Neurobiology - Neurons and Glial Cells

Neurons

• main cells of the nervous system that respond to stimuli and transmit signals

• Send impulses (messages) from one part of the body to another

Cell Body

• contains genetic info

• receives info from dendrites and integrates it into electrical impulses

Dendrites

receive information at a synapse and transfer that information toward the cell body

Axon

transport electrical impulses through the neuron

Axon Terminal

end of axon where info gets transferred by neurotransmitters, which act as messengers to convey signals across synapses

Myelin Sheath

fatty layer that protects the axon and help speed transmission of information

Nodes of Ranvier

spaces between Schwann cells that assist in speeding up transmission by allowing signals to bounce between nodes

Synapse

space between axon terminal of a nerve cell that allow them to pass an electrical or chemical signal to something else

Glial Cells or Neuroglia

• surround, support, and protect neurons

• fills spaces between neurons, act as “glue”

Astrocytes

• Most abundant glial cell

• Anchor neurons to blood capillaries

• Exchange material between neurons and capillaries

• Part of the Central Nervous System

Microglial Cells

• Provide immune defense against invading microorganisms

• Able to sense and approach injured neurons

• Phagocytose/clean up bacteria and debris

• Part of the Central Nervous System

Ependymal Cells

• Create, secrete, and circulate cerebrospinal fluid around the brain and spinal cord

• Line cavities in the brain and spinal cord

• Part of the Central Nervous System

Oligodendrocytes

• Form myelin sheath in the Central Nervous System (an insulating covering)

• Insulates and protects axons

Schwann Cells

• Form myelin sheath in the Peripheral Nervous System

• Insulates and protects axons

Satellite Cells

• Surround the cell body of a neuron

• Regulate levels of oxygen, CO2, and nutrients

• Part of the Peripheral Nervous System

Action Potential

• the transmission of information down an axon

• travels the length of the axon and causes release of neurotransmitter into the synapse

Sensory (afferent) neurons

transmit impulses from sensory receptors towards the CNS

Motor (efferent) neurons

transmit impulses from CNS to the rest of the body

Interneurons

transmit impulses between sensory and motor neurons

Central Nervous System

• consist of the brain and spinal cord

• receive info from the PNS and send signals to the PNS

Peripheral Nervous System

• consist of every other part of the nervous system beyond the brain and spinal cord

• send sensory info to the CNS and receive orders from the CNS