EXAM 2 Reproduction Flashcards
(839 cards)
What is gametogenesis?
Creation of reproductive cells
Gametogenesis is the process that leads to the formation of gametes, which are the reproductive cells in organisms.
Define meiosis.
Reduction cell division in gametes that halves the number of chromosomes in each cell
Meiosis is crucial for sexual reproduction and ensures genetic diversity.
What is mitosis?
Cell division
Mitosis results in two identical daughter cells and is essential for growth and repair.
What is oogenesis?
Process of forming an ovum during female prenatal development
Oogenesis begins before birth and continues until menopause.
What is spermatogenesis?
Formation of male gametes in the testes
Spermatogenesis occurs continuously after puberty and produces sperm.
What is ovulation?
The release of an ovum into the fallopian tubes
Ovulation typically occurs about once a month in females.
What is ejaculation?
Expression of sperm and semen from penis
Ejaculation is a key part of male reproductive function.
Define zygote.
Cell formed by union of an ovum and a sperm
The zygote undergoes multiple divisions to develop into an embryo.
What is a morula?
An early stage of embryonic development around 4 days after fertilization, consisting of a solid ball of 12-16 cells
The morula resembles a mulberry and precedes the blastocyst stage.
What is the decidua?
The modified endometrium (uterine lining) that provides nutrients for the developing embryo/fetus during pregnancy
The decidua plays a vital role in supporting embryo development.
Define blastocyst.
An early stage of embryonic development around 5-6 days after fertilization, consisting of an outer trophoblast layer and an inner cell mass
The blastocyst is critical for implantation in the uterine wall.
What is the trophoblast?
The outer cell layer of the blastocyst that forms part of the placenta and surrounds the inner cell mass
The trophoblast is essential for establishing pregnancy.
What is the embryonic period?
The stage of pregnancy from day 15 through 8 weeks after fertilization when major organ systems develop
This period is critical and vulnerable to teratogens.
Define teratogens.
Substances, exposures, infections, or health problems that can cause abnormal fetal development and birth defects
Teratogens can have severe effects on the developing fetus.
What is the fetal period?
The stage after the embryonic period, from 9 weeks after fertilization until birth, when the developing baby is called a fetus
During this period, growth and maturation of organs continue.
What is the chorion?
The outer membrane surrounding the fetus that contributes to the placenta
The chorion plays a key role in nutrient and gas exchange.
Define amnion.
The inner membrane surrounding the fetus that contains amniotic fluid
Amniotic fluid protects the fetus and allows for movement.
What is monozygotic twinning?
When a single fertilized egg splits, resulting in identical twins with the same genetic makeup
Monozygotic twins share 100% of their genes.
Define dizygotic twinning.
When two separate eggs are fertilized by two different sperm, resulting in fraternal twins with different genetic makeups
Dizygotic twins share about 50% of their genes.
What are the three germ layers?
Ectoderm, Mesoderm, Endoderm
The germ layers are the primary layers of cells in the developing embryo.
What does the ectoderm develop into?
Nervous system, sensory organs, skin, nails, hair, tooth enamel
The ectoderm is the outermost layer of the germ layers.
What are the derivatives of the mesoderm?
Muscles, bones, connective tissues, blood, blood vessels, reproductive and excretory systems
The mesoderm is the middle layer of the germ layers.
What does the endoderm give rise to?
Digestive system, respiratory system, urinary bladder, thyroid, parathyroid glands
The endoderm is the innermost layer of the germ layers.
Which germ layer is responsible for developing the nervous system?
Ectoderm
The nervous system is a key derivative of the ectoderm.