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Power Point 1 Male Reproductive System Objective 1 Explain the parasympathetic and sympathetic innervations of the male reproductive system and the effects of each Male Reproductive System Primary sex organs Testes produce gametes secrete sex hormones Accessory sex organs Epididymis ductus deferens ejaculatory duct urethra seminal vesicles prostate bulbourethral glands Testes produces sperm which follows this pathway Epididymis ductus deferens ejactulatory duct urethra opens to outside of body Sex glands empty their secretions into these ducts Seminal vesivles prostate bulbourethral glands Anatomy Male Sexual Response Erection Objective 2 Describe the exocrine and endocrine function of the testes Example Sertoli and Leydig cells The male gonad Ejaculation the propulsion of semen from the male duct system PNS stimulates increase in NO Relaxation and vasodilation of arterioles Erectile bodies fill with blood SNS stimulation of spinal reflex Contraction of ducts and glands Constriction of the bladder Contraction of bulbospongiosus muscles The testes serve two physiological roles EXOCRINE FUNCTION ENDOCRINE FUNCTION Promotion of mature sperm spermatogenesis Involves the seminiferous epithelium and SERTOLI CELLS Production of androgens steroidogenesis Involves the interstitial compartment and LEYDIG CELLS Objective 3 Explain IN DETAIL the entire process of spermatogenesis as we described in class what happens in each phase and it s time frame through the seminiferous epithelium Spermatogenesis Takes place in the seminiferous tubules of the testes Produces sperm gametes or spermatozoa Comparison of Mitosis and Meiosis Begins at about 14 years old and makes about 4 million sperm everyday Mitosis Meiosis Number of divisions one consisting of prophase metaphase anaphase and telophase Number of daughter cells and genetic composition two each diploid 2n and identical to the mother cell Importance in the body development of multicellular adult from zygote to produce cells for growth and tissue repair ensures constancy of genetic makeup of all body cells Number of divisions two each consisting of prophase metaphase anaphase and telophase DNA replication does not occur between the two nuclear divisions an event unique to meiosis is that during meiosis II the homologous chromosomes synapse join along their length forming tetrads groups of four chromatids Number of daughter cells and genetic composition four each containing half as many chromosomes as the mother cell hence haploid or n nonidentical to mother cell Importance in body to produce cells for reproduction gametes introduces genetic variability in the gametes and reduces chromosomal number by half so that when fertilization occurs the normal diploid chromosomal number is restored in humans 2n 46 Spermatogenesis Proliferative Phase Proliferative phase meiotic phase spermiogenic phase Spermatogonia 46 chromosomes mitosis differentiation primary spermatocyte 46 chromosomes first meiotic division secondary spermatocyte 23 chromosomes second meiotic division spermatids 23 chromosomes differentiation sperm 23 chromosomes o o o o o o o o o o o o o o o At least 3 types of spermatogonia described Type A dark Ad dense chromatin Type A pale Ap chromatin less dense Type B Type Ad give rise to a Type Ap as well as generating more Type Ad for future generations of sperm Type Ap gives rise to Type B Meiotic Phase Meiosis I Type B divide by mitosis to primary spermatocytes Replicated chromosomes seek out a partner After meiosis 1 Each daughter cell has 2 copies and the number of chromosomes is cut in half Chromosomes go from 46 to 23 Meiosis II Spermiogenic Phase Key point further division but keeps number of chromosomes the same Differentiation of a spermatid into a sperm through 4 steps 1 Golgi phase tail filament appears 2 Cap phase head cap appears from acrosomal granule 3 Acrosome phase nucleus and head cap elongate and acrosomal granule differentiates to form acrosome 4 Maturation phase cell completes differentiation to become a mature sperm Cycle of the Seminiferous Epithelium 1st cycle Type A gives rise to Type B 2nd cycle primary spermatocyte of first cycle form 3rd cycle spermatids of first cycle appear 4th cycle spermiogenesis completed spermiation begins 16 days 16 days 16 days 16 days Spermatogonia initiate a new cycle every 16 days and there are a total of 4 cycles 4 X 16 64 days Once sperm are released into lumen another 10 days is required for movement to epididymis total 74 days Sperm are stored in epididymis Sperm Structure and Motility Head Contains either X or Y chromosome Head region is covered by acrosome which contains enzymes which function in fertilization Neck also called the connecting piece Midpiece contains mitochondria machine for motility Principal Piece flagellum of tail Objective 4 Explain the hormonal control of spermatogenesis as it relates to FSH and LH Hormonal Regulation of Testicular Function GnRH in hypothalamus anterior pituitary Anterior pituitary produces and releases LH and FSH LH stimulates production of testosterone Leydig cell Leydig cell has binding protain for LH stimulates production of testosterone FSH goes to bloodstream to seminiferous tubules Bind to receptor and stimulates sertoli cell stimulates spermatogenesis Testosterone also regulates sperm production Inhibin is produced by seminiferous tubule sustentacular cell for negative feedback of GnRH Testosterone production in seminiferous tubules stimulates inhibin Testosterone production also a negative feedback for GnRH Hormonal Control of Spermatogenesis FSH and testosterone are both required for regulation of spermatogenesis FSH binds to receptors in SERTOLI cells and thus helps to initiate spermatogenesis also causes increase in ABP FSH also increases number of LH receptors on LEYDIG cells causing an increase in testosterone production which maintains spermatogenesis Objective 5 Explain the role of the epididymis and where the ejaculate comes from Epididymis Sperm migration through epididymis takes about 10 16 days add this to the time required for spermatogenesis about 74 days about 90 days for mature sperm to appear in ejaculate Insult to testis today not seen until 3 months later sperm are stored in cauda epididymis and vas deferens not in seminal vesicles o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o Maturational changes sperm acquire capacity for motility in epididymis Elimination of aged sperm phagocytosis Prostate has


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FSU PET 3323C - Male Reproductive System

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