Neural Control and Coordination

Topics in this chapter

• Neural Impulses and Conduction
• Synapses and Neuromuscular Signalling
• Reflex Arcs and Spinal Pathways
• Vision and Optical Accommodation
• Hearing and Vestibular Equilibrium
• Brain, Autonomic and Homeostatic Control

Cheat sheet

Practice questions

1. Question 1Q-E12457

   Which sequence correctly describes the major ionic events during an action potential in a neuron?

   1. A.Opening of voltage-gated K+ channels followed by Na+ influx and depolarisation
   2. B.Opening of voltage-gated Na+ channels, Na+ influx and depolarisation, followed by K+ efflux and repolarisation
   3. C.Na+ efflux followed by K+ influx, causing depolarisation
   4. D.Simultaneous opening of Na+ and K+ channels causes only hyperpolarisation
   See the answer and solution
2. Question 2Q-1DC3E1

   A drug selectively blocks voltage-gated Ca2+ channels in the presynaptic membrane of a chemical synapse. What is the most immediate consequence when an action potential reaches the axon terminal?

   1. A.The action potential cannot travel along the axon
   2. B.Synaptic vesicles cannot release neurotransmitter into the synaptic cleft
   3. C.The postsynaptic membrane remains permanently depolarised
   4. D.The neurotransmitter is released continuously without stimulation
   See the answer and solution
3. Question 3Q-1F6715

   Damage to which part of the human brain would most directly impair the maintenance of posture, balance and coordination of muscular activity?

   1. A.Cerebellum
   2. B.Hypothalamus
   3. C.Medulla oblongata
   4. D.Corpus callosum
   See the answer and solution
4. Question 4Q-30CAFF

   When the human eye changes its focus from a distant object to a nearby object, which change occurs?

   1. A.Ciliary muscles relax and the lens becomes flatter
   2. B.Ciliary muscles contract and the lens becomes more convex
   3. C.Suspensory ligaments become taut and the lens becomes more convex
   4. D.The pupil dilates and the focal length of the lens increases
   See the answer and solution
5. Question 5Q-BFFCA4

   In a myelinated axon, rapid conduction of an action potential is mainly due to:

   1. A.Continuous depolarisation along the entire axonal membrane
   2. B.Saltatory conduction of the impulse between successive nodes of Ranvier
   3. C.Movement of neurotransmitters through the myelin sheath
   4. D.Absence of ion channels at the nodes of Ranvier
   See the answer and solution