Also known as sensory neurons, afferent neurons transmit sensory signals to the central nervous system from receptors in the body. There are 3 basic classes of neurons: afferent neurons, efferent neurons, and interneurons. Long transmitting processes called axons extend from the cell body to send signals onward to other neurons or effector cells in the body. Small tree-like structures called dendrites extend from the cell body to pick up stimuli from the environment, other neurons, or sensory receptor cells. The cell body is the roughly round part of a neuron that contains the nucleus, mitochondria, and most of the cellular organelles. Neurons look quite different from other cells in the body due to the many long cellular processes that extend from their central cell body. Neurons, also known as nerve cells, communicate within the body by transmitting electrochemical signals. The majority of the nervous system is tissue made up of two classes of cells: neurons and neuroglia. Efferent nerves in the PNS carry signals from the control center to the muscles, glands, and organs to regulate their functions. The sensory nerves and sense organs of the peripheral nervous system (PNS) monitor conditions inside and outside of the body and send this information to the CNS. The brain and spinal cord form the control center known as the central nervous system (CNS), where information is evaluated and decisions made. Together, these organs are responsible for the control of the body and communication among its parts. The nervous system consists of the brain, spinal cord, sensory organs, and all of the nerves that connect these organs with the rest of the body.

Types of neurons in the brain