BI-205 Ch 25

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  1. BI-205 Ch 25 LO
    Reproductive System
  2. 1.Name the male and female gametes and gonads:
    • Female: Revised female gamete: Secondary oocyte; gametes - ovum (egg) ; gonads - ovaries
    • Male: gametes - sperm; gonads - testes
  3. 1.Define fertilization:
    during fertilization the gentic material from a haploid sprem cell and a haploid secondary oocyte merge into a single diploid nucleus.
  4. 1.Define pregnancy:
    Pregnancy is the series of events that occur following fertilization leading to implantation, development of embryo and fetus in the uterus ending usually in 38-40 weeks.
  5. 2.State the location and function of Leydig cells.
    • Located in the triangular spaces between seminiferous tubules of the testes
    • Function is to produce and secrete testosterone.
  6. 3.Defining spermatogenesis
    The process of production of sperms by the seminiferous tubules of the testes.
  7. 3.Describing the events in spermatogenesis
    • 1) During mitotic division, some stem cell Spermatogonia (2n) migrate away from the basement membrane of a seminiferous tubule, pass through the blood-testis barrier, and differentiate into Primary Spermatocytes (2n)
    • 2) 1 Primary Spermatocyte (2n) undergoes Meiosis I to become 2 Secondary Spermatocytes (2n, but with two matching chromatids)
    • 3) The 2 Secondary Spermatocytes (2n) undergo Meiosis II to become 4 Spermatids (n)
    • 4) The 4 Spermatids (n) undergo spermiogenesis to become 4 sperm cells (spermatozoa) after gaining an acrosome, flagellum, and undergoing nucleus elongation)
    • 5) Sperm cells are pushed into the lumen of the seminiferous tubule (by Sertoli cell fluid as the flagella are not yet final)
  8. 3.[See textbook Chapter 3.] Defining meiosis and explain why gametes must form by meiosis rather than mitosis
    Meiosis produces gametes with 23 chromosomes ( so in fertilization they fuse to create zygote with 46 chromosomes, the ideal number) while mitosis cannot achieve this.
  9. 4.State the functions of the sperm cell's head:
    contains the nucleus where the 23 chromosomes are.
  10. 4.State the functions of the sperm cell's acrosome:
    contains acrosomal enzymes (e.g.hyaluronidase) that helps break the corona radiata surrounding the secondary oocyte for penetration
  11. 4.State the functions of the sperm cell's middle piece:
    Contain mitochondria----> supplies the energy needed for sperm locomotion and metabolism.
  12. 5.Define puberty and state what marks the onset of puberty.
    Puberty is the period in life during which secondary sex characteristics start appearing and the person becomes capable of sexual reproduction
  13. 6.Describing hormonal control of spermatogenesis including the production site and influence of each hormone
    • Gonadotropin-releasing hormone (GnRH) by hypothalamus--> Follicle-stimulating and Luteinizing hormone by Anterior Pituitary gland
    • LH--> Leydig cells release testosterone (required for spermatogenesis)
    • Testosterone--> negative feedback--> suppress LH from Anterior Pituitary gland and GnRH from Hypothalamus
    • Prostate: Testosterone-->Dihydrotestosterone (DHT)
    • FSH+Testosterone-->Sertoli cells-->Release androgen-binding protein (ABP) that binds testosterone to maintain the levels of testosterone needed for final stages of spermatogenesis
    • When adequate levels of sperm cells produced-->
    • Inhibin released by Sertoli cells-->inhibition of FSH
  14. 6.Stating the male secondary sex characteristics:
    Muscular and skeletal growth result to wide shoulder and narrow hips, pubis, axillary, facial and chest hair, thickening of the skin, deepening of the voice and increase oil gland secretion.
  15. 6.Defining libido:
    sexual desires
  16. 6.Stating testosterone�s influence on libido in both men and women:
    it stimulates development of male and female sex drive, reproductive structures and secondary sex characteristics. Testosterone contributes strongly to libido (sex drive) in both men and women .
  17. 7.Stating in which male reproductive duct sperm become mature
    seminiferous tubule
  18. 7.Defining sperm maturation
    when the sperm gains the ability to swim (or accquire motility)
  19. 7.Describing the role of the epididymis and ductus deferens in ejaculation
    Function: Storage of mature sperm for several months and by peristaltic contractions of smooth muscle during sexual arousal help propel sperm along the ducts
  20. 7.Describing the sequence of passageways through which sperm pass from the time they leave the testes until they exit the male body
    sertoli cells-lumen of seminiferous-straigth tubules-ductus epididymis-ductus deferens-ejaculatory ducts-urethra-external urethral.
  21. 8.Describe the vasectomy procedure:
    A portion of each ductus deference is removed. An incision is made on either side of the scrotum ducts are located and cut. each is tied in two places with stitches and the portion between the ties is removed. production of sperms still continues in the testes but no longer reach the exterior
  22. 8.Explain how vasectomies can prevent fertilization,
    Since the vas deferens are ligated the sperms are unable to exit the persons body to reach an oocyte so prevents fertilization.
  23. 8.State if a vasectomy interferes with testosterone production or libido
    Vasectomy doesn't interfere with testosterone production by Leydig cells,Vasectomy excises a portion of ductus deferens, not Leydig cells, which are found in the interstitial space in the testes. Libido is not effected, since testosterone production still takes place.
  24. 9.Stating the functions of the secretions by each accessory sex gland
    Neutralize acid in the male urethra and female reproductive tract,Provide fructose for ATP production by sperm, Contribute to sperm motility and viability, Help semen coagulate after ejaculation and subsequently break down the clot,Lubricate the lining ofthe urethra and the tip of the penis during sexual intercourse.Glands includes: seminal vesicle, the prostate and the bulbourethral glands.
  25. 9.Describing semen including its composition, structures that produce it, and its functions
    Semen is a thick, whitish fluid mixture containing sperm and the secretions of the male accessory reproductive glands. The functions of the semen include: Protection of the sperm cell and also help in fertilization by assisting the movement of sperm to the uterus.
  26. 9.Describing the average number of sperm in a milliliter of semen and why this huge number is required for fertilization
    50-150 million sperms are present in a milliliter of semen. Why the large number, Only a tiny fraction of this large number ever reaches the secondary oocyte.
  27. 10.Describe the physiologic mechanisms that produce erection:
    • Erection: Erectile tissue found in the corpora cavernosa penis and corpora spongiosum penis, each surrounded by tunica albuginea. Erectile tissue is filled with blood sinuses, smooth muscle and elastic tissue.
    • Erection= the state of enlarged and stiffened penis upon stimulation by the parasympathetic nerves from the sacral part of the spinal cord, this stimulation causes smooth muscle in the walls of arterioles to relax, allowing vessel dilation and large amount of blood surge into the area, in addition the smooth muscle relaxes, widening the blood sinuses
  28. 10.Describe the physiologic mechanisms that produce ejaculation:
    • Sexual stimulation-->Sympathetic stimulation of lumbar nerves initiates a reflex, in which the smooth muscles sphincter at the base of urinary bladder closes and a powerful release of semen form the urethra to the exterior takes place.
    • Before ejaculation, peristalsis in epididymis, ductus deferens, seminal vesicles, ejaculatory ducts and prostate propel semen into the penile portion of the urethra.
  29. 10.Describe the physiologic mechanisms that produce return the penis to its flaccid state:
    Sexual stimulation ended-->penile arterioles constrict-->penile smooth muscle contracts, decreasing blood sinuses--> Pressure on penile veins is released and blood is drained
  30. 11.Describe oogenesis and follicular development.
    Oogenesis is the formation of gametes in the ovaries. Follicular development in the fetal period matures (Mitosis) to the level of primordial follicle and then pauses development during childhood (Meiosis in progress to form Primary Oocyte). From puberty to Menopause Primordial follicles become Primary follicles (Prophase I) and continue development to become (Meiosis I complete) a Secondary follicle. Mature follicles housing Secondary Oocytes (in metaphase II) lead to ovulation. Meiosis II may complete if fertilization occurs.
  31. 12.Explain the mechanisms that move the oocyte into the uterine tube and then onward to the uterus.
    • What function does the corona radiata serve in movement of the oocyte? See 5th paragraph of Mini 25.3
    • The oocyte is moved into the uterine tube from the ovaries via movement of the fimbriae.
    • The oocyte is then propelled along the tube toward the uterus by the cilia of the ciliated simple columnar cells of the uterine tube epithelium and by peristaltic contractions of smooth muscle in the uterine tube�s muscularis.
  32. 13.State the uterine tissue layer involved in labor and childbirth and the muscle tissue type composing that layer.
    MYOMETRIUM (middle layer) composed of 3 layers of smooth muscle fibers; involved in labor and delivery.
  33. 14.State the effect of the acidic environment of the vagina on microbial growth and sperm.
    Acidic environment of vagina inhibits microbial growth and is harmful to sperm (the alkalinity of semen helps neutralize this acid to increase the viability of the sperm)
  34. 15.State the collective name for the female external genitals and know that the labia majora and labia minora protect the vestibule and aid sexual stimulation.
  35. 16.State how men can minimize the risk of prostate cancer or testicular cancer, and women can minimize the risk of breast cancer or cervical cancer.
    Healthy diet, eat more fruits, limit alcohol intake, exercise, keep fit, do not smoke.
  36. 17.Stating production sites and influence of each hormone on the ovarian cycle
  37. 17.Stating production sites and influence of each hormone on the uterine cycle
  38. 17.Listing the female secondary sex characteristics
    caused by estrogen: distribution of adipose tissue in the breasts, abdomen, hips, and mons pubis; the voice pitch, the broadness of the pelvis and pattern of hair growth on the body (including underarm and pubic hair).
  39. 17.Explaining why only one graafian follicle usually develops during each ovarian cycle
  40. 17.Describing ovulationO:
    Ovulation is the ejection of an immature egg (oocyte) from the ovary.
  41. 17.Stating when ovulation usually occurs in a 28-day ovarian cycle
    Day 14
  42. 17.Stating the fate of the corpus luteum if the secondary oocyte is not fertilized and if it is fertilized
    if the secondary oocyte is NOT fertilized, the corpus luteum degenerates after 2 weeks into a corpus albicans. If the secondary oocyte is fertilized, the corpus luteum stays active. Levels of progesterone and estrogen depend on whether or not the presence of hCG is around to rescue the corpus luteum (to stimulate its secretory activity).
  43. 17.Explaining the influence of human chorionic gonadotropin and its use in detecting pregnancy
  44. 17.Describing hormonal changes that initiate menstruation if fertilization does not occur
  45. 18.Define menopause, state its cause, and list common symptoms.
    • Menopause is the termination of menses and therefore fertility. The cause of menopause is age. With age, estrogen production declines and fertility decreases due to a decrease in remaining ovarian follicles and ovaries being less responsive to hormonal stimulation and their surface area scarred and pitted from past ovulation.
    • Symptoms include: hot flashes, heavy sweating, headache, hair loss, muscular pains, vaginal dryness, insomnia, depression, weight gain and mood swings
  46. 19.Define sexually transmitted disease and name the developed country where STDs are rising to near-epidemic proportions:
    STDs are diseases that spread through sexual contacts; In the United States,STDs have been rising to near-epidemic proportions; they currently affect more than 65 million people.
  47. 20.Describing fertilization
  48. 20.Stating the function of the tail of the sperm cell
    Enables motility so it can swim to the secondary oocyte
  49. 20.Describing sperm penetration
    Enzymes on sperm cell heads/strong tail movements help sperm penetrate corona radiata and come in contact with zona pellucida; one glycoprotein in zona pellucida acts as sperm receptor that binds to sperm cell head, triggering acrosomal reaction; acrosomal reaction breaks down plasma membrane of acrosome covering sperm head; acrosomal enzymes released that digest a path through zona pellucida as sperm�s tail pushes it onward; first sperm cell to penetrate entire zona pellucia/reach oocyte�s plasma membrane fuses with oocyte
  50. 20.Explain how polyspermy is blocked
  51. 20.Distinguish between fraternal and identical twins
    Fraternal twins result from independent release of two secondary oocyte and subsequence fertelization of each by different spermed they have the same age but genetically dissimilar, Identical twins developed from a single ferterlized Ovum ,have exactly the same genetic material and are always the same sex
  52. 21.Describe ectopic pregnancy.
    • This occurs when a fertilized egg attaches itself somewhere besides the lining of the uterus.
    • Implantation in the pelvic cavity
    • When the fertilized egg gets implanted outside of the uterus
  53. 22.Define contraception (see textbook Glossary):
    prevention of fertilization/impregnation without destroying fertility
  54. 22.Explain the mechanism in preventing fertilization of tubal ligation:
    Known as having your "tubes tied"; the uterine tubes are either clamped or severed and sealed to prevent the eggs from reaching the uterus for fertilization.
  55. 22.oral contraceptives
    prevent pregnancy mainly by preventing ovulation though a pill (taken orally) containing progestin/estrogen or progestin alone. Progestin inhibits ovulation by suppressing leutenizing hormone (LH) from the anterior pituitary.
  56. 22.condoms
    provides a physical barrier so that ejaculated sperm doesn't reach the femail reproductive tract
  57. 22.diaphragm
    a dome-shaped device which is placed over the cervix with s spermicide to prevent conception.
  58. 22.rhythm method.
    Having unprotected sex only on infertile days of the menstrual cycle. The first seven days and then the 20th day on are considered infertile periods (the pre and postovulatory periods, respectively). Requires knowledge of the length of the woman�s menstrual cycles and the current progression in the cycle.
  59. 23.Defining the embryo
    the stage of development from fertilization to 8 weeks
  60. 23.Describing implantation
    After 6 days of fertilazation the blastocytes loosely attaches to the Endometrium more firmly, endometrial glands in the vicinity enlarge and endometrium became more vascularized.
  61. 23.Explaining how the embryo receives nourishment
  62. 23.Defining the amnion
    it is a thin protective membrane which is developed from the epiblast while the amniotic cavity enlarges.
  63. 23.Stating the function of amniotic fluid
    this fluid that fills the amniotic cavity serves as a shock absorber for the fetus, regulates body temperature, prevents drying out of the fetus, and helps prevent injuries to the fetus from surrounding tissues.
  64. 24.Describing the placenta
    Formed from the chorion (fetal) and decidua basalis (mother), serves the purpose for exchange of respiratory gases and nutrients and wastes between the mother and the fetus
  65. 24.Defining the umbilical cord and afterbirth.
    the umbilical cord is the connection between the placenta and the embryo(later, the fetus); the afterbirth is the detached placenta from the uterus after pregnancy.
  66. 24.Defining the fetus
    begins at week 9 of development, continues until birth
  67. 25.State the production sites and pregnancy-related functions of human chorionic gonadotropin:
    produced by chorion of embryo (roughly 8 days after fertilization); stimuates secretory activity of corpus lutem; hormone detected by home pregnancy tests
  68. 25.State the production sites and pregnancy-related functions of progesterone:
    during the first 3-4months of pregnancy progestron and estrogen are secreted by the corpus luteum in the ovary to maintain the lining of uterus during pregnancy and prepare the mammary glands to secrete milk
  69. 25.State the production sites and pregnancy-related functions of estrogens:
    during the first 3-4months of pregnancy progestron and estrogen are secreted by the corpus luteum in the ovary to maintain the lining of uterus during pregnancy and prepare the mammary glands to secrete milk
  70. 25.State the production sites and pregnancy-related functions of relaxin.
    produced by the corpus luteum; increases flexibility of the pubic symphysis and dilates the cervix
  71. 26.Define labor, state its other name, and state the influence of oxytocin on labor.
    • Partuition= process by which the fetus is expelled from the uterus through the vagina.
    • Oxytocin stimulates uterine contractions.
  72. 27.Define lactation.
    secretion/ejection of milk by the mammary glands
  73. 28.Structure and function: Scrotum
    a sac that hangs from the root of the penis and consists of loose skin and underlying hypodermis; it supports the testes.
  74. 28.Structure and function: Cremaster muscle
    a series of small bands of skeletal muscle that descends as an extension of the internal oblique to surround the testes.
  75. 28.Structure and function: Testis
    (pl: testes) or testicles, are paired oval glands in the scrotum. Contains Seminiferous tubules.
  76. 28.Structure and function: Seminiferous tubule
    Production and secretion of sperm
  77. 28.Structure and function: Sperm cell (spermatozoon)*
  78. 28.Structure and function: Epididymis
    site of sperm maturation (acquires motility and ability to fertilize a secondary oocyte)
  79. 28.Structure and function: Ductus deferens (vas deferens)
    stores sperm
  80. 28.Structure and function: Ejaculatory duct
    eject sperm/seminal vesicle secretions
  81. 28.Structure and function: Urethra
    Serves as a passageway for urine and sperm to exit the body
  82. 28.Structure and function: External urethral orifice
  83. 28.Structure and function: Seminal vesicle
    contributes 60% of seminal vesicle fluid to the semen, alkaline secretion
  84. 28.Structure and function: Prostate
    ATP production
  85. 28.Structure and function: Bulbourethral glands
    secretes fluid to protect sperm from urine and lubricates the lining of the urethra
  86. 28.Structure and function: Penis
    Mechanism and housing of passageway for the ejaculation of semen
  87. 28.Structure and function: Corpora cavernosa (their plural name)
  88. 28.Structure and function: Corpus spongiosum
  89. 28.Structure and function: Glans penis
  90. 28.Structure and function: Perineum*
  91. 28.Structure and function: Ovary
  92. 28.Structure and function: Follicle*
  93. 28.Structure and function: Oocyte*
  94. 28.Structure and function: Corona radiata
  95. 28.Structure and function: Corpus luteum
    produces progesterone, estrogens to maintain the endometrium for fertilized ovum implantation, but if ovum is not fertilized, it generates and menstruation begins
  96. 28.Structure and function: Broad ligament
    encloses the ovaries and attaches them to the pelvic wall
  97. 28.Structure and function: Ovarian ligament
    anchors the ovaries to the uterus
  98. 28.Structure and function: Suspensory ligament
    attaches the ovaries laterally to the pelvic wall
  99. 28.Structure and function: Uterine (fallopian) tube
    Provide a route for sperm to reach an ovum
  100. 28.Structure and function: Infundibulum*
  101. 28.Structure and function: Fimbriae
  102. 28.Structure and function: Uterus
    pathwasy for sperm, and implantation of a fertilized ovum
  103. 28.Structure and function: Cervix*
  104. 28.Structure and function: Myometrium
    the middle layer of the uterus; 3 smooth muscle layers that function during childbirth (uterine contractions).
  105. 28.Structure and function: Endometrium
    lines the lumen of the uterus; 2 layers, where the lumenal layer functions by sloughing off during menstruation.
  106. 28.Structure and function: Vagina
    receptacle for penis during sexual intercourse, outlet for mentrual flow, and the passageway for childbirth
  107. 28.Structure and function: Vulva*
  108. 28.Structure and function: Labia majora
    protectively enclose medial components of the vulva.
  109. 28.Structure and function: Labia minora
  110. 28.Structure and function: Clitoris
    point of sexual excitement in female.
  111. 28.Structure and function: Vestibule*
  112. 28.Structure and function: Vaginal orifice*
  113. 28.Structure and function: Vestibular gland
    release mucus into the vestibule and help keep it moist and lubricated, facilitating intercourse
  114. 28.Structure and function: Vestibular bulb (bulb of the vestibule)
    squeezes urtheral orifice shut which prevents semen from traveling into the bladder during intercourse
  115. 28.Structure and function: Perineum*
  116. 28.Structure and function: Breast*
  117. 28.Structure and function: Nipple*
  118. 28.Structure and function: Areola*
  119. 28.Structure and function: Mammary gland
    prodcues milk
Card Set:
BI-205 Ch 25
2011-12-16 02:21:24
Anatomy Physiology Reproductive System

Chapter 25 LO
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