CH.26 Reproduction, Fetal Development

What are the cells of the early zygote called?

blastomere

Which primary germ layer gives rise to the sense organs (retina, olfactory epithelium, and taste buds)?

ectoderm

As the fetus grows and develops, the syncytiotrophoblast and cytotrophoblast layers give rise to what protective structure?

chorion

How long is the average length of time (in weeks) for a pregnancy?

39

In simple Mendelian genetics, if an allele’s expression demonstrates a trait over another allele, it is said to be what kind of allele?

dominant

Full dilation of the cervix is usually achieved at what diameter (in cm)?

10

During which stage of development is the zygote separated into trophoblast cells and the inner cell mass?

blastulation

Material exchange between the maternal and fetal blood takes place between which of the following structures?

intramembranous space - villus

The acrosome reaction is necessary to penetrate which of the following structures?

the zona pellucida

apposition

the uterine walls swell due to stromal edema

attachment

interaction between microvilli on the blastocyst and uterine wall

penetration

invasion of the trophoblast cells into the endometrial stroma

progesterone

prevents uterine contractions and thus prevents parturition

estrogen

favors uterine contractions and thus favors parturition

relaxin

potent vasodilator and increases the force and rate of contraction of the heart

placental lactogen

favors nutrient mobilization towards the fetus

prolactin

favors nutrient mobilization toward the mother during periods of homeostatic imbalance

During lactation, oxytocin is responsible for which of the following processes?

the let-down reflex

During which stage of parturition would you expect the strongest contraction to be found?

transition

Which of the following molecules is directly responsible for myometrial contractions?

prostaglandins

Implantation is said to have three phases. Place these phases in the correct order in which they occur.

apposition

attachment

penetration

chordamesoderm

forms the notochord and establishes the anterior-posterior body axis

intermediate mesoderm

forms the urogenital structures

lateral plate mesoderm

forms the structures of the circulatory system

paraxial mesoderm

forms the musculoskeletal system

Which stage of parturition is usually the longest?

cervical effacement and dilation

Men and women share many common phases during the sex response cycle. Which of the following phases is specific to only males?

refraction

At which point does the uterus begin to grow beyond the shelter of the pelvis?

between week 4 and week 20

Identify the proper order for the following physical responses during the female sexual response cycle.

vaginal lubrication

uterine fibrillations

vasocongestion of the vaginal introitus

strong muscular contractions of the proximal third of the vagina

decrease in heart rate and breathing rate

Capacitation is best described as ______.

the process of sperm activation in the vagina

Which of the following would you expect to decrease during pregnancy?

circulating CO2