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
twins, fraternal twins, may or may not be of the same sex and develop from two separate ova fertilized by two seperate sperm
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.
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
Any substance, agent, or process that interferes with normal prenatal development, causing the formation of one or more developmental abnormalities in the fetus.
46, 22, 1
Each body cell contains ___ chromosomes, made up of ___ autosomes and __ pair of sex chromosomes that determines the sex of the fetus.
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)?
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.
What two levels in the female reproductive tract can effect the outcome of the sex of a child?
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).
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)
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.
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?
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.
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
red blood cells
The yolk sac only functions during embryonic life and initates the production of ____ ______ ______.
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
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.
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:
Causes the corpus luteum to persist and to continue the production of estrogen and progesterone to sustain pregnancy
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?
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?
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?
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?