Reproductive System Male
Comparison of Male and Female Reproductive Systems Spermatogenesis Occurs throughout life from puberty to ? Primary sex organ is the testes Primary male sex hormone is testosterone Oogenesis Begins at puberty ends at menopause Women are born with all the gametes they will ever have Primary sex organ is the ovary Several hormones, estrogen, progesterone.
Male Reproductive System Principal Structures Testes Epididymis Ductus deferens (vas deferens) Urethra Ejaculatory duct Prostate gland (1) Seminal vesicle (2) Bulbourethral gland (2)
Male Reproductive System
Position of Testes Testes are located in the scrotum Spermatic cord contains the ductus deferens, as well as several arteries and veins Contractions of the DARTOS muscle in the scrotum gives the scrotum its wrinkled appearance The CREMASTER muscle can pull the testes closer to the body, also regulates testes position for optimum sperm production in relation to temperature
Male Reproductive System
Structure of Testes Testes are divided into lobules by the tunica albuginea There are 200-300 lobules containing 1-3 coiled seminiferous tubules Sperm production occurs in the seminiferous tubules
Spermatogenesis
Spermatogenesis Production of sperm Occurs in the seminiferous tubules of the testes Stimulated by testosterone - produced by the interstitial cells Testosterone production is stimulated by luteinizing hormone (LH)
Seminiferous Tubules and Interstitial Cells (Leydig cells)
Sustentacular cells (Sertoli cells) and Spermatogenesis
Spermatogenesis
Epididymis Coiled tubules adjacent to the testes Stores sperm Recycles damaged sperm Adjusts composition of tubular fluid
Ductus Deferens Sperm carrying tube that begins at the epididymis and ends at the prostate gland 16-18 in long Runs in the spermatic cord Joins with the seminal vesicles to form the ejaculatory duct Epithelial lining of pseudostratified columnar cells with apical sterocilia
Histology of the Ductus Deferns
Ductus Deferens Epithelial lining
Ductus Deferens, Seminal Vesicles, Prostate, and Bulbourethral glands
Seminal Vesicles Accessory gland Contribute 60% of the volume of semen Viscous, whitish-yellow alkaline fluid Seminal secretion contains fructose Sperm use this sugar to make ATP Sperm become motile when mixed with this fluid Prostaglandins also in the secretion Promotes widening and slight dilation of cervix to allow sperm entry into the uterus
Prostate Gland Small gland at the base of the bladder Encircles the prostatic urethra as it leaves the bladder Prostatic fluid contributes 20-30% of the volume of semen Weakly acidic secretion to protect the sperm in the acidic female vagina. Seminalplasmin - antibiotic that helps prevent urinary tract infections in males
Bulbourethral Glands Located at base of penis Secrete a thick, sticky, alkaline mucus Helps neutralize urinary acids
Semen Sperm – 20-100 million/ml Seminal fluid – the fluid component of semen 60% from seminal vesicles 30% from prostate 5% from bulbourethral gland 5% from sustentacular cells and epididymis Enzymes Total volume 2-5ml – 99% of the volume of semen is added from accessory glands
Composition of semen Sperm – gamete – seminiferous tubules Mucus – lubricant – bulbourethal gland Water – liquid medium – all glands Buffers – neutralize vaginal acid – prostrate, bulbourethral glands Fructose – nourish sperm – seminal vesicle Citric acid – nourish sperm – prostate Vitamin C – nourish sperm – seminal vesicle Carnitine – nourish sperm – epididymis Enzymes – clot and liquefy semen – seminal vesicle, prostate Zinc – fertility? – unknown Prostaglandins – sperm transport – seminal vesicles
Urethra Prostatic urethra Membranous urethra Penile urethra
Penis
Penis
Sildenafil citrate (Viagra) How stuff works Sildenafil citrate (Viagra)