Inquiry to Life Chapter 17
The nerve impulse has a resting potential of what?
-65mL
When the sodium gates open, the membrane potential changes from what to what?
-65mV to +40mV
In a milunated action potential, gated ion channels are concentrated in what?
Nodes of Ranvier
What generates an action potential?
a threshold
What is an effector?
a type of muscle
If a threshold is reached in a nerve impulse, what occurs?
action potential
What does the myelin sheath do in the peripheral nervous system?
acts as an insulator
What do the potassium gates change the membrane potential charge to?
back to -65mV
What do motor neurons do?
carry messages from the CNS to an effector
Where are excitatory signals?
close to the firing
What is the function of the myelin sheath?
covers some axons
What are the three parts of a neuron?
dendrites, cell body, axon
What is the change from negative to positive charge mean?
depolarization
What does the peripheral nervous system consist of?
everything but the brain and spinal cord
true or false: The CNS tissue is only composed of gray matter
false
Where are inhibitory signals?
farther from the firing
What are the nodes of ranvier?
gaps in the myelin sheath
What does synaptic integration determine?
if an action potential will travel along an axon
Where are interneurons located?
in the CNS
Where is potassium located during resting potential?
inside
When action potential is prevented from moving backwards, the sodium potassium pump causes what to happen?
ions to restore to original positions
In milunated action potential, the Nodes of Ranvier do what, and what is the scientific name for this action?
jump from node to node and saltatory conduction
When sodium gates cannot open, it prevents the action potential from what?
moving backwards
What are the two main types of cells in the nervous system?
neurons and neurological cells
What occurs during a synapse?
neurons are separated by the synaptic cleft
What is the myelin sheath in the central nervous system formed by?
oligodendroglial cells
In a non-milunated action potential, the action potential travels down what?
one small segment at a time
In a refractory period, sodium gates cannot do what?
open
Where is sodium located during resting potential?
outside
What gates open second?
potassium gates
What are the two types of synaptic neurons?
presynaptic neurons and postsynaptic neurons
What do interneurons do?
recieve input from sensory neurons and other interneurons
As soon as action potential moves on, the previous section under-gos what?
refractory period
What is it called when something is brought back to its original polarity?
repolarization
What is the myelin sheath formed by in the peripheral nervous system?
schwan cells
What do sensory neurons do?
send messages to the CNS
What are the three classes of neurons?
sensory, interneurons, motor neurons
The membrane is somewhat permeable to what?
sodium and potassium
What are the two types of gated channel proteins required for action potential?
sodium and potassium gated channels
What gates open first?
sodium gates
What do neurological cells do?
support and nourish neurons
What is transmission across a synapse called?
synaptic integration
What does the central nervous system consist of?
the brain and spinal cord
What are the two anatomical divisions of the nervous system?
the central (CNS) and peripheral (PNS)
During synaptic integration, a single neuron can receive many signals from where?
the excitatory and inhibitory signals
The strong impulse does not change the rate of action potential, but it changes what?
the frequency of firing
Where does a neurotransmitter cross in a synapse?
the presynaptic membrane
How is resting potential maintained?
the sodium-potassium pump
What is synaptic integration?
the summing up of excitatory and inhibitory signals
What is the function of the sodium potassium pump?
to actively transport sodium and potassium in
What is the purpose to excitatory signals?
to depolarize
What is the purpose of inhibitory signals?
to repolarize
What do neurons do?
transmit nerve impulses
true or false: Gray matter is located on the surface layer of the brain and the central part of the spinal cord
true
true or false: White matter is located deep in the brain
true
true or false: White matter surrounds gray matter in the spinal cord
true
true or false: action potential travels faster in milunated action potential than non-milunated action potential.
true
true or false: there is little nerve regeneration in the CNS
true
When is the presynaptic membrane released?
when action potential reachers an axon terminal
