Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Notice: This presentation contains actual pictures of human reproductive anatomy Chapter 16 The Reproductive System Intro & Male The Reproductive System 1. Gonads – primary sex organs Testes in males Ovaries in females 2. Gonads produce gametes (sex cells) and secrete hormones Sperm – male Ova (eggs) – female Male Reproductive System Testes Accessory organs Duct system External genitalia - Seminal vesicle - Penis - Epididymis - Prostate gland - Scrotum - Ductus deferens - Bulbourethral gland - Urethra Testes Tunica albuginea – capsule that surrounds each testis Septa – extensions into testis; dividing it into lobules Testes Each lobule contains 1-4 seminiferous tubules Tightly coiled Sperm-forming factories Empty sperm into the rete testis Sperm travels through the rete testis to epididymis Interstitial cells produce androgens such as testosterone Epididymis Comma-shaped, tightly coiled tube Superior and along posterior lateral side Matures and stores sperm cells (at least 20 days) Expels sperm with the contraction of muscles in the epididymis walls to the vas deferens Ductus Deferens Carries sperm from epididymis to ejaculatory duct Passes through inguinal canal & over bladder Moves by peristalsis Ends in the ejaculatory duct which unites with urethra Spermatic cord – ductus deferens, Vasectomy – cutting of the ductus deferens at the level blood vessels, and nerves in a of the testes to prevent connective tissue transportation of sperm Urethra Extends from the base of bladder to the tip of penis Carries both urine and sperm Sperm enters from the ejaculatory duct Regions: Prostatic urethra –surrounded by prostate Membranous urethra – from prostatic urethra to penis Spongy (penile) urethra – runs the length of the penis Seminal Vesicles Located at the base of the bladder Produces a thick, yellowish secretion (60% of semen) - Fructose (sugar) - Vitamin C - Prostaglandins - Substances that nourish & activate sperm Prostate Gland Encircles upper part of urethra Secretes a milky fluid - Helps activate sperm - Enters urethra through several small ducts Bulbourethral Glands Pea-sized gland inferior to prostate Produces a thick, clear mucus - Cleanses urethra of acidic urine - Lubricant during intercourse - Secreted into penile urethra Semen Mixture of sperm & gland secretions Advantages of secretions - Fructose provides energy - Alkalinity neutralizes acidic vagina - Semen inhibits bacterial growth - Elements of semen enhance sperm motility External Genitalia Scrotum - Divided sac of skin outside abdomen - 3°C lower than body temp to protect sperm External Genitalia Penis- Delivers sperm into female repro tract - Shaft - Glans penis (enlarged tip) - Prepuce (foreskin) Folded cuff of skin around proximal end Often removed by circumcision External Genitalia 3 areas of spongy erectile tissue around the urethra Spermatogenesis Production of sperm cells Begins at puberty and continues throughout life Occurs in the seminiferous tubules Processes of Spermatogenesis Follicle stimulating hormone (FSH) regulates Spermatogonia (stem cells) rapid mitosis to produce more stem cells before puberty First division of a stem cell becomes 1 stem cell & 1 primary spermatocyte Primary spermatocytes undergo meiosis Haploid spermatids Anatomy of a Mature Sperm Cell Late spermatids - distinct regions - Head –DNA covered by acrosome - Midpiece - Tail Sperm cells = mature spermatids Spermatogenesis takes 64 to 72 days Only human flagellated cell Testosterone Production - Most important hormone of testes - Produced in interstitial cells - Functions Organ development Sex drive Secondary sex characteristics - Deepening of voice - Increased hair growth - Larger skeletal muscles - Thicker bones Regulation of Male Androgens (Sex Hormones)