Reproduction, Development, Genetics Flashcards Preview

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Flashcards in Reproduction, Development, Genetics Deck (32):

What is the length of the typical female reproductive cycle? The duration of the flow? What three things does it consist of?

Cycle length is 21-36 days. Duration of flow is 3-7 days.
Ovarian cycle, uterine cycle, hormones


Released by the hypothalamus to being the phase.
Released by the pituitary to signal ovaries to produce multiple immature follicles and eggs to ripen.



Secreted in the ovaries, causes the endometrium and myometrium to thicken.
From the anterior pituitary, responsible for final development and rupture of the mature follicle



Begins with the egg (ovum) developing in the ovary.

Ovarian cycle. Follicular cells (ovum and surrounding) start to swell and mature. Usually only one of the many follicles reaches ovulation. Starts on day 1 of menstrual cycle to ovulation, which is usually 10-14 days later but can be inconsistent.


What happens from day five of the ovarian cycle to ovulation?

Estrogen causes endometrial thickening of the uterus to support implantation. Cervical mucus becomes thin, clear, stretchy, alkaline to better accept sperm. Dependent on estrogen stimulation from the follicle.


Surge of LH causes mature follicles to rupture, releasing mature oocyte and causing a drop in estrogen.

Ovulation. Usually day 14 of 28 day cycle, 14 days before menstruation. Ovulation 12 hours after LH peaks. Fallopian tubes become active at ovulation to carry ovum to uterus by currents. Ovum only lives 12-24 hours unless fertilized.


What are symptoms of ovulation?

Vaginal wetness, cramping. Increased libido. Slight increase in body temperature.


What happens after ovulation?

At the site of the follicle rupturing, corpus luteum forms. Secretes progesterone to help prepare endometrium of the uterus for implantation. Progesterone causes an increase in temperature (0.5-1) a day or two after ovulation. Without fertilization, corpus luteum degenerates and estrogen and progesterone levels drop.


Day 15 to 28 of a 28 day cycle.

Progesterone causes continued thickening of the endometrium with increased vascularity. By a few days before the end of the cycle, if no fertilization, estrogen and progesterone levels drop and involution (shrinkage) of the uterus occurs.


Stages of an egg from before fertilization to implantation?

Oocyte. Oocyte in tube. Fertilization. Zygote. Two-cel stage. Four-cell stage. Eight-cell stage. Monula. Blastocysts.


After fertilization, may cell divisions become differentiated structures. Explain?

Inner layer of the division becomes the embryo and amnion. Outer layer becomes the chorion and helps to form the placenta.
XX is female. XY is male.


What is the most critical time for the baby?

Through week 8. Embryonic membranes form the amniotic fluid-filled sac surrounding the embryo.


What fluid fluctuates during pregnancy? What are its functions?

Amniotic fluid. Later in pregnancy, it helps to determine the well-being of the pregnancy. Physical protection of fetus for muscle development, temp regulation, symmetrical growth, provision of unrestricted movement, allows the cord to be from compression.


What is amniotic fluid composed of?

Water, shed epithelial cells, hair, sebaceous secretions. Fetal urine: the fetus swallows amniotic fluid and voids it.


Explain the umbilical cord.

Length is determined by genetics, space, and fetal activity. Maternal and fetal blood do not circulate together, but maternal blood can leak in to the fetal in small amounts. Can have two different blood types.


What is the umbilical cord covered in?

Wharton's jelly. Connective tissue, gelatinous. Protects the cord against compression.


Formed from the chorionic villa. Function depends on the mother's BP supplying blood circulation. Functions?

Placenta. Acts as a barrier against harmful things, protects the fetus from attack by the mother's immune system and things that would be seen as a foreign body. Nourishes the fetus with oxygen and nutrients. Removes fetal wastes. Produces hormones.


Supplies oxygenated blood and nutrients to the placenta.
Removes deoxygenated blood and wastes from the fetus and takes it to the placenta where it is diffused over the placental barrier.

Maternal uterine arteries
Umbilical arteries


Takes the oxygen and nutrients to the fetus after diffusion over the placental barrier.
Removes deoxygenated blood and wastes from the placenta.

Umbilical vein
Maternal uterine veins


What does human chorionic gonadotropin do?

hCG. Preserves the corpus luteum and its production of progesterone so that the endometrial lining is maintained.


What does human placental lactogen do?

hPL. Controls fetal and maternal metabolism. Increases insulin availability to the fetus. Helps in milk production.


What does estrogen do? Progesterone?

Estrogen enlarges the breasts and uterus, stimulates the contractility of the uterus.
Progesterone maintains the endometrium, decreases contractility to avoid premature labor.


What does relaxin do?

Works with progesterone to maintain pregnancy. To soften the cervix and pelvic ligaments for delivery.


What happens at 4 weeks of embryonic development?

Differentation of brain. Arms and legs: bud-shaped features. Foundation for the body systems in place.


What happens at 8 weeks of embryonic development?

Looks human. Heart development is complete. Fingers and toes are distinct and separate.


What happens at 12 weeks of fetal development?

Teeth buds complete. Face is well-formed. Gender can be determined. Heartbeat is audible via doppler. Digestive system working, urination occurs.


What happens at 16 weeks of fetal development?

Actively moving. Weight has quadrupled. Quickening may be felt by the mother.


What happens at 20 weeks of fetal development?

Vernix covers the fetus. Well-developed muscles. Fetal movement is definitely felt by the mother.


What happens at 24 weeks of fetal development?

Lungs start to produce surfactant. Alveoli forming in the lungs. Hand grasp and startle reflexes.


What happens at 38 weeks of fetal development?

Fetus is considered to be full-term.


Can either be inherited or due to random events during early embryonic development? Monosomy? Trisomy?

Chromosome abnormalities.
Monosomy is a chromosome that has only one copy, whereas trisomy is three copes.


Explain recessive x-linked chromosomes?

One only allele is needed and only men are effected. It is found on the X chromosome and is donated by the woman.