45. Nervous System
Neurons and Action Potentials
- Textbook QuestionUsing microelectrodes, a researcher recorded nerve signals in four neurons in the brain of a snail, called A, B, C, and D in the table below. A, B, and C can all transmit signals to D. In three experiments, the animal was stimulated in different ways. The number of nerve signals transmitted per second by each of the cells is recorded in the table. Write a short paragraph explaining the different results of the three experiments.1087views
- Textbook Question
Explain why drugs that prevent neurotransmitters from being taken back up by a presynaptic neuron have dramatic effects on the activity of postsynaptic neurons.
822views - Textbook Question
Certain species of frogs in the genus Phyllobates have a powerful defensive adaptation—their skin can secrete a milky fluid that contains an extremely toxic compound called batrachotoxin (BTX). These frogs, which are found in Colombia, are known as poison dart frogs because some indigenous Colombian hunters coat the tips of their blowgun darts with the frogs' skin secretions. An animal hit by one of these darts dies quickly.
What is the mechanism of action of BTX? The graph here shows the effect of BTX on the membrane potential of a squid giant axon.
Which of the following is the most likely explanation for the effect of BTX on the squid giant axon?
a. Inactivation of Na+/K+-ATPase
b. Closing of sodium channels
c. Opening of sodium channels
d. Opening of potassium channels
778views - Textbook Question
Certain species of frogs in the genus Phyllobates have a powerful defensive adaptation—their skin can secrete a milky fluid that contains an extremely toxic compound called batrachotoxin (BTX). These frogs, which are found in Colombia, are known as poison dart frogs because some indigenous Colombian hunters coat the tips of their blowgun darts with the frogs' skin secretions. An animal hit by one of these darts dies quickly.
What is the mechanism of action of BTX?
Identify a research technique that could be used to discover how BTX affects specific membrane proteins.
Based on the graph in Question 11, what would you expect this technique to show?
555views - Textbook Question
Certain species of frogs in the genus Phyllobates have a powerful defensive adaptation—their skin can secrete a milky fluid that contains an extremely toxic compound called batrachotoxin (BTX). These frogs, which are found in Colombia, are known as poison dart frogs because some indigenous Colombian hunters coat the tips of their blowgun darts with the frogs' skin secretions. An animal hit by one of these darts dies quickly.
What is the mechanism of action of BTX? As the graph in Question 11 shows, BTX depolarizes the membrane and prevents repolarization.
What effect would this have on electrical signaling by the nervous system?
816views - Textbook Question
Certain species of frogs in the genus Phyllobates have a powerful defensive adaptation—their skin can secrete a milky fluid that contains an extremely toxic compound called batrachotoxin (BTX). These frogs, which are found in Colombia, are known as poison dart frogs because some indigenous Colombian hunters coat the tips of their blowgun darts with the frogs' skin secretions. An animal hit by one of these darts dies quickly.
What is the mechanism of action of BTX?
Like neurons, cells in skeletal and cardiac muscle also produce action potentials. Create a concept map showing how BTX could kill a mammal through its effects on nervous and muscle tissues.
619views - Textbook Question
Certain species of frogs in the genus Phyllobates have a powerful defensive adaptation—their skin can secrete a milky fluid that contains an extremely toxic compound called batrachotoxin (BTX). These frogs, which are found in Colombia, are known as poison dart frogs because some indigenous Colombian hunters coat the tips of their blowgun darts with the frogs' skin secretions. An animal hit by one of these darts dies quickly.
What is the mechanism of action of BTX?
Although BTX is a powerful antipredator poison, one snake species in Colombia eats poison dart frogs. Suggest a hypothesis that might explain how the snake is resistant to the toxin.
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