PATHOLOGY

Detailed explanation-1: -Nerve cells are also called neurons. Neurons are present all over your body, especially in your brain and spinal cord. Nerves, together with your brain and spinal cord, are the foundation of your nervous system.

Detailed explanation-2: -The nervous system develops from the ectoderm following an inductive signal from the mesoderm. The initial mesodermal cells condense to form the notochord, which elongates under the primitive streak along the anterior-posterior axis of the developing embryo.

Detailed explanation-3: -For half a century, neuroscientists thought the human brain contained 100 billion nerve cells. But when neuroscientist Suzana Herculano-Houzel devised a new way to count brain cells, she came up with a different number-86 billion.