Male Reproduction S2M3

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  1. What are the three ways to determine sex
    • Chromosomal sex
    • Gonadal sex
    • Phenotypic sex
  2. What are the germ cells in males, and female
    • Males - Spermatogonia
    • Female - Oogonia
  3. From the indifferent stage of male production to the male genitalia, what degenerates
    • Mullerian ducts
    • Caused by the secretion of antimullerian hormone from Sertoli cells
  4. In the absence of what is a female produced
    SRY gene & Dihydrotestosterone (DHT)
  5. What cells releases Testosterone
    Leydig cells
  6. What is the effect of testosterone released in a male during development
    Testosterone is converted to DHT via 5-alpha reductase helping develop the external and internal genital features
  7. How does testosterone cycle through out life
    • There is a large surge during fetal development
    • A drop just prior to birth
    • A spike during the first year
    • No testosterone till puberty
    • A decrease around 70 years old
  8. What inhibts the release of GnRH during pre-puberty
    • GABA neurons
    • Endorphins
    • Melatonin
    • Neuropeptide Y (NPY)
    • Testosterone
    • Estrogen
  9. What happens to the levels of hormones during male puberty
    • Increase in LH, Testosterone, FSH, and Leptin
    • Decrease in NPY, Melatonin, and GABA
  10. Spermarchy
    Nocturnal emission of sperm
  11. What are some secondary characteristics effected by male puberty
    • Body hair
    • Pitch in voice
    • Skeletal muscle increase
    • Thicker longer bones
    • Thickness of skin
    • BMR increase
    • Increase blood volume
  12. What do spermatozoa contain that assist in energy
    GLUT 5 fructose transporters and mitochondria
  13. How long does a spermatazoa survive in the epididymis
    6 weeks (under the best conditions)
  14. What influences the motility and life of sperm
    • High temp increases motility
    • Neutral-Alkaline medium increases motility
    • Acidic environment kills the sperm
  15. Why does increase in temperature decrease the lifespan of sperm
    It increases the metabolic rate and therefore utilizes the energy stores
  16. What effects the rate of spermatogenesis
    It is constant, not accelerated by androgens or gonadotropins
  17. What are the primary roles of the Sertoli cells
    • Secrete Androgen binding protein
    • Secrete plasmin
    • Spermiation (remove excess organelles ect.)
    • Blood testes barrier
  18. What is the comparison of daily sperm production as it relates to the age of the male
    • 20 year old - 6.5 million sperm
    • 50-90 year old - 3.8 million sperm
  19. How many days does it take to make sperm
    65-75 days
  20. What is found in the head of the sperm, and how is it important
    Acrosome which is filled with enzymes to break through the walls of the oocyte
  21. What inhibits the hypothalamus from releasing GnRH
    • Dopamine and Endorphins
    • Inhibin (released from gonads)
    • Testosterone and Estrogen
  22. What inhibits the release of FSH and LH from the Pituitary gland
    • Follistatin (released from gonads)
    • Inhibin (released from gonads)
    • Testosterone and Estrogen
  23. What triggers the release of GnRH from the hypothalamus
  24. What triggers the release of FSH and LH from the pituitary
    • GnRH (released from the hypothalamus)
    • Activin (released from the gonads specifically causes the release of FSH)
  25. POMC
    • Pro-Opiomelanocortin
    • When broken down it yields ACTH (Corticotropin), MSH (melanocyte stimulating hormone), Endorphins, and Lipotropin
  26. Testosterone and Estrogen have what effects during puberty
    They increase body growth, Growth hormone (GH), and Insulin like growth factor (IGF)
  27. Insulin like growth factor (IGF) has what effect during puberty
    • Increase in GnRH
    • Increase in Gonadal function
    • Enhances testosterone and estrogen synthesis
  28. What causes the growth of Leydig cells
    • LH
    • "Looting leydies"
  29. LH has its primary action in males on Leydig cells through what pathway
    G protein stimulation, Adenylyl cyclase, then cAMP to stimulate testosterone production
  30. What facilitates LH effects on Leydig cells
    • FSH
    • Prolactin (increases the amount of LH receptors)
  31. LH stimulates testosterone synthesis by its action at what enzyme, on what cell
    • CYP 11A1
    • Leydig cells
  32. What are the effects of FSH on Sertoli cell functions
    • Stimulates the maturation of germ cells
    • Increases glucose metabolism of Sertoli cells
    • Stimulates the synthesis of Inhibin B, Activin, and other growth factors
  33. What receptors do Sertoli cell lack
  34. What receptors do Leydig cell lack
  35. Aromatase
    Enzyme used in the conversion of testosterone to estradiol in the Sertoli cells as well as other cells
  36. Sertoli cells produce
    • Androgen Binding Protein (ABP)
    • Anti-Mullerian hormone
    • Activin
    • Inhibins
  37. Leydig cells produce
    • Testosterone
    • DHT
  38. What is the role of Estrogen receptors on Leydig cells
    • They decrease the proliferation and activity of Leydig cells
    • "Ester stops Leydi's"
  39. LH receptors on the Leydig cells can respond to what during gestation
  40. In the Leydig cells, what series of products cause testosterone poduction
    Cholesterol to Pregnenolone to Testosterone
  41. Testosterone secreted from the Leydig cells has what effect on the Sertoli cells
    • Formation of Estradiol
    • Formation of Androgen binding protein which is secreted in to the seminiferous tubule
    • Protein formation
  42. Estradiol secreted from the Sertoli cells has what effect on the Leydig cells
    Causes the formation of proteins
  43. What effect does testosterone have on the kidneys
    • Stimulates erythropoietin synthesis
    • Stimulation of renal sodium reabsorption
  44. How does Testosterone effect the liver
    • Increase VLDL and LDL
    • Decrease HDL
  45. What is the result of a male lacking 5 alpha-reductase
    They have female phenotype at birth but rising testosterone levels at puberty produce a more male phenotype
  46. What is the effect of Estradiol on the efferent ductules
    It causes them to concentrate sperm for the final ejaculation
  47. What hormone is associated with closing the epiphyseal after puberty
  48. What nerve is important in the initiation of an erection
    Pudendal nerve
  49. What are the five phases of a male erection
    • Flaccid phase
    • Tumescence phase
    • Full erection
    • Rigid phase
    • Resolution phase
  50. What nervous system dominates in the flaccid stage of an erection
    Sympathetic nervous system dominates
  51. What is the driving action of the Tumescence stage of an erection
    • Release of NO and Prostaglandin E1 increasing intracellular cGMP.
    • These relax the cavernosa vascular smooth muscle causing initial erection
  52. What happens in the rigid phase of the an erection
    • Cavernosa pressure exceeds systolic blood pressure
    • Ejaculation occurs by sympathetic innervation
  53. What muscles are important to ejaculation
    • Ischiocavernosa
    • Bulbocavernosa
  54. What happens in the resolution phase of an erection
    Sympathetic activity constricts supplying arteries decreasing blood flow and reversing the erectile process
  55. What is the role of the sympathetic and parasympathetic nervous systems in an erection
    • Para - mediates the arteriole vasodilation
    • Symp - Mediates constriction of the arterial venous anastomoses
  56. What are the four stages of the male sexual act and what causes them
    • Excitement (Parasympathetic)
    • Plateau (Parasympathetic)
    • Orgasm (Sympathetic L1-2, Somatic L1-S4)
    • Resolution (Sympathetic L1-2)
  57. What helps determine the amount of consistency of semen
    Parasympathetic stimulation
  58. What do the seminal vesicles contribute to semen
    • Fructose
    • Citric acid
    • Prostaglandins
    • Fibrinogen
  59. What does the prostate gland contribute to semen
    • Citric acid
    • Calcium phosphate
    • Clotting enzyme
    • Fibrinolysin
  60. What does the Cowpers gland add to the semen
  61. What is the pH of semen
  62. During what phase of the male sexual act does the bulbourethral gland (cowpers) secrete fluid
  63. What artery constricts reducing the blood to the penis in the resolution phase
    Internal pudendal
  64. What causes the ejaculate to coagulate and then liquify after an hour
    Clotting enzyme released from the prostate gland
Card Set:
Male Reproduction S2M3
2011-08-15 02:36:18
Ross S2M3

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