ch. 27 Reproductive System

Comprehensive vocabulary flashcards covering the male and female reproductive systems, including anatomy, physiology, meiosis, and hormonal regulation.

Gametes

Specialized cells formed for sexual reproduction, specifically sperm in males and ova (eggs) in females.

Zygote

The first cell of a new organism, formed when a sperm and egg fuse during fertilization.

Gestation

The period of supporting the development of a fetus.

Parturition

The process of the birth of a baby.

Homologues

Male and female reproductive structures that share a common origin and often common functions, such as the testes and ovaries.

Gonads

The primary sex organs (testes in males and ovaries in females) that produce gametes and steroid sex hormones.

HPG axis

The hypothalamic-pituitary-gonadal axis, which involves hormonal interactions between the hypothalamus, anterior pituitary, and gonads to regulate reproduction.

GnRH

Gonadotropin-releasing hormone from the hypothalamus that stimulates the anterior pituitary to release FSH and LH.

Inhibin

A hormone from the gonads that exerts negative feedback at the anterior pituitary, specifically inhibiting FSH release.

Sister chromatids

Identical copies of the same chromosome joined by a centromere that result from DNA replication.

Homologous pairs of chromosomes

Pairs where one member is from the father (paternal) and the other is from the mother (maternal); they generally carry genes for the same characters.

Diploid

Cells having two sets of chromosomes ($2n$); in humans, the diploid number is $46$ ($23$ pairs).

Haploid

Gametes having only one member of each chromosome pair ($n$); in humans, the haploid number is $23$.

Synapsis

The event in prophase I where homologous chromosomes pair up to form tetrads consisting of four chromatids.

Crossing over

The exchange of DNA between nonsister chromatids during synapsis, occurring at sites called chiasmata.

Independent assortment

The random alignment of maternal and paternal chromosomes on either side of the metaphase plate during metaphase I.

Scrotum

A pouch of skin and superficial fascia that houses the testes outside the abdominopelvic cavity to maintain a temperature lower than the core body temperature.

Seminiferous tubules

The specific sites of sperm production located within the lobules of the testes.

Epididymis

A comma-shaped organ where immature, nonmotile sperm pass through for $20$ days to mature and gain the ability to swim.

Vasectomy

A surgical procedure where the ductus deferens is cut and ligated or cauterized to serve as a form of birth control.

Urethra (male)

A duct that conveys both urine and semen (at different times) and consists of three regions: prostatic, intermediate (membranous), and spongy.

Prepuce

Also known as the foreskin, it is a cuff of loose skin surrounding the glans penis.

Corpora cavernosa

Paired erectile bodies that make up most of the penis and engorge with blood to maintain an erection.

Seminal glands

Accessory glands that produce a yellowish viscous alkaline fluid containing fructose and prostaglandins, accounting for $70\%$ of semen volume.

Prostate

An unpaired, peach-pit-sized gland that encircles the urethra and secretes a milky, slightly acidic fluid containing citrate and PSA.

Bulbo-urethral glands

Pea-sized glands that produce thick, clear mucus to lubricate the glans penis and neutralize acidic urine in the urethra.

Semen

A milky-white, sticky mixture of sperm and accessory gland secretions with an alkaline pH of $7.2-8.0$.

Erection

Enlargement and stiffening of the penis under parasympathetic control, triggered by the release of nitric oxide ($NO$).

Ejaculation

The propulsion of semen from the male duct system under sympathetic control.

Spermatogenesis

The sequence of events in the seminiferous tubules that leads to the formation of sperm, starting at puberty around ages $14$ to $16$.

Sustentocytes

Also called nurse cells, these large columnar cells surround spermatogenic cells, provide nutrients, and form the blood testis barrier.

Interstitial endocrine cells

Also known as Leydig cells, these produzce androgens (mainly testosterone) and are located between seminiferous tubules.

Spermiogenesis

The streamlining process during the final stage of spermatogenesis where a spermatid elongates, loses excess cytoplasm, and forms a tail.

Ovaries

The female gonads that produce ova and the sex hormones estrogens and progesterone.

Ovarian follicles

Saclike structures in the ovarian cortex that contain an immature egg (oocyte) surrounded by support cells.

Ovulation

The monthly event where a mature follicle ruptures at the surface of the ovary, releasing a secondary oocyte.

Ampulla

The wide region of the uterine tube where fertilization usually occurs.

Uterus

A hollow, thick-walled muscular organ that receives, retains, and nourishes a fertilized egg.

Myometrium

The bulky middle layer of the uterine wall composed of smooth muscle that contracts rhythmically during childbirth.

Stratum functionalis

The functional layer of the endometrium that undergoes cyclic changes in response to ovarian hormones and is shed during menstruation.

Vagina

A thin-walled tube that functions as the birth canal, passageway for menstrual flow, and female organ of copulation.

Mons pubis

A mound of adipose tissue overlying the pubic symphysis, covered with hair after puberty.

Clitoris

A richly innervated erectile tissue in females that is homologous to the male penis.

Mammary glands

Modified sweat glands that function in lactating females to produce milk in response to hormonal stimulation.

Oogenesis

The production of female gametes, which begins during the fetal period.

Follicular phase

The period of the ovarian cycle (days $1-14$) characterized by follicle growth and increased estrogen secretion.

Luteal phase

The period of the ovarian cycle (days $15-28$) characterized by corpus luteum activity.

Corpus luteum

A glandular structure formed from a ruptured follicle that secretes high levels of progesterone and estrogen to sustain a potential pregnancy.

Menarche

A female's first menstrual period.

Menstrual phase

Days $0-4$ of the uterine cycle when the functional layer of the endometrium degenerates and is shed as menstrual flow.

Proliferative phase

Days $5-14$ of the uterine cycle when rising estrogen levels prompt the generation of a new functional layer.

Secretory phase

Days $15-28$ of the uterine cycle when the endometrium prepares for embryo implantation under the influence of progesterone.

Menopause

The period after a year has passed without menstruation, typically occurring between ages $46$ and $54$ due to declining estrogen.