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![the Male Genitourinary System Empty](https://2img.net/i/empty.gif) | موضوع: the Male Genitourinary System 3/11/2009, 03:10 | |
| Components of the Male Genitourinary System Paired gonads or testes Genital ducts Accessory organs Penis Functions of the Male Genitourinary System Testes Produce male sex androgens, mainly testosterone Spermatozoa (male germ cells) Internal accessory organs Produce the fluid constituents of semen Ductile system aids in the storage and transport of spermatozoa Penis Urine elimination and sexual function Embryonic Development of the Reproductive System Fertilization Sex chromosomes determine the sex Early stages The tissues from which the male and female reproductive organs develop are undifferentiated By the seventh week Two wolffian ducts determine male genitalia and two müllerian ducts determine female genitalia Embryonic Development of the Reproductive System (cont.) Sixth to eighth week of gestation The testes begin development under the influence of the Y chromosome The testicular cells of the male embryo begin producing an anti-müllerian hormone (AMH) and testosterone AMH suppress development or uterus and fallopian tubes in the male; stimulates development of male structures
Systems Maintaining Temperature of Testes Pampiniform plexus of testicular veins Surrounds the testicular artery Absorbs heat from the arterial blood, cooling it as it enters the testes Cremaster muscles Respond to decreases in testicular temperature by moving the testes closer to the body Male Accessory Organs Seminal vesicles Prostate gland Bulbourethral glands Component Glands of the Prostate Small mucosal glands Associated with the urethral mucosa Intermediate submucosal glands Lie peripheral to the mucosal glands Large main prostatic glands Situated toward the outside of the gland Composition of the Penis Three masses of erectile tissue held together by fibrous strands and covered with a thin layer of skin Corpora Cavernosa: Two lateral masses of tissue Corpus Spongiosum: Third ventral mass Both are cavernous sinuses that normally are relatively empty but become engorged with blood during penile erection
Spermatogenesis The generation of spermatozoa or sperm Begins at an average age of 13 years and continues throughout the reproductive years of a man’s life Occurs in the seminiferous tubules of the testes For spermatogenesis to occur, FSH binds to specific receptors in Sertoli’s cells Testosterone is also required (the intra-testicular concentration of testosterone is 100-fold greater than serum levels)
Male Sex Hormones (Androgens) Testosterone Dihydrotestosterone Androstenedione Main Actions of Testosterone Induce differentiation of the male genital tract during fetal development Induce development of primary and secondary sex characteristics Create anabolic effects Promote spermatogenesis and maturation of sperm Primary and Secondary Sex Characteristics Agonadal function External genitalia and accessory organs Male voice timbre Male skin characteristics Male hair distribution Anabolic Effects of Testosterone Promotes protein metabolism Promotes musculoskeletal growth Influences subcutaneous fat distribution Drugs Used to Enhance Performance Androgen Stimulants Erythropoietin Growth hormone Insulin Creatine Gonadotropic Hormones Secreted by the Pituitary Gland FSH Luteinizing hormone (LH) Diagnosis of Androgen Deficiency Appearance of certain clinical features Fatigue, depression, decreased libido Confirmation by appropriate laboratory testing A measure of ‘free testosterone’ (testosterone not bound [especially to SHBG], and therefore available for binding to, and activating, androgen receptors) Free Testosterone is low in hypogonadism
Neural Control of the Sex Act The glans penis contains a highly organized sensory system Afferent impulses from sensory receptors in the glans penis pass through the pudendal nerve to ascending fibers in the spinal cord by way of the sacral plexus Stimulation of other perineal areas can transmit signals to higher brain centers, adding to sexual satisfaction Erection Involves The shunting of blood into the corpus cavernosum Controlled by Sympathetic systems Parasympathetic systems Non-sympathetic—non-parasympathetic systems Effect of Aging on the Male Reproductive System Degenerative changes occur as a result of the aging process It becomes less efficient with age The declining physiologic efficiency of male reproductive function occurs gradually Involves the endocrine, circulatory, and neuromuscular systems Diseases Affecting Potency Cardiovascular disease Respiratory diseases Hormonal disease Neurologic and hematologic disorders | |
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عدي الزعبي
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![the Male Genitourinary System Empty](https://2img.net/i/empty.gif) | موضوع: رد: the Male Genitourinary System 3/11/2009, 17:20 | |
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![the Male Genitourinary System Empty](https://2img.net/i/empty.gif) | موضوع: رد: the Male Genitourinary System 22/2/2010, 03:28 | |
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