in first part of menstrual cycle - causes uterus and cervix to create a watery secretion that aids in sperm transport C. second part of cycle progesterone is high - secretion prevents good sperm travel

3.  3. when sperm penetrates egg membrane, nuclei of the two combine = 46 chromosomes A. first cell of life = ZYGOTE B. after 32 hrs = zygote starts dividing = mitosis C. zygote now called EMBRYO D. after 3 days, embryo arrives to uterus E. after 1 week – embryo attached in uterine wall Endometrium F. after 8 weeks – now called FETUS Body is recognizable as human G. outer embryo/fetus cells and endometrium form the placenta Def: bloody sac that exchanges nutrients, gases, and wastes between mother and baby Also acts as a barrier to some toxins

4.  1. human chorionic gonadotropin (HCG)  A. def: hormone that prevents normal decline in estrogen and progesterone that causes uterine lining to shed away (menstruation) Hormone that a pregnancy test detects  B. if this hormone fails or there is not enough = miscarriage will result  2. placental estrogen  A. def: hormone secreted by placenta that maintains thick uterine wall 1. also causes relaxation of pelvic joints – helps in birthing process

5.  3. placental lactogen  A. hormone secreted by the placenta that allows for breast development and milk production

6.  A. germ layers  1. def: layers of cells in an embryo that arise to form body structures A. ectoderm: nervous system, hair, nails, skin, mouth, anal canal B. mesoderm: muscle, bone, blood, lymph, reproductive organs C. endoderm: digestive, respiratory, and urinary tracts  B. pre-natal nourishment  1. amnion A. membrane around embryo B. filled with fluid = amniotic fluid Contains same cells as baby = samples used for genetic testing

7. C. umbilical cord forms 1. provides a pathway for nutrients from placenta to embryo  C. By the end of the 8 th week  Baby length = 30 mm  Baby weight = less than 5 g.  ** THESE FIRST FEW MONTHS ARE VERY CRITICAL IN BABIES’ DEVELOPMENT - mother should immediately see Dr. when suspect pregnant - nutrition is very important!

8.  ** Lunar month = 28 days  A. 3 rd lunar month  1. body length grows greatly  2. head growth slows  3. ossification centers develop  4. by end of 12 th week, reproductive organs visible  B. 4 th lunar month  1. body grows to 13-17 cm  2. skeleton ossifies

9.  C. 5 th lunar month  1. growth supresses  2. skeletal muscles active = mother feels movement  3. hair develops  D. 6 th lunar month  1. large weight gain  2. eyebrows and eyelashes appear  E. 7 th lunar month  1. fat deposited = smooths out skin  2. eyelids open  3. approx 37 cm in length

10.  F. 8 th lunar month  1. testes of male descend * sometimes this doesn’t happen and surgery is needed  G. 9 th lunar month  1. body chubby b/c of fat deposits  2. skin pink  H. 10 th lunar month  1. full term  2. skin sebum coated  3. scalp has hair  4. skull bones ossified  5. nails developed  6. head positioned to cervix

11.  A. blood in the pulmonary artery bypasses the lungs by entering DUCTUS ARTERIOSUS  - which brings blood back to aorta

12.  A. uterine & vaginal stretching in late pregnancy  1. initiates hypothalamus to signal posterior pituitary gland  2. PPG releases oxytocin - stimulates uterine contractions  3. rhythmic contractions send uterine contents to cervix - signals stronger contractions = POSITIVE FEEDBACK  4. fetus forced outside  5. 10-15 minutes after birth, placenta separates from uterine wall & is delivered