Topic 6.6 & 11.4 Male Reproductive System. Further functions Urethra: tube from ejaculatory duct...
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Transcript of Topic 6.6 & 11.4 Male Reproductive System. Further functions Urethra: tube from ejaculatory duct...
Topic 6.6 & 11.4Topic 6.6 & 11.4
Male Reproductive SystemMale Reproductive System
Further functionsFurther functions
Urethra: tube from ejaculatory duct through penis that carries semen and urine (but not at the same time)
Prostate: also neutralizes acidity of vaginaBulbourethral gland: also “cleans out”
urethra, releases fluid before ejaculation, contributes to unplanned pregnancies
Sperm make only a small part of semen; 90+% of volume from seminal vesicles
Urethra: tube from ejaculatory duct through penis that carries semen and urine (but not at the same time)
Prostate: also neutralizes acidity of vaginaBulbourethral gland: also “cleans out”
urethra, releases fluid before ejaculation, contributes to unplanned pregnancies
Sperm make only a small part of semen; 90+% of volume from seminal vesicles
1.Mitosis makes enough cells to keep epithelium and produce sperm2.Cells grow3.Cells divide through meiosis4.Cells (spermatids) differentiate as they develop
Sertoli cells support developing sperm.
1.Mitosis makes enough cells to keep epithelium and produce sperm2.Cells grow3.Cells divide through meiosis4.Cells (spermatids) differentiate as they develop
Sertoli cells support developing sperm.
(germinal epithelium)
(spermatozoa)
(produce testosterone)
(nurse cell)
Structure of a Mature Sperm (50 um)
Acrosome: chemicals to enter egg
Nucleus: haploidMidpiece: “motor”,
many mitochondriaFlagellum: protein,
9+2 microtubule patternFlagellum ~40 um
Structure of a Mature Sperm (50 um)
Acrosome: chemicals to enter egg
Nucleus: haploidMidpiece: “motor”,
many mitochondriaFlagellum: protein,
9+2 microtubule patternFlagellum ~40 um
Hormonal Control of Spermatogenesis
Hormonal Control of Spermatogenesis
Luteinizing hormone (LH): increases testosterone levels
Follicle Stimulating hormone (FSH): controls meiosis / number of sperm
Testosterone: helps sperm production and development
Luteinizing hormone (LH): increases testosterone levels
Follicle Stimulating hormone (FSH): controls meiosis / number of sperm
Testosterone: helps sperm production and development
* FSH and LH named for role in females (menstrual cycle)* FSH and LH named for role in females (menstrual cycle)
Secondary sexual characteristicsSecondary sexual characteristics
Related to sexual development, but not necessary for reproduction
Related to sexual development, but not necessary for reproduction
Roles of Testosterone in MalesRoles of Testosterone in MalesFetal development of male
genitalia: around week 7 (normally caused by gene on Y chromosome)
Development of secondary sexual characteristics at puberty
Production of spermMaintenance sex drive
Fetal development of male genitalia: around week 7 (normally caused by gene on Y chromosome)
Development of secondary sexual characteristics at puberty
Production of spermMaintenance sex drive
Timing and Number of Sperm Production
Timing and Number of Sperm Production
Begins at puberty, continues until deathContinually produced, millions each dayComplete process takes several monthsOne diploid cell produces 4 haploid
sperm with equal amounts of cytoplasmMay be released whenever needed
Begins at puberty, continues until deathContinually produced, millions each dayComplete process takes several monthsOne diploid cell produces 4 haploid
sperm with equal amounts of cytoplasmMay be released whenever needed
Homework: Draw and label a diagram of the male reproductive system.
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