APHY 102: Ch 28: Pregnancy and
Human Development Ivy Tech Test
Questions and Answers.
Pregnancy - Answer events that occur from fertilization until infant born
Conceptus - Answer developing offspring
Gestation - Answer lasts an average of 266 days from conception to childbirth
Gestation period - Answer time from last menstrual period until birth (~280 days)
prenatal period - Answer the time between conception and birth. This period is generally
divided into three stages: the pre-embryo (germinal) stage, the embryonic stage, and the fetal
stage.
Pre-embryonic stage - Answer from fertilization to end of two weeks which is a period of cell
division and initial differentiation (cell maturation)
Embryonic stage - Answer conceptus from fertilization through week 8
Fetal stage - Answer conceptus from week 9 through birth. Time of rapid growth of body
structures established in embryo.
First trimester - Answer from fertilization through 12 weeks. More than half of all embryos
die during this period because conceptus is most vulnerable to stress, drugs, nutritional
deficiencies during this time.
Second trimester - Answer weeks 13 through 24. Organs complete most of their
development and fetus looks distinctly human. Chance of survival if born near end of this
trimester.
Third trimester - Answer week 25 to birth. Fetus grows rapidly and organs achieve enough
cellular differentiation to support life outside the womb. At week 35 a 5.5 lb fetus is considered
mature.
How long is the ovulated secondary oocyte viable? - Answer for 12 to 24 hours (average is
about 14 hours)
, How long are sperm viable in the female reproductive tract? - Answer 24 to 72 hours after
ejaculation (average is about 48 hours)
What is the window of opportunity for fertilization? - Answer 48 hours before ovulation to
about 14 hours after ovulation.
Fertilization - Answer sperm's chromosomes combine with those of ovum to form fertilized
egg (zygote); moment when membranes of two pronuclei rupture and chromosomes combine.
Why do most sperm not make it to the egg? - Answer Leak out of vagina
Destroyed by acidic vaginal environment
Fail to make it through cervix
Dispersed in uterine cavity or destroyed by phagocytes
How are sperm assisted by female physiology? - Answer Thinning of cervical mucus
Uterine contractions (reverse peristalsis)
Chemical attraction
Capacitation - Answer a functional maturation of the spermatozoon that takes about 10
hours. The changes take place via the sperm cell membrane in which receptors are made
available through the removal of a glycoprotein layer. The area of the acrosomal cap is also
altered to be fagile thereby the acrosome reaction becomes possible. In addition, sperm
motility is enhanced.
capacitated - Answer Sperm must be _______________ before they can penetrate an oocyte.
Steps of fertilization - Answer 1. Deposit semen in female.
2. Capacitance of sperm is initiated and start swimming.
3. Swim through cervix and into uterine tube seeking the secondary oocyte.
4. Sperm that find the secondary oocyte (and are fully capacitated) digest through the corona
radiata by releasing acrosomal enzymes.
5. The sperm that digests through the zona pellucida and binds to a sperm-binding receptor will
fuse plasma membranes with the oocyte's plasma membrane, so the sperm's nucleus enters
the oocyte.
6. Plasma membrane fusion will induce calcium surge to block polyspermy. Fast block hardens
zona pellucida and slow block removes sperm-binding receptors. Also induces secondary oocyte
to complete meiosis II and form another polar body to make a mature ovum with 23 single-
stranded chromosomes.
Human Development Ivy Tech Test
Questions and Answers.
Pregnancy - Answer events that occur from fertilization until infant born
Conceptus - Answer developing offspring
Gestation - Answer lasts an average of 266 days from conception to childbirth
Gestation period - Answer time from last menstrual period until birth (~280 days)
prenatal period - Answer the time between conception and birth. This period is generally
divided into three stages: the pre-embryo (germinal) stage, the embryonic stage, and the fetal
stage.
Pre-embryonic stage - Answer from fertilization to end of two weeks which is a period of cell
division and initial differentiation (cell maturation)
Embryonic stage - Answer conceptus from fertilization through week 8
Fetal stage - Answer conceptus from week 9 through birth. Time of rapid growth of body
structures established in embryo.
First trimester - Answer from fertilization through 12 weeks. More than half of all embryos
die during this period because conceptus is most vulnerable to stress, drugs, nutritional
deficiencies during this time.
Second trimester - Answer weeks 13 through 24. Organs complete most of their
development and fetus looks distinctly human. Chance of survival if born near end of this
trimester.
Third trimester - Answer week 25 to birth. Fetus grows rapidly and organs achieve enough
cellular differentiation to support life outside the womb. At week 35 a 5.5 lb fetus is considered
mature.
How long is the ovulated secondary oocyte viable? - Answer for 12 to 24 hours (average is
about 14 hours)
, How long are sperm viable in the female reproductive tract? - Answer 24 to 72 hours after
ejaculation (average is about 48 hours)
What is the window of opportunity for fertilization? - Answer 48 hours before ovulation to
about 14 hours after ovulation.
Fertilization - Answer sperm's chromosomes combine with those of ovum to form fertilized
egg (zygote); moment when membranes of two pronuclei rupture and chromosomes combine.
Why do most sperm not make it to the egg? - Answer Leak out of vagina
Destroyed by acidic vaginal environment
Fail to make it through cervix
Dispersed in uterine cavity or destroyed by phagocytes
How are sperm assisted by female physiology? - Answer Thinning of cervical mucus
Uterine contractions (reverse peristalsis)
Chemical attraction
Capacitation - Answer a functional maturation of the spermatozoon that takes about 10
hours. The changes take place via the sperm cell membrane in which receptors are made
available through the removal of a glycoprotein layer. The area of the acrosomal cap is also
altered to be fagile thereby the acrosome reaction becomes possible. In addition, sperm
motility is enhanced.
capacitated - Answer Sperm must be _______________ before they can penetrate an oocyte.
Steps of fertilization - Answer 1. Deposit semen in female.
2. Capacitance of sperm is initiated and start swimming.
3. Swim through cervix and into uterine tube seeking the secondary oocyte.
4. Sperm that find the secondary oocyte (and are fully capacitated) digest through the corona
radiata by releasing acrosomal enzymes.
5. The sperm that digests through the zona pellucida and binds to a sperm-binding receptor will
fuse plasma membranes with the oocyte's plasma membrane, so the sperm's nucleus enters
the oocyte.
6. Plasma membrane fusion will induce calcium surge to block polyspermy. Fast block hardens
zona pellucida and slow block removes sperm-binding receptors. Also induces secondary oocyte
to complete meiosis II and form another polar body to make a mature ovum with 23 single-
stranded chromosomes.
