The Reproductive System

Flashcards covering the key vocabulary and concepts of the reproductive system, including male and female anatomy, gametogenesis, and hormonal regulation.

Reproductive System

The only system that is not essential to the life of the individual, but does affect other systems; male and female reproductive organs produce/store specialized reproductive cells that combine to form new individuals

Gonads

Organs that produce gametes and hormones.

Reproductive tract

All chambers and passageways that connect ducts to exterior of body

Testes

Organs secrete male sex hormones (androgens) and produce male gametes (sperm)

Ovaries

Release one immature gamete (oocyte) per month and produce hormones

Uterine tubes

Carry oocytes to uterus—if sperm reaches oocyte, fertilization is initiated; oocyte matures into ovum

Uterus

Encloses and supports developing embryo

Vagina

Connects uterus with exterior

Pathway of sperm

Testis, Epididymis, Ductus deferens, Ejaculatory duct, and Urethra

Accessory glands in male reproductive system

Seminal glands, Prostate, and Bulbo-urethral glands

Scrotum

Fleshy pouch that encloses testes and is suspended inferior to perineum, anterior to anus, and posterior to base of penis

Spermatic cords

Extend between abdominopelvic cavity and testes; consist of layers of fascia and muscle

Inguinal hernias

Protrusions of visceral tissues into inguinal canal that are fairly common in males because the spermatic cord creates weak point in abdominal wall

Dartos muscle

Layer of smooth muscle in dermis of scrotum that causes characteristic wrinkling of scrotal surface

Cremaster

Layer of skeletal muscle deep to dermis that tenses scrotum and pulls testes closer to body

Seminiferous tubules

Location of sperm production; connect to rete testis, a network of interconnected straight tubules

Interstitial endocrine cells (Leydig cells)

Produce androgens, dominant male sex hormones; testosterone is most important androgen

Epididymis

Start of male reproductive tract; coiled tube almost 7 m long bound to posterior border of each testis

Functions of epididymis

Monitor and adjust composition of fluid produced by seminiferous tubules, recycle damaged sperm, and store/protect sperm and facilitate their functional maturation

Ductus deferens

Part of spermatic cord; begins at tail of epididymis and ascends through inguinal canal; curves inferiorly along urinary bladder toward prostate and seminal glands

Male urethra

Used by urinary and reproductive systems; extends 18–20 cm from urinary bladder to tip of penis

Accessory glands

Produce fluid component of semen with distinctive biochemical characteristics: Seminal glands, Prostate, and Bulbo-urethral glands

Major functions of accessory glands

Activate sperm, provide nutrients sperm need for motility, propel sperm and fluids along reproductive tract, and produce buffers to counteract acidity of urethral and vaginal environments

Prostate

Small, muscular organ (about 4 cm in diameter) that encircles proximal portion of urethra below urinary bladder

Prostatitis

Can occur at any age and most commonly afflicts older men

Bulbo-urethral glands (Cowper’s glands)

Secrete thick, alkaline mucus that helps neutralize urinary acids in urethra and lubricates tip of penis

Semen

Mixture of secretions, each with distinctive biochemical characteristics

Penis

Tubular organ through which distal portion of urethra passes that conducts urine to exterior and introduces semen into female’s vagina

Root of penis

Fixed portion that attaches penis to body wall inferior to pubic symphysis

Body of penis

Tubular, movable portion of penis

Glans penis

Expanded distal end of penis that surrounds external urethral orifice

Foreskin

Fold of skin surrounding tip of penis that attaches to neck and continues over glans penis

Circumcision

Surgical removal of foreskin that can help prevent infections and penile cancer

Erectile tissue

In body of penis; consists of network of vascular channels

Corpora cavernosa

Two cylindrical masses of erectile tissue that diverge at their bases, forming crus of penis

Corpus spongiosum

Relatively slender erectile body that surrounds distal portion of urethra; extends to tip of penis and expands to form glans penis

Mitosis

Part of somatic cell division that produces two diploid (2n) daughter cells

Meiosis

Special form of cell division involved only in production of gametes that produces four haploid (n) gametes

Synapsis

Maternal and paternal chromosomes come together; four matched chromatids form tetrad

Meiosis

Includes two division cycles: Meiosis I and meiosis II

Meiosis I

Reduces number of chromosomes from diploid (2n = 46) to haploid (n = 23)

Meiosis II

Number of chromosomes is unchanged

Spermatogenesis

Process of sperm production that begins at puberty and continues past age 70

Spermatogonia (stem cells)

Divide by mitosis to produce two daughter cells and begin meiosis and form secondary spermatocytes

Spermatids

Immature gametes that differentiate into sperm

Contents of seminiferous tubules

Spermatogonia, Spermatocytes, Spermatids, Sperm, and Large nurse cells

Spermiogenesis

Last step of spermatogenesis; each spermatid matures into one sperm

Nurse cells (Sertoli cells)

Play a critical role in spermatogenesis and have major functions including support of mitosis/meiosis/spermiogenesis, maintenance of blood testis barrier, and secretion of inhibin/androgen-binding protien

Capacitation of sperm

Sperm become motile when mixed with secretions of seminal glands and become capable of fertilization when exposed to female reproductive tract

Head of sperm

A flattened ellipse that contains nucleus with chromosomes and Acrosome contains enzymes essential to fertilization

Middle piece of sperm

Attached to head by short neck and contains mitochondria that provide ATP to move tail

Tail of sperm

The only flagellum in human body that moves sperm

Nurse Cell Stimulation

Under FSH stimulation, and with testosterone from the interstitial endocrine cells, nurse cells (1) secrete inhibin in response to factors released by developing sperm, (2) secrete androgen-binding protein (ABP), and (3) promote spermatogenesis and spermiogenesis.

Estradiol

Found in small amounts (2 ng/dL) in plasma of adult males; 70 percent is formed from circulating testosterone

Female reproductive system

Produces sex hormones and functional gametes, Protects and supports developing embryo, and Nourishes newborn infant

Uterine tubes

Run along broad ligament and Open into pelvic cavity lateral to ovaries

Three main functions of ovaries

Production of immature female gametes (oocytes), Secretion of female sex hormones (estrogens and progesterone), and Secretion of inhibin

Uterine tubes

Transport oocyte to uterus

Infundibulum

Expanded funnel near ovary; Fimbriae (projections) extend into pelvic cavity

Ampulla

Middle segment of uterine tubes

Isthmus

Short segment between ampulla and uterine wall

Oocyte transport

Involves ciliary movement and peristaltic contractions in walls of uterine tube

Uterine tube and fertilization

Secondary oocyte must meet sperm within the first 12–24 hours in uterine tube

Uterus

Provides for developing embryo (weeks 1–8) and fetus (week 9–delivery)

Uterine body

Largest portion of uterus that ends at isthmus (constriction)

Fundus

Rounded portion of uterine body

Cervix

Inferior portion of uterus that extends from isthmus to vagina

Blood supply of uterus

Branch of uterine arteries and ovarian arteries

Perimetrium

Incomplete serous membrane that covers fundus and posterior surface of uterine body and isthmus

Myometrium

Thick, middle, muscular layer that provides force to move fetus from uterus into vagina

Endometrium

Thin, inner, glandular layer that supports physiological demands of growing fetus

Vagina

Elastic, muscular tube that extends between cervix and vestibule

Two bulbospongiosus muscles

Cover bulb of vestibule

Hymen

Elastic epithelial fold that partially blocks entrance to vagina

Vaginal bacteria

Harmless resident bacteria in vagina that creates acidic environment and restricts growth of many pathogens

Vaginitis

Inflammation of vagina caused by fungi, bacteria, or parasites

Vulva (pudendum)

Area containing female external genitalia

Vestibule

Central space bounded by small folds (labia minora)

Clitoris

Small projection in vestibule that is derived from same embryonic structures as penis

Vestibular glands

Secrete onto exposed surface of vestibule and secrete into vestibule near vaginal entrance during sexual arousal

Mammary glands

Specialized organs of integumentary system that produce milk (lactation) to nourish infant

Oogenesis (ovum production)

Begins before birth, accelerates at puberty, and ends at menopause

Oogonia

Female reproductive stem cells

Primary oocytes

Those that survive remain at prophase I until puberty

Cytoplasm of primary oocyte divides unevenly

Producing one secondary oocyte with most of original cytoplasm and two or three polar bodies that disintegrate

Ovary releases secondary oocyte

Released in suspended metaphase II

Ovarian follicles

Specialized structures in cortex of ovaries where oocyte growth and meiosis I occur

Primordial ovarian follicle

Primary oocyte and its surrounding follicle cells

Zona pellucida

Area of intermingling microvilli of follicle cells and surface of oocyte

Ovarian cycle

Monthly process of maturation, ovulation, and degeneration of tertiary ovarian follicle

Follicular phase

Oocyte & its follicular cells project into antrum and Surrounded by granulosa cells

Ovulation

Tertiary follicle releases secondary oocyte into pelvic cavity

Corpus luteum

Forms from remaining granulosa cells under stimulation of LH

Corpus albicans

Forms scar tissue and Marks end of ovarian cycle

Uterine cycle (menstrual cycle)

Repeating series of changes in endometrium

Menarche

Beginning of uterine cycle, typically at age 11–12

Menopause

Termination of uterine cycles, Age 45–55

Menstrual phase

Degeneration of endometrial functional layer that occurs in patches. Caused by constriction of spiral arteries

Epithelial cells of uterine glands

Multiply and spread across endometrial surface and Restore integrity of uterine epithelium

Proliferative phase

Stimulated and sustained by estrogens secreted by developing ovarian follicles