Neurons- Anatomy

Neuron

Neurons are the cells that transmit nerve impulses between parts of the nervous system.

Dendrite

Dendrites are extensions leading toward cell body that receives signal from other neurons and send them to the cell body.

Cell body

Part of neuron that holds the nucleus as well as other organelles, also called the soma.

Nucleus

Contains the genetic material of the neuron.

Axon

A long strand attached to the cell body. Conducts nerve impulses away from the cell body toward other neurons or effectors.

Myelin sheath

A lipid layer around the axon. It carries the message to one of these lipids to another, making transporting an impulse efficient.

Schwann cells

A type of Neuroglia, that produce myelin in the PNS.

Sensory neuron

Known as an afferent neuron, this neuron transports message to the CNS. These neurons may be equipped with specialized nerve endings called sensory receptors.

Motor neuron

Known as an efferent neuron, takes message away from the CNS to an effector ( an organ, muscle fiber, or gland). Effectors carry out our responses to environmental changes.

Inter-neuron

A neuron that connects afferent and efferent neurons. Lies entirely within the CNS. Can receive input from sensory neurons and also from other inter-neurons in the CNS. These inter-neurons sum up all the messages from these neurons before they communicate with the motor neurons.

Reflex arc

Simple connection from a sensory neuron to an inter-neuron to a motor neuron.

Impulse

A chemical change in a neuron that travels from to dendrite to cell body to axon. It is self- propagating.

Self- propagating

Keeps on going from sensory neuron to inter-neuron to motor neuron.

Mechanism Na+ K+

This pump is responsible for transporting impulses.

Neurotransmitters

Chemicals made by neurons that are released by impulse.

Synapse

The junction between two nerve cells through which impulses pass by the diffusion of neurotransmitters.