ch 2: prenatal development Flashcards
zygote
the single cell formed from seperate spem and egg cells at conception
ovum
the cell released monthly from a woman’s ovaries, which, if fertillized, forms the basis for the developing organism
fallopian tube
the tube between the ovary and the uterus down which the ovum travels to the uterus and in which conception usually occurs
uterus
the female organ in which the embryo/fetus devlops(popularly reffered to as the womb)
sperm
the cells produced in a mans testes that may fertilized an ovum following intercoruse
chromosomes
the structures, arrayed in 23 pairs, within each cell in the body that contain genetic information. Each chromosome is made up of many segments called genes
gametes
sperms and ova. These cells, unlike all other cells of the body, contain only 23 chromosomes rahter than 23 paris
deoxiribonucleic acid( DNA)
the chemilcal of which chromosomes are composed
what is a locus?
a gene that controlling or influencing a specific characteristic always appears in the same place. ex: blood type
what is the Human Genome Project (HGP)
a project that has identified every locus of every human gene
autosomes
the 22 chromosomes pairs
sex chromosomes
comes in two variety, referred to as the X and the Y chromosomes
polygenic pattern of inheritance
any pattern of genti transmission in which multiple genes contribute to the outcome, such as is presumed to occur for complex traits such as intelligence or temparent
multifactorial pattern of inheritance
the pattern of gentic transmission in which both genes and environment influence the phenotype
What is genomic imprinting?
in which some genes are biochemically markat the time ova and sperm devlop in the bodies of potential mothers and fathers.
mitochondrial inheritance
chidlren inherit genes located outside the nucleus of the zygote
mitochondria
DNA that is passed from mother- and duaghter
fraternal(dizygotic) twins
children carried in the same pregnancy but develop from two sperately fertilized ova. They are no more alike than other paris of siblings
identical (monzygotic) twins
Children carried in the smae pregnancy who develop from two sperately fertilized ovum. They are gentic clones of each other
germinal stage
the first stage of prenatal devlopment beginning at conception and ending at implantation of the zygote in the uterus (approximately in the first 2 weeks)
blastocys
Name for the mass of cells from roughly 4-10 days after fertlization
embryo
the name given to the developing organism during the period of prenatal devleopment between about 2 weeks and 8 weks after conception, begining with implanatation of the blastocyst in the uterine wall.
embryonic stage
the second stages of prenatal developmet from week 2 through week 8, when embryo’s organs form,
amnion
the sac, or bag, filled with liquid in which the emryo/ fetus floats during prenatal life
chorion
the outer layer of cells of the blastocyst during prenatal devlopment, from which both the plancenta and the umbilical cord are formed
placenta
an organ that develops between the fetus and the wall of the uterus during gestation