LO11

3. Define morula, blastocyst, and trophoblast

Morula: A solid ball of cells that makes up an embryo; in humans, this stage occurs within four days of fertilization Blastocyst: A fluid-filled sphere formed about 5 days after fertilization of an ovum that is made up of an outer ring of cells and inner cell mass. THis is the structure that implants in the endometrium of the uterus. trophoblast: The outer layer of cells that develops in the germinal period. These cells provide nutrition and support for the embryo.

6. What is organogenesis?

the process of organ formation during the first two months of prenatal development

7. What are the physiological changes during pregnancy?

-moring sickness due to increased levels of hCG, estrogen, and progesterone, -hearburn due to reflux of stomach acid from esophagus displacement -constipation due to decrease in digestive motility -frequent urination -congestion from thickening of mucus -decrease in tidal volume and dyspnea -increase in blood volume

14.A color-blind man marries a woman who is heterozygous for the trait. What proportion of their sons, if they have any, can be expected to be color blind?

1/2

2. Where do the sperm and egg meet?

Fallopian tube (uterine tube)

11. Name the hormone that increases the flexibility of the pubic symphysis and causes dilation of the cervix during pregnancy

Relaxin

9. What is a Punnett square and how is it used?

a 2 column 2 row box used to predict phenotype based on the combination of 2 genotypes.

8. Define the following: alleles, homozygous, heterozygous, dominant and recessive genes, genotype, and phenotype

alleles: Alternative versions of a gene Homozygous: An organism that has two identical alleles for a trait heterozygous: An organism that has two different alleles for a trait dominant gene: The "stronger" form of a gene that is always expressed when it is present. recessive gene: Gene that is hidden when the dominant gene is present Genotype: An organism's genetic makeup, or allele combinations. Phenotype: An organism's physical appearance, or visible traits.

17.Pregnant women are advised against taking aspirin during their third trimester. Why?

asprin can deley labor, increase bleeding risk, and is potentially harmful to the fetus in third trimester.

10. What is the process of cell division that occurs after fertilization?

cleavage, blastocyste, implantation, gastration, organogenesis

16.What activity during oocyte activation prevents penetration by additional sperm?

cortical reaction

5. Name and briefly describe the primary germ layers, including what each specializes in

endoderm: innermost germ layer; develops into the linings of the digestive tract and much of the respiratory system mesoderm: develops into muscles, and much of the circulatory, reproductive, and excretory systems ectoderm: ultimately forms external structures such as the skin, hair, nails, and inner linings of the mouth and anus, as well as the entire nervous system

12.Name the hormones produced by the placenta.

estrogen, progesterone, human placental lactogen, placental growth hormone, relaxin, kisspepsin, human chorionic gonadotrophin.

1. Define gestation period, embryo, zygote and fetus.

gestation period: the length of time between fertilization and birth of a mammal embryo: A fertilized egg in the first eight weeks after conception zygote: fertilized egg fetus: is a fertilized egg after eight weeks

4. What is hCG and where does it come from?

hormone, produced by the trophoblast cells, stimulates the production of progesterone by the corpus luteum

13.What is an ectopic pregnancy and where does it occur?

implantation of the zygote outside of the uterus. This usually occurs in the uterine tube.

15.What are the genes that appear on the X chromosome called?

sexlinked genes