Diploid
Normal number of chromosomes in nonreprocutive cells
Gamete
An ovum or spermatozoon
Haploid
normal number of chromosomes in each mature sperm or ovum
Meiosis
Cell division in sex cells
Mitosis
Cell division in non-sex cells to allow growth and replacement of cells
Oogenesis
Formation of ova
Spermatogenesis
Formation of spermatozoa
Spermatogenesis results in the formation of how many sperm from each immature primary spermatocyte
4
Each sperm contains how many autosomes
23
Sperm has a what sex chromosome
X or Y
oogenesis results in the formation of how many mature ova from each primary oocyte
1
Each ovum contains ___ autosomes and a(n) ___ sex chromosomes
23 x
An ovum survivies about ___ hours after ovulation
24
Cell division that results in the formation of reproductive cells is known as
meiosis
How many chromosomes should be contained in the normal sperm or ovum
23
After fertilization, the zygote grows by
gametogenesis
Deoxyribonucleic acid (DNA)
programs a genetic code into the nucleus of teh cell; the nucleus controls the development and function of the cell
Chromosomes
begin in pairs, one supplied by the mother and other by father
Autosomes
body chromosomes
Teratogens
cause damage to growing cells
Fertilization
when the sperm and ova unite
A sperm can survive up to how many days after ejaculation
5
If the ovum is fertilized by a sperm bearing a Y chromosome, the baby will be a
male
If the ovum is fertilized by a sperm bearing an X chromosome, the baby will be a
female
What influences does a woman have on the sex of the baby that is conceived
which sperm fertilizes the mature ovum
Fertilization usually occurs in the
outer third of the fallopian tube
The fertilized ovum usually implants in the ___ section of the ___ uterus
upper, posterior
Amnion
inner fetal membrane that envelopes the embryo and fetus
Blastocyst
Solid cluster of cells that is approximately the same size as the zygote
Blatomere
Eight cell stage of prenatal development
Chorion
Outer fetal membrane that envelops the aminion and embryo/fetus
Decidua Basalis
uterine lining after implantation that gives rise to the maternal side of the placenta
Embryo
Prenatal development from the second week until the end of the eighth week after fertilization
Fetus
Prenatal development from the ninth week after fertilization until birth
Morula
Zygote containing an inner cell mass that will develop into the embryo
Chorionic villi
Projections on the outer part of fetal side of the placenta that extend into the decidua basalis
Zygote
cell formed by union of a sperm and ovum
The normal amount of amniotic fluid near the end of pregnancy is about
1000 ml
Five functions of amniotic fluid
maintains an even temperature, prevents the amniotic sac from adhering to the fetal skin, allows symmetrical growth, allows buoyancy and fetal movement, acts as a cushion to protect the fetus and umbilical cord from injury
Red blood cells are formed by the ___ for the first six weeks after gestation and then are formed by the ___ and ___ and finally the ___
blastocyst, yok sac, embryonic liver, umbilical cord
Tissues that form in the ectoderm
outer layer of skin, oil glands and hair follicles of skin, nails and hair, external sense organs and mucous membranes of mouth and anus
Tissues that form in the mesoderm
true skin, skeleton, bone and cartilate, connective tissue, muscles, blood and blood vessels and kidnesy and gonads
Tissues that form in the endoderm
lining of trachea, pharynx, and bronchi, lining of digestive tract and lining of bladder and urethra
Four functions of the placenta
respiration, nutrition, excretion and endocrine gland
Functions of Progesterone
maintains uterine lining for implantation of the zygote, reduces uterine contractions to prevent spontaneous abortion, prepares the glands of the breasts for lactation and stimulates testes to produce testosterone
Functions of Estrogen
stimulates uterine growth, increases the blood flow to uterine vessels, stimulates development of the breast ducts to prepare for lactation, increases skin pigmentation, vascular chagnes in the skin and mucous membranes of the nose and mouth and increased
Function of Human Chorionic Gonadotropin
causes the corpus luteum to persist and to continue the production of estrogen and progesterone to sustain pregnancy
Function of Human Placental Lactogen
causes decreased insulin sensitivity and utilization of glucose by the mother
The umbilical cord should have ___ vein and ___ artery
1 and 2
Ductus arteriosus functionally
15 hours
Ductus arteriosus permanently
3 weeks
Ductus venosus functionally
cord is cut
Ductus venosus permanently
1 week
Foramen ovale functionally
2 hours
Foramen ovale permanently
3 months
3 weeks
tubular heart begins beating, earliest evidence of brain and spinal cord
6 weeks
heart ahs all four chambers
8 weeks
basic structure of all systems established
10 weeks
External genitalia may be determined by ultrasound
14 weeks
Extremities will move in response to external atimuli
20 weeks
Possible to monitor fetal status with kick coutns
28 weeks
Fetal eyes open
38 weeks
Fetus now considered full term
Where is the umbilical cord inserted into placenta
center
Length of umbilical cord
55 cm (22in)
Umbilical cord vessels
coiled
Characteristic of a monozygotic
same sex, 1 ova, 1 placenta, 1 membrane and 1 umbilical cord
Characteristic of a dizygotic
same or different sex, 2 ova, 2,placentas, 2 membranes and 2 umbilical cords
Between the second and the eigth week of pregnancy, the developing baby is known as a
embryo
Which sex chromosome combination results in conception of a male
XY
Hereditary or genetic traits are passed from one generation to the next within the
chromosomes
After sex weeks gestation, fetal red blood cells are manufactured in the
liver
Which is the outer fetal membrane
chorion
The primary function of Wharton's jelly is to
separate maternal blood from fetal blood in the placenta
Most fetal blood bypasses circulation to the lungs by way of the
foramen ovale
The fetal circulatory structures that carries blood with the lowerest oxygen saturation is the
ductus arteriosus
The formane ovale closes permanently in about ___ after birth
3 months
The primary purpose of amniotic fluid is to
protect the fetus during development
Fetal waste products are disposed of by the
placenta
Inadequate progesterone is likely to result in
spontaneous abortion
Fraternal (dizygotic) twins result when
two sperm fertilize two ova
The sex of identical (monozygotic) twins
is always the same
Three primary germ layers
ectoderm, mesoderm and endoderm
Age of viability
lungs have matured functionally enough for the fetus to survive outside the uterus
The child's sex is determined by the following
sperm which contains either an X or a Y chromosome
A woman who wants to become pregnant should avoid all medications unless they are prescribed by a physician who knows she is pregnant, because
The placenta allows most medications to cross into the fetus
The umbilical cord normally contains
two arteries and one vein
The purpose of the foramen ovale is to do
reduce blood flow to the lungs
Why are twins born early
the distended uterus becomes irritable