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22 Cards in this Set
- Front
- Back
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Two types of neuron |
Motor and sensory |
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Structure of a neuron |
dendrites, cell body Soma, axon hillcock, axon, myelin sheath, nodes or ranvier, presynaptic terminal, |
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What are dendrites |
tree like fibres that are lined with specialized synaptic receptors which helped them receive messages from other neurons. Dendrite spines allow them to cover more area and receive more information |
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What is the cell body or Soma |
Contains nucleus, ribosome, and mitochondria. majority of metabolic work occurs here, and is covered with receptors. |
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What is the Axon |
Thin fibre of constant diameter butt varying lengths that sends impulses from cell body to neurons, organs, and muscles. Only one per neuron. |
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Afferent vs. Efferent vs. Intrinsic neuron |
One brings information to the structure, sensory neurons are afferent to the rest of the system. One carries information away from structure.every neuron is afferent to one and efferent to another. Intrinsic or interneurons have cells axons and dendrites within a structure |
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What is a glia |
They are smaller cells than neurons and more numerous than neurons. There are five main types. Astrocytes, microglia, oligodendrocytes, Schwann, and radial. |
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What are Astrocytes |
Type of glial cell that wraps around presynaptic terminals shielding synapse from chemicals. They take up ions from the axon and regulate activities so it comes in waves. They eliminate waste and synapses that are no longer in use. They are the equivalent of a bouncer at a club door. |
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What is a microglia |
A type of glial cell that functions as part of our immune system removing waste, viruses, and fungi from the brain. They proliferate increase in speed post brain damage and in most brain diseases. They also remove week synapses. They are the equivalent of a nurse on an emergency Ward |
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Oligodendrocytes and Schwann cells. |
1. In spinal cord 2. Periphery of the body they build the myelin sheath, insulate vertebrate axon, and supply nutrients to the Axon. They are like a tutor making you work more efficiently. |
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What is the radial glia |
Guide the migration of neurons and axons during embryonic development,and when this ends most become neurons, son becoming astrocytes, and some becoming oligodendrocytes |
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What is the blood-brain barrier and what is its use |
- inhibits dangerous chemicals from reaching the brain. - vertebrate brain does not replace all damaged cells in the immune system cannot fight off all cells, there for the blood-brain barrier is necessary to inhibit the rest. |
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What is the resting potential |
The stable reoccuring electrical charge that a neuron consistently returns to post electrical charge. The average resting potential is -70mV. At this charge the neuron is not sending information, but is available to. |
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Explain the chemical exchange in a resting potential neuron |
sodium and potassium are positively charged, and the inside of the neuron is negatively charged, therefore the inside a truck sodium and potassium into the neuron. The negativecharge inside the neuron is maintained because sodium-potassium pumps regulate what comes in and what goes up.the gate is only effective because the membrane around the neuron is selectively permeable |
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What is an action potential |
A message sent along the axon from the dendrites.if enough positive current is added to the axon, then the resting potential gets closer to the threshold, and if it is stimulated beyond the threshold and action potential occurs, which means a message is sent to the following neuron. |
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What is hyperpolarization |
When a negative current is sent through the axon and the resting potential goes below resting potential. This is further from the threshold. |
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What is depolarization |
When a positive current is sent down the Axon bringing it's charge closer to or surpassing threshold |
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Three parts of the molecular basis of action potential |
1. Sodium ions are mostly outside, potassium mostly inside. 2. when membrane is depolarized, sodium and potassium channels in the membrane open 3. at the peak of action potential the sodium Channel closes. |
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What is the all-or-none law |
the intensity and velocity of an action potential is the same regardless of stimuli. Although action potentials are consistent for each axon, they vary across axons example thicker axons convey a message at greater velocity |
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What two parts of the refractory period |
First the absolute refractory period: immediately after an action potential, no stimulation cause another action potential. Then, relative refractory period : still below resting potential, but closer than the absolute refractory period, Stronger than usual stimuli can trigger another action potential |
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Propogation of an action potential (how the action potential travels along the axon |
the flow of ions trigger move it meant down the axon, and it is the refractory. That stops cats that were just closed from reopening. Allowing the action potential to make its way to the end of the Axon.it is possible for the action potential to flow in the wrong direction, but it cannot flow back and forth down an axon |
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Four steps to action potential |
Channels open when depolarized Sodium channels shut at peak Hyperpolarization Potassium channels shut soon after |
