Ch 27 Reproductive System

Ch 27 Reproductive System - Ch. 27: The Reproductive System...

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Ch. 27: The Reproductive System The reproductive system functions to produce, store & deliver gametes. and, if fertilization occurs, support the growth and development a new human. None of these functions is essential to maintaining homeostasis, although the process as a whole is necessary to the preservation of the species. Components of a Reproductive System 1. Gonads a. Gamete production 2. Ducts a. Storage and transport of gametes b. Connect reproductive organs, external environment 3. Accessory glands and organs a. Aid in maintenance of ducts 4. External genitalia Anatomy of the Male Reproductive System TESTIS 1. Male gonads a. Testes (1=testis) (Fig. 28-4) 1. Develop inside peritoneal cavity 2. Descend into scrotum(skin sac outside body cavity) prior to birth 3. Temperature in scrotum = 97 o F =>increases sperm viability b. Histology of testes 1. Divided internally by connective tissue septa into lobules 2. Lobules contain coiled semiferous tubules (~ ½ mile/testis) 3. Interstitial cells ( Leydig cells ) nestle into spaces around coiled tubules a. Target of LH (also called ICSH, interstitial cell stimulating hormone) b. LH stimulates testosterone production by interstitial cells 4. Seminiferous tubules connected to each other by rete testis 5. Efferent ductules (lge) connect rete testis to male reproductive tract 6. Sustenacular cells ---> 5 impt. Functions a. Maintenance of blood-testis barrier=>exhanges btwn blood<--->seminiferous tubules stringetly controlled b. Support of spermatogenesis => target of FSH, testosterone c. Secretion of inhibin => regulates rate of sperm production d. Secretion of Androgen Binding Protein (ABP) => stimulates spermiogenesis e. Secretion of Mullerian-inhibiting factor => causes regression female duct structure during fetal development 2. Spermatogenesis = Male gamete production (Fig. 28-7) a. Site = seminiferous tubules coiled in lobules of testis b. 3 processes 1. Mitosis (Fig. 28-6a) a. Occurs in spermatogonia (primary germ cells) throughout adult life b. Parent cell is diploid c. Mitosis results in 2 identical daughter cells d. Primary functions 1. Growth 2. Maintenance 3. Repair 2. Meiosis (Fig. 28-6b) a. Occurs only in gamete production b. Parent cell is diploid
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c. Gametes are haploid 3. Spermiogenesis (Fig. 28-8) a. Morphologic maturation from spermatid ---> spermatzoon b. Head 1. Nucleus 2. Acrosomal cap(enzyme-containing) c. Neck d. Middle piece 1. Centrioles 2. Mitochondria e. Tail 1. Flagellum EPIDIDYMIS Beginning of male reproductive tract (ducts) 3 functions 1. Monitoring and adjusting semiferous tubule fluid composition 2. Detection and recycling of damaged spermatazoa 3. Storage, protection, maturation site for spermatzoa a. Duration of passage ~ 2wks b. Sperm leave mature but immotile (can’t swim or navigate yet) =>requires capacitation c. DUCTUS DEFERENS (Vas deferens) Connects epididymis to urethra Moves sperm from outside to inside the peritoneal cavity
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This note was uploaded on 07/23/2009 for the course BIOL 1141 taught by Professor Loripaul during the Summer '09 term at UMSL.

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Ch 27 Reproductive System - Ch. 27: The Reproductive System...

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