True/False | Answer |
The output of a neuron is a binary signal. | True, the output is all or nothing. Intensity of a stimulus is coded by the frequency of the firing neuron. |
Projection neurons typically have short axons. | False, projection neurons (Golgi type I neurons) have long axons which enable them to influence distant cells within the nervous system. |
The resting neuron contains a higher concentration of potassium within the cell compared with the outside. | True, in addition, the resting cell contains far less sodium than outside. |
The equilibrium potential for potassium is -74.8 V. | False, the equilibrium potential for potassium is -74.8 mV. |
The smaller the axonal diameter, the faster an action potential travels along the axon. | False, the larger the diameter of the axon, the lower the internal resistance and the faster the action potential travels. |
The majority of synapses in the nervous system are electrical. | False, the majority of synapses are chemically operated. |
In an electrical synapse there is cytoplasmic continuity between cells. | True, as opposed to chemical synapses where there is no such continuity. |
Typically, the distance between cells at an electrical synapse is less than that at a chemical synapse. | True, the space between cells of an electrical synapse is approx. 2nm whereas the distance between cells of a chemical synapse is approx. 30-50nm. |
Electrical synapses are invariably unidirectional. | False, electrical synapses may work one way or both ways. Chemical synapses are one way. |
Axosomatic synapses are usually inhibitory. | True, when axosomatic synapses are placed close to the axon hillock, they inhibit firing more efficiently than an axodendritic synapse. |
Noradrenaline is the neurotransmitter at the neuromuscular junction. | False, acetylcholine is the neurotransmitter at the neuromuscular junction and also at many synapses in the autonomic nervous system. |
Glutamate and aspartate are examples of excitatory amino acid neurotransmitters. | True, there are two main types of glutamate receptor, AMPA and NMDA. |
Neuropeptide-Y is an example of an inhibitory amino acid neurotransmitter. | False, neuropeptide-Y is a peptide neurotransmitter. Examples of inihibitory amino acid neurotransmitters include GABA and glycine. |
Myasthenia gravis is a condition caused by antibodies to the pre-synaptic acetylcholine receptor. | False, myasthenia gravis is caused by antibodies to the post-synaptic acetylcholine receptor. |
Myasthenia gravis can be diagnosed by improvement of symptoms when given a short-acting anticholinesterase. | True, this is called the Tensilon test. |
C fibres are myelinated. | False, C fibres are unmyelinated. |
Information from nociceptors is transported in A delta and C fibres. | True, information from cold thermoreceptors is also transmitted in A delta fibres. |
Proprioceptive information is carried in A delta fibres. | True, these fibres have a large axonal diameter (20 micrometers) and a high conduction speed (120 m/s). |
A beta fibres are unmyelinated. | False, A alpha fibres are myelinated. |
C fibres have a higher conduction velocity than A alpha fibres. | False A alpha fibres have a higher conduction velocity than C fibres because they are myelinated. |