Chapter 28- Pregnancy and Fetal Development

capacitation

change that sperm go through to be able to fertilize the egg

acrosome reaction in fertilization

Release of digestive enzymes that allows it to penetrate the zona pellucida of the egg

blocks to polyspermy

shedding all sperm binding receptors

zona reaction- granules release ZIP enzymes to destroy sperm binding receptors

formation of the zygote

the male and female pronuclei fuse to form a diploid zygote

role of hCG in fertilization and early pregnancy

maintains the corpus luteum, which continues to produce progesterone to maintain the uterine lining (stops menstruation)

cleavage in the embryonic period

multicellular structure called morula is made

implantation

trophoblast (cytotrophoblast and syncytiotrophoblast) implants on the uterine wall

Gastrulation

Formation of the three primary germ layers—ectoderm, mesoderm, and endoderm

decidua capularis

seals off the baby

decidua basalis

area where nutrients are exchanged

Chorion

outermost layer of the fetal membrane

morphogenesis

The process by which an organism takes shape and the differentiated cells occupy their appropriate locations.

germ layers

ectoderm, mesoderm, endoderm

ectoderm

the outer germ layer that develops into skin and nervous tissue

mesoderm

middle germ layer; develops into muscles, and much of the circulatory, reproductive, and excretory systems

Endoderm

innermost germ layer; develops into the linings of the digestive tract and much of the respiratory system

Amnion

surrounds the membrane and contains amniotic fluid

Yolk sac

a specialized structure that leads to the digestive tract of a developing organism and provides it with food during early development

Allantois

involved in early fluid exchange between the embryo and the yolk sac

Cervical Dilation

Cervix opens to 10 cm during labor.

Expulsion

fetus moves through birth canal

Placental Delivery

expulsion of the placenta, the third and final stage of labor

hormonal control in Parturition

CRH leads to cortisol release which leads to an increase in estrogen to prepare uterus

oxytocin arrives and contractions start

prolactin

stimulates milk production

Oxytocin

triggers milk ejection

suckling

stimulates receptors in the nipple so milk can be released

Umbilical arteries

carry deoxygenated blood from the fetus to the placenta

Umbilical vein

delivers oxygenated blood from the placenta to the fetus

Ductus venosus

connects the umbilical vein to the inferior vena cava, bypassing the liver

foramen ovale

allows blood to flow from right to left atrium, bypassing lungs

Ductus arteriosus

connects pulmonary artery to aorta to bypass lungs

cardiovascular changes that occur at birth

lungs inflate

foramen ovale, ductus venous close

blood flows to lungs

relaxin

Hormone that relaxes pelvic ligaments and softens the cervix to prepare for childbirth

Progesterone

Maintains the uterine lining, prevents uterine contractions, and supports pregnancy.

Positive feedback in labor

Uterine contractions stimulate oxytocin release, which strengthens contractions, causing more oxytocin release until birth occurs.

Breast anatomy in lactation

Mammary glands contain lobes made of alveoli that produce milk; ducts carry milk to the nipple