Chapter 7-8 Flashcards
Embryonic Period
Development from during the first 8 weeks
Fetal period
Development from the start of the 9th week until birth
Fertilization
Involves the joining of male and female gametes (sperm and eggs) to form a single cell with 46 chromosomes
Zona pellucida
Plasma membrane of the egg surrounded by a thin clear layer of protein and carbohydrates
Corona Radiata
Several jelly like layers of follicle cells that adhere to one another
Zygote
Formed from fertilized egg (46 chromosomes)
Polyspermy
Fertilization of an egg by multiple sperm, is lethal as embryo inherits multiple paternal centrioles
Cleavage
Process of cell division without cell growth, this happens to the zygote
Morula
Zygote is a sphere of 16 cells, which reached the uterus 3-5 days after fertilization
Blastocyst
Embryo at the stage in which it is implanted in the wall of the uterus and consists of a nearly hollow ball of cells
Trophoblast
Nourishes the germ, develops into the chorion (means membrane)
Chorion
Will develop to form part of the placenta
Placenta
Structure that provides nutrients and oxygen to and removes waste from the developing offspring. Secretes estrogen and progesterone to maintain the endometrium. Rich in blood vessels, that attaches to the embryo and fetus to the uterine wall where metabolic change can take place
Innercell mass
Inner cells of the blastocyst, that will develop into the embryo
Implantation
The nestling of the blastocyst into the endometrium, complete by the 10-14 day
Human Chorionic Gonadotropin
Maintains the corpus Luteum past the time when it would otherwise degenerate
Amniotic Cavity
Between the inner cell mass and trophoblast that fills with fluid baby will develop here
Amnion
Sac that supports the embryo
Embryonic disk
Supported by a short stalk that connects blastocyst with the endometrium
Gastrulation
The formation of the three primary germ layers in embryogenesis. The ectoderm, endoderm, and the mesoderm
Endoderm
Develops the liver, lining of the respiratory tract, intestinal tract, bladder and urethra. The gall bladder, the pancreas, thymus, thyroid, and parathyroid glands
Ectoderm
Develops the outer skin, nervous system, tooth enamel, eye lens, adrenal medulla, and pituitary gland
Mesoderm
Dermis of skin, muscle tissue and connective tissue, skeleton, internal reproductive organs. Heart, spleen, kidneys, and ureters
Gastrula
Developing embryo
Morphogenesis
Series of events that form distinct structures of the developing organism
Differentiation
Cellular process that enables a cell to develop a particular shape, and to perform specific functions that are different from the functions of other cells
Notochord
Rod like structure that will form the basic framework of the skeleton
Neurulation
Process of forming the neural tube which develops into the brain and spinal cord
Extra-embryonic membranes
Any membrane external to the embryo, responsible for the protection, nutrition, respiration and excretion of the embryo and fetus
Afterbirth
Expelled membranes and structure during childbirth
Chorion
First membrane to form, is the outermost membrane that encloses all other membranes and the embryo. Forms from the trophoblast
Amnion
Second membrane to form, filled with fluid that acts as a constant temperature incubator and protects the embryo from jarring
Yolk sac
Source of nourishment for vertebrates (not for humans), contributed to the digestive tract and produces the first blood cells
Allantois
Small pouch that forms from the intestinal tract that contributes to the formation of the umbilical cord
Umbilical cord
Rod like structure that leads from the navel area of the fetus to the center of the placenta. Contains two arteries that transport oxygen depleted blood from the fetus to the placenta, and one vein to bring oxygen rich blood to the fetus
First trimester
Weeks 1-12, growth in body length and cartilage of skeleton begins to harden
Second trimester
Weeks 13-24
Third trimester
Weeks 25-38
Teratogen
Any agent that causes a structural abnormality due to exposure during pregnancy
Fetal alcohol spectrum disorder
Described all the disorders related to alcohol consumption during pregnancy. Alcohol is the most damaging teratogen, affects the brain, nervous system and physical development
Nutrients as a teratogen
If ingested in large amounts the baby becomes accustomed to large doses and after birth the supply drops, so the baby has a deficiency
Parturition
Birthing process, commonly referred to as labour. Events begin with uterine contractions
Onset of labour
Marked by uterine contractions occurring every 15-20 minutes and lasting 40 seconds or longer.
Contractions
Induced by a stretching of the cervix and brings about the release of oxytocin from the posterior pituitary gland
Caesarean Section
Incision in the mothers abdomen and uterus, the baby is delivered through the incision
Dilation stage
Uterine contractions and oxytocin cause the cervix to open or dilate. Amniotic sac breaks releasing fluid from the vagkna
Expulsion stage
Forceful contractions push the baby through the cervix to the birth canal
Placental Stage
10-15 minutes after the baby is born, the placenta and umbilical cord are expelled from the uterus called after birth
Lactation
Secretion and formation of breast milk in the mother. Baby suckles stimulating nerve endings in nipple and Areola, travels to the hypothalamus, stimulates posterior pituitary to release oxytocin. Oxytocin causes contraction of mammary lobules and produces milk.
Prolactin
Hormone needed for milk production
Sterile
Describes men and women who are unable to have any children
Infertile
Difficulty conceiving children, after unsuccessfully trying to have children for a year or more
Artificial insemination
Sperm are collected and concentrated before being placed in the woman’s vagina
In vitro fertilization
Ultrasound machines are used to identify specific follicles that are close to ovulation eggs can be retrieved from these follicles. Combined with sperm in glassware. Fertilization occurs and then the embryo is placed in the uterus
Surrogate mothers
Infertile couple has another woman carry their baby, one or both gametes may be contributed by the couple
Super ovulation
Production of multiple eggs as a result of hormone treatment used by women who ovulate rarely or not at all
Abstinence
Not having sexual intercourse, cannot contact stis
Tubal ligation
In women, involves cutting the oviducts and tying off the cut ends. Ensures ovum never reached the uterus or encounters sperm
Vasectomy
Ductus Deferens is cut and tied, man still has an erection and ejaculates but semen does not contain any sperm
Contraceptive technologies
Changed the balance of reproductive hormones in a women’s body. Mimics the effect of progesterone and inhibits the release of FSH and LH from anterior pituitary. Women does not ovulate
Morning after pill
Emergency hormone treatment after unprotected sexual intercourse, release high levels of estrogen and progesterone that disrupt or delay the ovarian cycle
Physical or Chemical Barriers
Include condoms, latex cap, and contraceptive sponge. Spermicides (kills sperm) can be used together to increase effectiveness
Natural Family planning
Refrain from intercourse when a women is most fertile (week before ovulation to a day or two after)
