U6T6 – Nerves: Synaptic Transmission

Using the diagram, name C

Using the diagram, name E

Using the diagram, name D

Using the diagram, name B

On the diagram, F is a voltage gated ion channel on an excitatory synapse, but which type of ion does it allow through?

On the diagram, which type of ion will D allow through when opened on an excitatory synapse?

Put the following statements in order to explain what happens at an excitatory synapse:

• a) Voltage gated calcium channels open.
• b) Synaptic vesicles fuse with the pre-synaptic membrane
• c) If threshold is reached, an action potential is generated
• d) Calcium ions diffuse into the presynaptic neurone.
• e) Arrival of an action potential
• f) Neurotransmitters bind to receptors with associated sodium channels
• g) Neurotransmitters diffuse across the cleft
• h) Sodium ions diffuse into post synaptic membrane

True or False: Synapses can only transmit an impulse in one direction?

What reduces the concentration of neurotransmitter in a synapse after it has diffused across?

Whether a synapse is excitatory or inhibitory depends on what?

What effect do inhibitory synapses have on the post-synaptic membrane?

If a neurotransmitter binds to the post synaptic membrane and causes potassium ion channels to open, would it be excitatory or inhibitory?

If the concentration of neurotransmitter secreted is very low, then threshold may not be reached. What term describes the process of increasing neurotransmitter release? either by multiple presynaptic neurones forming a single synapse or increasing the frequency of neurotransmitter release. Type your answer

What term is used to describe when more than one presynaptic neurone releases its neurotransmitter onto single post-synaptic neurone? ( Type your answer carefully)

What term is used to describe when more than one presynaptic neurone releases its neurotransmitter onto single post-synaptic neurone? ( Type your answer carefully)

Dopamine is a neurotransmitter which has a role in numerous processes in the brain including pain relief. The release of dopamine can be stimulated by chemicals called endorphins produced in the brain. Endorphins attach to opioid receptors on presynaptic neurones that release dopamine. Morphine is a drug that has a similar structure to endorphins and can provide pain relief, explain how.

GABA is a neurotransmitter released in some inhibitory synapses in the brain. GABA causes negatively charged chloride ions to enter postsynaptic neurones. Explain how this inhibits postsynaptic neurones

Synaptic knobs contain mitochondria, which of the following is NOT a use of ATP in the presynaptic neurone?

Doctors investigated two ways of measuring the effect of general anaesthetics. In one method they timed how long it took to stop blinking, and then repeated the investigation using a machine to record when brain activity showed they were unconscious. Blinking involves cholinergic synapses. Anaesthetic S is a similar shape to acetylcholine. Suggest how anaesthetic S stops the transmission across the synapse.

The table shows the results on investigating how fast an anaesthetic works. Using the results from the machine, was there a significant difference between anaesthetics S and Q?