Neurons, nerves and glia Lucija Milošević 2nd year University of Zagreb, School of Medicine 2013/14 Mentor: A. Žmegač Horvat

Introduction  Neuron – individual nerve cell – microscopic structure  Nerve – bundle of neurons which travel together – macroscopic structure  Glial cell – individual stromal cell

What is the main function of a neuron?  Conducting impulses (in one direction)

Neuron  Dendrites – branching fibers  Cell body – contains the cell nucleus

Neuron  Axon – the biggest branch extending from the cell body  Myelin sheath – fatty tissue which covers axons

White and gray matter

Synapse  Space where the nervous impulse jumps from one neuron to another

Neurotransmitters  Contained in tiny sacs  E.g. acetylcholine, epinephrine, dopamine, serotonin

Nerves  Sensory nerves – carry impulses to the brain and the spinal cord  Motor nerves – carry impulses from the CNS to organs  Mixed nerves – contain both sensory and motor fibers

Do glial cells and neurons have the same origin?  Neurons - ectodermal origin - parenchymal tissue  Glial cells - mesodermal origin - stromal tissue

Glial cells  Do not transmit impulses  Far more numerous than neurons  Can reproduce

Three types of glial cells  Oligodendrocytes – form the myelin sheath which protects neurons in the CNS  Microglia – as phagocytes protect neurons in response to inflammation

Astrocytes  Transport water and salts between capillaries and neurons  Blood-brain barrier – regulates passage of potentially harmful substances from the blood

References  The language of medicine, Davi-Ellen Chabner   Thank you for your attention!