Exam 48: Neurons, Synapses, and Signalling

An inhibitory postsynaptic potential (IPSP) occurs in a membrane made more permeable to ________.

Which of the following ions is most likely to cross the plasma membrane of a resting neuron?

Suppose a particular neurotransmitter causes an IPSP in postsynaptic cell X and an EPSP in postsynaptic cell Y. A likely explanation is that

What would probably happen if a long neuron had one continuous myelin sheath down the length of the axon with no nodes of Ranvier?

A neurophysiologist is investigating nerve reflexes in two different animals: a crab and a fish. Action potentials are found to pass more rapidly along the fish's neurons. What is the most likely explanation?

The activity of acetylcholine in a synapse is terminated by its ________.

In a simple synapse, neurotransmitter chemicals are released by ________.

Neurotransmitters are released from axon terminals via ________.

The motor (somatic nervous) system can alter the activities of its targets, the skeletal muscle fibres, because ________.

In a simple synapse, neurotransmitter chemicals are received by ________.

A graded hyperpolarisation of a membrane can be induced by ________.

At the neuromuscular junction, the neurotransmitter acetylcholine (ACh) is degraded by acetylcholinesterase. If a neurophysiologist applies the naturally occurring acetylcholinesterase inhibitor, onchidal (produced by the mollusc Onchidella binneyi), to a synapse, what would you expect to happen?

Conduction and refractory periods (states) are typical of ________.

Refer to the following graph of an action potential to answer the question. The membrane potential is closest to the equilibrium potential for potassium at label ________.

What happens if twice as many inhibitory postsynaptic potentials (IPSPs) as excitatory postsynaptic potentials (EPSPs) arrive in close proximity at a postsynaptic neuron?

Which of the following statements about action potentials is correct?

Tetrodotoxin blocks voltage-gated sodium channels, and ouabain blocks sodium-potassium pumps. If you added both tetrodotoxin and ouabain to a solution containing neural tissue, what responses would you expect?

What happens when a resting neuron's membrane depolarises?

Refer to the following graph of an action potential to answer the question. At label ________, the cell is not hyperpolarised; however, repolarisation is in progress, as the sodium channels are inactivated or becoming inactivated, and many potassium channels have opened.

Acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium/potassium channel and opens it. This is an example of ________.