As a neuroscientist with a focus on cellular biology, I can provide you with a detailed explanation of where nerve cells, or neurons, are located and their function within the human body.

Nerve cells, also known as neurons, are the fundamental units of the nervous system. They are specialized cells that are responsible for transmitting information throughout the body. The nervous system is divided into two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS).

The central nervous system is composed of the brain and spinal cord. The brain, which is the control center of the body, contains approximately 86 billion neurons, as you mentioned. These neurons are organized into various regions, each responsible for different functions such as cognition, emotion, memory, and motor control. The cerebral cortex, the outer layer of the brain, is particularly dense with neurons and is involved in higher cognitive functions. Deeper within the brain, structures like the basal ganglia and the thalamus play roles in movement control and relaying sensory information, respectively.

The spinal cord extends from the brainstem and runs down the vertebral column. It is a conduit for signals traveling between the brain and the rest of the body. Neurons within the spinal cord are involved in reflex actions and the transmission of sensory and motor information.

The peripheral nervous system consists of all the neural elements outside the CNS. It is divided into the autonomic nervous system, which controls involuntary functions like heart rate and digestion, and the somatic nervous system, which controls voluntary muscle movements. Neurons of the PNS are found throughout the body, in structures such as the nerves that branch out from the spinal cord and extend to the limbs and organs, and in the ganglia, which are clusters of neuron cell bodies located outside the CNS.

Each neuron has a distinct structure that includes the cell body (soma), dendrites, and an axon. The cell body contains the nucleus and other organelles necessary for the cell's function.
Dendrites are branching extensions that receive signals from other neurons. The axon is a long projection that carries electrical impulses away from the neuron's cell body to other neurons, muscles, or glands.

Neuronal communication occurs at specialized junctions called synapses. At the synapse, the axon terminal of one neuron releases neurotransmitters into the synaptic cleft, which are then detected by receptors on the dendrites or cell body of another neuron, thus facilitating the transfer of information.

In summary, nerve cells are distributed throughout the entire body, with the highest concentration in the brain and spinal cord. They form complex networks that allow for the integration and coordination of information, enabling all the functions that make us who we are.

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Types of Neurons (Nerve Cells) The human body is made up of trillions of cells. Cells of the nervous system, called nerve cells or neurons, are specialized to carry "messages" through an electrochemical process. The human brain has approximately 86 billion neurons.read more >>