Chapter 10: Conception, Pregnancy, and Childbirth R7-12 Flashcards
Conception
union of a sperm cell and an ovum
Y chromosomes
Creates a boy
-faster swimming sperm than X (why more boys than girls)
Male fetuses are more likely to be lost in spontaneous _____
abortions
-which often occur in the first month
Upon ejaculation, ___ to ___ million sperm are released and only ___ in ___ get in the vicinity of an ovum
200-400 million
1 in 1000
Sperm cells are apparently attracted by
Sperm cells are apparently attracted by
zona pellucida
A gelatinous layer that surrounds an ovum
hyaluronidase
An enzyme that briefly thins the zona pellucida, enabling one sperm to penetrate
Physicians often recommend that couples try to conceive on their own for ___ months before seeking medical assistance
six
Infertility
Inability to conceive a child
-failed to conceive for over a year
In vitro fertilization can cost up to
$15 000
About __% of infertility lies in men, while ___% lies in both partners
40% men
20% both
Motility
Self-propulsions. Motility is a measure of the viability of sperm cells
Autoimmune responses
The production of antibodies that attack naturally occuring substances that are (incorrectly) recognized as foreign or harmful
Problems in producing normal, abundant sperm may be caused by:
genetic factors, advanced age, hormonal problems, diabetes, injuries to the testes, varicose veins in the scrotum, drugs (alcohol, narcotics, marijuana, and/or tobacco), antihypertensive medications, environmental toxins, excess heat, and emotional stress
Low sperm count (or the absence of sperm)
the most common problem
To be considered normal, sperm must be able to:
- To be considered normal
- sperm must be able to
artificial insemination
The introduction of sperm into the reproductive tract through means other than sexual intercourse
Women encounter the following major fertility problems:
Irregular ovulation, including failure to ovulate (MOST COMMON)
Obstructions or malfunctions of the reproductive tract, often caused by infections or diseases involving the reproductive tract
Endometriosis
Declining hormone levels of estrogen and progesterone that occur with aging and may prevent the ovum from becoming fertilized or remaining implanted in the uterus
The following fertility problems are found in men:
Low sperm counts
Irregularly shaped sperm (e.g., malformed heads or tails)
Low sperm motility
Chronic diseases such as diabetes
Infections such as sexually transmitted infections
Injuries to the testes
Autoimmune responses, in which the man produces antibodies that deactivate his sperm
A pituitary imbalance and/or thyroid disease
Ovulation can often be induced by fertility drugs such as
- clomiphene (sold as Clomid), which stimulates the pituitary gland to secrete FSH and LH, which in turn stimulate the maturation of ova.
- Pergonal, contains a high concentration of FSH, which directly stimulates maturation of ovarian follicles
Endometriosis (1 in 6 cases)
A condition caused by the growth of endometrial tissue in the abdominal cavity, or elsewhere outside the uterus, and characterized by menstrual pain
Laparoscopy
A medical procedure in which a long, narrow tube (a laparoscope) is inserted through an incision in the naval, permitting visual inspection or organs in the pelvic cavity
In Vitro Fertilization (IVF)
A method of conception in which mature ova are surgically removed from an ovary and placed in a laboratory dish with sperm
gamete intrafallopian transfer GIFT
sperm and ova are inserted together into a fallopian tube for fertilization. Conception occurs in a fallopian tube, rather than in a laboratory dish.
Zygote intrafallopian transfer (ZIFT)
involves a combination of IVF and GIFT. Sperm and ova are combined in a laboratory dish. After fertilization, the zygote is placed in the mother’s fallopian tube, to begin its journey to the uterus for implantation.
ZIFT’s advantage over GIFT
the fertility specialists can ascertain that fertilization has occurred before insertion is performed.
Donor IVF
Ovum is taken from one women, fertilized, and injected into the uterus or fallopian tube of another women
Embryonic transfer
Female volunteer is artificially inseminated by the male partner of the intended mother, than the embryo is removed from the volunteer and inserted intot he uterus intended mother
Intracytoplasmic sperm injection (ICSI)
A single sperm is injected directly into an ovum
-may lead to: increase in birth defects, including heart, stomach, kidney, and bladder problems, cleft palates, hernias, and malformation of the penis.
surrogate mother
artificially inseminated by the partner of an infertile woman or by one of two men who are a couple. She carries the baby to term and then turns the baby over to the father and his partner
Surrogate mother in Canada
Legal
- must be no contract
- can not pay women
The main provisions of the Assisted Human Reproduction Act include:
A ban on human cloning
A ban on selection of a baby’s sex for non-medical purposes
A ban on payment to a surrogate mother
A ban on payment to a sperm donor
For many women, the first sign of pregnancy is (most common)
a missed period.
-Missing a period is therefore not a fully reliable indicator, as stress can delay periods
human chorionic gonadotropin (hCG)
-Found as early as 10 days after conception
Hormone produced by women shortly after conception. hCG stimulates the corpus luteum to continue producing progesterone. The presence of hCH in a women’s urine indicates that she is pregnant
human chorionic gonadotropin (hCG)
refers to the nausea, food aversions, and vomiting a woman may experience during pregnancy
-subsides by about the 12th week of pregnancy.
Miscarriage
A spontaneous abortion
- specific cause is not identified
- prevalent among older mothers
The normal gestation period ____ days is from the onset of the last menstrual cycle before conception
280
The normal gestation period is ___ days when we measure from the date at which fertilization is assumed to have taken place, which normally corresponds to two weeks after the beginning of a woman’s last menstrual cycle
266
Naegele’s rule to calculate the delivery date:
1) Write down the date of the first day of the last menstrual period.
2) Add seven days.
3) Subtract three months.
4) Add one year.
The Germinal Stage
- Within 36 hours of conception, the zygote divides into two cells (dividing rapidly, becomes 32 cells in another 36 hours)
- Takes zygote three or four days to reach the uterus
Germinal Stage definition (aka period of the ovum)
The period of prenatal development before implantation in the uterus
Blastocyst
Embryo that consists of a sphere of cells surrounding a cavity of fluid
-Occurs at the germinal stage of embryonic development
Jenny;s baby is in day 9… it is called a blastocyst
Embryonic Stage
Lasts from implantation through the eighth week
-characterized by the differentiation of major organ systems
amniotic sac
A sac containing the fetus
amniotic sac
Fluid within the amniotic sac
-suspends and protects the fetus
placenta (after birth)
An organ connected to the fetus by the umbilical cord. The placenta serves as a relay station between the mother and the fetus, allowing the exchange of nutrients and wastes
umbilical cord
A tube that connects the fetus to the placenta
The Fetal Stage
- begins by the ninth week and continues until birth
- By about the ninth or tenth week, the fetus begins to respond to the outside world by turning in the direction of external stimulation
By the end of the first trimester
The major organ systems, fingers, toes, and external genitals are formed, the gender can be visually determined, and the eyes are clearly distinguishable.
By the end of the first trimester,
Maternal Diet Maternal Diseases and Disorders Critical Periods of Vulnerability Rubella (German Measles) Syphilis HIV and AIDS Pregnancy-Induced Hypertension Ectopic Pregnancy Rh Incompatibility Maternal (and Paternal) Drug Use Vitamins Narcotics Marijuana Alcohol Cigarette Smoking
Teratogens
Environmental influences or agents that can damage an embryo or fetus
-They include alcohol, aspirin, the metals lead and mercury, radiation, and disease-causing organisms such as viruses and bacteria
critical periods of vulnerability
A period when an embryo or fetus is vulnerable to the effect of a teratogen
Rubella (aka German measles)
Viral infection that can cause deafness, intellectual disabilities, and heart disease in an embryo