L7 Reproductive System Slide 1 the Reproductive System Slide 2 The Reproductive System Gonads are the primary sex organs o Testes in males o Ovaries in females o We start off life as biopotential the ability to form male and or female genitalia Gonads produce gametes sex cells and secrete hormones o Sperm are the male gametes o Ova eggs are the female gametes Sexual reproduction involves the fusion of gametes from two parents resulting in genetic variation among offspring o Greater chance for survival May enhance reproduction success in changing environments Allows for variety in phenotypes Both sexes in humans o Have set of gonads where gametes are produced o Have ducts for delivery of the gonads and structures for copulation Slide 3 Male Reproductive System Testes Duct system o Epididymis o Ductus vas deferens o Bulbourethral glands External genitalia o Penis o Scrotum Slide 4 Testes Coverings of the testes o Tunica albunginea is the capsule that surrounds each testis o Septa are the extensions of the capsule that extend into the testis and divide it into lobules Each lobule contains one to four seminiferous tubules o Tightly coiled structures o Function as sperm forming factories o Empty sperm into the rete testis first part of the duct system Sperm travels though the rete testis first part of the duct system Intestinal cells in the seminiferous tubules produce androgens such as testosterone Slide 5 Ductus Deferns Vas Deferens Carries sperm from the epididymis to the ejaculatory duct Passes through the inguinal canal and ove the bladder Moves sperm by peristalisis Spermatic cord includes the ductus deferens blood vessels and nerves in connective tissue sheath Slide 6 Urethra Extends from the base of the urinary bladder to the tip of the penis Carries both urine and sperm Sperm enters from the ejaculatory duct Regions of the urethra o Prostatic urethra surrounded by prostate o Membranous urethra from prostatic urethra to penis o Spongy penile urethra runs the length of the penis Slide 7 Accessory Organs Help Produce Semen Semen is a mixture of sperm and accessory gland secretions o Seminal vesicles o Prostate o Bulbourethral glands Slide 8 Seminal Vesicles Located at the base of the bladder Produces a thick yellowish secretion 60 of semen o Fructose sugar For nourishing the sperm Carbs o Vitamin A antioxidant Free radicals created during cellular respiration This neutralizes them Body cant produce this o Prostaglandins promote smooth muscle contractions Affect uterine contraction as well o Other substances that nourish and activate sperm Slide 9 Prostate Encircles the upper part of the urethra Secretes a milky alkaline fluid o Helps to activate sperm and neutralize acidic environment in vagina In the vagina the acidic environment protects from pathogens Sperm can be adversely affected if this wasn t there o Fluid enters the urethra through several small ducts Slide 10 Bulbourethral Glands Pea sized gland inferior to the prostate Produces a thick clear mucus know as pre ejaculate o Cleanses the urethra of acidic urine o Serves as a lubricant during sexual intercourse o Secreted into the penile urethra Slide 11 External Genitalia Scrotum o Divided sac of skin outside the abdomen o Maintains testes at about 3 degrees C lower than the normal body temp to protect sperm viability Some men boil water and emerge their testes into it as a form of birth control 60 days Penis o Delievers sperm into the female reproductive tract o Regions Shaft Glans Penis enlarged tip Prepuce foreskin folded cut of skin around proximal end that may be removed by circumcision Slide 12 Descending Testes A boy s testes normally develop in the abdomen Before birth at around 32 36 weeks they normally descend through a flexible tube called inguinal canal and end up in the scrotum Un descended testes can occur in premature boys and may be corrected with surgery Slide 13 External Genitalia Internally there are three areas of spongy erectile tissue around the urethra Erection occur when this erectile fills with blood during sexual excitement Slide 14 Spermatiogenesis Production of sperm cells Begins at puberty and continues throughout life Occurs in the seminiferous tubules Spermatigonia stem cells undergo rapid mitosis to produce more stem cells before puberty Follicle stimulating hormone FSH modulates spermatogonia division o One cell produced is a stem cell called a type A daughter cell o The other cell produced is called a primary Spermatocyte called a type B daughter cell Slide 15 Spermatigenesis Primary spermatocytes undergo meiosis One primary spermatocyte produces four haploid spermatids Spermatids have 23 chromosomes half as much material as other body cells Later spermatids are produces with distinct regions Head Midpeice Tail Sperm cells result after maturing of spermatids Spermatogenesis entire process inclusing spermiogenesis the final stage take from 65 75 days Function of sperm deliver DNA Slide 16 Anatomy of a Mature Sperm Cell The only human flagellated cell Head o Contains DNA o Acrosome is a helmet protecting the nucleus similar to a large lysosome which breaks down and releases enzymes to help the sperm penetrate an egg Midpiece wrapped by mitochondria for ATP generation Tail allows for motion contains a mitochondria Slide 17 Testosterone Production Produced by interstitial cells The most important hormone of the testes During puberty lutenizing hormone LH activates the interstitial cells In turn testosterone is produced Fucntions of testosterone o Stimulates reproductive organ development o Underlies sex drive o Causes secondary sex characteristic Increased hair growth Deepening of voice Enlargement of skeletal muscles Thickening of bones Hypothalamus releases hormone pituitary glands FSH LH LH testosterone Slide 18 Female Reproductive System A woman s ovaries contain follicales in the ovaries that nurture eggs and produce sex hormones Oviducts fallopian tubes convey eggs to the uterus The uterus opens into the vagina which receives the penis during intercourse and forms the birth canal Orgasms o For our species cannot persist without sex offspring o Positive reinforcement Slide 19 Ovaries Composed of ovarian follicles sac like structures Each follicle consists of o Primary oocyte immature eggs o Follicular cells surround the oocyte Corpus luteum estrogen and progesterone prepare FSH stimulates follicle Burst of estrogen ovulate Match ovaries and uterus Slide 20 Duct System Uterine tubes
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