Exam 1 Flashcards
Explain the menstrual cycle.
Menstration is the periodic uterine bleeding that begins about 14 days after ovulation. Day1: average blood loss = 50mL (20-80ml)
Uterine discharge includes mucus and epithelial cells in addition to blood. The menstrual cycle prepares the uterus for pregnancy, when pregnancy does not occur, menstration follows.
Describe ovarian cycle:
Before ovulation, from 1-30 immature follicles begin to mature in each ovary under the influence of FSH and estrogen. A surge of LD affects a selected follicle. The oocyte matures, ovulation occurs, and the empty follicle begins its transformation to the corpus luteum. After ovulation, estrogen levels decrease.
Describe the luteal phase.
The luteal phase begins immediately after ovulation and ends with the start of mestration. The postovulatory phase of the funcional activity 3 days afer ovulation, secreteing the steroids estrogen and progesterone. While this is happening, the fertilized ovum is implanted in the endometrium. If implantation does not occur, the corpus luteum regresses, steroid levels decrease, and the functional layer of the uterine endometrium are shed through menstruation.
What are the 4 cycles of the endometrial cycle?
Menstrual phase
Proliferative phase
Secretory phase
Ischemic phase
Describe the 4 phases of the endometrial cycle.
Menstrual: Shedding of the funcional two thirds of the endometrium ( the compact spongy layers) is initiated by periodic vasoconstriction in the upper layers of teh endometrium. Basal layer is always retained.
Proliferative: Period of rapid growing lasting from about the fifth day to the time of ovulation. This phase depends on estrogen stimulation derived from teh ovarian follicles.
Secretory: Extends from the day of ovulation to about 3 days before the next mestrual period. After ovulation larger amounts of progesterone are produced. At the end of the secretory pahse, the fully matured secretory endometrium reaches the thickness of heavy, soft vlevet. It becomes a suitble protetive and nutritive bed for fertilized ovum. Implantation of the fertilized ovum generally occurs about 7-10 days after ovulation. If fertilization and implantation does not occur, the corpus luteum, which secretes estrogen and progesterone, regresses.
Ischemic: with rapid decrease in progesterone and estrogen levels, the spiral arteries go into spasm. During the ischemic phase the blood supply to the function endometrium is blocked, and necrosis develops. The functional layer separates from the basal layer, and menstrual bleeding begins, marking day 1 of the next cycle.
How long does the stage of the fetus last?
The stage of the fetus lasts from 9 weeks (when the fetus becomes recognizable as a human being) until the pregnancy ends.
What does viability mean?
Viability refers to the capability of the fetus to survive outside the uterus. Whith technology and admancemnts in maternal and neonatal care, infants who are 22-25 weeks gestation are now considered to be on the threshhold of viability.
How many chromosomes do all normal human somatic cells contain?
46 chromosomes, arranged as 23 pairs of homologous (matched) chromosomes; one chromosome of each pair is inherited from each parent.
How many pairs of autosomes are there?
There are 22 pairs of autosomes taht control most traits in the body, and one pair of sex chromosomes.
What are the Y chromosomes primarily concerned with?
Sex determination
What are the X chromosimes concerned with?
The X chromosome contains genes that are involvedd in much more than sex determination.
What does dominant mean in regards to a trait or disorder?
A trait or disorder is said to be dominant if it is expressed or phenotypically apparent when only one copy of an allele associated with the trait is present.
What does recessive mean in regards to a trait or disorder?
It is considered recessive if the trait or disorder is expressed only when two of the alleles associated with teh trait or disorder are present.
What does multifacator inheritance mean?
The most common congenital malformations result from this. It is a combination of genetic and environmental factors. Examples are: cleft lip, cleft palate, congenital heart disease, neural tube defects, and pyloric stenosis. A neural tube defect can range from spina bifida, a bony defect in the lumbar region of the vertebrae with little or no neurological impairment, to anencephaly, absence of brain development, which is always fatal.
What does Autosomal Recessive Inheritance mean?
The chance of the trait occurring in each child is 25%. Autosomal recessive disorder is usually observed in one or more siblings, but not in earlier generations. Examples: PKU, maple syrup urine disease, Tay-Sachs disease, sickle cell anemia, and CF.
