Human Biology: Chapter 17 - Reproduction

Vocabulary practice flashcards covering human reproductive anatomy, gametogenesis, hormonal regulation, menstrual and ovarian cycles, contraception, and assisted reproductive technologies.

Somatic cells

Body cells comprising all tissues except gametes, each containing $46$ chromosomes (arranged in $23$ pairs) within the nucleus.

Diploid ($2n$)

A condition or cell possessing the full set of $23$ pairs of chromosomes ($46$ chromosomes total in humans).

Gametes

Specialized reproductive cells (eggs and sperm) that carry half the normal complement of genetic material, having only $23$ chromosomes in their nuclei.

Haploid ($n$)

A condition or cell possessing only one member of each chromosome pair ($23$ total chromosomes in humans).

Meiosis

A form of reduction cell division occurring exclusively in the gonads that reduces the chromosome number from diploid to haploid ($2n \rightarrow n$) to produce gametes.

Mitosis

A form of cell division in which a cell divides into two genetically identical daughter cells ($2n \rightarrow 2n$), used for body growth and tissue repair.

Zygote

A single diploid ($2n$) cell formed when the nucleus of a haploid sperm fuses with the nucleus of a haploid egg during fertilization.

Testes

Paired male reproductive gonads responsible for producing sperm and male sex hormones, regulated by the hypothalamus and anterior pituitary gland.

Vas deferens

A male reproductive duct that transports sperm from the testes/epididymis to the urethra.

Seminal vesicles

Accessory glands in the male that secrete a nutrient-rich, sugary fluid to provide metabolic energy for swimming sperm.

Prostate gland

A male gland surrounding the urethra that secretes an alkaline fluid to buffer the naturally acidic pH of the female vagina.

Bulbourethral glands

Paired glands in the male reproductive system that produce a mucous fluid functioning as a lubricant.

Acrosome

A specialized enzyme-containing cap covering the head of a mature sperm cell, required to digest and penetrate the outer layers of the egg.

Gonadotropin-releasing hormone (GnRH)

A hypothalamic hormone that controls reproduction by stimulating the anterior pituitary gland to release FSH and LH.

Follicle-stimulating hormone (FSH)

An anterior pituitary hormone that stimulates sperm production in the testes of males and stimulates ovarian follicle development and estrogen secretion in females.

Luteinizing hormone (LH)

An anterior pituitary hormone that induces testosterone production by interstitial cells in males and triggers ovulation and corpus luteum formation in females.

Testosterone

The primary male steroid sex hormone, essential for the development and normal function of male reproductive organs and secondary sex characteristics.

Ovaries

Paired female reproductive gonads that produce egg cells (ova) and the female sex hormones estrogen and progesterone.

Oviducts

Also called Fallopian or uterine tubes; ducts that transport secondary oocytes toward the uterus and serve as the normal site of fertilization.

Uterus

The hollow, muscular female reproductive organ that provides the normal site for blastocyst implantation, embryonic and fetal development, and gestation.

Cervix

The narrow inferior opening of the uterus that connects to the vagina and dilates significantly during childbirth.

Ovulation

The monthly physiological release of a secondary oocyte from the ovary resulting from the rupture of a mature vesicular (Graafian) follicle.

Corpus luteum

An endocrine tissue formed from the collapsed remnants of a ruptured ovarian follicle after ovulation that secretes progesterone and some estrogen.

Follicular phase

The first phase of the ovarian cycle preceding ovulation, characterized by FSH-stimulated follicle maturation, increasing estrogen secretion, and an LH surge.

Luteal phase

The second phase of the ovarian cycle following ovulation, during which LH promotes the maintenance of the corpus luteum to secrete progesterone.

Menstruation

Days $1\text{--}5$ of the uterine cycle, during which low circulating levels of estrogen and progesterone cause the functional endometrium to disintegrate and shed.

Proliferative phase

Days $6\text{--}13$ of the uterine cycle, driven by ovarian estrogen secretion, leading to the repair and thickening of the endometrium.

Secretory phase

Days $15\text{--}28$ of the uterine cycle, driven by progesterone, during which the endometrium doubles or triples in thickness in preparation for embryo implantation.

Intrauterine device (IUD)

A small plastic piece placed into the cavity of the uterus by a physician to prevent pregnancy by blocking embryo implantation.

Diaphragm

A barrier contraceptive device consisting of a soft latex dome placed over the cervix to prevent sperm from entering the uterine cavity.

Vasectomy

A surgical method of permanent male sterilization that involves cutting and sealing both vasa deferentia to prevent sperm delivery.

Tubal ligation

A surgical method of permanent female sterilization involving the cutting and sealing of the oviducts (Fallopian tubes) to block sperm and egg transit.

Preven

A morning-after emergency contraceptive kit that disrupts the normal uterine cycle to impair embryo implantation, having an $85\%$ effectiveness rate.

RU-486 (mifepristone)

A medical abortifacient pill that induces the detachment and loss of an already implanted embryo with an effectiveness rate of $95\%$.

Infertility

The medical inability of a couple to achieve pregnancy after one year of regular, unprotected sexual intercourse.

In vitro fertilization (IVF)

An assisted reproductive procedure where immature eggs and sperm are combined in laboratory glassware for conception, after which embryos are transferred to the uterus.

Gamete intrafallopian transfer (GIFT)

An assisted reproductive technology in which collected eggs and sperm are placed directly into the oviducts immediately following their collection and combination.

Intracytoplasmic sperm injection (ICSI)

An assisted reproductive technology where a single sperm cell is directly injected into an egg using a microscopic micropipette.