Human Physiology 20

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  1. What are chromosomes having the same or allelic genes with genetic loci usually arranged in the same order?
  2. How many chromosomes make up the human karyotype?
    46 in 23 homologous pairs
  3. What is a karyotype?
    the species-specific chromosomal characteristics of a cell
  4. What are the chromosome other than the sex chromosomes?
  5. What sex chromosomes occur in humans?
    X & Y
  6. What are the sex chromosomes in male and female humans?
    • male= XY
    • female=XX
  7. Why are X-linked genetic diseases in humans more common in mans?
    Males have about 1,000 genes that are only represented by a single allele from the X chromosome.
  8. What sex chromosome(s) may an egg carry?
  9. What sex chromosome(s) may a sperm carry?
    X or Y
  10. Which gamete determines sex at conception?
    the sperm
  11. Only one of two X chromosomes in females becomes active. What does the other one form?
    A clump of inactive heterochromatin called a Barr body.
  12. What is the immediate cause of gonads differentiating into testes in males?
    testis-determining factor (TDF)
  13. What genetic factor causes the formation of testis-determining factor?
    the sex-determining region of Y (SRY) gene
  14. What structures within the testes produce sperm?
    seminiferous tubules
  15. What cells within the testes produce testosterone?
    Leydig cells
  16. When is testosterone produced during the prenatal period?
    It begins at 8 weeks, peaks at 12-14 weeks, and then declines to very low levels until puberty.
  17. What is the medical term for undescended testes?
  18. Why do testes occur in the scrotum outside of the pelvic cavity?
    Spermatogenesis requires about a 30 C lower temperature than that of the body core.
  19. From what structures are male accessory organs derived?
    wolffian ducts
  20. From what structures are female accessory organs derived?
    Mullerian ducts
  21. How do testes and ovaries compare in their activity before birth?
    Testes produce testosterone during the first trimester. Ovaries donít produce much sex steroid until puberty. Both testes and ovaries remain inactive after birth until puberty.
  22. What group of hormones produced by the hypothalamus controls the release of LH and FSH?
    gonadotropic releasing hormones
  23. What is the full term for LH?
    luteinizing hormone
  24. What is the complete term for FSH?
    follicle-stimulating hormone
  25. What hormone stimulates follicle maturation in the ovary and sperm production in the testes?
    follicle-stimulating hormone
  26. What hormone stimulates the production of estrogen and progesterone in the ovary and testosterone in the testis?
    luteinizing hormone
  27. What hormone produced by the testes negatively feeds back on FSH secretion?
  28. At puberty what hormone produced by the hypothalamus stimulates an increase in the production of LH and FSH?
    gonadotropic releasing hormone
  29. At the beginning of female puberty, what hormone stimulates growth?
  30. At what age do girls normally experience their greatest growth spurt?
    about 12 years
  31. At what age do boys normally experience their greatest growth spurt?
    about 14
  32. How does the onset of puberty in girls with low body fat and high activity levels compare with girls with normal body fat and activity levels?
    It occurs at an older age.
  33. List the four phases of human sexual response.
    • arousal
    • plateau phase
    • orgasm
    • resolution phase (includes a refractory period in men)
  34. Within what microscopic structures of the testes does spermatogenesis take place?
    seminiferous tubules
  35. Within what cells and tissue of the testes is testosterone formed?
    Leydig cells of the interstitial tissue
  36. What cells within the testes respond to FSH?
    Sertoli cells
  37. What cells within the testes respond to LH?
    Leydig cells
  38. What cells within the testes produce inhibin?
    Sertoli cells
  39. At what age does the level of testosterone begin to decline?
    about 50 years
  40. In males what hormone and its derivatives are responsible for body changes such as growth of the larynx, bone, muscle mass, hemoglobin levels and the onset of spermatogenesis?
  41. What are the stem cells for sperm?
  42. What process allows spermatogonia to replicate themselves?
  43. What process gives rise to haploid sperm?
  44. What is the cap of digestive enzymes on the head of a sperm?
  45. What cells prevent the autoimmune destruction of developing sperm?
    Sertoli cells
  46. Developing sperm are embedded in what cells?
    Sertoli cells
  47. What part of a sperm propels it forward?
    the flagellum
  48. What part of a sperm contains a large concentration of mitochondria?
  49. What part of a sperm contains the genetic material?
    the head
  50. In what anatomical structure do spermatozoa mature and become motile?
    the epididymis
  51. What structures carry sperm into the pelvic cavity?
    vas deferens
  52. What male accessory organs add fluid to the sperm leaving the epididymis and provide fructose as an energy source for sperm?
    seminal vesicles
  53. The vas deferens converge to form what structure?
    the ejaculatory duct
  54. What accessory glands of the male reproductive system lies at the base of the urinary bladder and has the urethra passing through it?
    the prostate
  55. What is the name of the fluid emitted during ejaculation?
  56. What are the two main components of semen?
    sperm and seminal fluid
  57. What are the functions of seminal fluid?
    to provide a fluid medium for sperm; to provide an energy source for sperm; to protect sperm from the acidic environment of the vagina; to provide prostaglandins to produce contraction of the uterus
  58. What division of the ANS is responsible for erection of the penis?
    the parasympathetic
  59. What neurotransmitter is involved in erection of the penis?
    nitrous oxide (NO)
  60. List the three columns of erectile tissue in the penis.
    two dorsal columns (corpora cavernosa) and a ventral column (corpus spongiosum)
  61. What is the movement of semen in the urethra?
  62. What is the forcible expulsion of semen from the urethra out of the penis?
  63. Emission and ejaculation are stimulated by what division of the ANS?
    the sympathetic
  64. What is the normal volume of the ejaculate?
    1-5 ml
  65. How many sperm normally occur in each milliliter of ejaculate?
    60-150 million
  66. List three factors that may cause a low sperm count.
    • heat
    • lead or arsenic poisoning
    • drugs (marijuana, cocaine, anabolic steroids)
  67. What surgical procedure cuts the vas deferens to produce sterility?
  68. What structures carry the egg from the ovary to the uterus?
    the oviducts (fallopian tubes)
  69. What is the outermost layer of the uterus?
    the perimetrium
  70. What is the muscular layer of the uterus?
    the myometrium
  71. What is the inner most, hormonally-responsive layer of the uterus?
    the endometrium
  72. What portion of the uterus projects into the vagina?
    the cervix
  73. What is the anatomical term for the birth canal?
    the vagina
  74. What are the lateral folds of the vulva?
    the labia majora
  75. What are the medial folds of the vulva?
    the labia minora
  76. What structure within the vulva is homologous with the penis?
    the clitoris
  77. When are oocytes formed?
    before birth
  78. At what stage of meiosis are oocytes arrested in their development?
    prophase 1
  79. About how many oocytes exist at puberty?
  80. When is meiosis completed by oocytes?
    only after fertilization
  81. Meiosis of oocytes is an assymetric division. What is the small daughter cell produced by this
    uneven division?
    a polar body
  82. What two layers surround an ovulated ovum?
    the cellular corona radiata and the zona pellucida
  83. In the menstrual cycle, what hormone is produced in the largest quantity by the ovary before ovulation?
  84. How long is the menstrual cycle on average?
    28 days
  85. What is considered the first day of the menstrual cycle?
    the first day of menstruation
  86. What day does ovulation normally occur on?
  87. What becomes of a follicle after ovulation?
    It becomes a corpus luteum
  88. What hormone does a corpus luteum produce in the largest quantity?
  89. If fertilization does not take place, what becomes of the corpus luteum?
    It becosme as scar tissue
  90. What is the shedding of the endometrial lining of the uterus?
  91. The menstrual cycle consists of two separate cycles. What are they?
    the ovarian cycle and the uterine cycle
  92. What phase of the ovarian occurs from day 1 through ovulation?
    the follicular phase
  93. What phase of the ovarian cycle occurs from ovulation to menstruation?
    the luteal phase
  94. What phase of the uterine cycle occurs from the end of menstruation to ovulation?
    the proliferative phase
  95. What phase of the uterine cycle occurs from ovulation to menstruation?
    the secretory phase
  96. What phase of the ovarian cycle occurs as the follicle is maturing before ovulation?
    the follicular phase
  97. What part of the ovarian cycle occurs when the follicle ruptures to release the egg?
  98. In what phase of the ovarian cycle is the most estrogen produced?
    the follicular phase
  99. In what phase of the ovarian cycle is the most progesterone produced?
    luteal phase
  100. In what phase of the uterine cycle is lining of the uterus increasing in thickness but is not yet secreting its products?
    the proliferative phase
  101. In what phase of the uterine cycle is the lining of the uterus producing a product to capture the fertilized egg?
    the secretory phase
  102. What structure produces inhibin in females?
    the corpus luteum
  103. What is the function of inhibin in females?
    It suppresses FSH
  104. What phase of the uterine cycle occurs during the follicular phase of the ovarian cycle?
    proliferative phase
  105. What phase of the uterine cycle occurs during the luteal phase of the ovarian cycle?
    the secretory phase
  106. What causes the dormitory effect in the menstrual cycles of female roommates?
    The olfactory system sends information to the hypothalamus in response to pheromones from roommates
  107. What are two causes of functional amenorrhea?
    stress and low body weight
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Human Physiology 20
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