Reproductive System and Human Reproduction

Vocabulary flashcards covering male and female anatomy, gametogenesis, hormonal control, fertilization, pregnancy, and childbirth.

Sex determination

Process by which genetic sex directs development of sexual characteristics; occurs around week 7 of gestation.

SRY gene

Sex-determining region Y gene; triggers genes essential for male development when present on the Y chromosome.

Y chromosome

Male sex chromosome carrying the SRY gene.

XY genotype

Karyotype typical of males (one X and one Y).

XX genotype

Karyotype typical of females (two X chromosomes).

Seminiferous tubules

Coiled tubules in the testes where meiosis and spermatogenesis occur.

Sertoli cells

Support germ cells in the seminiferous tubules; regulate spermatogenesis and release inhibin.

Leydig cells

Testicular interstitial cells that produce testosterone.

Nucleus (in sperm)

Genetic material (DNA) contained within the sperm head.

Acrosome

Cap at the tip of the sperm head containing enzymes to penetrate the egg's zona pellucida.

Flagellum

Tail of the sperm enabling movement.

Midpiece

Sperm segment rich in mitochondria supplying energy for movement.

Spermatozoa

Mature sperm cell.

Sperm concentration

Average sperm count in ejaculate; about 40 million per milliliter.

Epididymis

Coiled duct where mature sperm are stored and gain motility.

Vas deferens

Duct that transports sperm from the epididymis to the urethra during ejaculation.

Urethra

Duct through which urine and semen pass; runs through the penis.

Penis

Male copulatory organ; contains erectile tissue that fills with blood to cause erection.

Erectile tissue

Tissue in the penis that becomes engorged with blood to enable an erection.

Semen

Sperm-containing fluid produced by accessory glands around the urethra.

Accessory glands

Glands (seminal vesicles, prostate, bulbourethral glands) that add most of semen volume.

Ejaculation

Expulsion of semen from the penis at peak arousal.

Orgasm

Peak pleasurable sensation accompanying ejaculation.

Refractory period

Recovery interval after orgasm during which erections cannot occur.

Testes

Gonads that produce sperm and testosterone.

Seminal vesicles

Glands that contribute most of the semen volume; provide energy-rich fluid.

Prostate gland

Gland surrounding the urethra that produces a fluid helping sperm viability; surrounds the urethra.

Corpus cavernosum

One of the two erectile bodies of the penis.

Corpus spongiosum

Erectile tissue surrounding the urethra; keeps it open during erection.

Glans

Head of the penis.

Foreskin

Skin covering the glans; removed in circumcision.

Circumcision

Surgical removal of the foreskin, exposing the glans.

Digital rectal examination (DRE)

Medical test to check prostate size/consistency.

BPH (benign prostatic hyperplasia)

Age-related enlargement of the prostate that can slow urine flow.

Spermatogenesis

Process of sperm formation in the testes via meiosis and maturation.

Spermatogonial stem cells (SSCs)

Stem cells at the periphery that self-renew or differentiate to begin spermatogenesis.

Primary spermatocytes

Cells that enter meiosis I to form haploid secondary spermatocytes.

Secondary spermatocytes

Haploid cells produced after meiosis I that enter meiosis II.

Spermatids

Haploid cells that differentiate into mature sperm (spermiogenesis).

Meiosis I

First meiotic division producing two haploid cells.

Meiosis II

Second meiotic division producing four haploid spermatids from two secondary spermatocytes.

Inhibin

Hormone from Sertoli cells that inhibits FSH when sperm count is high.

Testosterone

Primary male sex hormone; drives spermatogenesis and male characteristics.

FSH (follicle-stimulating hormone)

Stimulates sperm production in the seminiferous tubules.

LH (luteinizing hormone)

Stimulates testosterone production by Leydig cells.

GnRH (gonadotropin-releasing hormone)

Hypothalamic hormone that stimulates release of FSH and LH.

Negative feedback

Regulatory mechanism where high testosterone inhibits GnRH, FSH, and LH.

Ovary

Female gonad producing oocytes and hormones (estrogen, progesterone).

Fallopian tubes

Tubes carrying oocytes from ovaries to the uterus; site of fertilization often.

Uterus

Muscular organ where embryo implants and grows during gestation.

Cervix

Narrow lower part of the uterus that opens to the vagina.

Endometrium

Vascular lining of the uterus that thickens and sheds during the menstrual cycle.

Vagina

Muscular canal leading from the cervix to the exterior; birth canal.

Oocytes

Egg cells produced in ovarian follicles.

Follicle

Oocyte-containing structure in the ovary; produces estrogen.

Corpus luteum

Temporary endocrine structure formed after ovulation; secretes progesterone and estrogen.

Corpus albicans

Scar-like remnant of the corpus luteum after it degenerates.

Ovulation

Release of a mature oocyte from the ovary.

Oogenesis

Process of egg development in females.

Oogonium

Diploid germ cell that gives rise to oocytes.

Primary oocyte

Oocyte that begins meiosis I and is arrested in prophase I until puberty.

Secondary oocyte

Oocyte that completed meiosis I and is arrested in metaphase II until fertilization.

Ovum

Mature egg after fertilization; often used to mean egg.

Polar body

Small cell produced during meiosis that usually degenerates.

Zygote

Diploid cell formed by the fusion of sperm and egg; contains 46 chromosomes.

Blastocyst

Early embryo stage after cleavage with a fluid-filled cavity.

Corona radiata

Layer of granulosa cells surrounding the oocyte providing nourishment.

Zona pellucida

Glycoprotein layer surrounding the oocyte that sperm must penetrate.

Capacitation

Biochemical changes that increase sperm motility and ability to fertilize.

Acrosome reaction

Sperm enzymes released to penetrate the zona pellucida and fuse with the egg.

Polyspermy block

Mechanisms to prevent more than one sperm from fertilizing an egg.

Placenta

Organ connecting fetus to mother; facilitates nutrient and waste exchange without blood mixing.

Umbilical cord

Cord containing vessels that connect fetus to placenta.

Amniotic fluid

Fluid surrounding the fetus in the amniotic sac.

Amnion

Innermost fetal membrane surrounding the fetus.

Chorion

Outer fetal membrane; forms part of the placenta and contains chorionic villi.

hCG (human chorionic gonadotropin)

Hormone produced by the placenta; detected by pregnancy tests.

Gestation

Period of pregnancy from fertilization to birth.

Embryo

Early developing organism from fertilization up to about 8 weeks.

Fetus

Developing baby from about 8 weeks until birth.

Implantation

Embedding of the blastocyst into the endometrium.

Amniocentesis

Test to sample fetal cells from amniotic fluid for abnormalities.

Ultrasound

Imaging technique using sound waves to view the fetus and its position.

Breech birth

Delivery with the baby feet or buttocks first; often requires turning or C-section.

Ectopic pregnancy

Fertilized egg implants outside the uterus, usually in a fallopian tube; not viable.

Gestational diabetes

Pregnancy-related insulin resistance causing high blood glucose.

Preeclampsia

Pregnancy complication with high blood pressure and organ involvement; delivery cures.

IVF (in vitro fertilization)

Eggs fertilized outside the body and embryos transferred to the uterus.

Hysterectomy

Surgical removal of the uterus (partial or total).

Cesarean section

Surgical delivery of baby through abdomen.

Episiotomy

Surgical incision in the perineum to widen the vaginal opening during birth.

Placenta previa

Placenta attaches low in the uterus, blocking the cervix and causing bleeding.

Mucus plug

Cervical mucus barrier protecting the uterus during pregnancy.

Menopause

Time when a woman's menstrual cycles cease; typically 45–55 years.

Pap test

Screening test for cervical abnormalities using cells from the cervix.

Speculum

Instrument used to visualize the cervix during exams.