Lecture 4 9-24-07 Mothers, Fetuses, Placentas, and Birth

Lecture 4 9-24-07 Mothers, Fetuses, Placentas, and Birth -...

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Lecture 4 9/24/07 Mothers, Fetuses, Placentas, and Birth 16/10/2007 18:03:00 in abstract sense, reproduction is the process of capturing energy from the environment  and turning it into more organisms metabolism:  involves both  catabolism  (breakdown of molecules for energy)  and  anabolism  (assembly of large molecules, cells, and tissues)  o storage of energy is also possible Hormones  (signal molecules)  help regulate metabolism  both at a distance as  endocrine  signals and locally as  paracrine  signals o can regulate transcription of genes or activity of enzymes o cells have receptors for specific hormones Pregnancy mother, fetus, and placenta placenta:  medium through which the metabolic process of pregnancy occurs o intermediate between mother and fetuses  o glucose, amino acids, oxygen go to fetus through placenta o urea, carbon dioxide sent from fetus to mother through placenta Implantation begin w/ crisis:  o embryo is running out of food, will soon have too many tissue layers to  rely on diffusion of nutrients and gases o it must establish a connection to the maternal blood supply  o endometrium  (uterine lining) is about to be shed in menstruation Endometrium (uterine lining) o maintained by  progesterone  secreted by  corpus luteum  in the  maternal ovary progesterone supports pregnancy by maintaining endometrium
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o loss of progesterone (or blocking of progesterone receptors with  RU486  degradation of endometrium o estrogen causes endometrium to build up, then estrogen and  progesterone maintain the lining blastocyst  must implant itself in the endometrium at exactly the right time
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Lecture 4 9-24-07 Mothers, Fetuses, Placentas, and Birth -...

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