Human Reproduction – Key Vocabulary

Vocabulary flashcards covering the major structures, processes, and hormones involved in human reproduction, from gametogenesis and reproductive anatomy to pregnancy, birth, and lactation.

Viviparous

Giving birth to live young rather than laying eggs; characteristic of humans.

Gametogenesis

The process of forming gametes (spermatogenesis in males, oogenesis in females).

Testes

Paired male gonads housed in the scrotum; produce sperm and androgens.

Scrotum

Skin-covered sac that keeps testes 2–2.5 °C below body temperature for spermatogenesis.

Testicular Lobule

One of ~250 compartments in a testis containing 1–3 seminiferous tubules.

Seminiferous Tubule

Highly coiled tubule where spermatogenesis occurs inside the testes.

Spermatogonia

Male germ cells lining seminiferous tubules; divide to form sperm.

Sertoli Cells

‘Nurse’ cells inside seminiferous tubules that provide nutrition and support to developing sperm.

Leydig Cells

Interstitial cells between seminiferous tubules that secrete androgens (e.g., testosterone).

Rete Testis

Network of tubules that receives sperm from seminiferous tubules before they enter vasa efferentia.

Epididymis

Coiled duct on posterior testis where sperm mature and are stored.

Vas Deferens

Muscular duct transporting sperm from epididymis to ejaculatory duct.

Seminal Vesicle

Paired accessory gland adding fructose-rich fluid to semen.

Prostate Gland

Single gland that adds Ca²⁺ and enzymes to seminal plasma.

Bulbourethral (Cowper’s) Gland

Paired gland secreting mucus for lubrication of penis and urethra.

Semen

Mixture of sperm (≈10 %) and seminal plasma (≈90 %).

Penis

Male copulatory organ containing three erectile tissues; ends with glans penis.

Foreskin (Prepuce)

Loose fold of skin covering the glans penis.

Ovaries

Paired female gonads that produce ova and hormones; almond-shaped, 2–4 cm long.

Stroma

Connective tissue inside ovary, differentiated into outer cortex and inner medulla.

Oviduct (Fallopian Tube)

10–12 cm muscular tube conveying oocyte from ovary to uterus.

Infundibulum

Funnel-shaped ovarian end of oviduct bearing fimbriae to catch ovulated oocyte.

Ampulla

Wider mid-portion of oviduct; usual site of fertilisation.

Isthmus (Oviduct)

Narrow segment connecting ampulla to uterus.

Uterus

Muscular, pear-shaped organ where embryo implants and fetus develops.

Perimetrium

Thin outer serous layer of uterine wall.

Myometrium

Thick middle smooth-muscle layer of uterus responsible for labour contractions.

Endometrium

Inner glandular layer of uterus undergoing cyclic changes and implantation.

Cervix

Lower narrow part of uterus opening into vagina.

Vagina

Elastic muscular tube (~7.5 cm) forming lower part of birth canal.

Hymen

Thin membrane partially covering vaginal opening.

Mons Pubis

Fatty pad overlying pubic bone, covered with hair.

Labia Majora

Outer fleshy folds surrounding vaginal opening.

Labia Minora

Inner thin folds situated inside labia majora.

Clitoris

Highly sensitive erectile structure homologous to male penis.

Mammary Gland

Modified sweat gland producing milk; consists of 15–20 lobes.

Alveolus (Breast)

Milk-secreting sac within mammary lobes.

Lactiferous Duct

Duct conveying milk from ampulla to nipple.

Spermatogenesis

Formation of sperm from spermatogonia through mitosis, meiosis, and spermiogenesis.

Spermiation

Release of mature sperm from Sertoli cells into lumen of seminiferous tubule.

Acrosome

Cap on sperm head containing lytic enzymes for penetration of ovum.

Middle Piece (Sperm)

Sperm segment packed with mitochondria supplying ATP for motility.

Oogenesis

Formation of ovum from oogonia, beginning before birth and completing after fertilisation.

Primary Oocyte

Diploid cell arrested in prophase I from fetal life until puberty.

Zona Pellucida

Glycoprotein membrane secreted by secondary oocyte; binds sperm.

Graafian Follicle

Mature ovarian follicle containing secondary oocyte and large antrum.

Ovulation

Rupture of Graafian follicle releasing secondary oocyte into oviduct.

Menstrual Cycle

≈28-day cyclic changes in ovaries and uterus involving menstruation and hormones.

Menarche

First menstrual bleeding marking onset of reproductive life.

Menopause

Permanent cessation of menstruation, typically around 50 years.

LH Surge

Sharp mid-cycle rise in luteinising hormone triggering ovulation.

Corpus Luteum

Yellow endocrine body formed from ruptured follicle; secretes progesterone and estrogen.

Fertilisation

Fusion of haploid sperm and ovum nuclei in ampulla forming diploid zygote.

Implantation

Embedding of blastocyst into endometrium about 6–7 days after fertilisation.

Trophoblast

Outer layer of blastocyst forming chorion and part of placenta.

Chorionic Villi

Finger-like projections of trophoblast interfacing with maternal tissue.

Placenta

Foeto-maternal organ for nutrient, gas exchange and hormone secretion; connected by umbilical cord.

hCG (Human Chorionic Gonadotropin)

Placental hormone maintaining corpus luteum during early pregnancy; detected in pregnancy tests.

hPL (Human Placental Lactogen)

Placental hormone promoting fetal growth and maternal metabolic adaptation.

Relaxin

Hormone (placental & ovarian) that loosens pubic symphysis for childbirth.

Umbilical Cord

Flexible cord connecting fetus to placenta, containing blood vessels.

Ectoderm

Outer embryonic germ layer forming skin, nervous system, hair, and nails.

Mesoderm

Middle germ layer giving rise to muscles, bones, circulatory and excretory systems.

Endoderm

Inner germ layer forming gut lining, liver, pancreas, and lungs’ inner epithelium.

Gestation Period

Duration of human pregnancy (~9 months or 280 days).

Parturition

Process of delivering the fully developed fetus; labour.

Oxytocin

Posterior pituitary hormone causing strong uterine contractions during labour and milk ejection.

Colostrum

Yellow, antibody-rich (IgA) milk secreted during first few days postpartum; boosts newborn immunity.