Nervous System: Effects of Chemical Factors on Neural Activity

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What is the primary mechanism of action of local anaesthetics?

Stimulation of ACh release
Inhibition of ACh release
Blockage of voltage-gated Na+ channels (correct)
Inhibition of acetylcholinesterase

Which neurotoxin is obtained from a scorpion?

Maurotoxin (correct)
Organophosphates
Tetrodotoxin
Botulinum

What is the effect of neurotoxins on the nervous system?

Enhance normal nervous system functioning
Disrupt normal nervous system functioning (correct)
Increase acetylcholinesterase activity
Have no effect on nervous system functioning

What is the mechanism of action of botulinum toxin?

Inhibits ACh release (D) Signup and view all the answers

What is the mechanism of action of tetrodotoxin?

Blocks voltage-gated Na+ channels (D) Signup and view all the answers

What is the effect of organophosphates on the nervous system?

Inhibits acetylcholinesterase (B) Signup and view all the answers

What is the effect of a high blood K+ concentration on the resting membrane potential?

It becomes more positive (C) Signup and view all the answers

Which of the following neurotransmitters is NOT classified as an amine?

Acetylcholine (D) Signup and view all the answers

What is the effect of hypokalaemia on the firing of action potentials?

The cell requires a larger-than-normal stimulus to fire (C) Signup and view all the answers

Which neurotransmitter is classified as a purine?

ATP (D) Signup and view all the answers

What is the effect of hyperkalaemia on neurons?

They become more excitable (D) Signup and view all the answers

Which of the following is NOT a major group of neurotransmitters?

Hormones (A) Signup and view all the answers

What happens to the entire neuron if the cell body of a neuron dies?

The entire neuron dies (D) Signup and view all the answers

During Wallerian degeneration, what do Schwann cells do?

They proliferate to form a solid cord (D) Signup and view all the answers

What guides the growing tip of an axon during regeneration?

Neurotrophic factors secreted by Schwann cells (B) Signup and view all the answers

What is the primary basis for learning and recovery in the brain?

Synaptic plasticity (C) Signup and view all the answers

What is the outcome of axonal regeneration in the Central Nervous System (CNS)?

Axonal regeneration is inhibited by oligodendrocytes and astrocytes (B) Signup and view all the answers

Which of the following is a consequence of decreased synaptic plasticity?

Impaired recovery from brain injuries (C) Signup and view all the answers

What is the term for the proliferation of astrocytes that seal off and scar the damaged region?

Gliosis (A) Signup and view all the answers

What is the most vulnerable step in the neural signaling process?

Synaptic transmission (A) Signup and view all the answers

What is the difference between axonal regeneration in the PNS and CNS?

Axonal regeneration is inhibited in the CNS but not in the PNS (D) Signup and view all the answers

Why are synapses more accessible to drugs than intracellular receptors?

Because they are exposed to the extracellular fluid (ECF) (C) Signup and view all the answers

What is an example of a disorder caused by problems in synaptic transmission?

Parkinson's disease (B) Signup and view all the answers

What is the primary function of synaptic plasticity in terms of sensory input?

To increase existing synaptic efficiency (B) Signup and view all the answers