Ch 38 pregnancy and human development

How long is the secondary oocyte viable and capable of being fertilized after it is ovulated?

12-24 hours

At what point of pregnancy would the uterine fundus be located between the umbilicus and the xiphoid process?

8 months The fundus is beyond the umbilicus at 7 months and would be between the umbilicus and xiphoid process at 8 months.

In the block to polyspermy, fusion of the sperm and oocyte plasma membranes causes ________ levels in the oocyte's cytoplasm to rise, triggering the cortical reaction.

Calcium ions

Implantation

Embedding of the blastocyst in the uterine wall

A zygote is usually formed within the uterus

False

By 72 hours after fertilization, the egg has divided into more than 160 cells and is called the morula

False

Humans do not have a yolk sac associated with embryonic development.

False

At what point is meiosis II completed for the female gamete?

Fertilization

Capacitation

Leads to enhancement of sperm motility and increasing membrane fragility to enable enzyme release from acrosomes

Define Cleavage

Leads to the development of a morula and then a blastocyst.

Gastrulation

Leads to the establishment of the three primary germ layers.

Fertilization

Leads to the formation of the first cell of the new individual.

Select the correct statement about fertilization.

Millions of sperm are destroyed by the vagina's acidic environment

What role does oxytocin play in promoting labor?

Oxytocin stimulates the uterus to contract. Oxytocin from fetal cells, and eventually the posterior pituitary, stimulates the uterus to contract both directly and through the release of prostaglandins.

A lack of _____ can, without treatment, lead to _____ in premature infants

Surfactant; alveolar collapse

An episiotomy is an incision made to widen the vaginal orifice, aiding fetal expulsion

True

By the end of the embryonic period, at 8 weeks, all the adult organ systems are recognizable

True

Implantation begins six to seven days after ovulation.

True

The "fluid-filled, hollow ball of cells" stage of development is the blastocyst.

True

The embryonic period lasts until the end of the eighth week.

True

The period from fertilization through week eight is called the embryonic period.

True

Drinking alcohol during pregnancy is ________.

associated with microencephaly and intellectual disorders of the fetus

Which of the following implants in the mucosa of the endometrium?

blastocyst The blastocyst implants after about seven days. It consists of a hollow ball of cells with a smaller, inner cell mass pressed to the inside wall.

Once sperm are deposited into the vagina, the sperm's motility must be enhanced and they must be prepared to release hydrolytic enzymes from their acrosomes. What is this process called?

capacitation Sperm must undergo capacitation in order to gain the ability to penetrate and fertilize an oocyte.

Prior to the let-down reflex, the mammary glands secrete a yellowish fluid called ________ that has less lactose than milk and almost no fat.

colostrum

Which of proposed events prevents more than one sperm from binding to an oocyte during fertilization? acrosomal reaction cortical reaction capacitation gestation

cortical reaction The cortical reaction occurs upon sperm penetration of the oocyte. This prevents polyspermy.

Which of the following is the longest stage of labor, lasting 6-12 hours or more? delivery stage placental stage dilation stage expulsion stage

dilation stage The dilation stage often lasts the longest, up to 12 hours or more

Which of the following is a primary germ layer that gives rise to the skin?

ectoderm The ectoderm is the most superficial of the three primary germ layers and becomes the and CNS.

Which primary germ layer gives rise to the nervous system?

ectoderm In forming the neural plate and later the neural tube, the ectoderm gives rise to the brain, spinal cord, and peripheral nerves

The corpus luteum prevents loss of the implanted embryo through menstruation by secreting ________.

estrogens and progesterone

During which stage of labor is the fetus delivered?

expulsion stage

Which fetal vascular shunt directly connects the right atrium to the left atrium so as to bypass the nonfunctional lungs?

foramen ovale The foramen ovale is a direct passage through the interatrial septum, so blood may bypass the nonfunctional lungs. It closes at birth.

Which of the following refers to the transfer of sperm and harvested oocytes together into the woman's uterine tubes in the hopes that fertilization will take place there? rhythm methodin vitro fertilization (IVF) gamete intrafallopian transfer (GIFT) zygote intrafallopian transfer (ZIFT)

gamete intrafallopian transfer (GIFT)

Which of the following is NOT one of the primary germ layers?

gastroderm

Which hormone is required to maintain the corpus luteum and prevent menstruation?

hCG Human chorionic gonadotropin (hCG) secreted by the placenta is required to maintain the corpus luteum and prevent menstruation.

A urine test reveals a positive result for human chorionic gonadotropin (hCG). This indicates ________ was successful.

implantation

Which of the following is true in reference to what may pass through the placental barriers? nutrients, respiratory gases, wastes, and alcohol respiratory gases, hormones, nutrients, and blood cells hormones, blood cells, and nutrients nutrients and respiratory gases only

nutrients, respiratory gases, wastes, and alcohol

Milk ejection (the letdown reflex) is stimulated by which of the following hormones associated with pregnancy?

oxytocin

During what stage is the afterbirth delivered?

placental stage The uterus will expel the placenta, or afterbirth, within 30 minutes after expulsion of the baby

Which of the following serve(s) as the direct trigger to begin the more vigorous, rhythmic contractions of true labor?

prostaglandins Prostaglandin release from the placenta in response to oxytocin serves as the trigger to begin the vigorous, rhythmic contractions of true labor.

Which of the following is NOT assessed as part of the Apgar score?

temperature

During which of the following stages does the amnion rupture, an event also known as the mother's "water breaking"?

the dilation stage During dilation, increasing pressure of the baby's head on the amnion ruptures the amnion and releases amniotic fluid.

Which method of contraception is most reliable?

vasectomy