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Chapter 21
Human Development and Genetics
Question | Answer |
---|---|
How many chromosomes does the human female egg have? | 23 |
How many chromosomes does the human male sperm have? | 23 |
The union of a human egg and sperm form a? | Zygote |
How many chromosomes does the human zygote have? | 46 |
The human _________ contains 46 chromosomes. | Zygote |
The zygote is formed by the union of? | Egg and sperm |
Where does fertilization of the ovum take place? | In the fallopian tube |
Fertilization of the ________ takes place in the fallopian tube. | Ovum |
When a zygote undergoes cleavage, the process of cell division is called? | Mitosis |
The zygote begins a series of cell divisions called? | Cleavage |
Mitosis is the process of? | Cell division |
The early embryonic stage is called the? | Morula |
The morula is a solid sphere of? | Cells |
The early embryonic stage that is a solid sphere of cells is the? | Morula |
The morula stage of early embryonic development may be described as? | Solid sphere of cells |
The early embryonic stage that is a hollow sphere of cells with an inner cell mast is the? | Blastocyst |
The cells of the blastocyst are called? | Stem cells |
The are called stem cells because they are not yet? | Specialized |
What part of the blastocyst secretes enzymes to permit implantation? | The trophoblast |
The trophoblast is the part of the blastocyst that secretes enzymes to? | Permit implantation |
The trophoblast secretes enzymes to permit implantation in the? | Uterus |
Where does normal implantation of a blastocyst take place? | Endometrium of the uterus |
The endometrium of the uterus is where implantation of a __________ takes place. | Blastocyst |
The average human gestation period is? | 40 weeks |
During an average gestation period, the period of embryonic growth lasts? | 8 weeks |
During an average gestation period, the period of fetal growth lasts? | 32 weeks |
During gestation, the first 8 weeks are considered the _________ growth period. | Embryonic |
During gestation, the last 32 weeks are considerd the _________ growth period. | Fetal |
In the embryo, how many germ or primary layers are there? | Three |
The ectoderm, mesoderm, and endoderm are the __________ of the embryo. | Primary or germ layers |
In the embryo, the epidermis and nervous system are derived from the? | Ectoderm |
In the embryo, the bones and muscles are derived from the? | Mesoderm |
In the embryo, the liver and lungs are derived from the? | Endoderm |
The embryonic membrane that forms the fetal part of the placenta is the? | Chorion |
The embryonic membrane that has villi to provide for nourishment of the early embryo is? | Chorion |
The embryonic membrane that forms the first blood cells is the? | Yolk sac |
The yolc sac is the embryonic membrane that forms the? | First blood cell |
The embryonic membrane that contains fluid to cushion the embryo is the? | Amnion |
Amnion is the embryonic membrane that contains fluid to cushion the? | Embryo |
Where is the site of exchanges between maternal blood and fetal blood? | The placenta |
The placenta is the site of exhange between maternal blood and? | Fetal blood |
The umbilical arteries carry blood from the? | Fetus |
The umbilical arteries carry blood from the fetus to the? | Placenta |
The ____________ carry blood from the fetus to the placenta. | Umbilical ateries |
The umbilical vein carries blood from the? | Placenta |
The umbilical vein carries blood to the? | Fetus |
The __________ carries blood from the placenta to the fetus. | Umbilical vein |
Blood is carried from the fetus to the placenta by the? | Umbilical arteries |
The umbilical arteries contain blood with high levels of the gas? | Carbon dioxide |
Blood is carried from the placenta to the fetus by the? | Umbilical vein |
The umbilical vein contain blood with high level of the gas? | Oxygen |
In the placenta, oxygen and carbon dioxide move by with the process of? | Diffusion. |
In the placenta, nutrients are taken into fetal vessels by the process of? | Active transport |
The placental hormone that maintains the corpus luteum during early pregnancy is? | hCG |
The placental hormone hCG maintains the ________ during early pregnancy. | Corpus luteum |
Where is the hormone hCG produced? | The choroin of the embryo |
The placental hormone hCG is produced in the chorion of the? | Embryo |
In later pregnancy, what hormones does the placenta secrete? | Estrogen and progesterone |
During pregnancy, what placental hormone inhibits contractions of the myometrium? | Progesterone |
The placental hormone progesterone inhibits contractions of the? | Myometrium |
During pregnancy, what placental hormones inhibit ovulation? | Estrogen and progesterone |
During pregnancy, the placental hormones estrogen and progesteron inhibit? | Ovulation |
During pregnancy, the hormones that prepare the mammary glands for lactation are? | Estrogen and progesterone |
During what stage of labor is the placenta delivered? | The third stage |
During what stage of labor is the baby delivered? | The second stage |
During what stage of labor does the cervix dilate? | The first stage |
During the third stage of labor, the ________ is delivered. | Placenta |
During the seckond stage of labor, the _______ is delivered. | Baby |
During the first stage of labor, the ________ dilates. | Cervix |
When does the amniotic sac rupture? | During the first stage of labor |
During the first stage of labor the _________ ruptures. | Amniotic sac |
When do the cervix dilate? | During the first stage of labor |
The ________ dilate during the first stage of labor. | Cervix |
The cervix dilate and the amniotic sac ruptures during the? | First stage of labor |
During labor, the hormone that causes strong contractions of the uterus is? | Oxytocin |
Oxytocin is the hormone that causes strong contractions of the ________ during labor. | Uterus |
Just before birth, all of the fetus,s organ systems are functioning except the? | Respiratory system |
When does the respiratory system of a fetus start functioning? | A few moments after birth |
After birth the babys respiratory system begins funtioning because? | The lungs have been inflated. |
After birth, the foramen ovale in the babys ________ is closed. | Heart |
After birth, the ___________ in the babys heart is closed. | Foramen ovale |
When the foramen ovale closes in the babys heart, this ________ pulmonary circulation. | Increases |
After birth,the babys ductus arteriosus? | Constricts |
After birth, the babys ductus arteriosus constricts, which allows more? | Blood flow to the lungs |
After birth, the babys ductus venosus? | Constricts |
After birth, the babys ductus venosus constricts because? | The umbilical cord has been cut |
When the umbilical cord is cut blood no longer enters the? | Umbilical vein |
A gene is a genetic code for? | One protein |
The genetic code for one protein is called? | One gene |
Where is the genetic code in the nucleus of a cell contained? | In the DNA of the chromosome |
A person has ____ genes for each genetic traight. | 2 |
A person has two genes for each genetic trait, and the genes are called? | Maternal and paternal |
A human cell contains _____ chromosomes. | 46 |
A human cell contains 46 chromosomes and 22 pairs of these are? | Autosomes |
A human cell contains 22 autosomes and 1 pair is called? | Sex chromosomes |
The sex chromosome in women are called? | XX |
XX is the sex chromome in? | Women |
The sex chromosome in men are called? | XY |
XY is the sex chromosome in? | Men |
Homologous chromosomes are a pair of chromosomes that may aslo be called? | Maternal and paternal |
A pair of chromosomes that has maternal and paternal genes for the same traits is a? | Homologous pair |
The two members of a homologous pair of chromosomes have genes for? | The same traits |
The possibilities for the expression of a gene are called? | alleles |
A person who is homozygous for a particular trait has two _________ genes for it. | Similar |
A person who is heterozygous for a particular trait has two ________ genes for it. | Different |
A person who has two similar genes for a particular trait is ______ for the trait. | Homozygous |
A person who has two different genes for a particular trait is _______ for the trait. | Heterozygous |
The genes a person has for a particular trait are called the? | Genotype |
The expression of genes a person has for a particular trait is called the? | Penotype |
A persons genotype for a particular trait refers to the? | Genes that are present |
A persons phenotype for a particular trait refers to the? | Expression of the genes |
If a trait may appear in a persons phenotype when only one gene is present for it, the trait is called? | Dominant |
If a trait may appear in a persons phenotype only when two genes are present for it, the trait is called? | Recessive |
In order for a recessive trait to appear in a persons phenotype the person must? | Have two genes for it |
In order for a dominant trait to appear in a perons phenotype the person must? | Have one gene for it |
A trait that is ________ requires two genes for it's expression. | Recessive |
A trait that is ________ requires only one gene for it's expression. | Dominant |
For the ABO blood types in people, the O allele is? | Recessive |
For the ABO blood types in people, the A,B alleles are? | Co-dominant |
For the ABO blood types in people, the ____ allele is recessive. | O |
For the ABO blood types in people, the ____ alleles are co-dominant. | A,B |
The genes for sex-linked traits are found on the ____ chromosome. | X |
When the gene for a trait is found only on the X chromosome, the trait said to be? | Sex linked; X linked |
Sex-linked traits are considered? | Recessive |
Sex-linked traits are considered recessive because women must? | Have two genes to express such traits |