PREGNANCY AND CHILDBIRTH

layers of the oocyte

oocyte membrane (inside)

zona pellucida (middle)

corona radiata (outside)

sperm capacitation

period of sperm conditioning in female reproductive tract

prepares the acrosome for fertilization

increases sperm motility

where does fertilization happen

uterine tube

three phases of fertilization

1. corona radiata penetration

2. acrosome reaction and zona pellucida penetration

3. fusion of sperm and oocyte plasma membranes and pronuclei

pre embryonic period length

week 1-2

implantation

usually begins 7 days after fertilization

trophoblast subdivides

syncytiotrophoblast

burrows into the stratum functionals of the endometrium

produces human chorionic gonadotropin (hCG)

placenta funcitons

exchange of nutrients, respiratory gases, waste products, and antibodies

production of estrogen and progesterone

placenta anatomy

formed from maternal tissues (stratum functionals) and fetal tissues (chorion)

chorionic villi immersed in a pool of maternal blood

mother and baby’s blood do not mix

embryonic period length

weeks 3-8

embryonic period

primitive streak forms

gastrulation

body folding

neurulation

limb buds form

organogenesis

sexual differentiation

no difference in male and females before week five of development

embryos initially contain indifferent gonads and two duct systems

two duct systems embryos initially have

paramesonephric ducts (female)

mesonephric ducts (male)

internal female development

gonads differentiate into ovaries

paramesonephric ducts from the uterine tube and uterus

mesonephric ducts degenerate

internal male development

gonads differentiate into testes

paramesponephric ducts degenerate

mesonephric ducts form the male duct system and seminal vesicles

testes descend into the scrotum

external development uniform parts

genital tubercle

urogenital fold

labioscrotal swelling

genital tubercle turns into

F: clitoris

M: glans of penis

urogenital fold turns into

F: labia minora

M: shaft of penis

labioscrotal swelling turns into

F: labia majora

M: scrotum

common functions of ovaries and testes

produce gametes and sex hormones

common fucntions of clitoris and glans of the penis

contain autonomic nervous system axons that stimulate feelings of arousal and sexual climax

common funciton of labia majora and scrotum

protect and cover reproductive structures

common function of vestibular glands and bulbourethral glands

secrete mucus for lubrication

fetal period length

weeks 9-38

fetal period

growth and maturation of existing organs

fetal period organs

bone ossify

reproductive organs develop

brain enlarges

body elingates

lines grow

organ systems become functional

baby movement begins

baby gains weight

how long does gestation last

38 weeks from conception

40 weeks from last menstrual period

how much does uterus expand

20 times larger than normal

late pregnancy

breasts enlarge and devlelop ability to produce milk

uterus myometrium becomes more active during last trimester mild contractions may occur

the hormone relaxin softens the cervix and loosens the pubic symphysis

baby “drops” and is normally oriented head down with face posterior

staged of labor

cervical dilation

expulsion

placental

cervical dilation

begins with first regular contractions and ends when the cervix is fully dilated

longest stage

expulsion

lasts from full dilation to delivery of the baby

placental

eliminates the placenta

accomplished within 15-30 minutes after birth of infant