BI 121 HW #10 Questions with 100% Correct
Answers
Briefly explain how nerve impulses are initiated
Impulses are initiated either by the binding of neurotransmitter to Na+ channel proteins on
the dendrites or cell body of a neuron, or by an environmental stimulus at a sensor receptor.
In both cases, the result is that Na+ ion channels are stimulated to open.
Briefly explain how nerve impulses are transmitted
The opening of Na+ channels in one region causes Na+ to flow in, causing membrane
depolarization as the electrical charge inside the cell jumps from slightly negative to positive.
This spike in electrical charge stimulates neighboring Na+ channels to open, and the
depolarization continues to the neighboring area. As this depolarization of the membrane (the
"action potential") propagates from one area to another, it is transmitted from its source down
the axon of the neuron.
Why conduction at synapses is always one-way.
Conduction at synapses is always one way because, at each synapse, only one neuron has
neurotransmitter (which is released into the synaptic cleft), while the other has the
neurotransmitter receptors that open Na+ ion channels. Therefore, the transmission can never
be in the opposite direction.
What is a major function of the pons
The pons has important cell bodies (nuclei) that regulate breathing
Why is the medulla the most vital part of the brain
Answers
Briefly explain how nerve impulses are initiated
Impulses are initiated either by the binding of neurotransmitter to Na+ channel proteins on
the dendrites or cell body of a neuron, or by an environmental stimulus at a sensor receptor.
In both cases, the result is that Na+ ion channels are stimulated to open.
Briefly explain how nerve impulses are transmitted
The opening of Na+ channels in one region causes Na+ to flow in, causing membrane
depolarization as the electrical charge inside the cell jumps from slightly negative to positive.
This spike in electrical charge stimulates neighboring Na+ channels to open, and the
depolarization continues to the neighboring area. As this depolarization of the membrane (the
"action potential") propagates from one area to another, it is transmitted from its source down
the axon of the neuron.
Why conduction at synapses is always one-way.
Conduction at synapses is always one way because, at each synapse, only one neuron has
neurotransmitter (which is released into the synaptic cleft), while the other has the
neurotransmitter receptors that open Na+ ion channels. Therefore, the transmission can never
be in the opposite direction.
What is a major function of the pons
The pons has important cell bodies (nuclei) that regulate breathing
Why is the medulla the most vital part of the brain
