Age of viability
20 weeks of gestation
bag of waters
develops from the trophoblast and evelops the amnion, embryo, and yolk sac
the part of the mucous membrane lining the uterus that in higher placental mammals undergoes special modifications in preparation for and during pregnancy and is cast off at parturition, being made up in the human of a part lining the uterus, a part enveloping the embryo, and a part participating with the chorion in the formation of the placenta
the 46 chromosomes in a body cell
twins, fraternal twins, may or may not be of the same sex and develop from two separate ova fertilized by two seperate sperm
when the sperm and ova unite
is a process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes.
After implantation the zygote in the blastocyst stage transforms its embryonic disc into three primary germ layers known as ectoderm, mesoderm, and endoderm.
23 chromosomes per cell
twins, often called identical twins, are genetically identical, are of the same sex, and look a like, because they develop from a single fertilized ovum
The process of mitosis in the ovum
The process of mitosis in the sperm
Any substance, agent, or process that interferes with normal prenatal development, causing the formation of one or more developmental abnormalities in the fetus.
covers and cushions the cord vessels and keeps the three vessels seperated
DNA or Deoxyribonucleic acid
programs a genetic code into the nucleus of the cell.
Chromosomes begin in ___________?
46, 22, 1
Each body cell contains ___ chromosomes, made up of ___ autosomes and __ pair of sex chromosomes that determines the sex of the fetus.
What is the basis of human growth and regeneration>
During prenatal development environmental factors (also called ___________) can have a determental affect on the growing cells of the fetus.
In what part of the cell does division begin (which also contains the gene-bearing chromosomes)?
How many different types of cell division are there?
One type of cell division in which a continuious process by which the body grows and develops and dead body cells are replaced is called _________? (In this type each daughter cell contains the same amount of chromosomes as the parent cell)
In this type of cell division the reproductive cells undergo two sequential divisions. The number of chromosomes in each cell is reduced to half (23 per) and each having only one sex chromosome. Upon fertilization of the sperm and ova (each having 23 cells) they unite to form one cell having 46 chormosomes and traits are inherited from both the father and mother.
Occurs when a sperm penetrates an ovum and unites with it, restoring the total number of chromosomes to 46. This usually occurs in the outer third of the fallopian tube, near the ovary.
Within how many minutes after intercourse can the sperm reach the fallopian tubes?
How many hours can the mature ovum survive after ovulation?
After entering the cervix how many days can the sperm survive to fertilize the ovum?
How many days before ovulation can pregancy occur after intercourse?
The ______ of human offspring is determined at fertilization?
What can carry an X or Y chormosome?
What two types of chromosomes are requried to cause the sex of the child to be female?
If the sperm that fertilizies the egg has XY what will be the sex of the child?
What two levels in the female reproductive tract can effect the outcome of the sex of a child?
A _____ is a segment of the DNA chain.
The ______ traits usually overpower the _______ traits and are passed on to the offspring
If one parent only carries the dominant trait what percentage of the offspring will inherit that trait?
If _______ parents carry a ________ trait it is likely that one of the offspring will display that trait.
The ________ is the cell formed by the union of the sperm and the ovum, and it is transported through the fallopian tube and into the uterus.
During transport through the fallopian tubes the zygote undergoes rapid ________ division (or cleavage).
How many cells does cleavage begin with that subdivide into four and then into eight?
The zygote is called a ___________ once it has divided into eight cells. (The size has not changed of the zygote itself, rather the divided cells are smaller in size)
Once a blastomere has become a solid ball it is called a _______?
The morula enters the uterus on the ______ day and floats there for another 2 to 4 days. The cells form a cavity and two distinct layers evlove.
The inner layer is a solid mass of cells called a __________, which develops into the embryo and embronic membranes.
The outter layer, called the ________, develops into the chorion.
When a zygote does not move through the fallopian tube and instead becomes implanted into the lining of the tube, this results in a _______ __________ pregnancy?
The zygote normally implants in the _______ section of the _________ uterine wall.
What gives rise to the maternal part of the placenta?
What thick membrane with fingerlike projections (villi) on its outermost surface develops from the trophoblast and evelops the amnion, embryo, and yolk sac?
The villi immediately below the embryo extend into the decidua basalis on the uterine wall and form the _______/_________ portion of the placenta.
The _________ is the second membrane and is a thin structure that envelops and protects the embryo. It forms the boundaries of the amniotic cavity, and its outer aspect meets the inner aspect of the chorion.
The combination of the chorion and amnion together form an _____ ____ filled with fluid that permits the embryo to float freely.
What color is amniotic fluid?
Does amniotic fluid have an odor?
What two items does the amniotic fluid usually contain?
Fetal skin covering
Fetal hair on skin
How much amniotic fluid is usually present at 10 weeks?
How much amniotic fluid is usually present at 20 weeks?
How much amniotic fluid is usually present at 37 weeks?
During the latter portion of pregnancy how much amniotic fluid does the fetus usually swallow per day? (It is then excreted back into the fluid)
temperature, skin, symmetrical, movement, cushions
Name five functions of the amniotic fluid? Maintains an even _______; prevents the sac from adhering to the fetal _____; allows __________ growth; allows buoyancy and fetal _______: ______ and protects the fetus and umbilical cord from injury
What forms on the ninth day after fertilization in the blastocyst?
red blood cells
The yolk sac only functions during embryonic life and initates the production of ____ ______ ______.
The function of the yolk sac last for about six weeks until the embryonic _____ takes over.
The ________ cord encompasses the yolk sac, and the yolk sac degenerates.
Outer layer of skin; oil glands and hair follicles of skin; nails and hair; external sense organs; mucous membrane of mouth and anus
true skin; skeleton; bone and cartilage; connective tissue; muscles; blood and blood vessels; kidneys and gonads
linging of trachea; pharynx; and bronchi; lining of digestive tract; lining of bladder and urethra
zygote, embryo, fetus
There basic stages characterize prenatal development:
The second to eighth week of development (the infant is called an embryo)
From the ninth week till birth the developing infant is called a _____
The fetus is considered full term at ___ to ____ weeks
Is a temporary organ for fetal respiration, nutrition, and excretion. It also functions as an endocrine gland.
Provides some protection but is not a barrier to most substances ingested by the mother.
progesterone, estrogen, hCG, hPL
Four hormones produced by the placenta:
1) Maintains uterine lining for implantation of the zygote; 2) Reduces unterine contractions to prevent spontaneous abortion; 3) Prepares the glands of the breast for lactation; 4) Stimulates testes to produce testosterone, which aids the male fetus in developing the reproductive tract
What are the four functions of progesterone during pregnancy?
1) Stimulates uterine growth; 2) Increases the blood flow to uterine vessels; 3) Stimulates development of the breast ducts to prepare for lactation
Estrogen has three important functions during pregnancy:
1) Increased skin pigmentation, "mask of pregnancy" 2) Vascular changes in the skin and the mucous membranes of the nose and mouth; 3) Increased salivation
Effects of estrogen that are not related directly to pregnancy are:
What is the "signal" sent to the corpus luteum that conception has occured?
Causes the corpus luteum to persist and to continue the production of estrogen and progesterone to sustain pregnancy
When is hCG detectable in maternal blood?
hPL (or hCS)
Causes decreased insulin sensitivity and utilization of glucose by the mother.
What is the lifeline between mother and fetus?
_____ artery(ies) carry blood away from the fetus, and ____ vein(s) returns blood to fetus.
The normal length of the umbilical cord is usually about ___ inches.
The umbilical cord is usually inserted near the _____ of the placenta.
AVA (The name of a woman -- artery -vein-artery)
What is the easy method used to remember the amount of arteries and veins in the umbilical cord?
How many sperm develop from one spermatocyte?
4 weeks of gestation
Circulation of blood through the placenta to the fetus is well established after how many weeks of gestation?
Which fetal circulatory shunt diverts some blood away from the livers as it returns from the placenta?
Which fetal circulatory shunt diverts most blood from the right atrium directly to the left atrium, rather than circulating it to the lungs?
Which fetal circulatory shunt diverts most blood from the pulmonary artery into the aorta?
Oxygenated blood enters the fetal body through the which vein?
Half of the oxygenated blood goes to the liver through the end of the umbilical vein which is also known as what?
The remainder of the blood goes to the inferior vena cava through which fetal circulatory shut?
Blood in the inferior vena cava enters the right atrium when most passes directly into the left atrium through which fetal circulatory shut?
A small amount of blood is pumped to the lungs by the right ventricle. The rest of the blood from the right ventricle joins that from the left ventricle through which fetal circulatory shut?
Blood containing waste products is returned to the placenta through what arteries?
No, because the blood is now circulated through the lungs.
Are fetal shunts needed after birth?
Which shunt closes after birth because of pressure in the right side of the heart falls as the lungs become fully inflated and there is little resistance to blood flow?
Which shunt closes after birth because the infant's blood oxygen level rises?
Which shunt closes after birth when the flow to the umbilical cord stops?
2 hours after birth; 3 months
When does the foramen ovale close functionally and permanently?
15 hours after birth; 3 weeks
When does the ductus arteriosus close functionally and permanently?
When the cord is cut; 1 week
When does the ductus venosus close functionally and permanently?
Ductus venosus, Ductus arteriosus
Which two shunts become ligaments?
If the blood oxygen level decreases after birth, which shunt can reopen?
A condition that impedes full lung expansion after birth can increase causing which shunt to reopen?