Human Reproduction: Fertilization and Pregnancy

Study Notes

Fertilization occurs when a sperm fertilizes an egg in the fallopian tube
Sperm capacitation: the process by which sperm become capable of fertilization
Acrosome reaction: the release of enzymes from the sperm head that help break down the zona pellucida
Fertilization usually occurs in the ampulla of the fallopian tube
The resulting zygote has a unique combination of genetic material from both parents

Pregnancy lasts approximately 38 weeks from fertilization to birth
Gestational age: the age of the fetus from the first day of the last menstrual period (LMP)
Trimesters:
1. Week 1-12: embryonic development
2. Week 13-26: fetal development
3. Week 27-38: fetal growth and maturation
Pregnancy is divided into three stages:
1. Implantation: the blastocyst embeds into the uterine lining
2. Embryonic development: rapid growth and differentiation of cells
3. Fetal development: growth and maturation of the fetus

Week 1-2: zygote undergoes several cell divisions to form a blastocyst
Week 3-4: gastrulation: the blastocyst undergoes complex cellular movements to form three primary germ layers
Week 5-8: organogenesis: the formation of major organs and body systems
Critical periods: specific times during embryonic development when the embryo is most susceptible to teratogens
Morphogenesis: the formation of shape and structure of the embryo

Ovarian cycle: the cyclical production of hormones that regulate the reproductive process
Follicular phase: the growth and maturation of follicles in the ovaries
Luteal phase: the production of progesterone by the corpus luteum
Estrogen and progesterone: hormones produced by the ovaries that regulate the reproductive cycle
Human chorionic gonadotropin (hCG): a hormone produced by the placenta that maintains pregnancy

Female reproductive system:
- Ovaries: produce eggs and hormones
- Fallopian tubes: transport the egg from the ovary to the uterus
- Uterus: supports fetal development during pregnancy
- Cervix: the lower, narrow part of the uterus that opens into the vagina
Male reproductive system:
- Testes: produce sperm and hormones
- Epididymis: stores and transports sperm
- Vas deferens: muscular tube that transports sperm to the penis
- Prostate gland: produces fluids that make up semen

Fertilization occurs in the fallopian tube, resulting in a zygote with a unique combination of genetic material from both parents
Sperm capacitation is necessary for fertilization to occur
The acrosome reaction releases enzymes that break down the zona pellucida, allowing sperm to fertilize the egg

Pregnancy lasts approximately 38 weeks from fertilization to birth
Gestational age is calculated from the first day of the last menstrual period (LMP)
The three trimesters of pregnancy are: embryonic development (week 1-12), fetal development (week 13-26), and fetal growth and maturation (week 27-38)
Pregnancy is divided into three stages: implantation, embryonic development, and fetal development

The zygote undergoes several cell divisions to form a blastocyst in the first two weeks
Gastrulation occurs in weeks 3-4, forming three primary germ layers
Organogenesis occurs in weeks 5-8, forming major organs and body systems
Critical periods are specific times during embryonic development when the embryo is most susceptible to teratogens
Morphogenesis forms the shape and structure of the embryo

The ovarian cycle regulates the reproductive process through the cyclical production of hormones
The follicular phase is the growth and maturation of follicles in the ovaries
The luteal phase is the production of progesterone by the corpus luteum
Estrogen and progesterone regulate the reproductive cycle
Human chorionic gonadotropin (hCG) is produced by the placenta to maintain pregnancy

The female reproductive system consists of ovaries, fallopian tubes, uterus, cervix, and vagina
The ovaries produce eggs and hormones
The fallopian tubes transport the egg from the ovary to the uterus
The uterus supports fetal development during pregnancy
The male reproductive system consists of testes, epididymis, vas deferens, prostate gland, and penis
The testes produce sperm and hormones
The epididymis stores and transports sperm
The vas deferens is a muscular tube that transports sperm to the penis
The prostate gland produces fluids that make up semen