birth Flashcards
quiz one (64 cards)
How do gametes differ from other normal human cells?
they only have one half of the total amount of human genetic information.
conception
Ovulation: An egg is released from the ovary into the fallopian tube.
Sperm Journey: During intercourse, sperm travel through the cervix and uterus to the fallopian tube to meet the egg.
Fertilization: One sperm enters the egg, combining their genetic material to form a zygote.
Cell Division: The zygote starts dividing and forms a blastocyst.
Implantation: The blastocyst attaches to the uterine lining, beginning pregnancy.
What determines the sex of the child?
Y chromosome
How are monzygotic and dizygotic twins formed? Describe each from a genetic standpoint.
Monzygotic = one egg + one sperm → one zygote splits = genetically identical twins.
Dizygotic = two eggs + two sperm → two separate zygotes = genetically different twins.
How are monzygotic and dizygotic twins formed? Describe each from a genetic standpoint.
Monzygotic = one egg + one sperm → one zygote splits = genetically identical twins.
Dizygotic = two eggs + two sperm → two separate zygotes = genetically different twins.
What factors related to the process of fertilization might impact its success?
Sperm Health:
Low sperm count
Poor sperm motility (movement)
Abnormal sperm shape
DNA damage in sperm
Egg Health:
Age (older eggs are less viable)
Poor egg maturation
Timing of Ovulation:
Must coincide with sperm presence (fertile window)
Ovulation problems (e.g., luteal phase deficiency)
Cervical Mucus:
Thin and fertile mucus helps sperm travel
Thick mucus can block sperm
Hormonal Imbalances:
In women (e.g., PCOS, thyroid issues)
In men (e.g., low testosterone affecting sperm production)
Fallopian Tube Health:
Blocked or damaged tubes prevent sperm from reaching egg
Uterine Health:
Fibroids, polyps, infections can affect implantation
Lifestyle Factors:
Smoking, alcohol, drugs reduce fertility
Poor diet and nutrition affect egg and sperm quality
High stress can disrupt ovulation
Environmental Factors:
Exposure to toxins (e.g., pesticides, plastics) harms reproductive health
Prenatal
Development
Is the process of rapid change and growth that occurs in the 40 weeks prior to the birth of a child
Follows three stages:
Preeembryonic
embryonic
fetal
Preembryonic
conception to implantation or end of week 2
Embryonic
implantation to end of week 8
Fetal
week 9 to birth
Gestation
Intrauterine development from conception through birth is called gestation
Length of human gestation
40 weeks after first day of last menstrual period, or 280 days
38 weeks after fertilization, or 266 days
Most born within 10 to 14 days of calculated date of birth
Gestation is also divided into 3 equal parts, but trimesters are different time frames then the periods of prenatal development
Age of Viability
The term for the first chance of survival to live outside the womb
Is reached at about 22 to 26 weeks
The fetus weighs up to 1.4 pounds
Hearing has developed, so the fetus can respond to sounds.
The internal organs, such as the lungs, heart, stomach, and intestines, have formed enough that a fetus born prematurely at this point has a chance to survive outside of the mother’s womb
Fetal circulation
Oxygenated blood is carried from the placenta to the fetus via the umbilical vein
Blood from the vena cava is mostly deflected through the foramen ovale – left atrium & ventrical – up ascending aorta – allows brain & heart to receive highest concentration of oxygenation
Deoxygenated blood travels from fetus to placenta through the 2 umbilical arteries
Teratogens
Teratogens are factors outside the fetus that can contribute to birth defects
About 10% of all birth defects are caused by teratogens
Can also increase the risk for miscarriage, preterm labor or stillbirth
The first 12 weeks of pregnancy are when most miscarriages occur
Examples include some STIs, maternal diseases, viruses, tobacco, drugs and alcohol, air pollution, poor maternal malnutrition, stress, and environmental and occupational exposures.
Some teratogen-caused birth defects are potentially preventable
Gravidity
Gravidity refers to the number of times a woman has been pregnant, regardless of the outcome (whether the pregnancies resulted in live births, stillbirths, or miscarriages).
Gravida
Definition: Refers to a woman who is pregnant or the number of times a woman has been pregnant.
Nulligravida
Nulli- means “none” or “zero,” and gravida refers to pregnancy, so a nulligravida is a woman with a gravid status of zero.
Primigravida
Primigravida refers to a woman who is pregnant for the first time.
Primi- means “first,” and gravida refers to pregnancy, so a primigravida is a woman who is experiencing her first pregnancy.
Multigravida
Multigravida refers to a woman who has been pregnant more than once.
Multi- means “many,” and gravida refers to pregnancy, so a multigravida is a woman who has had multiple pregnancies.
Viability
Viability refers to the ability of a fetus to survive outside the uterus, typically with medical support. This is often determined by the gestational age (how many weeks into the pregnancy the fetus is) and developmental maturity.
Parity
Parity refers to the number of pregnancies a woman has carried to a stage where the fetus has the potential to live outside the uterus, typically after 20 weeks of gestation. It is often used alongside gravidity (the total number of pregnancies) to describe a woman’s pregnancy history.
Nullipara
Nullipara refers to a woman who has never given birth to a viable fetus (i.e., a fetus that has reached at least 20 weeks of gestation).
Primipara
Primipara refers to a woman who has given birth once to a viable fetus (i.e., a fetus that has reached at least 20 weeks of gestation).
Multipara
Multipara refers to a woman who has given birth multiple times to viable fetuses (i.e., fetuses that have reached at least 20 weeks of gestation).
