What is the innermost, vascular connective tissue (loose C.T.) that closely covers the brain?

The innermost vascular connective tissue that closely covers the brain is known as the pia mater. The pia mater is a delicate and thin membrane that adheres closely to the surface of the brain and spinal cord, providing a protective layer and housing blood vessels that supply oxygen and nutrients to the nervous tissue. It is one of the three meninges, which are membranes that envelop the brain and spinal cord, the others being the dura mater (the outer layer) and the arachnoid mater (the middle layer). The pia mater plays a critical role in maintaining the overall health and function of the central nervous system.