Introduction to Neuroanatomy What is Neuroanatomy? The human body consists of numerous tissues and organs that are diverse in structure and function. Yet they function together, and in harmony, for the well being of the body as a whole. It is obvious that there has to be some kind of influence that monitors and controls the working of different parts of the body. Although there are other mechanisms that help in such control (e.g. hormones) the overwhelming role in directing the activities of the body rests with the nervous system. Neuroanatomy is the study of the structural aspects of the nervous system. It cannot be emphasised too strongly that the study of structure is meaningless unless correlated with function. Division of a study of the nervous system into neuroanatomy and neurophysiology is only a matter of convenience. Divisions of the Nervous System The nervous system may be divided into (a) the  central nervous system , made up of the brain and spinal cord, and (b) the  peri

  Divisions of the Nervous System The nervous system may be divided into (a) the  central nervous system , made up of the brain and spinal cord, and (b) the  peripheral nervous system , consisting of the peripheral nerves and the ganglia associated with them.         The brain consists of (a) the  cerebrum , made up of two large cerebral hemispheres, (b) the  cerebellum , (c) the  midbrain , (d) the  pons ,  and (e) the  medulla oblongata . The midbrain, ponsand medulla together form the  brainstem . The medulla is continuous, below, with the spinal cord.         Peripheral nerves attached to the brain are called  cranial nerves ; and those attached to the spinal cord are called  spinal nerves .         The peripheral nerves include those that supply skin, muscles and joints of the body wall and limbs, and those that supply visceral structures e.g., heart, lungs, stomach etc. Each of these sets of peripheral nerves is intimately associated with the brain and spinal cord. The nerves sup

  What is Neuroanatomy? The human body consists of numerous tissues and organs that are diverse in structure and function. Yet they function together, and in harmony, for the well being of the body as a whole. It is obvious that there has to be some kind of influence that monitors and controls the working of different parts of the body. Although there are other mechanisms that help in such control (e.g. hormones) the overwhelming role in directing the activities of the body rests with the nervous system. Neuroanatomy is the study of the structural aspects of the nervous system. It cannot be emphasised too strongly that the study of structure is meaningless unless correlated with function. Division of a study of the nervous system into neuroanatomy and neurophysiology is only a matter of convenience.

  Tissues constituting the nervous system        The nervous system is made up, predominantly, of tissue that has the special property of being able to conduct impulses rapidly from one part of the body to another. The specialised cells that constitute the functional units of the nervous system are called neurons . Within the brain and spinal cord neurons are supported by a special kind of connective tissue that is called neuroglia .Nervous tissue, composed of neurons and neuroglia, is richly supplied with blood. It has been taught that lymph vessels are not present, but the view has recently been challenged. The nervous system of man is made up of innumerable neurons. The total number of neurons in the human brain is estimated at more than 10 12 . The neurons are linked together in a highly intricate manner. It is through these connections that the body is made aware of changes in the environment, or of those within itself; and appropriate responses to such changes are produced e.g.,

  Elementary Structure of a Typical Neuron Neurons vary considerably in size, shape and other features. However, most of them have some major features in common and these are described below (Figs. 1.1 to 1.4).          A neuron consists of a  cell body  that gives off a number of  processes . The cell body is also called the soma or  perikaryon . Like a typical cell it consists of a mass of cytoplasm surrounded by a cell membrane. The cytoplasm contains a large central nucleus (usually with a prominent nucleolus), numerous mitochondria, lysosomes and a Golgi complex (Fig. 1.2). In the past it has often been stated that centrioles are not present in neurons, but studies with the electron microscope (usually abbreviated to EM) have shown that centrioles are present. In addition to these features, the cytoplasm of a neuron has some distinctive characteristics not seen in other cells. The cytoplasm shows the presence of a granular material that stains intensely with basic dyes; this mater

  How the Nervous system can be affected by disease Some knowledge of anatomy is an essential prerequisite for the practice of any clinical discipline, but no where is this more true than in the diagnosis of neurological disorders. The localisation of the areas of the nervous system involved in disease calls for a fairly thorough knowledge of the location of various masses of grey matter, and of the courses of various tracts. In recent years, considerable advances in neurological diagnosis have become possible by the use of sophisticated imaging techniques like computed tomography (CT), and magnetic resonance imaging (MRI). In interpreting these images a thorough knowledge of the gross anatomy of the head, neck and brain (or of other regions concerned) is invaluable. Damage to nervous tissue can occur in various ways. Any part of the brain or spinal cord may be damaged by direct injury ( trauma ). Apart from other obvious causes such injury may occur during child birth. If nervous tiss