Reproductive Flashcards
Default Female Development:
All embryos start as female.
SRY gene (Sex-Determining Region of Y Chromosome): Triggers male development by forming testes.
Homologous Structures
Labia majora ↔ Scrotum.
Clitoris ↔ Penis.
Path of Sperm:
Testes → Epididymis → Ductus deferens → Ejaculatory duct → Urethra → Penis.
Testes
Structure: Tunica vaginalis (serous sac), tunica albuginea (fibrous capsule), lobules with seminiferous tubules (site of sperm production).
Cells:
Leydig Cells: Respond to LH; produce testosterone.
Sertoli Cells: Respond to FSH; support sperm development.
Scrotum
Temperature Regulation:
Dartos Muscle: Wrinkles scrotal skin.
Cremaster Muscle: Raises or lowers testes
Spermatic Cord
contains vas deferens, testicular artery, pampiniform plexus (cools arterial blood), nerves, and lymphatics.
Seminal Vesicles
~60% of semen; contains fructose (nourishes sperm) and prostaglandins (stimulate uterine contractions).
Prostate Gland
~25-30% of semen; enhances sperm motility and liquefies semen.
Bulbourethral Glands
Secretes mucus to neutralize urethra’s acidity before ejaculation.
Penis
Corpus Spongiosum: Surrounds urethra.
Corpora Cavernosa: Main erectile tissue.
Functions: Delivers sperm, eliminates urine.
Spermatogenesis
Formation of sperm in seminiferous tubules.
Spermatogenesis
Process:
Spermatogonia (Diploid, 2n): Undergo mitosis.
Primary Spermatocyte: Enters meiosis I.
Secondary Spermatocytes (Haploid, n): Undergo meiosis II.
Spermatids: Mature through spermiogenesis into spermatozoa.
Sperm Structure:
Head: Contains nucleus and acrosome (enzymes to penetrate egg).
Midpiece: Packed with mitochondria (energy for swimming).
Tail: Propels sperm.
Path of Egg
Ovary → Uterine Tube → Uterus → Vagina.
Ovaries:
Structure: Outer cortex (houses follicles), inner medulla (blood vessels, nerves, lymphatics).
Follicular Development:
Primordial Follicle → 2. Primary Follicle → 3. Secondary Follicle → 4. Graafian Follicle → 5. Ovulation → Corpus Luteum (secretes progesterone).
Uterine Tubes (Fallopian Tubes)
Sections: Fimbriae → Infundibulum → Ampulla (site of fertilization) → Isthmus.
Lined with ciliated columnar epithelium for egg transport.
Uterus
Wall Layers:
Perimetrium: Outer layer.
Myometrium: Smooth muscle for contractions.
Endometrium: Inner mucosal lining with two layers:
Stratum Functionalis: Shed during menstruation.
Stratum Basalis: Regenerates the functional layer.
Vagina
Layers: Mucosa (stratified squamous), muscularis, adventitia.
Functions: Receives sperm, serves as the birth canal.
Oogenesis
Formation of eggs in ovaries.
Oogenesis process
Oogonia: Stem cells (diploid, 2n); divide by mitosis during fetal development.
Primary Oocyte: Arrested in meiosis I until puberty.
Secondary Oocyte: Released during ovulation; arrested in meiosis II until fertilization.
Mature Ovum: Forms only after fertilization.
Polar Bodies
Byproducts of meiosis; degenerate.
Ovarian Cycle
Follicular Phase (Days 1–14): Follicles grow; FSH stimulates estrogen production.
Ovulation (Day 15): Triggered by an LH surge.
Luteal Phase (Days 15–28): Corpus luteum secretes progesterone.
Uterine Cycle
Menstrual Phase (Days 1–5): Shedding of stratum functionalis.
Proliferative Phase (Days 6–14): Rebuilding of endometrium.
Secretory Phase (Days 15–28): Endometrium prepares for implantation.
FSH (Follicle-Stimulating Hormone)
Males: Stimulates Sertoli cells for sperm production.
Females: Stimulates follicular growth.
LH (Luteinizing Hormone)
Males: Stimulates Leydig cells for testosterone production.
Females: Triggers ovulation.
Estrogen
Maintains female secondary sex characteristics; thickens endometrium.
Progesterone
: Prepares uterus for implantation.
hCG (Human Chorionic Gonadotropin)
Maintains corpus luteum during early pregnancy.
