questions 1

Pregnancy

Author:
Topic updated on 04/25/17 7:43am

Overview 
  • Fertilization and implantation
    • ovum is fertilized in ampulla of Fallopian tube several hours after ovulation
    • blastocyst implants in endometrium 6 to 7 days after ovulation
      • syncytiotrophoblast cells secrete hCG that rescues corpus luteum
    • hCG
      • in first trimester, hCG sustains corpus luteum in presence of falling LH levels
        • corpus luteum produces progesterone
          • progresterone is necessary for maintenance of pregnancy
      • hCG levels detectable in blood (1 week post-conception)
      • hCG levels detectable in urine (2 weeks post-conception)
        • e.g., home pregnancy test
    • in second and third trimesters, placenta produces estrogen and progesterone
      • corpus luteum degenerates
    • hCG levels elevated in certain pathologies
      • hydatidiform moles
      • choriocarcinoma
  • Lactation
    • post-delivery, ↓ progesterone levels, prolactin promotes lactation
      • initiation of milk production by alveolar cells
  • Suckling
    • stimulates sensory nerves that carry suckling signal from breast to hypothalamus via spinal cord, a process that mediates prolactin and oxytocin release
  • Prolactin
    • suckling sends signal from breast (nipple) to hypothalamus
      • suckling input in arcuate nucleus of hypothalamus inhibits dopamine release
        • dopamine travels via hypothalamic-portal system to anterior pituitary to inhibit prolactin (PRL) release by lactotrophs
        • suckling inhibits release of dopamine and causes ↑ PRL
    • prolactin promotes lactation and maintains lactation once established
    • prolactin → (-) hypothalamus → ↓ GnRH → ↓ FSH and ↓ LH
      • prolactin inhibits reproductive function
  • Oxytocin
    • suckling sends signal from breast (nipple) to hypothalamus
      • suckling input in supraoptic and paraventricular nuclei of hypothalamus triggers oxytocin release via posterior pituitary
    • oxytocin promotes contraction of myoepithelial cells promotes milk letdown
    • oxytocin may promote uterine contractions in childbirth
  • Physiologic changes 
    • increased blood volume
    • increased cardiac output
    • mild anemia
    • mild respiratory alkalosis
    • hypercoagulability
 


  RATE CONTENT
4.0
AVERAGE 4.0 of 3 RATINGS

Qbank (0 Questions)

This is a Never-Been-Seen Question that can only be seen in Study Plan Mock Exams.
Access to 600+ Questions not available in Free Qbank


Recent Videos

video
Great presentation
5/11/2017
70 views
0
video
This video gives an overview of breast anatomy and lactation. NOTE: All Khan Aca...
2/22/2015
91 views
0
video
This video describes the maternal changes in pregnancy. NOTE: All Khan Academy c...
2/22/2015
145 views
5

Evidence & References Show References




Topic Comments

Subscribe status: