Biological psyc 2
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Biological psyc 2
What does a motor neuron do?
- it receives excitation from other neurons and conducts impulses from its soma in the spinal cord to muscle or gland cells
What do sensory neurons do?
- are specialized at one end to be highly sensitive to a particular type of stimulation, such as touch information in the skin
What are dendritic spines?
- short outgrowths that increase the surface area available for synapses
What is an afferent axon?
- axon that brings information into a structure
What is an efferent axon?
- an axon that carries information away from a structure
What is an interneuron or intrinsic neuron?
- when a cell's dendrites and axon are entirely within a single structure
What are the 5 different kinds of glia?
- schwann cells
- radial glia
What are astrocytes ?
- star-shaped glia that wrap around the presynaptic terminals of several axons, presumably a functionally related group.
- they take up chemicals released by those axons and later release them back to the axons, helping synchronize the activity of axons
What are microglia?
- very small glia cells that remove water material as well as viruses, fungi, and other microorganisms.
What are oligodendrocytes?
- glia cells that are in the brain and spinal cord that build the myelin sheaths that surrounds and insulates certain vertebrate axons
What are schwann cells?
- glia cells in the periphery of the body that build the myelin sheaths that surround and insulate certain vertebrate axons
What are radial glia?
- a type of astrocyte, they guide the migration of neurons and the growth of their axons and dendrites during embryonic development
What is the blood brain barrier?
- the mechanism that keeps most chemicals out of the vertebrate brain
What is active transport?
- a protein-mediated process that expends energy to pump chemicals from the blood into the brain
What is an electrochemical gradient?
- when there is a difference in electrical charge between the inside and outside of the cell
What is polarization?
- a difference in electrical charge between two locations
What is a resting potential?
- the difference in voltage in a resting neuron
What is the sodium-potassium pump?
- a protein complex that repeatedly transports three sodium ions out of the cell while drawing two potassium ions into the cell
What is a concentration gradient?
- the difference in distribution of ions across the membrane
How do local anesthetic drugs work?
- they attach to the sodium channels of the membrane, preventing sodium ions from entering, thus blocking action potentials
How do general anesthetics work?
- they decrease brain activity by opening certain potassium channels wider than usual, thus preventing most action potentials
What is the "all-or-none law"?
- the amplitude and velocity of an action potential are independent of the intensity of the stimulus that initiated it
What is the refractory period?
- a period during which it resists the production of further action potentials
What is the absolute refractory period?
- when the sodium gates are firmly