Fertilization and Pregnancy S2M3

  1. What are the phases of the female sex act
    • Excitement phase
    • Plateau phase
    • Orgasm
    • Resolution
  2. What happens in the female excitement stage
    • Erectile tissue becomes engorged (PNS)
    • Vaginal secretions lubricate the vagina
  3. In the Plateau phase what happens
    • Maintenance of lubricating state
    • Uterus becomes vertical
    • Lower one third of vagina constricts
  4. What happens in the orgasm stage
    • Uterus and cervix contract rhythmically (SNS mediated)
    • Uterus position to open
    • Cervical opening becomes patent
  5. What happens in the resolution stage
    • Uterus returns to original position above the bladder
    • Cervical opening remains widely open for 20-30 min permitting the sperm to enter the uterus
  6. How many sperm are deposited by the male into the vagina during intercourse
    150-600 million sperm
  7. How many sperm reach the ampulla portion of the fallopian tube
  8. How thick is the lumen of the fallopian tube
    2x the thickness of a human hair
  9. What is the normal life of the egg after ovulation
    24 hrs
  10. Motility of spermatozoa is aided by what secreted in the female
  11. Motility of the uterine tube is aided by what secreted by the male
    Prostaglandins in the seminal fluid
  12. Capacitation of the sperm is under the hormonal control of
    • Fertilization-Promoting Peptide (FPP) (an inhibitory product of the prostate gland)
    • Only when sperm is absent from it can capacitation begin
  13. What actions happen for sperm to undergo capacitation
    • Ca++ influx
    • FPP dissipation
    • Loss of cholesterol on sperm head causing exposure of the acrosomal membrane
    • Merging of acrosomal and plasma membrane of sperm
  14. Ca++ influx has what effect on the sperm
    • The release of hydrolytic enzymes like hyaluronidase facilitating penetration of the zona pellucida
    • Increased motility
  15. Polar bodies released from the ovum are what
    A result of Meiosis II which discards the unused chromosomes
  16. What are the events of the fertilization of the egg by a sperm
    • 1. Sperm swims through the granulosa cells (corona radiata) to reach the zona pellucida
    • 2. Sperm binds to ZP3
    • 3. Sperm releases enzymes and bind to ZP2 (orienting sperm)
    • 4. Increase intracellular Ca+ and flagellar action
    • 5. Sperm penetrates ovum membrane
    • 6. Ova Ca+ rises blocking polyspermy
  17. What limits fertilization to one sperm
    • Ca+ rise hardening the ovum to further penetration
    • Cortical granules of oocyte fuse with the plasma membrane
    • Sperm receptors on ovum are inactivated
  18. What removes the remaining zona pellucida before implantation on around day 6
    Uterine secretions and contractions
  19. What does the uterus secrete to give nutrients to the blastocyst while it waits to be implanted
  20. What hormones are secreted to prepare the uterus for implantation of the blastocyst
    • Progesterone and estrogen from the corpus luteum
    • hCG secretion from the Blastocyst
  21. What are the three layers of the uterus upon implantation
    • Zona compacta - invasion zone
    • Zona spongiosum - lipid, cholesterol stores, & glands
    • Zona basalis
  22. What results from an absence of progesterone
    • Implantation of the blastocyst fails
    • Glands, lipids, and glycogen fail to proliferate in the endometrium
  23. What layer of the blastocyst makes contact with the maternal blood vessels
    Synctiotrophoblast layer
  24. What are the PaO2 levels of the maternal and fetal blood
    • Maternal - 50mmHg
    • Fetal - 30mmHg
  25. What are the hemoglobin subunits in the maternal and fetal blood
    • Maternal - 2 alpha and 2 beta
    • Fetal - 2 alpha and 2 gamma (higher affinity for O2)
  26. How do carbon dioxide levels compare in the mother and fetus
    The fetus has 2-3 mmHg higher then the mother
  27. Glucose is moved across the placenta how
    Facilitated diffusion
  28. Lipids, free fatty acids, ions (Na, K+, Cl-) move across the placenta how
    Simple diffusion
  29. hCG is produced by what and has what affect
    • Produced by syncytiotrophoblasts
    • This "rescues" the corpus luteum
    • Also acts on LH receptors on embryonic Leydig cells in a male baby
  30. What are the main effects of progestins
    • Support of the endometrium
    • Suppression of contractility in uterine smooth muscle
    • Prepares the breasts for lactation
  31. What is the role of placental estrogens
    • Stimulates the growth of the myometrium
    • Stimulates mammary gland development
    • Stimulates growth of uterus
    • Relaxation of pelvic ligaments
  32. The placenta produces primarily what type of estrogen
  33. What replaces hCG after several weeks
    Human chorionic somatomammotropin (hCS)
  34. Human chorionic somatomammotropin (hCS) is structurally related to what other hormones
    Prolactin and Growth hormones
  35. hCS has what effects during pregnancy
    • Maternal lypolysis
    • Antagonizes insulin actions on carb. metabolism
    • Switches metabolism from anabolic to catabolic
  36. Relaxin
    A hormone thought to act synergistically with progesterone to maintain pregnancy, and relax pelvic ligaments
  37. How does pregnancy effect insulin levels
    Increases them early in pregnancy and decreases sensitivity later in pregnancy potentially leading to gestational diabetes
  38. What are the main hormones made by the placenta
    • Relaxin
    • Inhibin
    • Progesterone
    • Estrogen
    • "RIPE"
  39. Aldosterone levels are effected how in pregnancy
    Secretion of Aldosterone goes up because renin and angiotensinogen are stimulated by estrogen, and because plasma levels are reduced
  40. What happens to cortisol levels during pregnancy
    • Levels increase because of rise of estrogen
    • This causes the cushy look of pregnant women
  41. What happens to Thyroxin (T4) levels during pregnancy
    Levels increase because of estrogen induced increases in thyroid binding globulin
  42. What happens to the levels of Calcitriol (active vit D) during pregnancy
    Production from the placenta increases ensuring adequate calcium absorption for fetal growth
  43. What happens to the PTH levels during pregnancy
    They are decreased by 50%, but because vit D stays high, bone loss is limited while Ca+ goes to the fetus
  44. How is blood volume effected during pregnancy
    40% increase
  45. By the end of pregnancy how much blood does the fetus receive a min
    650 ml/min
  46. What happens to blood pressure at mid gestation
    There is a decrease
  47. What happens to renal function during pregnancy
    • GFR increase
    • Urine increase
    • Water absorption increase
  48. How does catabolism and anabolism change during pregnancy
    During the first half of pregnancy anabolism is high preparing for needs of the fetus and for and the catabolism that takes place during the second half of pregnancy
  49. Why does insulin resistance set in during the second half of pregnancy
    • Use of the carbohydrates and amino acids slows allowing the fetus to take the unused nutrients
    • As a result lypolysis increases
  50. What happens to ventilation of the mother during pregnancy
    It is increased due to the needs of the fetus as well as the CO2 production of the fetus
  51. What type of diabetes does gestational diabetes present as
    Type 2
Card Set
Fertilization and Pregnancy S2M3