Human Reproductive System Gonads – make gametes! Ducts – gametes and fluid travel through. Accessory Organs and Glands External Genitalia Fertilization - union of sperm and egg = zygote. Structures Produces, stores, nourishes and transports functional gametes (egg and sperm).
Male Gonads –Testes produce sperm and testosterone. Female Gonads –Ovaries produces eggs, estrogen and progesterone.
Male Reproductive Structures
1 o Reproductive organ: Testes Dartos muscle wrinkles skin of scrotum. Cremaster muscle pulls testes closer to body. Male Reproductive Structures Scrotum - encloses testes.
Structure of the Testes Figure 27.4a
Seminiferous Tubules Site of sperm production - contain spermatogonia (stem cells) Interstitial cells - secretes testosterone. Efferent ducts connect rete testis to epididymis.
Epididymis – about 18 feet long (3 weeks). - Head - Body - Tail Stores spermatozoa (recycles damaged spermatozoa) Ductus deferens – starts after tail of epididymis Maturation of Sperm cells
Ductus Deferens Muscular tube that transports and stores spermatozoa - begins at epididymis. Passes through inguinal canal. Fuses into ejaculatory duct (see figure). Empties into urethra. Connected to abdominal cavity via spermatic cord.
Accessory Organs of the Male Seminal vesicles Prostate gland Bulbourethral glands All of these structures secrete semen into ejaculatory ducts and urethra Seminal Vesicles Paired glands - secretes 60% semen volume. Fructose – a sugar for energy! Fibrinogen – converts to fibrin. Prostaglandins – contract female tract.
Prostate Gland Single gland - secretes 30% semen volume. Bulbourethral Glands Lubricating properties. Fibrolysin – to liquefy clots. Alkaline mucus secretion (to neutralize). Clotting enzymes – to cause initial clots. Paired glands (~5% semen volume).
The Accessory Glands
Semen Sperm count typically 50 – 100 million per ml. Sperm count below 20 million per ml, considered “infertile”. Sperm must be 2-3 o F cooler than rest of body, hence kept ‘outside’ in scrotum. Typical ejaculation releases 2-5 ml.
Connective tissue, fascia and muscle. The Spermatic Cord Encloses these structures: ductus deferens, testicular artery, testicular vein, cremaster muscle. Pampiniform plexus, lymphatics and nerves. All these travel through inguinal canal.
Male Urethra Three regions –Prostatic urethra –Membranous urethra –Penile urethra Urinary bladder to tip of penis Lined with transitional epithelium.
The Penis Root, body (shaft) and glans. Prepuce (foreskin) surrounds tip. Erectile tissue (3 masses) –Two corpora cavernosa –One corpus spongiosum (surrounds urethra) Erection – dilation of arterial smooth muscles.