Hormones and Functions of Placenta
The placenta serves as a vital endocrine organ during pregnancy, producing several hormones essential for fetal development and maternal physiological adaptation.
The placenta produces hormones that can
- Stimulate ovarian function
- Maintain pregnancy
- Influence fetal growth
- Stimulate mammary function
- Assist in parturition
Placental hormones includes:
- Progesterone
- PMSG
- hCG
- Relaxin
- Placental lactogen
- Pregnancy specific protein B / PAG
- Prostaglandins
Placental function includes exchange of nutrients and metabolite between dam and fetus:
- Fetus synthesizes proteins from maternal AA.
- Lipids do not cross placenta- Placenta hydrolyses triglycerides and maternal phospholipids- new lipid materials are synthesized
- Large peptide hormones-TSH, ACTH, Growth hormone, insulin- do not cross placenta.
- Fat soluble vitamins-cross with difficulty, Water soluble vitamins-cross with ease.
- Viruses-cross with ease: Herpes, HIV.
- Simple diffusion: Gases and Water pass from high to low concentration.
- Facilitated diffusion: Glucose and aa are transported using specific carrier molecules.
- Active transport: Active transport pumps for Na, K and Ca.
