Chapter 27 Reproductive Anatomy 11 24 2014 Reproductive system Primary sex organs gonads o Testes and ovaries Produce sex cells gametes Secrete steroid sex hormones Androgens males Estrogens and progesterone females o Accessory reproductive organs ducts glands and external genitalia Male reproductive anatomy Scrotum sac that contains the male gonads testes regulates gamete production in the testes o Superficial fascia o Dartos muscles smooth muscle that cause the skin of the scrotum to wrinkle o Cremaster muscle the muscle that raises and lowers the testes within the scrotum skeletal muscle not under voluntary control regulate the temperature of the testes testes at lower temperature for sperm production Epididymis Testes have multiple lobes o Seminiferous tubule where sperm is produced Myoid muscle cells job is to squeeze the seminifierous tubule to move sperm Leydig where testosterone is produced immediately outside the seminiferous tubule necessary for sperm production Spermatogenic cells produce sperm Interstitial endocrine cells leydig cells Ductus vas deferens Ampalla of ductus deferens sperm can be stored here Inguinal canal testes drop through this canal Urethra Prostate gland contains the urethra and part of the vas deferens The male duct system Vasectomy cutting and ligating the ductus deferens which is a nearly 100 effective form of birth control Ductus deferens passes through the inguinal canal propels sperm from the epididymis to the urethra Urethra conveys both urine and semen has three regions prostatic urethra membranous urethra spongy penile urethra Ejaculatory duct where the ampulla of ductus deferens and seminal vesicle converge Accessory glands seminal vesicles Produces viscous alkaline seminal fluid o Fructose o Ascorbic acid o Coagulating enzyme vesiculase o Prostaglandins o 70 of the volume of semen o duct of seminal vesicle joins the ductus deferens to form the ejaculatory duct Prostate Encircle part of the urethra Secretes milky slightly acid fluid o Contains citrate enzymes prostate specific antigen PSA o Plays a role in sperm activation Male reproductive anatomy Bulbourethral glands cowper s glands Prior to ejaculation produce thick clear mucus Lubricates the glans penis Neutralizes traces of acidic urine in the urethra The penis The male copulatory organ 4 structures o spongy urethra o corpus spongiosum surrounds the urethra makes sure the urethra stays open so ejaculation can occur o corpora cavernosa x 2 erection erectile tissue fills with blood causing the penis to enlarge and become rigid Semen Mixture sperm and accessory gland secretions Contents and functions o Nutrients fructose o Protects and activates sperm o Prostaglandins in semen Decrease the viscosity of mucus in the cervix Stimulate reverse peristalsis in the uterus Alkaline neutralizes the acid in the male urethra and female vagina Only 2 5 ml of semen are ejaculated containing 20 150 million sperm ml Male sexual response Erection o Parasympathetic reflex promotes release of nitric oxide NO potent vasodilator erectile tissue becomes engorged impotent men don t produce enough NO o No causes vasodilation Corpora cavernosa Compresses drainage veins Corpus spongiosum keeps urethra open o Impotence the inability to attain erection Ejaculation o Propulsion of semen from the male duct system o Sympathetic spinal reflex causes Ducts and accessory glands contract Bladder sphincter muscle constricts Bulbospongiosus muscles to undergo a rapid series of contractions Spermatogenesis Sequence of events that produces sperm in the seminiferous tubules of the testes Most body cells are diploid and contain o 2 sets of chromosomes one maternal and one paternal o 23 pairs of homologous chromosomes gametes are haploid and contain o 23 chromosomes Meiosis Meiosis and mitosis both require nuclear replication DNA synthesis Two rounds of division in meiosis and the result is haploid cells Meiosis I go through S phase and duplicate DNA in metaphase during mitosis all the chromosomes line up vertically at the center line and the chromosomes are pulled apart in meiosis the chromosomes pair up and the chromosomes are pulled to each end Daughter cells are diploid 2 copies of every gene first division does not produce identical daughter cells Daughter cells undergo meiosis II with same phases this time in metaphase all the chromosomes will align spindles will separate chromosomes towards poles and 4 cells are ultimately produced with 23 chromosomes in each cell Spermatogenesis Spermatic cells give rise to sperm Spermatagonium stem cells goes through mitosis Spermatic cells gives rise to sperm o Mitosis o Meiosis o Spermatagenosis Substentacular cells Large supporting cells sertoli cells Surround developing cells o Nutrients o Signals Dispose of excess cytoplasm sloughed Secrete testicular fluid into lumen for transport of sperm Hypothalamic pituitary gonadal axis Testosterone production is under control by the hypothalamus GNRH travels to anterior pituitary where it stimulates the secretion of two hormones FSH and LH o FSH stimulates the follicles spermatogenic cells of the semineforous tubes antigen binding protein o Testosterone goes up GNRH goes down o Testosterone is necessary for spermatogenesis Inhibin produced when sperm count is high when testosterone levels are high negative feedback to inhibit GNRH and FH Internal and External female genitalia Ovaries and fallopian tubes of a female o Held in place by suspensory ligament Ovary o Produces eggs releases one every other month o Ovulation occurs egg is released in area near the fibrae o If egg doesn t reach fimbrae it is released into the body cavity o If fertilized and doesn t reach the fallopian tube it is an eptopic pregnancy o Fertilization normally occurs in the ampulla and isthmus o Women are born with a fixed number of eggs o Has a blood supply called the mesovarium rich vascular supply to maintain the ova o Outer covering called germinal epithelium Fallopian tube o Fimbriae o Infundibulum o Ampulla o Isthmus narrow connection between the fallopian tube and the uterus Uterus o Isthmius is the connection between the ovaries and the uterus o Perimetrium is the outerlayer o Myometrium is the smooth muscle layer thickest part o Endometrium is the lining o Fundus is the upper portion where uterine tubes attach o Isthmus is where the uterus meets the cervix o Cervix is the extension of the uterus Produces mucus mucus plug here that prevents things from