35 Fertilization, Embryology, Parturition and Lactation

Flashcards covering fertilization, embryology, parturition, and lactation based on lecture notes.

Fertilization

Begins with the union of gametes.

Developmental biology

Studies changes from fertilized egg to old age.

Embryology

Studies 38 weeks of development.

Prenatal period

Time in the womb.

Postnatal period

Period following birth.

Conceptus

Growing offspring that develops during gestation period.

Gestation period

Lasts 38 weeks and divided into 3 stages: pre-embryonic, embryonic, fetal.

Pre-embryonic period

Weeks 1 and 2; zygote divides mitotically many times to produce a multicellular blastocyst that implants in the uterus.

Embryonic period

Weeks 3 through 8; blastocyst grows, folds, and forms rudimentary organ systems, now called an embryo.

Fetal period

Weeks 9 through 38 (until birth); embryo is now called a fetus that grows larger and develops until its organ systems can function without assistance from the mother.

Senescence

Development ends and degeneration of tissues and organs, leading to death.

Fertilization

Fusion of sperm and secondary oocyte forming zygote.

Capacitation

Sperm becomes fully motile and fuse with oocyte; alkaline semen allows sperm to swim faster.

Acrosomal Reaction

Releases hyaluronidase and acrosin from acrosome in head of sperm; hyaluronidase breaks down granulosa cells and acrosin is a protease.

Cortical Reaction

Penetration of sperm produces changes in oocyte and zona pellucida preventing additional sperm from entering; sperm entry releases cortical granules destroying sperm binding receptors.

Polyspermy

Additional sperm entry, resulting in a 3n zygote.

Amphimixis

Pronuclei combine forming diploid zygote.

Cleavage

Zygote begins cleavage 30 hours after fertilization producing identical cells called blastomeres.

Morula

Conceptus in 16 cell stage covered by zona pellucida.

Uterine milk

Glycogen rich secretions from endometrial glands nourishes conceptus.

Trophoblast cells

Outer layer surrounding fluid filled cavity to help form placenta.

Inner cell mass

Inner cluster that becomes embryo.

Monozygotic twins

Identical twins formed when cells separate into 2 individuals in the first 8 days.

Dizygotic twins

Fraternal twins; occurs when 2 secondary oocytes ovulate.

Ectopic pregnancy

Blastocyst implants in a different site than the uterus.

Extraembryonic Membranes

Protects embryo and assists with vital functions.

Yolk sac

From hypoblast cells. forms part of digestive tract, first blood cells and vessels, and first germ cells.

Amnion

Develops from epiblast enclosing embryo in fluid filled amniotic cavity; protects embryo from trauma, maintains temperature, and allows freedom of movement.

Allantois

Out pocketing of yolk sac, forms base of umbilical cord and part of urinary bladder.

Chorion

Develops from cytotrophoblast and syncytiotrophoblast; encloses all other membranes and embryo; forms chorionic villi that blends with the stratum functionalis forming placenta.

Gastrulation

Rearrangement and migration of bilaminar embryonic disc to form trilaminar embryonic disc.

Primitive streak

Week 3, forms groove on surface of epiblast; forms head and tail regions, right and left sides and dorsal and ventral surfaces of embryo.

Neurulation

Formation of brain and spinal cord.

Notochord

Supports body and remain as intervertebral discs.

Placenta

Temporary organ for exchange of O2, nutrients and waste between mother and fetus through umbilical cord.

Umbilical cord

Connects placenta to fetus, containing 2 umbilical arteries and 1 umbilical vein.

Decidua basalis

At placentation stratum functionalis becomes the decidua basalis.

Placental barrier

Maternal and fetal blood do not mix due to placental barrier formed by maternal and fetal basal lamina, fetal connective tissue, cytotrophoblast and synctiotrophoblast.

Hemoglobin F

Fetal hemoglobin that has a higher affinity to O2 than adult hemoglobin.

Teratogens

Agents that cross placenta and harm embryo mostly during organogenesis.

hCG

Human chorionic gonadotropin secreted by the placenta.

hPL

Human placental lactogen; prepares mammary glands.

Lanugo

Hair covering the skin of the fetus.

Surfactant

Produced by fetal lungs.

Parturition

Childbirth.

Lactation

Production and release of breast milk from mammary glands.

Colostrum

Secreted after birth; rich in protein and IgA but low in fat.

Meconium

Fecal material first excreted by newborn.

Relaxin

From placenta, suppresses uterine contractions and loosens pubic symphysis and sacroiliac joints.

CRH

Corticotropin-releasing hormone; at week 12, cortisol from adrenal cortex matures fetal lungs.

Oxytocin

From fetal and maternal hypothalamus during labor to stimulate uterine contractions and milk release.

Fertilization

Begins with the union of gametes.

Developmental biology

Studies changes from fertilized egg to old age.

Embryology

Studies 38 weeks of development.

Prenatal period

Time in the womb.

Postnatal period

Period following birth.

Conceptus

Growing offspring that develops during gestation period.

Gestation period

Lasts 38 weeks and divided into 3 stages: pre-embryonic, embryonic, fetal.

Pre-embryonic period

Weeks 1 and 2; zygote divides mitotically many times to produce a multicellular blastocyst that implants in the uterus.

Embryonic period

Weeks 3 through 8; blastocyst grows, folds, and forms rudimentary organ systems, now called an embryo.

Fetal period

Weeks 9 through 38 (until birth); embryo is now called a fetus that grows larger and develops until its organ systems can function without assistance from the mother.

Senescence

Development ends and degeneration of tissues and organs, leading to death.

Fertilization

Fusion of sperm and secondary oocyte forming zygote.

Capacitation

Sperm becomes fully motile and fuse with oocyte; alkaline semen allows sperm to swim faster.

Acrosomal Reaction

Releases hyaluronidase and acrosin from acrosome in head of sperm; hyaluronidase breaks down granulosa cells and acrosin is a protease.

Cortical Reaction

Penetration of sperm produces changes in oocyte and zona pellucida preventing additional sperm from entering; sperm entry releases cortical granules destroying sperm binding receptors.

Polyspermy

Additional sperm entry, resulting in a 3n zygote.

Amphimixis

Pronuclei combine forming diploid zygote.

Cleavage

Zygote begins cleavage 30 hours after fertilization producing identical cells called blastomeres.

Morula

Conceptus in 16 cell stage covered by zona pellucida.

Uterine milk

Glycogen rich secretions from endometrial glands nourishes conceptus.

Trophoblast cells

Outer layer surrounding fluid filled cavity to help form placenta.

Inner cell mass

Inner cluster that becomes embryo.

Monozygotic twins

Identical twins formed when cells separate into 2 individuals in the first 8 days.

Dizygotic twins

Fraternal twins; occurs when 2 secondary oocytes ovulate.

Ectopic pregnancy

Blastocyst implants in a different site than the uterus.

Extraembryonic Membranes

Protects embryo and assists with vital functions.

Yolk sac

From hypoblast cells. forms part of digestive tract, first blood cells and vessels, and first germ cells.

Amnion

Develops from epiblast enclosing embryo in fluid filled amniotic cavity; protects embryo from trauma, maintains temperature, and allows freedom of movement.

Allantois

Out pocketing of yolk sac, forms base of umbilical cord and part of urinary bladder.

Chorion

Develops from cytotrophoblast and syncytiotrophoblast; encloses all other membranes and embryo; forms chorionic villi that blends with the stratum functionalis forming placenta.

Gastrulation

Rearrangement and migration of bilaminar embryonic disc to form trilaminar embryonic disc.

Primitive streak

Week 3, forms groove on surface of epiblast; forms head and tail regions, right and left sides and dorsal and ventral surfaces of embryo.

Neurulation

Formation of brain and spinal cord.

Notochord

Supports body and remain as intervertebral discs.

Placenta

Temporary organ for exchange of O2, nutrients and waste between mother and fetus through umbilical cord.

Umbilical cord

Connects placenta to fetus, containing 2 umbilical arteries and 1 umbilical vein.

Decidua basalis

At placentation stratum functionalis becomes the decidua basalis.

Placental barrier

Maternal and fetal blood do not mix due to placental barrier formed by maternal and fetal basal lamina, fetal connective tissue, cytotrophoblast and synctiotrophoblast.

Hemoglobin F

Fetal hemoglobin that has a higher affinity to O2 than adult hemoglobin.

Teratogens

Agents that cross placenta and harm embryo mostly during organogenesis.

hCG

Human chorionic gonadotropin secreted by the placenta.

hPL

Human placental lactogen; prepares mammary glands.

Lanugo

Hair covering the skin of the fetus.

Surfactant

Produced by fetal lungs.

Parturition

Childbirth.

Production and release of breast