Anatomy of a Synapse
axondendrite synapse
Synapse at dendrite (axon to dendrite)
axosomatic synapse
Synapse at soma (axon to cell body)
synapse
a small gap at the end of a neuron that allows a signal to pass from one neuron to the next
Calcium (Ca2+)
in extracellular fluid
Chloride (Cl-)
in the extracellular fluid (which is in the synaptic cleft) (NOTICE HOW THIS IS negative)
Sodium (Na+)
mainly in extracellular fluid (which is in the synaptic cleft)
Potassium (K+)
mainly inside the cytoplasm
calcium protein channels
on sides of axon terminal
2 places where synapses occur
1) between a neuron and another neuron -synaptic Transmission 2) between a neuron and a muscle -neuromuscular Junction -very similar physiology
first steps of muscular contraction
1) nerve impulse sent to muscle from brain in order to tell muscel to contract 2) ACH is released which triggers a muscle impulse
CNS synapses
-axondendrite synapse -axosomatic synapse
presynaptic neuron
-first neuron -axon terminal -transfers information to next neuron
synaptic vesicles
-in the terminal axon, small membrane-enclosed spheres -store neurotransmitters
neurotransmitter junction
-nerve interaction with muscle -Ach (Acetylcholine) is the neurotransmitter that elicits the muscle to contract
protein channels
-on postsynaptic membrane -allow ions to enter
postsynaptic neuron
-second neuron -receives information from presynaptic neuron
synaptic cleft
-space between pre and postsynaptic neuron -filled with matrix, helps neurons adhere to each other
neurotransmitters
chemical that an axon end secretes to stimulate a muscle fiber OR a neuron to fire an action potential 2 types: -Stimulate: Ones that stimulate an action potential -Non-stimulate: Ones that do NOT stimulate an action potential