Neurons

The ratio between extracellular and intracellular K+ concentration:

• will cause hyperpolarisation of resting membrane potential if intracellular K⁺ concentration increases:

• is the main factor controlling neuronal resting membrane potential

• has little effect on neuronal resting membrane potential

• will cause depolarisation of resting membrane potential if extracellular K⁺ concentration decreases

• is able to vary freely in brain tissue

Complete the following statement with the CORRECT ending. The dendrites of neurons are:

• where action potentials are initiated

• where neurotransmitters are released onto other neurons

• uniform in length

• myelinated

• where neurotransmitters are received by neurons

Which of the following statements about chloride-dependent synaptic inhibition is INCORRECT?

• Chloride-dependent synaptic inhibition always causes membrane hyperpolarisation

• GABAA receptor activation opens chloride ion channels

• Synaptic inhibition at the soma is more effective at preventing action potentials than synaptic inhibition on distal dendrites

• Glycine receptor activation opens chloride ion channels

• The reversal potential for chloride-dependent inhibitory postsynaptic potentials (IPSPs) can be more positive or more negative than the resting membrane potential

How would the amplitude time and course of the action potential change if voltage-gated Na⁺ channels did not undergo fast inactivation?

• The action potential would get smaller and briefer

• The action potential would get taller and briefer

• The action potential would get taller and wider

• The action potential would get smaller and wider

• The action potential would not change at all

Which of these statements about neuronal axons is CORRECT?

• Axons with a larger diameter have slower conduction velocity than those with a small diameter

• Voltage-gated sodium channels are concentrated at nodes of Ranvier

• Unmyelinated axons have faster conduction velocity than myelinated axons

• Nodes of Ranvier are present in unmyelinated axons

• Myelinated axons have voltage-gated sodium channels distributed evenly along their length

  
  

Which of these statements about electrical and chemical neurotransmission is CORRECT?

• Electrical neurotransmission is bi-directional, whereas chemical neurotransmission is one way

• Chemical neurotransmission is more reliable than electrical neurotransmission

• Electrical neurotransmission can be modulated in many ways, and chemical neurotransmission has limited mechanisms for modulation

• Chemical, but not electrical, neurotransmission is found in fetal brain tissue

• Electrical neurotransmission is slow compared to chemical neurotransmission

Which of the following is NOT an amine neurotransmitter?

• histamine

• glycine

• noradrenaline

• dopamine

• acetylcholine

Synaptically-released glutamate can activate alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptors. The synaptic responses produced by these receptors can differ. Which of the following statements about AMPA and NMDA receptor-mediated responses is CORRECT?

• AMPA and NMDA responses are not voltage-dependent

• AMPA and NMDA responses both desensitize rapidly

• AMPA responses rise and decay more rapidly than NMDA responses

• NMDA responses do not allow postsynaptic Ca²⁺ influx, while AMPA responses do allow postsynaptic Ca²⁺ influx

• AMPA and NMDA responses cannot occur at the same synapse

Long term potentiation (LTP) at the CA1 to CA3 synapse in the hippocampus is dependent on:

• activation of NMDA receptors on the postsynaptic neuron

• a decreased intracellular Ca²⁺ concentration in the postsynaptic neuron

• low frequency stimulation of presynaptic axons

• hyperpolarisation of the postsynaptic neuron

• activation of metabotropic glutamate receptors

Which of the following does NOT belong to the ligand-gated ion channel family?

• GABAA receptor

• Nicotinic acetylcholine receptor

• 
  Glycine receptor

• AMPA glutamate receptor

• Muscarinic acetylcholine receptor