What is different about activities on the two sides of the synapse (axon next to

muscle or dendrite of other nerve)?

SALMAN UL ISLAM2013298039

31.03.2014

Contents o Introductiono Nerve Cello Synapseo Transmission across the synapse-----

Neuromuscular junction (NMJ)o Summary

Introduction o Neuron-----electrically excitable cell-----processing

and transmitting information through electrical and chemical signals.

o Neurons communicate with each other by synaptic transmission.

o Synapses transmit, process, and store information in brain.

Courtesy of the Südhof lab. See Südhof, T.C. 2008. Nature 455:903-911 for details .

NERVE CELLThree parts of a nerve cell are:o dendrites: branches that receive sensory input

and bring it to the neuron’s cell body;o cell body: contains the nucleus, mitochondria,

and ribosomes. The cell body carries on the normal metabolic cellular functions of the nerve cell.

o axon: a long fiber extending from the cell body. The role of the axon is to transmit a nerve impulse to another cell.

 http://highered.mcgraw-hill.com/sites/dl/free/0073403474/858357/answers2e_ch25.doc.

Parts of a Nerve cell

http://cnx.org/content/m44731/latest/?collection=col11448/latest

SY

NA

PS

E

SYNAPSEThe presynaptic cell ends in an axon terminal

that contains calcium channels and synaptic vesicles with neurotransmitters.

The postsynaptic cell has ion channels with receptors for the neurotransmitters.

Between the two cells is a small gap called the synaptic cleft.

 http://highered.mcgraw-hill.com/sites/dl/free/0073403474/858357/answers2e_ch25.doc.

Transmission across the synapse----- Neuromuscular junction (NMJ)

o “ The place where the motor neuron makes a functional contact with the skeletal muscle cell is called NEUROMUSCULAR JUNCTION or MYONEURAL JUNCTION”

Neuromuscular Junction

What is the mechanism of

Neuromuscular Transmission

Myasthenia Gravis, A Seminar Report Posted: September 21, 2010 in Physiology, Toxic Med

From LIFE: The Science of Biology (Sadava et al., 2010)

Fate of Acetylcholine

Summary The synapse is a connection between a neuron and

its target cell (which is not necessarily a neuron). The presynaptic element is the synaptic end bulb of

the axon where Ca2+ enters the bulb to cause vesicle fusion and neurotransmitter release.

The neurotransmitter diffuses across the synaptic cleft to bind to its receptor.

Resulting action potential leads to muscle contraction.

The neurotransmitter is cleared from the synapse either by enzymatic degradation or neuronal reuptake.