synaptic transmission Flashcards
what happens when an action potential reaches the end of the neurone
When an action potential arrives at the e n d o f a neurone, the information has to be passed on to the next cell
— this could be another neurone, a muscle cell or a gland cell
what is a synapse
A synapse is the junction between a neurone and another neurone,
or between a neurone and an effector cell, e.g. a muscle or gland cell.
what is a synaptic cleft
The tiny gap between the cells at a synapse is called the synaptic cleft.
what is a presynaptic neurone
a neurone before the synapse
what do presynaptic neurones contains
s a swelling
called a synaptic knob. This contains synaptic vesicles filled with
chemicals called neurotransmitters.
what happens when an action potential reaches the end of a neurone
it
causes neurotransmitters to be released into the synaptic cleft.
They diffuse across to the postsynaptic membrane (the one
after the synapse) and bind to specific receptors.
what happens when neurotransmitters bind to receptors
When neurotransmitters bind to receptors they might trigger an
action potential (in a neurone), cause muscle contraction
(in a muscle cell), or cause a hormone to be secreted (from a gland cell)
why does the impulse only travel in one direction (undirectional)
Because the receptors are only on the postsynaptic membranes, synapses make
sure impulses are unidirectional — the impulse can only travel in one direction.
why are neurotransmitters removed from the cleft
Neurotransmitters are removed from the cleft so the response doesn’t keep happening ,e.g. they’re taken back
into the presynaptic neurone or they’re broken down by enzymes (and the products are taken into the neurone).
what ends with “ine”
neuro transmitters
what are examples of some neurotransmitters
) There are many different neurotransmitters, e.g. acetylcholine (ACh) and noradrenaline.
what are cholinergic synapses
Synapses that use
acetylcholine are called cholinergic synapses.
what are all the constituents of a synapse
synaptic knob, post synaptic membrane, presynaptic membrane, synaptic cleft, receptors, vesicle filled with neurotransmitters
what does ACh transmit
ACh Transmits the Nerve Impulse Across a Cholinergic Synapse
what is step 1 of a nerve impulse transmitting across a cholinergic synapse
An action potential arrives
at the synaptic knob of the presynaptic neurone