2ģ Distention: uterine muscles stretch causing ↑ prostaglandin. Estrogen ↑ uterus response & progesterone ↓ it. THEORIES of LABOR: Combination of factors start labor: Oxytocin & prostaglandin - most important biochemical factors in stimulating uterine contractions. Myometrium - muscle layer – middle Perimetrium - outer layer -extra support to whole structure. Introduction Uterus: pear-shaped muscle made of 3 layers: Endometrium – inner lining - shed during menses. 2 Uterus: pear-shaped muscle made of 3 layers:
