Reproduction and Development Lecture Notes

A comprehensive set of vocabulary flashcards covering male and female reproductive anatomy, sperm and egg development, fertilization, the stages of pregnancy (trimesters), and the menstrual cycle based on the Biology Chapter 51 lecture notes.

Testes

Primary male reproductive organs that descend from the abdomen into the scrotum just before birth; clusters of hundreds of tiny tubules called seminiferous tubules are located within them.

Scrotum

An external sac containing the testes, where the temperature is a few degrees lower than the body cavity to allow proper sperm development.

Seminiferous tubules

Clusters of hundreds of tiny tubules within each testis where sperm develop.

Epididymis

The location where sperm are moved and stored after developing in the seminiferous tubules.

Vas deferens

A tube that extends upward from the scrotum to the abdominal cavity and eventually merges with the urethra.

Seminal fluid

A nutrient-enriched fluid produced by the seminal vesicles, the prostate, and the bulbourethral glands that nourishes and protects sperm from the acidity of the female reproductive tract.

Semen

The combination of sperm and seminal fluid; an average ejaculation contains about $2 ext{ to } 6 ext{ mL}$.

Sperm Head

The part of the sperm that contains the chromosomes; it is haploid and contains $23$ chromosomes.

Sperm Mid-piece

The part of the sperm containing mitochondria used for energy.

Sperm Tail

A flagella that provides movement for the sperm cell.

Ovaries

The primary reproductive organs of the female which produce egg cells; they usually release one mature ovum every $28 ext{ days}$.

Menstrual cycle

A regular sequence of events involving the ovaries, the lining of the uterus, and the endocrine system; regulated by hormones.

Fertilization

The joining of a haploid sperm nucleus with a haploid egg nucleus to form a zygote, occurring in the Fallopian tube if an egg is present.

Zygote

A fertilized egg formed by the fusion of two haploid nuclei; it is a diploid cell containing $46$ chromosomes.

Blastocyst

A ball of cells with a large, fluid-filled cavity formed through mitotic divisions of the zygote.

Implantation

The process where the blastocyst burrows and embeds itself in the thick uterine lining around day $6 ext{--} 9$.

Gestation

The process of carrying young from fertilization to birth, lasting about $9 ext{ months}$ in humans and divided into three trimesters.

Embryo

The developing human during the first $8 ext{ weeks}$ of pregnancy.

Fetus

The developing human from week $8$ until birth.

Amniotic sac

A fluid-filled sac that surrounds the developing embryo to cushion and protect it.

Placenta

A structure attached to the uterus that enables the exchange of nutrients, waste, and gasses between the mother and the fetus.

Human chorionic gonadotropin (HCG)

A hormone secreted by the developing placenta early in the $2nd ext{ week}$ after fertilization that signals the body to maintain the uterine lining.

Umbilical cord

The structure containing arteries and veins that attaches the embryo to the placenta to carry blood between them.

Labor

The process by which the fetus and placenta are expelled from the uterus through muscular contractions.

Afterbirth

The delivery of the placenta, amnion, and uterine lining shortly after the baby is born.

Follicle phase

The phase of the menstrual cycle (Day $1 ext{--} 12$) where FSH and LH hormones cause a follicle to mature and produce estrogen, thickening the uterine lining.

Ovulation

The release of the egg from the ovary into one of the Fallopian tubes, triggered by an increase in LH and FSH hormones (typically Day $12 ext{--} 16$).

Progesterone

A hormone released during the luteal phase that stimulates the growth and development of the blood supply in the thickening uterine lining.

Menstruation

The phase (Day $1 ext{--} 7$) where low estrogen levels cause the uterine lining, blood, and unfertilized egg to be discharged through the vagina.