Transcript Synapse - Mayfield City Schools

Read page 424-425 on
drugs and the brain
What 3 major concepts should we
study to understand this article
further?
Synapse
sin-aps, si-naps
Synapse
(noun) Small gap between nerve
cells
Use in a sentence: A synapse is
cool.
Neurotransmitters and
The Synapse
 Synapse:
unique junction that mediates
information flow from one neuron to
another or effector cell… huh?
 Most
synapses occur between axon of one
nerve and the dendrite of another… BUT
Pre vs Post
Presynaptic neuron- carries impulse towards
a synapse “Sender”
Postsynaptic neuron- carries impulse away
from a synapse “receiver”
 TWO
TYPES:
 A. electrical synapse
B.
chemical synapse
Electrical Synapse
 Allow
current carrying ions to flow directly
from one neuron to the next
 Found
 Most
in the brain, limited in adulthood
are replaced by chemical
synapses
Chemical Synapses
 -release/reception
of neurotransmitters
 Neurotransmitters
act to open/close ion
channels
Anatomy of the chemical synapse

axonal terminal
synaptic vesicles
receptor region
synaptic cleft
Information Transfer Across
Chemical Synapses
 1.
Calcium gates open in the presynaptic
axonal terminal
 Depolarization
causes voltage-gated Ca2+
channels to open
 2.
Neurotransmitter is released
Direct result of calcium being present
Exocytosis
 3.
Neurotransmitter binds to post-synaptic
receptors
 4.
Ion channels open in the post-synaptic
membrane Boom!
Neurotransmitters
-language of the nervous system
-50 known NT
Classification
1. Acetylcholine (ACh)
-first identified, best understood
2. Biogenic Amines
Include: dopamine, norepinephrine and
epinephrine, histamine and serotonin
3. Amino Acids
4. Peptides (neuropeptides)
substance P, endorphins,
5. Novel Messengers
ATP
Nitric Oxide
Carbon Monoxide
Synthesis of Neurotransmitters