Chapter 3- Reproduction Flashcards
Reproduction
Male gamete (sperm) + Female gamete (ovum)
= zygote (fertilized egg)Male reproductive system
pair of testes in scrotum, penis
Female reproductive system
pair of ovaries- their job?
- uterus - vagina
A woman has signal changes that announce monthly fertility:
egg-white cervical mucus
- spike in basal body temperature
- change in cervix position and shape
- “Mittleschmertz”
- breast tenderness
Ovulation/Time of Fertility
The egg can live for only 12-24 hours, but sperm can live 3-5 days in mucus!
ALL mucus days are fertile, plus the 4 days after mucus ends.
●Estrogen released from the ripening egg keeps the temperature low, progesterone from the corpus luteum after ovulation raises the temperature.
●If one becomes pregnant, the temperature remains high due to the high progesterone levels.
Fertilization
Fertilization usually occurs in upper part of fallopian tube
•Corpus luteum releases progesterone to prepare uterus for implantation
Multiple conceptions
Two ova fertilized = dizygotic twins (fraternal)
•One ovum fertilized and split = monozygotic twins (identical)
Many couples have difficulty conceiving and turn to…..
Assisted Reproductive Technology (ARTs) In vitro fertilization (IVF) •GIFT (gamete introfallopian transfer) •ZIFT (zygote intrafallopian transfer) •ICSI (intracytoplasmic sperm injection)
Cloning
Asexual reproduction ●Somatic Cell Nuclear Transfer (SCNT) ●Take nucleus of somatic cell (skin cell) and insert into an egg whose own nucleus has been removed •Nucleus transplantation •Begins embryonic divisions •98% genetic replica of donor body cell
Therapeutic cloning
grow cell for 4 to 5 days, take stem cells and grow to become other body cells or organs
●Conversion of patients own cells into specializes tissues
●Ectogenesis- develop baby outside of womb
Birth control methods
male and female condoms, cervical cap, diaphragm, birth control pills, vaginal contraceptives, Depo Provera, IUD, Norplant subcutaneous inserts, sponge, vaginal contraceptive chemical barriers, rhythm method, male or female sterilization.
•Abortion
The expanding reproductive years
Menarche now 11-12 yrs, some reach at 8 or 9
•Menopause is 50 yrs.
•Post-menopausal women can use
donated ova.
•Men have no age limit.
Genome
1990s- Human Genome Project
●Human genome-genetic blueprint of all genes on their appropriate chromosomes
●20-25,000 genes are present in humans
●Genomes to Life project– sequence genes of other species
Who determines the sex?
Male’s chromosome determines the sex
•X from mother, X or Y from father
•Dominant vs. recessive Traits
- Genotypes vs. phenotypes
- Homozygous (AA) or (aa) vs. heterozygous (Aa)
What is multifactorial inheritance?
Multifactorial inheritance means that “many factors” (multifactorial) are involved in causing a birth defect. The factors are usually both genetic and environmental, where a combination of genes from both parents, in addition to unknown environmental factors, produce the trait or condition
Sex-linked characteristics
Hemophilia, Muscular dystrophy
Chromosomal abnormalities
Down Syndrome- extra 21st chromosome
When does pregnancy officially start? How old is the embryo at conception?
Pregnancy counted from the first day of the mother’s last period.
•This means that at conception, the
embryo is already considered two
weeks old.
The Germinal Period
The first two weeks
Growth of the zygote
•Mitosis- 2 cells to 4 to 8…
●Cell division begins—one cell becomes two, two become four, etc.
●By the 14th day, cell division produces a sixteen-cell cluster called a blastocyst
at 100 cells makes contact with uterus
Mitosis
2 cells to 4 to 8
Blastocyst
●Cell division begins—one cell becomes two, two become four, etc.
●By the 14th day, cell division produces a sixteen-cell cluster called a blastocyst
at 100 cells makes contact with uterus
Maternal influences
Maternal practices exert a direct influence on fetal development, especially during the first three months
●Practicing a healthy lifestyle before and during pregnancy can reduce the risk of fetal birth defects
Fathers were more likely to have infants with birth defects if they:
smoked
•were exposed to contaminants
•were older
•used street drugs
Promoting Healthy Fetal Development
●Important practices include…
early prenatal care •nutritious diet •moderate physical activity •rest •weight management •maternal age •avoiding teratogens
