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BioPsych Chapter 2 (Kalat Tenth Edition)
Terms in this set (72)
cell that carries messages throughout the nervous system
surface of a cell-structure that separates the inside of the cell form the outside environment. Composed of two layers of fat molecules that are free to flow around one another.
All Animals have a...
Most chemicals cannot cross membrane except..
protein channels that let..water, oxygen,sodium, potassium, calcium, chloride and other important chemicals pass.
structure the performs metabolic activities, providing the energy the cell requires.
where proteins are made
building materials for the cell and facilitate various chemical reactions .
network of thin tubes that transports newly synthesized proteins to other locations.
Receive excitation from other neurons along its dendrites and conducts impulses along its axon to a muscle.
specialized at one end to be highly sensitive to a certain type of stimulation (light sound, tough) Cell's soma located on a little stalk off the main trunk.
the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body. Lined with synaptic receptors.
The bigger the surface of dendrites..
more information it can receive.
short outgrowths that increase the surface area available for synapses.
n fiber of constant diameter, in most cases longer than the dendrites. Information sender of the neuron, conveying and impulse toward other neurons or orange or muscle.
Axons are covered with..
insulating material that cover vertebrate axons.
Nodes of Ranvier
interruptions in myelin sheath.
Invertebrate axons do not have..
the point from which the axon releases chemicals that cross through the junction between one neuron and the next
neuron that brings information into a structure. "Admits"
neuron that carries information away from a structure (Exits)
if cell's dendrites and axon are entirely contained within a single structure.
The shape of a given neuron determines..
its connections with other neurons and its contribution to the nervous system.
cells that support, nurture, and insulate neurons, remove debris when neurons die, enhance the formation and maintenance of neural connections, and modify neuronal functioning. Dont transmit information over long distances like neurons.
Types of Glia
Astrocytes, Microglia, Oligodendocytes, Schwann cells, Radial Glia.
Star shaped cells found throughout the CNS, cleaning up debris in the extracellular space and removing neurotransmitters from the synaptic cleft, connects neurons to nearby cappilaries, components of the blood-brain barrier
smallest neuroglial cells; phagocytic cells that enculf cellular debris, waste products and pathogens. increase in number as a result of infection or injury
help produce myelin sheath inside CNS. In brain and spinal cord.
Part of the neuron that produces the myelin sheath; functions in repair and regeneration of damaged nerves; wrap around the axon; aid the myelin in insulation
type of glia cells that guides the migration of neurons and the growth of their axons and dendrites during embryological development
Blood brain barrier
Blood vessels (capillaries) that selectively let certain substances enter the brain tissue and keep other substances out
Advantage/Disadvantage of Blood Brain Barrier
Advantage: Keeps out Viruses
Disadvantage: Keeps out most Nutrients.
The blood brain barrier depends on..
lipid solubility and arrangement of endothelial cells that form the walls of the capillaries.
What chemicals cross the blood brain barrier passively?
Small uncharged molecules such as oxygen and carbon dioxide. So do chemicals that dissolves in the fats of the membrane.
transport of a substance (as a protein or drug) across a cell membrane against the concentration gradient
What chemicals cross the blood brain barrier by active transport?
Glucose, amino acids, purines, choline, certain vitamins, iron, and a few hormones.
a simple sugar. The vertebrate neurons depend almost entirely on this for nutrition. It is because it is practically the only nutrient that crosses the blood brain barrier in adults. Exceptions to this rule are ketones(find of fat) but they are seldom available in large amounts.
many chronic alcoholics have a deficiency in vitamin B1, thiamine, a chemical that is necessary for the use of glucose.
Death of neurons. Severe memory impairment.
when a neuron is in polarization; more negative ions are inside the neuron cell membrane with a positive ions on the outside, causing a small electrical charge; release of this charge generates a neuron's impulse (signal/message)
difference in positive and negative charges across a membrane
difference in electrical charge between two locations. Neuron inside-slightly negative electrical charge with respect ot the outside, primarily bc of negatively charged proteins in cell
the difference in voltage in a resting neuron. The result of negatively charged ions in the cell.
selectively permeable membrane
some chemicals can pass more freely than others can. Is analogous to the blood-brain barrier
Sodium potassium pump
protein complex-repeatedly transports three sodium ions out of the cell while drawing two potassium ions in it
the difference in the concentration of molecules across the membrane.
Sodium Ions more concentrated..
outside the cell.
Potassium ions more concentrated..
inside the cell
*when membrane is at rest..
the concentration gradient tends to drive potassium ions out of the cell; the electrical gradient draws them into the cell. The sodium potassium pump also draws them into the cell.
a neural impulse; a brief electrical charge that travels down an axon. The action potential is generated by the movement of positively charged atoms in and out of channels in the axon's membrane.
The movement of the membrane potential of a cell away from rest potential in a more negative direction.
Threshold of excitation
the level an impulse must exceed to cause a neuron to fire. Neuron suddenly opens sodium channels and permits rapid flow of ions across membrane.
the process during the action potential when sodium is rushing into the cell causing the interior to become more positive
A depolarization that passes the threshold ..
produces an action potential.
Voltage gated channels
gated channel that depends on a change in electrical potential on the cell membrane
novocain and xylocaine, attach to the sodium channels of the membrane, preventing sodium ions from entering. In doing so the drugs block the action potentials. Prevents messages of pain being sent to the brain.
During the action potential..
sodium ions move into the cell. The voltage dependent sodium gates have opened, so sodium can move freely. Sodium is attracted to the inside of the cell by both an electrical and concentration gradient
After the peak of the action potential,
potassium ions exit the cell, driving the membrane back to the resting potential (The sodium potassium pump is not the answer here: it is too slow)
All or none law
principle that the action potential in a neuron does not vary in strength; the neuron either fires at full strength or it does not fire at all. Does not apply to dendrites.
when the cell resists the production of further action potentials right after experiencing an action potential.
Absolute refractory period
A period of time following an action potential during which no additional action potential can be evoked regardless of the level of stimulation. (usually because Na+ channel closed whle K+ efflux)
Relative refractory period
a period after firing when a neuron is returning to its normal polarized state and will fire again only if the incoming message is much stronger than usual
Refractory period has two mechanisms:
1.The sodium channels are closed.
2.Potassium is flowing out of the cell at a faster than usual rate.
where the action potential begins, a swelling where the axon exits the soma
Propagation for the action potential
describe the transmission of an action potential down an axon.
a fatty and protein substance that helps insulate neurons and speeds the transmission of nerve impulses
those covered with myelin sheath,. Found only in vertebrates, interrupted periodically by short sections of axon called nodes of Ranvier.
nerve impulse jumps from one node of sheath to next
Nodes Closer/ Nodes Farther
If the nodes were closer, the action potential would travel more slowly. If they were farther apart, the current might not be able to diffuse from one node to the next and still remain above the threshold, so the action potential might stop.
neurons without axons exchange information only with their closest neighbors and are therefore known as local neurons. Receives information from other neurons (Produce Graded Potentials)
membrane potentials that vary in magnitude without following the all-or none law.
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BioPsych Chapter 2 (Kalat Tenth Edition)
BioPsych Chapter 2 (Kalat Tenth Edition)
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