BIO 211 Anatomy & Physiology - Chapter 27: Reproductive System

Vocabulary practice flashcards covering male and female reproductive anatomy, histology, spermatogenesis, oogenesis, ovarian and uterine cycles, and sexual development from Chapter 27 of BIO 211 Anatomy & Physiology.

Gametes

Specialized haploid cells produced for sexual reproduction, consisting of sperm in males and ova (eggs) in females.

Zygote

The first diploid ($2n$) cell of a new individual formed when a sperm cell fuses with an egg cell during fertilization.

Gestation

The developmental period during which the fetus grows and is supported within the female reproductive system.

Parturition

The biological process of giving birth to a baby.

Homologous Structures

Male and female reproductive structures that share a common developmental origin in the embryo (e.g., testes and ovaries; penis and clitoris).

Gonads (Primary Sex Organs)

The testes in males and ovaries in females that produce gametes and steroid sex hormones (testosterone, estrogens, and progesterone).

Hypothalamic-Pituitary-Gonadal (HPG) Axis

The hormonal regulatory sequence coordinating reproductive hormone secretion via GnRH from the hypothalamus, FSH and LH from the anterior pituitary, and gonadal sex hormones and inhibin.

Gonadotropin-Releasing Hormone (GnRH)

A hormone released by the hypothalamus that travels via portal blood to stimulate the anterior pituitary to secrete FSH and LH.

Inhibin

A hormone released by the gonads in both males and females that exerts negative feedback specifically on FSH release from the anterior pituitary.

Puberty

The period of life when reproductive organs grow to adult size and become functional in response to rising gonadal hormone levels.

Sister Chromatids

Two identical copies of a chromosome produced during interphase DNA replication, held together at the centromere.

Homologous Chromosomes

Pairs of chromosomes containing one paternal chromosome and one maternal chromosome that look alike and code for the same traits.

Crossing Over

The reciprocal exchange of genetic material between nonsister chromatids of homologous chromosomes during prophase I, increasing genetic variability.

Diploid ($2n$)

The normal chromosomal complement of body cells consisting of two complete sets of chromosomes ($46$ chromosomes or $23$ pairs in humans).

Haploid ($n$)

The chromosomal number characteristic of gametes containing only one member of each homologous pair ($23$ chromosomes in humans).

Synapsis

The pairing of homologous chromosomes along their lengths during prophase I of meiosis to form tetrads.

Dartos Muscle

A layer of smooth muscle in the superficial fascia of the scrotum that wrinkles the scrotal skin to regulate temperature.

Cremaster Muscles

Bands of skeletal muscle that elevate the testes closer to the pelvic cavity when exposed to cold temperatures.

Seminiferous Tubules

Tightly coiled tubules packed inside testicular lobules where sperm are actively produced.

Pampiniform Venous Plexus

A network of testicular veins surrounding each testicular artery that absorbs heat from arterial blood to maintain cool testicular temperature.

Cryptorchidism

The non-descent of the testes into the scrotum, which serves as a major risk factor for testicular cancer and sterility.

Epididymis

A coiled duct structure consisting of a head, body, and tail where immature sperm gain motility over approximately $20$ days and are stored prior to ejaculation.

Corpora Cavernosa

Paired dorsal erectile tissue bodies in the shaft of the penis that fill with blood to produce enlargement and rigidity during an erection.

Corpus Spongiosum

The midventral cylinder of erectile tissue that encloses the spongy urethra and expands distally into the glans penis to keep the urethra open during ejaculation.

Seminal Vesicles (Seminal Glands)

Accessory reproductive glands posterior to the urinary bladder that produce a viscous alkaline fluid containing nutrients, fructose, and a UV-fluorescing yellow pigment.

Prostate

A marble-sized gland encircling the urethra inferior to the bladder that secretes a milky, slightly acidic fluid that activates sperm.

Bulbo-Urethral Glands

Pea-sized glands inferior to the prostate that secrete a clear, viscous mucus during arousal to lubricate the glans penis and neutralize residual acidic urine in the urethra.

Semen

A milky-white alkaline fluid mixture consisting of sperm and secretions from the accessory glands that neutralizes urethral and vaginal acidity.

Benign Prostatic Hyperplasia (BPH)

A noncancerous enlargement of prostate stroma and glands that constricts the prostatic urethra, leading to difficult and incomplete urination.

Sustentocytes (Sertoli Cells)

Large columnar cells within the seminiferous tubules that nourish, protect, and support developing sperm, form the blood-testis barrier, and secrete ABP and inhibin.

Interstitial Endocrine Cells (Leydig Cells)

Steroid-secreting cells situated in the soft connective tissue between seminiferous tubules that produce testosterone.

Myoid Cells

Smooth muscle-like cells forming sheets around the seminiferous tubules that contract rhythmically to squeeze sperm and testicular fluid toward the rete testis.

Spermiogenesis

The final stage of spermatogenesis where nonmotile, spherical spermatids shed excess cytoplasm, grow a flagellum, and condense into streamlined sperm.

Acrosome

A helmet-like vesicle covering the anterior sperm nucleus that contains hydrolytic enzymes enabling penetration of an ovum.

Androgen-Binding Protein (ABP)

A protein secreted by sustentocytes under FSH stimulation that concentrates testosterone in the vicinity of spermatogenic cells.

Broad Ligament

A broad peritoneal fold supporting the uterine tubes, uterus, and vagina, comprising the mesometrium, mesovarium, and mesosalpinx.

Infundibulum

The funnel-shaped lateral opening of the uterine tube into the peritoneal cavity, fringed by ciliated fimbriae that drape over the ovary.

Ampulla (Uterine Tube)

The expanded lateral region making up half the length of the uterine tube where fertilization typically occurs.

Prolapse of the Uterus

A condition resulting from damaged or overstretched pelvic floor muscles where the unsupported uterus descends, causing the cervix to protrude through the vaginal opening.

Myometrium

The thick, bulky middle tunic of the uterine wall composed of interlaced bundles of smooth muscle that contract rhythmically during parturition.

Stratum Functionalis

The superficial mucosal layer of the endometrium that cyclically thickens and sloughs off during menstruation in response to ovarian hormones.

Stratum Basalis

The deeper, thinner endometrial layer that is unresponsive to ovarian hormones and continuously forms a new stratum functionalis after menstruation.

Spiral Arteries

Coiled blood vessels within the stratum functionalis that repeatedly degenerate, spasm, and regenerate during each menstrual cycle.

Greater Vestibular Glands

Flanking glands on each side of the vaginal orifice (homologous to bulbo-urethral glands) that secrete lubricating mucus into the vestibule.

Areola

The ring of pigmented skin that encircles the central protruding nipple of the breast.

Oogenesis

The sequence of events leading to the production of female gametes, which begins before birth in the fetus and finishes only if an oocyte is fertilized.

Polar Body

A tiny, nonfunctional haploid cell produced during unequal cytokinesis in oogenesis that lacks significant cytoplasm and deteriorates.

Ovarian Follicle

A saclike structure embedded within the ovarian cortex that encloses an immature developing oocyte surrounded by follicular or granulosa cells.

Atresia

The programmed apoptosis and degeneration of ovarian follicles and their enclosed oocytes throughout life.

Corpus Luteum

A temporary endocrine gland formed from the collapsed follicle wall after ovulation that secretes progesterone and estrogen to sustain the uterine lining.

Mittelschmerz

A twinge of abdominal pain felt by some women during the midcycle release of an oocyte during ovulation.

Menarche

A young female's very first menstrual period, which marks the establishment of the female reproductive cycle.

Follicular Phase

The initial phase of the ovarian cycle (days $1\text{--}14$) during which vesicular follicles grow and secrete estrogen under FSH regulation.

Luteal Phase

The postovulatory phase of the ovarian cycle (days $14\text{--}28$) characterized by corpus luteum endocrine activity; consistently lasts $14$ days.

Proliferative (Preovulatory) Phase

The stage of the uterine cycle (days $6\text{--}14$) wherein rising estrogen levels rebuild the stratum functionalis and stimulate progesterone receptor synthesis.

Secretory (Postovulatory) Phase

The constant $14$-day phase of the uterine cycle (days $15\text{--}28$) governed by progesterone, converting the functional layer into a nutrient-secreting mucosa.

SRY Gene

The sex-determining region gene located on the $Y$ chromosome that acts as a master genetic switch to initiate testicular development and male differentiation.

Menopause

The permanent cessation of menstruation diagnosed after a full year without a menstrual period, brought on by declining ovarian estrogen production.