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21 Cards in this Set
- Front
- Back
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What are the three main parts of a neuron (nerve cell)? Describe them. |
the dendrites RECEIVE stimuli from other neurons or sensory receptors.
The cell body PROCESSES the stimulus. It contains a nucleus
The axons TRANSMITS stimuli to a gland, muscle, organ or other neuron |
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explain how nerve cells are "highly differentiated" |
it means that they have a finite number of times they can divide. after a certain point, they die. |
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How is the Myelin Sheath related to Multiple Sclerosis? |
MS is essentially a disease of the myelin sheath that causes loss of muscle function. it interrupts |
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Classify the nerves by the 2 functions: |
Sensory (afferent) Motor (efferent)
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What is a sensory of afferent neuron? |
Conducts action potentials from sensory receptors TOWARDS the CNS |
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What is motor or efferent neurons: |
They conduct action potentials FROM the CNS to the effector organs, such as muscles or glands |
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What are the sensory input? |
Sensory input is when the sensory receptors monitor numerous external and internal stimuli |
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What is integration? (in context of function of the nervous system) |
how the brain processes the information and decided what should be done at that immediate moment. (the info could be stored as a memory, produce an immediate response, or simply be ignored) |
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what is the ANS or autonomic nervous system? |
it transmits action potentials to cardiac muscle and smooth muscle, and glands. it is also called the involuntary nervous system |
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What are Neurons and Neoroglia and how do they differ? |
Neurons receive stimuli, conduct action potentials, and transmit signals to other neurons or effector organs (like muscles) Neuroglia are the "support system". they are not true neurons but help neurons function better. they are more numerous than neurons and are able to divide, where as neurons can't. |
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What is the refractory period? |
It is the period of depolarization of the neuron during which it cannot respond to a second stimulus |
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What is depolarization? |
It is the state in which the resting potential is reversed as sodium ions rush into the neuron |
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When is a cell membrane polarized? (the inside of the cell is more negatively charged than the outside of the cell) |
The cell is polarized when it is resting. This is also known as Resting Membrane Potential |
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What is Resting Membrane Potential? |
This is the natural "resting" state of a cell- when the cell membrane of a neuron is polarized. That means it is more negatively charged inside the cell that outside. |
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What 3 factors contribute to the resting membrane potential? |
there is more Potassium immediately INSIDE the cell membrane
There is more sodium immediately OUTSIDE the cell membrane
the cell membrane is more permeable to potassium than to sodium |
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what are leak channels? |
they are always open, allowing ions to "leak" across the cell membrane
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Why is the cell membrane more permeable to K+ than to Na+? |
because there are many more potassium leak channels than sodium leak channels (about 50-100 times more) |
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What are Gated Channels? |
the gated channels are closed until they are opened by specific signals. (either by neurotransmitter chemicals or by electrical change in membrane potential) |
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what is the function of the sodium potassium pump? |
it is meant to compensate for the constant leakage of potassium ions across the cell membrane. It helps maintain a greater concentration of sodium outside the cell, and a greater number of potassium inside the cell. |
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What is the function of astrocytes? |
they are the most abundant, and form the blood-brain barrier **they sort of look star shaped** |
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What is the function of ependymal cells? |
they produce and circulate cerebrospinal fluid (they are kind of square shaped and have cilia) |
