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