Quiz, quiz, trade
1. Look back at the synapse and transmission of a
nerve impulse sequence.
2. Write a question you can answer on a piece of
card (put the answer on the back)
3. Mix around the room with your hand up
4. High five the nearest person to you
5. Ask them your question1.
2.
3.
Correct? Praise them and answer their question
Not correct? Give them a hint...
Tell them the correct answer and ask them the
question again! Trade questions and find someone
new!
Drugs and synapses
WAL:
An overview of the synapse
•How is information
Some transmitted across a
synapse?
•What functions do synapses
Most perform?
All
•What is a synapse?
Starter – Quiz, quiz, trade
Write down a question and answer about the topic.
Today we are covering from the specification:
Pages 177-179 of your textbook
Missing Words
diffuse
bind
electrical
impulse
neurotransmitters
axon
neurone
1) An ________ impulse travels along an ________.
2) This triggers the nerve-ending of a neurone to release chemical messengers called
______________.
3) These chemicals __________ across the synapse (the gap) and __________ with
receptor molecules on the membrane of the next neurone.
4) The receptors on the second ________ bind only to the specific chemicals released
from the first neuron. This stimulates the second neuron to transmit the electrical
_________.
Neurotransmitters
• The process of information transmission we’ve
looked is an example of a Cholinergic synapse
• i.e. Acetylcholine neurotransmitter
• Acetylcholine acts as an excitatory
neurotransmitter at synapses connecting
motor neurones with skeletal muscle=
Neuromuscular junction
Neuromuscular Junctions
• Same stages as cholinergic
synapses,
• But in this case the
postsynaptic membrane is
the muscle fibre
membrane, (Sarcolemma).
• Neurotransmitter and
sodium ions leads to
depolarisation of the
sarcolemma.
• Which leads to contraction
of muscle fibre.
Neurotransmitters
• There are dozens of different
neurotransmitters (NT) in the neurons of the
body.
• NTs can be either excitatory or inhibitory
• Each neuron generally synthesizes and
releases a single type of neurotransmitter
• The major neurotransmitters are indicated on
the next slide. There are more types of
neurotransmitter than just acetylcholine...
Table of neurotransmitters
•
•
•
•
•
•
•
Dopamine
GABA
Serotonin
Acetylcholine
Glycine
Norepineprine
Dopamine
Drugs Interfere with Neurotranmission
• Drugs can affect synapses at a variety of sites
and in a variety of ways.
• Look at the structure of the synapse and
sequence of events across a synapse.
• What ways can you identify how drugs might
affect synaptic transmission?
Drugs interfere with neurotransmission
1. Increasing number of impulses
2. Release NT from vesicles with or without
impulses
3. Block reuptake or block receptors
4. Produce more or less NT
5. Prevent vesicles from releasing NT
Drugs (of many) which
affect Neurotransmission
•
•
•
•
LSD
Cocaine
Marijuana
Nicotine
Various effects of drugs on synapses:
DRUG ACTION
EFFECT
Mimic a neurotransmitter
Switch on a synapse
Stimulate the release of a
neurotransmitter
Switch on a synapse
Open a neuroreceptor
(protein) channel
Switch on a synapse
Block a neuroreceptor
(protein) channel
Switch off a synapse
Inhibit the breakdown
enzyme
Switch on a synapse
Block the Na+ or K+
channels
Stop action potentials
Drugs
• Drugs that stimulate a nervous system are called
AGONISTS
• Drugs that inhibit a nervous system are called
ANTAGONISTS.
• http://outreach.mcb.harvard.edu/animations/synap
se.swf
Neurotransmitters
http://www.vuutv.info/8ae947a3d8:sPLTLhWcgSo.ht
ml
Watch this video and answer the questions:
• What substance did the scientist find that was
affected by the drug chlorpromazine?
• What condition has dopamine been linked to?
• What condition has serotonin been linked to?
• What condition has acetylcholine been linked to?
Drugs and synapses
WAL:
An overview of the synapse
•How is information
Some transmitted across a
synapse?
•What functions do synapses
Most perform?
All
•What is a synapse?
Plenary– Mind map
Glossary
•
•
•
•
•
•
•
•
Synapse
Synaptic knob
Synaptic cleft
Synaptic vesicle
Neurotransmitter
Concentration gradient
Pre-synaptic neurone
Post-synaptic neurone
Glossary
•
•
•
•
•
•
•
•
Synapse- junction between two neurones
Synaptic knob- end of an axon, bulbous
Synaptic cleft- gap between neurones/target cell
Synaptic vesicle- membrane bound structures containing
neurotransmitter substances.
Neurotransmitter- hormone like substance that is released from
pre-synaptic neurone and diffuses across to post-synaptic
neurone/target cell
Concentration gradient- caused by differences in a substances
concentration
Pre-synaptic neurone- neurone sending the impulse
Post-synaptic neurone- neurone receiving the impulse