Chapter 28 - pregnancy and human development

fertilization

joining of two haploid gametes; sperm and oocyte join 

morula

3 days old ( after fertilization ) ; in uterine tube

blastocyst

fluid-filled hollow sphere lined by a single layer or trophoblast cells and a small cluster of inner cell mass

trophoblast

outside of blastocyst to become chorion and placenta 

inner cell mass 

cells that become the embryo, amnion, and yolk sac 

implantation

burrowing of the fertilized egg unto the uterine wall

human chorionic gonadotropin

secreted by trophoblast cells that causes the corpus lute to continue releasing progesterone and estrogen

gastrulation 

seperate into three germ layers; end up forming embryo itself (ecto, meso, and endo derms).

ectoderm

outermost germ layer, gives rise to nervous system skin epithelium

mesoderm 

middle germ layer, gives rise to muscle, all CT, organs, endothelium 

endoderm

the innermost of the three primary germ layers in an embryo, forming the epithelial linings of the digestive and respiratory tracts and their associated organs like the liver, pancreas, lungs, and thyroid.

chorion

extension of layer of the trophoblast cells which stretches finger of tissue to contact the mothers BVs in endmetrium; outermost embryonic membrane that helps form the placenta

decidua capsularis

endometrial cells that surround the implanted embryo

teratogens 

environmental compounds that cause birth defects 

FAS

fetal alcohol syndrome; caused by extreme alcohol exposure to the fetus → low birth weight; mental retardation, developmental delays, premature birth, birth defects

amnion

embryonic membrane; arises from the epiblast cells of the ICM

`yolk sac

embryonic membrane; arises from the hypoblast cells of the ICM; nourishes embryo until placenta is fully formed

allantois

embryonic membrane; out pocketing of the yolk sac; structural base for constructing the umbilical cord, becomes part of bladder

first two months 

embryonic period

3rd month

genitiallia growth, hr detection, maturation

4th and 5th month

maturity development of whats already there

6th and 7th months 

maturity of immune system, genitallia extension

8th and 9th months

fat acculmates in hypdermis, skin thickens

Chadwicks sign

when the female reporductive organs become increasingly vascular, developing a purple hue; increases vaginal sensitivity

chloasma/melasma 

malanocytes responding to hormone changes

morning sickness

nausea during the first few months of pregnancy due to increased estrogen and progesterone

stress incontinence

when the uterus compresses the bladder leading to leakage

dyspnea 

decrease in the residual volume of the lungs → difficulty breathing during the last few months of preganncy 

relaxin

produced by placenta → loosens pelvic ligaments and the pubic symphysis so that the baby can push through the pelvic canal easer, also allows the pelvic canal to expand as the baby gets in the last few months

human placental lactogen

made by placenta; drive hyperplasia of mammary gland tissue

Braxton hicks contractions 

irregular myometrial contractions often in the weeks preceding labor and delivery; false labor 

parturition

labor and delivery

oxytocin

drives smooth muscle contraction around uterus

vertex presentation 

baby head down and is deliver head first 

breech presentation

baby is head up or horizontal and is delivered feet or rear end is first

episiotomy

surgical incision of periotoneum from vagina to anal canal

cesarean section

delivery through an incision in the lower abdomen through the uterus 

dystocia

female has more male like pelvis

physiological jaundice

when fetal RBCs breakdown quickly and the liver is unable to handle the resulting bilirubin so it gets deposted in the body tissues

colostrum 

thick yellow secretion just prior to lactation that is rich in proteins, vitamins, mineral and antibodies 

ectopic pregnancy

implantation of the fertilized egg in the wall of fallopian tube

placenta abruptio

premature separation of the placenta from the wall of the uterus

placenta previa 

attachment of the placenta over the cervical canal (partially)