Set C

• What is involved in generation of the resting membrane potential in a neuron?

  Membrane permeability of potassium ions greater than sodium ions.

  Presence of negative charge proteins in the cytoplasm of the neuron.

  Efflux of potassium, influx of sodium ions.
• What happens during saltatory conduction?

  Action potentials occur at successive nodes along the length of the axon
• What influences time it takes for an action potential to pass from the axon hillock to the axon terminal?

  Presence/absence of nodes of Ranvier/myelin sheath

  length/diameter of axon
• What is the result of opening of sodium channels in the membrane of a neuron?

  Depolerisation
• What is opened when an action potential depolarizes the axon terminal?

  Voltage gated calcium channels
• What is the name of a neuron that has one dendrite leading to the cell body and one axon leaving the cell body?

  Bipolar
• Which part of the CNS regulates respiratory rhythm, blood pressure and vomiting?

  Brainstem
• What are areas of the cerebral cortex?

  Sensory cortex

  Motor cortex

  Visual cortex

  Auditory cortex
• Once an action potential is initiated, the first major electrial change occuring is?

  Reversal of membrane polarity and the inside of the neuron becomes positively charged
• Cholinergic synapses utilize which one of the following as a neurotransmitter?

  Acetylcholine
• Which one of the following pathways controls the function of the internal organs?

  Autonomic pathway
• Which part of the central nervous system is most associated with emotions?

  Limbic system
• In which part of the brain are the relay synapses found for sensory pathways that project to the sensory cortex?

  Thalamus
• EPSPs occur due to which one of the following?

  Influx of Na ions
• IPSPs are?

  Caused by K ion efflux
• The effect that a neurotransmitter has on a post-synaptic cell (excitatory or inhibitory), depends on which one of the following?

  the nature of its receptor
• A neuron that has one axon and one dendrite connected to the cell body is called what?

  Bipolar neuron
• Which of the following substances will act on muscarinic receptors to decrease the heart rate?

  Acetylcholine
• What will affect the conduction velocity of an action potential in a neuron?

  Temperature change

  Presence of myelin around a neuron

  Differences in the diameter

  Exposure to a local anaesthetic
• If a neuron has a conduction velocity of 25 ms-1, how long would it take an action potential to travel 0.25 m?

  10 milliseconds
• Which one of the following has the fastest conduction velocity and axon diameter?

  A-alpha
• Which one of the following neurons is a slow conducting non-myelinated neuron?


  C
• Which of the following is a preganglionic autonomic neuron?


  B
• Which one of the following is true for neurons in a compound nerve?

  The diameter, presence of myelin and conduction velocities of the neurons are all variable
• hich of the following is NOT correct for adrenalin (Ad) compared to nor-adrenalin (Nor-Ad) at high doses?

  Ad and Nor-Ad both increase diastolic blood pressure
• Which one of the following is a hormone that will act on Beta-receptors to increase heart rate?

  Adrenaline
• What is the effect of increasing vagal tone?

  Slower heart rate
• When many excitatory potentials occur together a larger EPSP (excitatory post synaptic potential) is generated. What causes this generation?

  Spatial summation