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62 Cards in this Set
- Front
- Back
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What are the primary organs of the male reproductive tract?
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the Gonads: for men these are Testes.
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What is the function of testes?
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to produce germ cells, which are gametes (same thing as SPERM), as well as steroid hormones.
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What are the accessory organs in the male reproductive tract?
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1. a unique Ductal system design
2. Accessory glands (they produce juice to support sperm) |
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How are the testes composed anatomically?
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They have seminiferous tubules - coiled very tightly inside, where the sperm develop.
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What structures do sperm pass through as they go from the testes to the vas deferens?
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1. Seminiferous tubules,
2. Rete testes 3. Epididymis 4. Vas deferens |
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Why are the testes outside the body?
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to keep the temp a couple degrees below body temp, better for the little sperms to develop.
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What hormones act on the testes?
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The SAME ONES that act on the female reproductive organ (ovary) - FSH and LH!
(whew that makes things easy) |
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So how are the testes stimulated to develop?
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1. Age, environment, emotion act on Higher Brain Centers.
2. Hypothalamus releases GnRH in pulses; stimulates FSH/LH release from pituitary; 3. LH/FSH act on testes to produce TESTOSTERONE (has its biological effects). |
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How does testosterone presence feedback onto the hypothalamus and anterior pituitary?
Anything else inhibit the pituitary? |
Testosterone has negative feedback; inhibits LH/FSH, and GnRH from hypothal too.
Yes; Inhibit stops FSH release too. |
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what efect does continuous GnRH have on FSH and LH?
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It inhibits their release, AND CAUSES INFERTILITY!
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If a man takes anabolic steroids and abuses them, what will happen?
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The dummy, he'll be sterile because it decreases FSH and LH production; the testes aren't stimulated, and sperm don't develop.
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Where does Spermatogenesis take place?
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Inside the seminiferous tubule.
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How do sperm move as they develop inside the seminif tubule?
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They move toward the center, the lumen.
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What cells do sperm develop inside of, within the tubules?
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Sertoli cells. Think alliteration: Sertoli, Structure, Sperm, Support, fSh.
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What exactly do Sertoli cells do?
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-provide structure/support
-provide nutrients -garbage men -release inhibin |
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What hormone stimulates Sertoli cells?
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the one with s in it - FSH.
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Where are Leydig cells located?
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Outside the seminiferous tubules, in interstitial space.
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What do Leydig cells do?
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synthesize and release Testosterone, needed for spermatogenesis and Sertoli cells.
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what hormone stimulates Leydig cells?
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the hormone with the L - LH.
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what is Androgen binding protein, and where does it come from?
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A protein produced by Sertoli cells to carry testosterone and store it inside the seminif tubules.
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When in boys does spermatogenesis begin?
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at puberty - NOT in utero like in girls (ha we're more developed)
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how do sperm cells divide during spermatogenesis?
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one sperm produces two spermatogonium; one remains to maintain the germ line, the other continues to divide and differentiate.
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How many days does it take for one spermatogonium to become a mature spermatozoa?
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65 to 70 days!!
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how many chromosomes are in one spermatogonia?
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46; a set from each parent.
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how many chromosomes are in a 2ndary spermatocyte?
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23; that's b/c the cell has undergone one MEITIC division now, and in meiosis chromosomes don't replicate like they do in mitosis.
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so in general, how does the ploidy of sperm change during maturation in seminif tubules?
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They go from diploid spermatogonia to haploid spermatozoa.
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What is the maturation sequence of sperm?
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Spermatogonia ->
Primary spermatocytes -> 2ndary spermatocytes -> Spermatids -> Spermatozoa |
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How big is a spermatozoa fully mature?
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about 1-2 micra by 50 micra long
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What is contained in the acrosome (head) of a spermatozoa?
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PROTEOLYTIC enzymes to break down the ova membrane.
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What is the sperm's molecular motor made of?
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Microtubules, dynein arms, for a twisting motion.
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What is in high amounts in spermatozoa that provides energy for metabolism and locomotion?
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MITOCHONDRIA!!! (my favorite organelle)
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What effect does LH have on Leydig cells again?
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makes them synthesize TESTOSTERONE.
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In what 3 ways is testosterone used by the body?
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1. As testosterone, in muscles and testes (like you'd expect).
2. As ESTRADIOL (1?) produces effects on CNS/liver/fat. 3. As Dihydrotestosterone, has effects on reproduction/bone. |
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What converts testosterone to estradiol? (what enzyme)
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Aromatase
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What converts testosterone to dihydrotestosterone?
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5alpha-reductase.
This testosterone is much more potent than normal. |
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What are the 2 primary actions of androgens?
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1. Stimulates growth/function of the reproductive tract before and during puberty; maintains the same after puberty.
2. 2ndary sex characteristics - bone, muscle, hair, voice. |
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What happens if a man has no androgens?
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He has a high falsetto voice, decreased fertility, and is basically a girlie.
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What happens if a man has too much androgens?
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He gets Royd rage and is very violent, has aggressive libido, and better developed brain.
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After sperm enters the vas deferens, what structures does it flow through?
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1. Ampulla
2. Seminal vesicle 3. Prostate gland 4. Bulbourethral gland 5. Ejaculatory duct 6. Urethra |
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What does the Ampulla do?
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Stores sperm; after a vasectomy, have to make sure this is empty or the man will still be fertile.
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What is the function of the Seminal vesicle (don't confuse it with seminiferous tubule)
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secretes about 75% of the semen volume, which is not sperm, and fructose for energy, prostaglandins, etc.
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What is the prostate's function in making semen?
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It adds buffers to protect the sperm from the female tract acidity.
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What do the bulbourethral glands function in doing to semen?
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Give it mucus for lubrication.
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Where do sperm first become motile?
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In the epididymis, before ever going through the vas deferens.
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What is the corpus cavernosum?
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the muscle that causes erection.
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What nervous system causes erection?
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PARASYMPATHETIC!!
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would startling a man cause erection or not?
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NOT - it would inhibit erection.
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What are the 2 stimuli for erection?
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1. Higher brain centers
2. Mechanoreceptors on the penis |
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what does stimulis do to cause erection?
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1. Increases NO neuron activity
2. Decreases sympathetic activ. |
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What is the effect of NO and lack of SNS?
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Arterioles to the penis dilate and allow blood to engorge it. Directly causes erection and feeds-forward by causing venous compression.
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What is Viagra's mode of operation?
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it inhibits smooth muscle relaxation by inactivating cGMP
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Is parasymp nervous stimuli the only nervous involvement in erection?
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no; sympathetic stimulus is responsible for emission.
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How does emission take place?
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SNS stimulates smooth muscle contraction in the vas deferens and epididymis, so sperm go to the urethra.
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What prevents urine from mixing with sperm?
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the internal sphincter closes the bladder off to the ureter.
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What nervous tissue type is responsible for ejaculation?
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Again, Sympathetic; causes rythmic muscle contractions and semen expulsion.
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What are 3 male reproduction disorders to be aware of?
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1. Klinefelter's syndrome.
2. Hyperprolactinemia 3. Testicular feminization |
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what is klinefelter's syndrome?
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Chromosomal abnormality where the male has two X chromosomes and one Y - it's extra.
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What main symptoms result from klinefelter's?
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Decreased male 2' sex charact.
Decr. sperm/testosterone -> sterile and low IQ. |
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What characterizes testicular feminization?
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the patient has the gonads of one sex and the genitalia of the other.
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What causes testicular feminization?
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GENETIC defect in the testosterone receptor; there's plenty of the hormone, but no response.
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What phenotype is usually seen w/ testicular feminization?
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-Male testes and genotype
-Female external genitals. |
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What is hyperprolactinemia?
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Same as in females:
Pituitary tumor causes increased PROLACTIN which inhibits LH and FSH, so infertility and lack of sexual libido. |
