Reproductive System Flashcards
Primary purpose
Produce Gametes: generate sperm in males and eggs (oocytes) in females for reproduction.
Fertilization: facilitate the union of sperm and egg to form a zygote.
Support Development: provide an environment for embryo and fetal development (female system).
Hormone Production: secrete sex hormones like testosterone, estrogen, and progesterone to regulate reproduction and secondary sexual characteristics.
Delivery of Offspring: enable childbirth in females through the reproductive tract.
Genetic Continuity: ensure the transfer of genetic material to the next generation.
Primary organs
Male.
Testes: produce sperm and testosterone.
Epididymis: store and mature sperm.
Vas Deferens: transport sperm from the epididymis to the urethra.
Seminal Vesicles: produce seminal fluid that nourishes sperm.
Prostate Gland: secretes fluid that helps sperm motility and protection.
Penis: delivers sperm into the female reproductive tract.
Primary organs
Ovaries: produce eggs (oocytes) and secrete hormones (estrogen, progesterone).
Fallopian Tubes: transport eggs from the ovaries to the uterus; site of fertilization.
Uterus: houses and nourishes the developing fetus.
Vagina: birth canal and passage for menstrual flow; receives sperm during intercourse.
Cervix: the lower part of the uterus that opens into the vagina, facilitating childbirth and menstrual flow.
Secondary Organs
Scrotum: protective sac that holds the testes and regulates their temperature.
Urethra: carries semen and urine out of the body.
Seminal Vesicles: secrete fluids that form part of semen, providing nutrients for sperm.
Bulbourethral Glands (Cowper’s Glands): secrete a lubricating fluid that neutralizes acidic urine in the urethra prior to ejaculation.
Secondary Organs
Vulva: external genitalia, including the labia, clitoris, and vaginal opening.
Breasts (Mammary Glands): produce milk for breastfeeding.
Labia Majora/Minora: folds of skin that protect the vaginal opening.
Clitoris: sensitive organ that contributes to sexual pleasure.
Bartholin’s Glands: secrete mucus to lubricate the vagina during intercourse.
Structural differences
Functional differences
Testes
Layers of Testes
Tunica Vaginalis: outermost layer; derived from peritoneum, consists of two layers (parietal/visceral); provides a protective covering and allows movement of the testes.
Tunica Albuginea: tough, fibrous connective tissue beneath the tunica vaginalis; encapsulates the testes and gives them their shape; extends inward to form septa that divide the testes into lobules.
Tunica Vasculosa: inner layer of tunica albuginea; contains blood vessels that supply the testes.
Leydig Cells
Location: found in the interstitial spaces between the seminiferous tubules in the testes.
Function: produce testosterone, the primary male sex hormone.
Testosterone is crucial for spermatogenesis, development of male secondary sexual characteristics, and maintaining libido.
Stimulated by: luteinizing hormone (LH) from the pituitary gland.
Role in Development: essential for the formation of male reproductive organs during fetal development and puberty.
Structure: large, polygonal cells with abundant smooth endoplasmic reticulum and lipid droplets for steroid hormone production.
Sertoli Cells
Location: found inside the seminiferous tubules, surrounding developing sperm cells.
Function: support and nourish developing sperm during spermatogenesis; secrete androgen-binding protein (ABP) to concentrate testosterone in the tubules for sperm maturation; Produce inhibin, which regulates FSH levels via negative feedback; form the blood-testis barrier, protecting sperm from the immune system; phagocytose defective germ cells and excess cytoplasm shed during sperm development.
Stimulated by: Follicle-stimulating hormone (FSH) from the pituitary gland.
Structure: tall, columnar cells that extend from the tubule’s basement membrane to its lumen.
Epididymis
Location: coiled tube located on the posterior surface of each testis.
Structure: divided into three parts (head, body, tail); made of a single, tightly coiled duct.
Functions: sperm maturation (sperm gain motility and the ability to fertilize); sperm storage (stores mature sperm in the tail until ejaculation); sperm transport (moves sperm to the vas deferens via peristaltic contractions.
Environment: provides a nourishing environment for sperm development.
Duration: sperm spends about 2-3 weeks in the epididymis to fully mature.
Vas Deferens
Location: tube extending from the epididymis to the ejaculatory duct; travels through the spermatic cord, passes the inguinal canal, and joins the seminal vesicles near the prostate gland.
Structure: thick, muscular walls with a narrow lumen; lined with pseudostratified columnar epithelium.
Function: transports mature sperm from the epididymis to the ejaculatory duct during ejaculation; uses peristaltic contractions of smooth muscle for sperm movement.
Clinical Importance: target for vasectomy, a surgical procedure for male contraception by severing or sealing the vas deferens.
Accessory Glands
Seminal Vesicles
Location: behind the bladder, near the base of the prostate.
Secretion: produces about 60-70% of semen; fructose for sperm energy; prostaglandins to enhance sperm motility and aid in fertilization; alkaline fluid to neutralize the acidic environment of the female reproductive tract.
Prostate Gland
Location: below the bladder, surrounding the urethra.
Secretion: produces about 25-30% of semen; milky, slightly acidic fluid containing enzymes like PSA (prostate-specific antigen) to liquefy semen; citric acid and zinc for sperm health.
Bulbourethral (Cowper’s) Glands
Location: below the prostate, near the base of the penis.
Secretion: produces a small amount of pre-ejaculate; mucus-rich fluid to lubricate the urethra and neutralize residual acidity from urine.
Penis
External Parts: glans penis (enlarged, sensitive tip covered by the foreskin (if uncircumcised); shaft (main cylindrical part of the penis); prepuce (foreskin – retractable skin covering the glans in uncircumcised males).
Internal Parts: corpora cavernosa (two cylindrical, erectile tissues running along the shaft; fill with blood during erection); corpus spongiosum (single cylindrical tissue surrounding the urethra; prevents urethral compression during erection); urethra (passage for both urine and semen).
Functions: reproductive (delivers sperm into the female reproductive tract during intercourse); excretory (passageway for urine elimination).
Mechanism of Erection and Ejaculation: erection (blood fills erectile tissues, triggered by neural and vascular responses); ejaculation (rhythmic contractions propel semen out through the urethra).
Ovaries
Location: paired organs located on either side of the uterus in the pelvic cavity.
Shape and Size: almond-shaped, approx. 3 cm long.
Layers:
Germinal Epithelium: outer layer.
Tunica Albuginea: protective connective tissue layer beneath the germinal epithelium.
Cortex: outer region where follicles develop.
Medulla: inner region containing blood vessels and nerves.
Functions:
Oogenesis: production of eggs (ova).
Eggs develop within ovarian follicles.
Hormone Production:
Estrogen: regulates menstrual cycle and secondary sexual characteristics.
Progesterone: prepares the uterus for implantation and maintains pregnancy.
Follicular Development:
Follicle Stages: primordial –> primary –> secondary –> Graafian (mature follicle).
Ovulation: release of a mature egg during the menstrual cycle.
Corpus luteum: temporary structure formed after ovulation, secreting progesterone.
Ovulation
The release of a mature egg (oocyte) from a Graafian follicle in the ovary.
Occurs once during each menstrual cycle, typically around day 14 of a 28-day cycle.
Process:
- Follicle Growth: stimulated by follicle-stimulating hormone (FSH).
- LH Surge: a spike in luteinizing hormone (LH) triggers ovulation.
- Egg Release: the follicle ruptures, and the egg is released into the fallopian tube.
- Corpus Luteum Formation: the ruptured follicle transforms into the corpus luteum, which secretes progesterone.
Timing:
Egg is viable for 12-24 hours after release.
Fertilization must occur within this window for pregnancy.
Symptoms:
Mild abdominal pain (Mittelschmerz)
Changes in cervical mucus (becomes clear and stretchy)
Slight rise in basal body temperature
Fallopian Tubes
Location: extend from the ovaries to the uterus, one one each side.
Length: approx. 10-12 cm long.
Regions:
Fimbriae: finger-like projections near the ovary that catch the released egg.
Infundibulum: funnel-shaped opening near the fimbriae.
Ampulla: widest part where fertilization typically occurs.
Isthmus: narrow portion connecting to the uterus.
Function:
Egg Transport: cilia and smooth muscle contractions move the egg toward the uterus.
Site of Fertilization: sperm typically meets the egg in the ampulla.
Early Embryo Transport: moves the fertilized egg (zygote) to the uterus for implantation.
Clinical Importance:
Ectopic Pregnancy: occurs if the fertilized egg implants in the fallopian tube.
Blockages can lead to infertility.
