Ch 10 Fetal development and genetics Flashcards
Pre-embryonic stage
Fertilization through the second week
Fertilization
Union of ovum and sperm
Zygote
The cell produced by the union of two gametes; the fertilized ovum
Zona pellucida
The inner, solid, thick, membranous envelope of the ovum. Clear protein layer surrounding the ova
Morula
After a series of four cleavages, the 16 cells appear as a solid ball of cells. A solid mass of cells, resembling a mulberry, resulting from cleavage of an ovum
Blastocyte
The stage that follows the morula. It consists of an outer layer the tropho blast, and an inner cell mass the Blastocoeal. At this stage the implementation of the endometrium occurs
Trophoblast
The outer most layer of the developing blastocyte
Implantation
The process of attachment and placental formation
Ectoderm
Forms the central nervous system, special senses, skin, and glands
Mesoderm
Forms the skeletal, urinary, circulatory, and reproductive organs
Endoderm
Forms the respiratory system, liver, pancreas, and digestive system
Embryonic stage
Begins at day 15 and continues through week eight. Basic structures of all major body organs and the main external features are completed during this time period, including internal organs
Umbilical cord
Contains one large vein and two small arteries
Placenta
Protects the fetus from immune attack by the mother, removes waste products from the fetus, and this is the mother to bring more food to the placenta, and near the time of delivery, produces hormones that ready fetal organs for life outside the uterus allows the developing fetus to rely on the maternal circulation to fulfill its bio genetic needs while growing undisturbed in the protected environment of the uterus
hCH
Preserves the corpus luteum and its progesterone production so that the endometrium lining of the uterus is maintained; this is the basis for pregnancy test
Human placental lactogen (hPI)
Modulate fetal and maternal metabolism, participates in the development of maternal breast for lactation, and decreases maternal glucose utilization, which increases glucose availability to the fetus
Estrogen
Causes enlargement of a woman’s breast, uterus, and external genitalia; stimulates myometrial contractility
Progesterone
Maintains the endometrium, decreases the contractility of the uterus, stimulates maternal metabolism and breast development, provides nourishment for the early conceptus (The products of conception after fertilization in the early stages of growth and differentiation)
Relaxin
Act synergistically with progesterone to maintain pregnancy, causes relaxation of the pelvic ligaments, and softens the cervix in preparation for birth
Teratogens 
Any substance, organism, physical agent, or deficiency state present during gestation that is capable of inducing abnormal postnatal structure or function by interfering with normal embryonic and fetal development
Fetal stage
The end of the eighth week through birth
Genetics
Study of individual genes and their role in inheritance
Genomics
Study of all genes and include includes, interactions among genes, as well as interactions between genes and the environment
Genome
Genetic blueprint
