The cell signaling pathways induced by the steroid hormones regulate specific genes within the cell's DNA. The hormones and receptor complex act as transcription regulators by increasing or decreasing the synthesis of mRNA molecules from specific genes.
Steroid hormones are not able to target every cell within the body, so the overall response is slower. They bind to receptors on the cell's surface and the receptors aid in helping the steroid hormones enter the cell.
Hormones work by binding to protein receptors either inside target cells or on their plasma membranes. The binding of a steroid hormone forms a hormone-receptor complex that affects gene expression in the nucleus of the target cell.
Steroids pass into a cell's nucleus, bind to specific receptors and genes and trigger the cell to make proteins.
Between one-third and one-half of all fertilized eggs never fully implant. A pregnancy is considered to be established only after implantation is complete
Three meninges cover the brain and spinal cord. Pia mater refers to the deepest meninx of the brain. It is a thin delicate layer of connective tissue. It is a transparent connective tissue layer like that of cellophane. Being a transparent and thin tissue layer, it looks like a cellophane wrap adhered to the surface of the brain.
