11. Nervous Tissue and Nervous System

Casey is taking a new medication that blocks potassium channels. What stage of an action potential would be MOST affected by this drug? 

In the CNS, a neuron typically receives information from other neurons at its:

(a) Axon

(b) Nissl bodies

(c) Dendrites

(d) Nucleus

Explain what would happen if depolarization of the trigger zone led to a negative feedback loop instead of a positive one.

What happens when the neuron reaches threshold (-55 mV)?

Describe the three components of the neuromuscular junction.

During a surgical procedure, an anesthesiologist administers to the patient an inhaled anesthetic agent that opens Cl⁻ channels in the postsynaptic membranes of neurons in the brain. Explain why this would put the patient 'to sleep' for the duration of the surgical procedure.

Rochelle developed multiple sclerosis when she was 27. After eight years she had lost a good portion of her ability to control her skeletal muscles. How did this happen?

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

The Na⁺/K⁺ pumps and gated channels maintain the Na⁺ and K⁺ gradients necessary for action potentials to occur.

Predict the effect that tetrodotoxin would have on Albert's muscle fiber action potentials (see question 3). Would it affect end-plate potentials at the motor end plate? Why or why not?

The drug neostigmine blocks the actions of acetylcholinesterase in the synaptic cleft. What effect would this have on synaptic transmission? What effects might you expect to see as a result of this drug?

When admitted to the emergency room, Sean was holding his right hand, which had a deep puncture hole in its palm. He explained that he had fallen on a nail while exploring a barn. Sean was given an antitetanus shot to prevent neural complications. Tetanus bacteria fester in deep, dark wounds, but how do their toxins travel in neural tissue?

Albert accidentally ingests the poison tetrodotoxin from the pufferfish, which you know blocks voltage-gated Na⁺ channels. Predict the symptoms Albert will experience from this poisoning.