Once sperm are deposited into the vagina, sperm motility must be enhanced and they must be prepared torelease hydrolytic enzymes from their acrosomes. What is this process called?
Just inside the oocyte membrane represent vesicles containing calcium ions that are spilled into the extracellular space to prevent polyspermy. When does this take place?
Just after the sperm's head enters the oocyte membrane.
What is the first barrier that must be penetrated by the sperm in order to fertilize and oocyte?
Corona radiata (first coronas then comes the baby)
What is the name for the period of time that extends from the last menstrual period until birth, which is approximately 280 days?
What destroys the zone pellucida sperm-binding receptors?
zonal inhibiting proteins
The result of polyspermy in humans is _____.
a nonfunctional zygote.
It is impossible for sperm to be functional (able to fertilize the egg) until after _____.
they undergo capacitation.
How long is the secondary oocyte viable and capable of being fertilized after it is ovulated?
Millions of sperm cells are destroyed by the vagina's acidic environment.
_____ implants in the mucosa of the endometrium.
The 4-cell stage occurs 2 days after fertilization. How much time passes between the 4-cell stage and implantation?
The correct sequence of preembryonic structures is ______.
zygote, morula, blastocyst
Which of the following is the multinuclear cytoplasmic mass formed from the outer layer of the trophoblast as it implants into the endometrium?
The correct sequence of development from zygote to embryo...
cleavage, morula, blastocyst, gastrula
Secretes human chorionic gonadotropin (hCG)
This extra-embryonic membrane is formed from the trophoblast after implantation...
Together, what do the decider basalis and the chorionic villi form?
What is the innermost (closest) structure that envelops the embryo?
The embryo's blood supply mixes with that of the mother.
Blood from the fetus travels to the placenta via vessels in the umbilical cord.
The extraembryonic coelom lies between the chorion and the amnion.
The yolk sac is the source for the earliest blood cells and blood vessels.
The placenta, a vitally important metabolic organ, is made up of the contribution from mother and fetus. Which portion is from the fetus?
Forms the mother's part of the placenta.
Inner cell mass
Becomes the embryonic disc.
Forms the chorion.
Surrounds the uterine cavity face of the implanted embryo.
A solid sphere of undifferentiated cells.
Which hormone maintains the viability fo the corpus luteum?
What may pass through the placental barriers?
nutrients, respiratory gases, wastes, alcohol
If implantation is successful?
The corpus luteum is maintained until the placenta takes over its hormone-producing functions.
From what germ layer are the serosae of the peritoneal cavity (coelom) derived?
Epithelial layers arise from teh endoderm...
alveolar cells of the lungs
Which germ layer gives rise to the nervous system?
The fetal vascular shunt directly connects the right atrium to the left atrium to bypass the nonfuctional lungs is called _____.
Which fetal vessels or shunts will become the medial umbilical ligaments in the newborn?
_______ takes oxygenated blood to the liver from the placenta?
What is the primary germ layer that forms the basis for the musculoskeletal system?
The foramen oval and the ductus arteriosus are both examples of _______.
pulmonary bypass shunts, which serve to bypass the lungs.
The formation of the endodermal and ectodermal germ layers occurs at _____.
The first major event in organogenesis is _____.
Cells of the _______ gather around the notochord and neural tube and produce the vertebra and rib at their associated level.
What does the hormone relaxin promote?
Promotes the widening & increases flexibility of the pelvis ligaments and pubic symphysis.
Because of the increased bulkiness of the anterior abdomen and the change in a pregnant woman's center of gravity, what type of spinal curvature do many pregnant women develop?
Excessive lordosis of the lumbar spine.
A dangerous complication of prenancy called _____ results in an insufficient placentl blood supply, which can starve a fetus of oxygen. The pregnant woman becomes edematous and hypertensive, and proteinuria occurs.
Which body system of a pregnant woman undergoes the most dramatic physiological changes during pregnancy?
What role does oxytocin play in promoting labor?
Stimulates the uterus to contract
What serve(s) as the trigger to begin the vigorous, rhythmic contractions of true labor?
What tends to initiate Braxton Hicks contractions, or "false labor"?
How long does the expulsion stage typically last in the first birth?
During what stage is the afterbirth delivered?
During which stage does the amnion rupture, and event also known as the mother's "water breaking"?
Surfactant production in premature infants is rarely a factor in providing normal respiratory activity.
Milk ejection (the let-down reflex) is stimulated by which of the following hormones associated with pregnancy?
Prior to the let-down reflex, the mammary gangs secrete a yellowish fluid called _____ that has less lactose than milk and almost no fat.