|
|
||||||||
Department Physiology and Pharmacology, School of Medicine, Oregon Health Sciences University, Portland, Oregon 97201
Swallowing of amniotic fluid and lung fluid inflow were eliminated in 10 chronically instrumented fetuses. The urachus was ligated, and fetal was urine drained to the outside. At the beginning and the end of 21 experiments of 66 ± 5 (SE) h duration, all amniotic fluid was temporarily drained to the outside for volume measurement and sampling. Amniotic fluid osmolalities and oncotic pressures were experimentally controlled. Amniochorionic absorption of amniotic fluid depended strongly on the osmolality difference between amniotic fluid and fetal plasma (P < 0.001), but at zero osmolality difference there still was a mean absorption rate of 23.8 ± 4.7 (SE) ml/h (P < 0.001). Absorption was unaffected by the protein concentration difference between amniotic fluid and fetal plasma, but infused bovine albumin in the amniotic fluid was absorbed at a rate of 1.8 ± 0.4 g/h (P < 0.001), corresponding to a volume flow of fluid of 33.8 ± 6.1 ml/h (P < 0.001). Fluid absorption in the amniochorion is driven in part by crystalloid osmotic pressure, but about 25 ml/h is absorbed by a path that is permeable to protein. That path has the physiological characteristics of lymphatic drainage, although no anatomic basis is known to exist for a lymphatic system in the amniochorion.
oncotic pressure; volume homeostasis; lymphatics
This article has been cited by other articles:
![]() |
W. M. Gilbert Amniotic Fluid Dynamics NeoReviews, June 1, 2006; 7(6): e292 - e299. [Full Text] [PDF] |
||||
![]() |
J. Faber, D. Anderson, R. Hohimer, Q. Yang, G. Giraud, and L. Davis Function curve of the membranes that regulate amniotic fluid volume in sheep Am J Physiol Heart Circ Physiol, July 1, 2005; 289(1): H146 - H150. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Anderson, Q. Yang, A. Hohimer, J. Faber, G. Giraud, and L. Davis Intramembranous absorption rate is unaffected by changes in amniotic fluid composition Am J Physiol Renal Physiol, May 1, 2005; 288(5): F964 - F968. [Abstract] [Full Text] [PDF] |
||||
![]() |
Q. Yang, L. Davis, A. Hohimer, J. Faber, and D. Anderson Regulatory response to washout of amniotic fluid in sheep Am J Physiol Heart Circ Physiol, March 1, 2005; 288(3): H1339 - H1343. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |