Physiology of Parturition PDF
Physiology of Parturition PDF
Physiology of Parturition PDF
1
FIBRILLAR COLLAGEN SYNTHESIS AND ORGANIZATION. Three chains (A) are synthesized to form procollagen. B. Amino
terminal and carboxy terminal propeptide (indicated in green) are cleaved from procollagen by specific proteases outside the cell. C.
Tropocollagen results from this cleavage. D. Removal of these propeptides results in a decline in solubility of collagen and self-assembly of
collagen chains into fibrils. The enzyme lysyl oxidase catalyzes the formation of nonreducible cross-links between two triple helical regions
to make stable collagen fibrils (E). F. Fibrils, in turn, are assembled into collagen fibers. G. Fibril size and packing are regulated in part by
small proteoglycans that bind collagen such as decorin. Before cervical ripening, fibril size is uniform, and fibrils are well-packed and
organized. H. During cervical ripening, fibril size is less uniform, and spacing between collagen fibrils and fibers is increased and
disorganized.
PHASE 2
To prepare for labor, the myometrial tranquility of phase 1 of parturition must be suspended through what has been
called uterine awakening or activation
progression of uterine changes during the last 6 to 8 weeks of pregnancy
Friedman’s Curve
FETAL CONTRIBUTION
ACTIONS OF CORTICOTROPIN-RELEASING HORMONE ON THE FETAL ADRENAL GLAND
The human fetal adrenal glands are morphologically, functionally, and physiologically remarkable organs.
At term, the fetal adrenal glands weigh the same as those in the adult and are similar in size to the adjacent fetal kidney
The daily steroid production by the fetal adrenal glands near term is estimated to be 100 to 200 mg/day
Within the fetal adrenal gland, steroidogenic function and zonation differ from the adult.
Fetal cortisol levels increase during the last weeks of gestation. During this same period, levels of dehydroepiandrosterone sulfate (DHEA-S) production also are increasing significantly, leading to
increases in maternal estrogens, particularly estriol.
Fetal pituitary adrenocorticotropic hormone (ACTH) levels, which do not increase until actual labor onset.
Many favor CRH of placental origin to be a critical agent for fetal adrenal hypertrophy and increased steroidogenesis in late pregnancy
ANGIOTENSIN II
There are two G-protein-linked angiotensin II receptors-expressed in the uterus—AT1 and AT2.
In nonpregnant women, the AT2 receptor is predominant but the AT1 receptor is preferentially expressed in pregnant women
Angiotensin II binding to the plasma-membrane receptor evokes contraction.
Facilitates uterine contraction when AT receptors are activated
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TRANSCRIPTION DETAILS
Major: Book
(Sumpaico and/or
BASIS William’s) RECORDINGS - NOTES - DEVIATIONS 30-50% CREDITS
Minor: 125 slide
Powerpoint
E-mail me at bhen44@gmail.com for any comments, suggestions, and corrections for this topic.
REMARKS Correlate with pictures in William’s Obstetrics 23 rd Ed. Chapter 6.
This is a 125 slide powerpoint with footnotes incorporated.
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