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267 Cards in this Set
- Front
- Back
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What is the key ingredient in the cytosol, intracellular and extracellular fluid? |
water |
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Is water polar/nonpolar and what types of bond bind it together/ |
polar covalent |
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what are atoms or molecules with a net electrial charge called? |
ions |
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cations have a net (positive or negative) charge |
net positive charge |
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anions have a net (positive or negative) charge |
negative |
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what three ions are in the cytosolic and extracellular fluid |
cations, anions, and spheres of hydration |
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What makes up the phospholipid membrane? |
hydrophilic compounds hydrophobic compounds |
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why do hydrophilic compounds dissolve in water? |
due to an uneven electrical charge |
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why do hydrophobic compounds not dissolve in water |
due to an even electrical charge |
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lipids are hydrophobic t/f |
true |
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The polar head of the phospholipid bilayer is ______ the nonpolar tail is _________ |
hydrophilic hydrophobic |
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Molecules assembled from amino acids |
proteins |
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what do proteins make? |
enzymes, cytoskeletal elements, receptors |
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special proteins that span the phospholipid bilayer control what? |
resting and action potentials |
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Protein structure includes |
amino acids and alpha carbon and R groups peptide bonds polypeptides |
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what are the four levels of protein structure |
primary secondary tertiary quaternary |
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What is the term for "only ions that are allowed to pass will pass" |
ion selectivity |
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Briefly descriped gated channels |
the channels will either be closed, open, or inactivated. This will depend on the distribution of charges |
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What are ion pumps formed by |
membrane-spanning proteins |
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Ion pumps use energy from ATP breakdown for ______ _______ |
neuronal signaling |
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ion pumps will pump a substance ie potassium towards or against their chemical gradient? |
against |
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Ions flow down the concentration gradient when: |
channels are permeable to specific ions concentration gradient exists across the membrane |
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definition: Going down the chemical gradient until it reaches equilibrium |
diffusion |
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what influences ion movement
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electrical current (I)
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What is the difference in charge between anodes and cathodes? |
Electrical potential (voltage-V) |
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What is the ability of an electrical charge to migrate from one point to another. |
electrical conductance. Itdepends of number of ions and how easily they travel and resistance (R),inability of electrical charge to migrate |
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the term that explains how easy the ions are flowing from one side to the other |
conductance |
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Ohms law I=gV explains |
electrical current flow across a membrane |
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The voltage across the neuronal membrane at any moment |
membrane potential |
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equilibrium potential example |
a salt solution is dissolved inside of the cell consisting of K+ and A-. there is no movement of ions outside of the cell because of the phospholipid bilayer. Imagine a potassium channel opens in the bilayer. K+ would then begin to flow outside of the cell leaving A- behind. The inside of the cell becomes negative. As the inside becomes more negative the electrical forces will pull positively charged K+ ions back through the channels to counterbalance the force of diffusion pushing them out. Thus an equilibrium state is reached where the diffusional and electrical forces are equal and opposite |
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The electrical potential difference that exactly balances an ionic concentration gradient |
equilibrium potential
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Four important points of equilibrium potential |
1. large changes in membrane potential are caused by minuscule changes in ionic concentration 2. the net difference in electrical charge occurs at the inside and outside surfaces of the membrane 3. Ions are driven across the membrane at a rate proportional to the difference between the membrane potential and the equilibrium potential 4. If the concentration difference across the membrane is known for an ion, the equilibrium potential can be calculated for that ion. |
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The inside of the cell is more + or - |
+ |
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Sodium and calcium are more concentrated ______ the cell than _______ the cell at resting membrane potential |
sodium and calcium are more concentrated outside of the cell than the inside of the cell at resting membrane potential. |
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The nernst equation calculates the exact value of the equilibrium potential for each ion in mV. What does it take into consideration? |
charge of the ion temperature ratio of the external and internal ion concentrations •Ek =61.54 mV X log [K]o /[K]i |
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K+ is more concentrated inside or outside of the cell? |
inside |
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Na+ and CA2+ are more concentrated inside or outside of the cell |
outside |
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explain the sodium potassium pump |
K+ is more concentrated inside of the cell and the leakage channels allow potassium to go out Na+ is more concentrated outside of the cell so leakage channels allow sodium to go in The pumps are pumping sodium from inside to outside and pumping potassium from outside to inside/going against chemical gradients |
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membrane permeability determines ______ ______ |
membrane potential |
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What equation takes into account the permeability of a membrane to different ions? on the exam she will give equation and all values, but ask how much more permeable one ion is vs the other. The Pk and PNa values should tell you. if Pk is 40 and PNa is 1 then potassium is 40X more permeable than Na |
goldman equation |
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Which protein contains the "legs" for retrograde passport |
dynein |
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what are all of the thin tubes that extend away from the soma? |
Neurites |
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What is the node of ranvier |
region where axonal membrane is exposed |
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Why are glia called the sleeping giants of neuroscience |
glia likely contribute to neuron processing |
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what does the cell theory state |
the elementary functional unit of all animal tissues is the individual cell |
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idenitfy the process of assembling a piece of mRNA that contains information about a gene |
transcription |
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which term refers to branches of an axon that returned to communicate with the cell that had given rise to them |
recurrent collaterals |
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Cytosol is the watery fluid inside the cell of a neuron enclosed by a neuronal membrane. WHat is the composition of the cytosol? |
potassium rich solution |
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Rough ER is an important site for protein synthesis. What is the special quality of Rough ER that neurons benefit from |
information processing |
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how do the glial cells contribute to brain function |
they insulate, support, and nourish neurons |
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if you wanted to study the structure of an entire neuron, which stain would you use? |
Golgi stain |
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cytoarchitecture is the arrangement of neurons in different parts of the brain. WHat stain could help you visualize this? |
Nissl Stain |
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what occurs in polymerization of microtubules? |
joining small proteins called tubulin |
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what makes the structure of neurofilaments particularly strong? |
strands are ropelike |
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What does the action potential in the nervous system do? |
conveys information over long distances reversal of charge relative to extracellular space neural code from frequency and pattern |
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What are other names for an action potential? ? |
spike nerve impulse discharge |
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what is used to study action potentials? |
oscilloscope |
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what are the the phases of an action potential? |
rising phase, overshoot, falling phase, undershoot |
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what happens during the rising phase
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depolorization of the membrane. |
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what happens during the overshoot of an action potential |
inside of the cell is more positive than outside of the cell |
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what happens during the falling phase |
rapid repolarization until the membrane is more negative than the resting potential. potassium VGC are delayed in comparison with sodium VGC. Sodium gated channels pause when they overshoot and potassium VGCs open. Potassium is then going outside of the cell. when this happens we have the falling phase |
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what happens during the undershoot phase of action potential. |
There is a gradual restoration of the resting potentialmore negative than the value at theresting membrane potential. This happens because of the potassium VGCs closingwith a delay (membranepotential becomes even more negative than resting membrane potential bc ofthe delay) |
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James was gettingout of his car. As he placed his foot down on a sharp object, he shrieked withpain and moved his foot up reflexively. where is the mechanical injury first translated into an electrical response ? |
the breaking of the skin is translated into signals that travel up sensory nerve fibers |
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James was gettingout of his car. As he placed his foot down on a sharp object, he shrieked withpain and moved his foot up reflexively. 2)How does the information travel from the foot to his spinal cord? Whathappens to the signals in the spinal cord? |
the breaking of the skin is translated into signals that travel up sensory nerve fibers into the spinal cord |
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James was gettingout of his car. As he placed his foot down on a sharp object, he shrieked withpain and moved his foot up reflexively. 3)Where is the painful sensation registered? |
in the spinal cord the information is distributed to inerneurons. Some of these neurons send axons to the brain where the painful sensation is registered |
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James was gettingout of his car. As he placed his foot down on a sharp object, he shrieked withpain and moved his foot up reflexively.How are the motor neurons activated to pull back the foot? |
In the spinal cord the information is distributed to interneurons. some of these interneurons synapse on motor neurons which send descending signals to the muscles. The motor commands lead to muscle contraction and withdrawal of the foot. |
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what brings back the resting membrane potential after the action potential? |
sodiumpotassium pumps, leakage channels, the membrane is more permeable topotassium |
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What is the neurophilosophy |
There is no separation of mind and brain |
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What do Glia do |
insulate, support, and nourish neurons |
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What do neurons do? |
process information, sense environmental changes, communicate changes to other neurons, command body response |
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What is the microscopic study of tissue? |
Histology |
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What type of stain facilitates the study of cytoarchitecture in the CNS? |
Nissl Stain |
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What transmits information to other neurons/ |
Axons |
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What is the receiving part of the neuron? |
dendrites |
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What 2 parts of the neuron did the golgi stain reveal? |
soma and perikaryon neurites: axons and dendrites |
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Is the golgi stain or nissl stain better at differentiating axons from dendrites? |
golgi |
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the swollen region containing the cell nucelus has 3 names that are used interchangably. What are they? |
perikaryon, soma,
the cell body |
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what are the thin tubes that radiate from the soma? |
neurites |
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what are the two types of neurites |
axons and dendrites |
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how are harmful substances processed? |
axonal transportation |
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what are the two types of transports? |
1. low 2. fast axonal transplant |
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what structures are responsible for axonal transportation? |
microtubules |
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What was Cajal's contribution to neuroscience? |
Golgi thought neurons were all together in the network and connected by the axon. Cajal realized that the neurons aren't continuous and discovered that neurons are communicating. |
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what is the roughly sperical central part of the neuron?
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soma |
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Inside of the soma is.... |
cystosol (watery fluid inside the cell) organelles (membrane enclosed structures within soma) cytoplasm (contents within the cell membrane) |
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The neuron contains the same organelles found in all animal cells. What are the most important to remember? |
rough ER, nucleus, smooth ER, golgi apparatus, and mitochondria everything but the nucleus is within the cytoplasm |
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What is the barrier that encloses the cytoplasm? How thick is it ? |
The neuronal membrane ~5nm thick |
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What does the structure of the neuronal membrane influence? |
neuronal fiunction |
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What is the non-static internal scaffolding of neuronal membranes? |
the cytoskeleton |
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What are the three structuresof the cytoskeleton? |
microtubules, microfilaments, neurofilaments |
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What are formed by tubulin molecules that are assembled together through a polymerization process? |
microtubules |
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what structure does the fast actional transport |
microtubules |
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what do intermediate filaments/neurofilaments do? |
aggregate to form bundles called neurofibriles provide tensile strength through the neuron give the shape to a cell help to stabilize the tissue intracellular transport like movement of organelles and vesicles within the cell |
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The movement of material down the axon is called ____ _____ |
axoplasmic transport |
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Two types of axoplasmic transport and what they transport |
anterograde: transport of vesicles, organelles, glycoprotiens retrograde: transport of used vesicles and potentially harmful agents |
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______ moves material only from the soma to the terminal. all movement of material from this direction is called anterograde transport |
kinesin |
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_______ transport moves material up the axon from the terminal to the soma |
retrograde |
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what are the three parts of the axon? |
axon hillock (beginning) axon proper (middle) axon terminal (end) |
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what part of the axon contains a high concentration of voltage gated channels? |
axon hillock |
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Neurons communicate with each other through _____ ______ |
synaptic transmission |
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Synaptic vessicles carry ______ |
neurotransmitters |
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What type of transformation does synaptic transmission form |
electrical to chemical to electrical transformation |
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synaptic transmission dysfunction can lead to..... |
mental disorders |
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The space between the presynaptic and postcynaptic membranes is called the _____ ______ |
synaptic cleft |
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what are the "antennae" of neurons? |
dendrites |
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the dendrites from a single neuron are collectively called what? |
a dendritic tree |
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The dendritic membrane under the synapse has many specialized protein molecules called ____ ____ that detect the neurontransmitters in the synaptic cleft |
synapse- receptors |
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specialized structures that receive some types of synaptic input (postsynaptic receives signals from axon terminal |
dendritic spines |
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What are the three main types of neurons and their action potential movement |
1. sensory or afferent- action potentials towards CNS 2. Motor of efferent: action potentials away from CNS 3. Interneurons or association neurons: within CNS from one neuron to another |
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What are the three structural classifications of neurons |
multipolar: Most neurons in CNS; motor neurons bipolar: sensory in retina of the eye and nose Unipolar: single process that divides into two branches. Part that extends to the periphery , has dendrite like sensory receptors |
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Sensory Neurons are neurons of the _____ nervous system and conduct input from ______ and _____ receptors. Most are unipolar, few bipolar. Cell bodies are usually in the _______ _____ ______ outside the CNS |
•neurons of the sensory nervous system•conduct input from somatic and visceralreceptors•most unipolar, few bipolar•cell bodies usually in posterior rootganglia, outside CNS |
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Motor neurons are neurons of the ____ nervous system. THey conduct motor output to _____ and _____ effectors. They're all multipolar. Most cell bodies in the ______ |
•neurons of the motor nervous system•conduct motor output to somatic andvisceral effectors•all multipolar•most cell bodies in CNS |
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Interneurons are entirely within the ______. Receive stimulation from many other neurons. _____, ______, and ___ information. Facilitate communication between ____ and _____ neurons. 99% of neurons. Generally multipolar |
•entirely within the CNS•receive stimulation from many otherneurons•receive, process, and store information•facilitate communication between sensoryand motor neurons•99% of neurons•generally multipolar |
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what glial cell wraps around the capillary and neurons. They help to form the blood brain barrier. They also regulate extracellular brain fluid composition |
astrocytes |
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what protects the neurons from toxic substances, allows the exchange of nutrients and waste products between neurons and blood, prevents fluctuations in the composition of the blood from affecting the functions of the brain. |
blood brain barrier |
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what substances might pass through the blood brain barrier and destroy it? |
alcohol and drugs. |
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Glial cells that line the brain ventricles and spinal cord central canal |
ependymal cells |
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specialized version of ependymal cells form chloroid plexus's what do they do? |
they are within certain regions of ventricles and secrete cerebrospinal fluid. Cilia help move fluid through the cavaties of the brain. They have long processes on basal surfaces that extend within the brain tissue andmay have astrocyte-like functions |
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what type of clial cells produce and store the cerebrospinal fluid and the chloroid plexus? |
ependymal |
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What glial cells are specialized macrophages and respond to inflammation, phagocytize necrotic tissue, microorganisms, and foreign substances that invade the CNS? |
microglia |
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What type of glial cells form myelin sheaths if surroning the axon. Single types of them can form myelin sheaths around portion of several axons |
oligodendrocytes |
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what is the insulation of the neuron that make the action potential go faster |
myelin |
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what are the glial cells of the CNS? |
astrocytes ependymal microgila oligodendrocytes |
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what are the glial cells of the PNS |
Schwann cells/neurolemmocytes satellite cells |
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what type of glial cell of the PNS wraps around portion of only one axon to form a myelin sheath. THey wrap around many times. During development, as the cells grow around the axon, cytoplasm is squeezed out and multiple layers of the cell membrane wrap the axon. The cell membrane is primarily phoshpolipid |
schwann cells / neurolemmocytes |
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what glial cell of the PNS surrounds the neruon cell bodies in sensory ganglia, provide support and nutrients |
satellite cells |
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What is the region where axonal membrane is exposed. They're not insulated and are important because they have voltage gated channels |
node of ranvier |
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the generation of an action potential is caused by what? |
depolarization of the membrane beyond threshold |
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explain what happens when a thumbtack enters your foot |
1. the thumbtack enters the skin 2. the membrane of the nerve fibers in the skin is stretched 3. OpensNa+-permeable channels --> Na+influx -->depolarized membrane --> reaches threshold---> action potential |
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do ions move through the VGC's at the resting state?
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no
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Explain what happens during the action potential ie: resting state depolarization repolarization hyperpolorization |
Resting state: Ions move through VGC's Depolarization is caused by Na+ flowing into the cell Repolorization is caused by K+ flowing out of the cell Hyperpolorization is caused by K+ continuing to leave the cell. |
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After hyperpolarization there is a refractory period where you will not be able to generate another aciton potential no matter how much you give. What are the 2 kinds of refractory period? |
1. absolute refractory period- no matter how much current you give, you will not generate an action potential. after a few minutes you can regenerate the cell only if you give a higher level of voltage 2. relative refractory period- the amount of current required to depolarize the neuron to action potential threshold is elevated above normal |
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How can we generate multiple action potentials? |
artificially inject current into a neuron with microelectrode |
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To artificially control neuronal firing rates, neuroscientists historically have had to use microelectrodes to inject electrical current. This limitation was overcome with optogenetics. What does that do? |
it introduces into the neuron foreign genes that express membrane ion channels that open in response to light the photopigment ChR2 generates light energy and a neuron response. Introducing ChR2 gene into mammalian cells will encode a light sensitive cation channel permeable to Na and Ca. Channel opens in response to blue light |
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what is a protein derived from single cell microbe that inhibits neurons in response to yellow light? |
halorhodopsin |
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In the mouse brain, neurons firing is controlled by light delivered by ____ ______ |
optic fiber |
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the inside of the cell is more _____ charged in contrast to the outside of the cell What is the charge of potassium, sodium, and calcium |
inside is more positive potassium is more positive sodium and calcium are negative |
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K+ is more concentrated inside the cell and Na is concentrated outsid eof the cell. both sodium and calcium channels are both closed. Explain the process of taking the membrane potential from 0 mV to -80 mV |
Risingphase- inward sodium content. conduc. As soonas the membrane potential equals equilibrium to sodium then the situationstarts to invert. The sodium voltagegated channels will start to become inactivated and then they will close. falling phase: outward potassium current Potassium channels are still open so potassium is going out of the cell= insideof the cell will become less positive and more negative. Conductance ofmembrane to potassium is higher than conductance of membrane to sodium. Afterthis it is back to the resting potential because of the sodium potassium pump.Membrane is more permeable to potassium than to sodium. Inphases |
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what allowedHodgkin and Huxley to clamp the membrane potential at any chosen value? |
voltage clamp |
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What phase in the action potential is a transient increas in gNa, and and influx of Na+ ions |
rising phase |
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What Phase int he action potential is an increase in gK, efflux of K+ ions? |
falling phase |
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what is the voltage gated sodium channel structure |
transmembrane domains and ion selective pore. gating and pore selectivity |
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when the sodium enters the cell it is hydrated. T/F |
true |
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what is the characteristic pattern of sodium VGC's |
Open with a little delay, stay open a bout a milisecond then close. They cannot be opened again by depolorization until the membrane potential returns to a negative value near threshold |
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patch clamp |
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The action potential only goes in one direction. what direction does it go? |
from the soma to the action potential |
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what happens during the absolute refractory period: |
channels are inactivated |
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Some toxins can be used as experimental tools. The puffer fish tetrodotoxin clogs the Na+ permeable pore by binding a site on the outside of the channel. a variety of toxins affect channels. The batrachotoxin in a frog make channels open at more negative potentials and stay open longer than usual |
just info |
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Borth potassium and sodium gates open in response to depolarization t/f |
true |
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Do potassium gates open later/earlier than sodium gates |
later |
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Potassium conductance serves to rectify or rest membrane potential T/f |
true |
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what is the structure of the Voltage gated potassium channels |
four separate polypeptide subunits join to form a pore |
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What are the key properties of the action potential |
threshold, rising phase, overshoot, falling phase, undershoot, absolute refractory period, relative refractory period. |
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_______ means the action potential travels in one direction (down the axon to the axon terminal) |
orthodromic
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backward propagation (only experimental) |
antidromic |
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what is the typical conduction velocity |
10 m/sec |
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what is the typical length of action potential |
~2 msec |
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what are factors that indluence conduction velocity? |
Spread of action potential along membrane - dependent on axon structure Path of positive charge - inside the axon (faster) - across the axonal membrane (slower) Axonal excitability - axonal diameter (bigger=faster) - number of voltage-gated channels myelin: layers of myelin sheath facilitate current flow saltatory conduction at nodes of ranvier voltage gated sodium channels concentrated at nodes |
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The part of the neuron where an axon originates from the soma, sensory nerve endings aka: the axon hillock, which is often called ________ |
spike initiation zone |
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What are the differences between electrical and chemical synapses |
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what type of synapse is simple and allows the direct tranfer of ionic current from one cell to the next
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elecctrical |
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electrical synapses occur at specialized sites called.... |
gap junctions |
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at a gap jiunction the membranes of two cells are separated by only about 3nm and this narrow gap is spanned by clusters of special proteins called??? |
connexins |
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a Connexon is formed by how many connexins? |
6 |
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electrical synapses are bidirectional. because the electrical current can pass through these channels cells connected by gap junctions are said to be..... |
electrically coupled- flow of ions from cytoplasm of one cell to cytoplasm of another cell.b |
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how many connexons are in the gap junction |
2 |
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the electrical synapse has a fast/slow transmission? |
fast |
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what is it called when several postsynaptic potentials occur simultaneously to excite a neuron? |
synaptic integration |
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types of CNS synapses axon to dendrite |
axodendritic |
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types of CNS synapses axon to cell body |
axosomatic |
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types of CNS synapses axon to axon |
axoaxonic |
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types of CNS synapses axon to dendritic spine |
axospinous |
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types of CNS synapses dendrite to dendrite |
dendrodendritic |
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THere are two categories of CNS synaptic membrane differentiations. what are they? |
Gray's type I Gray's type II |
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Asymmetrical, usually excitatory A. Gray's type I B. Gray's type II |
A. Gray's type I |
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Symmetrical, usually inhibitory A. Gray's Type I B. Gray's type II |
Gray's type II |
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Studies of the neuromuscular junction established the principles of synaptic transmission. T/f |
true |
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Give an overview of chemical synaptic transmission |
1. neurotransmitter synthesis 2. load neurotransmitter into synaptic vesicles 3. vesicles fuse to presynaptic terminal 4. neurotransmitter spills into synaptic cleft 5. binds to postsynaptic receptors 6. Biochemical/electrical response elicited in postsynaptic cell 7. Removal of neurotransmitter from synaptic cleft |
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Explain the process of Neurotransmitter release |
1. action potentials arrive at axon terminal 2. voltage gated Calcium channels open 3. calcium enters the cell and signals to vesicles. 4. vesicles move to the membrane 5. docked vesicles release neurotransmitter by exocytosis 6. neurotransmitter diffuses across the synaptic cleft and binds to receptors. 7. vesicle membrane is recovered by endocytosis |
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What are the three neurotransmitter categories |
amino acids amines peptides |
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WHat are membrane spanning proteins consisting of four or five subunits that come together to form a pore between them. |
transmitter gated ion channels |
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transient postsynaptic membrane depolarization caused by presynaptic release of neurotransmitter Is this A. Excitatory Postsynaptic potential B. Inhibitory Postsynaptic potential |
EPSP |
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Transient hyperpolarization of postsynaptic membrane potential caused by presynaptic release of neurotransmitter A. EPSP B. IPSP |
IPSP |
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what are receptors that are commonly found in membrane of presynaptic axon terminal. THey're defined as presynpatic receptors that are sensitive to the neurotransmitter released by the presynaptic terminal |
autorececptors |
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Wwhat is a consequence of activating autoreceptors |
they vary, but the common effect is inhibition of neurotransmitter release. |
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what type of recptor is more widespread and lasts longer than ISP and ESP? |
g protein coupled receptor |
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what type of receptor functions as a safety valve? |
autoreceptor |
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Explain neurotransmitter recover and degradation |
diffusion of transmitter molecules away from the synapse reuptake (recovery) : neurotransmitter reenters presynaptic axon terminal enxymatic destruction inside terminal cytosol or synaptic cleft. desensitization: despite the presence of ACh, the transmitter gated channels close. Nerve gases inhibit AChE therefore ACh receptors become desensitized and neuromuscular transmission fails |
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what are the two types of receptor antagonists? |
reversible irreversible- permanently attached to the receptor |
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What type of agonist mimics actions of naturally occurring neurotransmitters? |
receptor agonist |
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WHat is the study of effects on drugs on nercouse system tissue? |
neuropharmacology |
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What is an inhibotor of neurotransmitter receptors ? |
receptor antagonist |
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What is the root cause of neurological and psychiatric disorders? |
Defective neurotransmission |
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what is the process by which multiple synaptic potentials combine within one postsynaptic neuron |
synaptic integration |
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What is the transformation of many synaptic inputs to a single neuron output? |
neural computation |
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Most CNS neurons receive thousands of synaptic inputs t/f |
t |
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what allows for neurons to perform sophisticated computations |
epsp |
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EPSPs added together to produce significant postsynaptic depolorization |
integration |
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EPSPs generated simultaneously at different sites |
Spatial summation |
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EPSPsgenerated at same synapse in rapid succession |
temporal summation
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Many dendrites have VG sodium, calcium, and potassium channels and can act as amplifiers of postsynaptic potentials |
ust info
j |
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what type of synapses take the membrane potential away from the action potential threshold |
inhibitory synapses |
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Inhibitory synapses exert powerful control over ____ ______ |
neuron output |
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what synapse acts as an electrical shunt preventing the current from flowing from soma to axon hillock
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shunting inhibition |
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what is synaptic transmission that modifies effectiveness of EPSPs generated by other synapses with transmitter gated ion channels? |
lation
modu |
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g proteins have second messengers so the physiological responses will last longer. G proteins can modulate the excitatory post synaptic potentials. This can happen in an indirect way through the activation of a _____ _____ |
biological cascade |
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give an example of a biological cascade |
Gproteins activate an enzyme, the enzyme transports ATP to cAMP andthat cAMP willtripper protein kinases which will then phosphorylate the channel which causesa change in the molecular configuration of that channel |
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What are the three classes of neurotransmitters |
amino acids amines peptides |
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what was the first identified neurotransmitter? |
Acetylcholine (ACh) |
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the same neurotransmitter binding to different receptors will have the same effects? t/f |
false, it will have different effects iE: ACh has an excitatory effect when it binds to the nicotinic receptors. When ACh binds to muscarinic receptor we have inhibition, reduce of heart rate, reducing blood pressure. |
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3 main kinds of glutamate receptors. Glutamate will bind to all of them |
AMPA, NMDA, Kainate |
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cotransmitters are when two or more transmitters are released from one ____ ____ |
nerve terminal |
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The idea that a neuron only has one neurotransmitter is _____ principle |
Dale's Principle |
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what is the life cycle of ACh |
acetyl choline is degraded by acetyl choline esterase. Thecholine will be reused through the cell. Choline will be sent inside of thepresynaptic cell. Choline + acetyl CoA will synthsize Ach and inside the vesicle to bereleased at the arrival of an action potential. Ach will be released and thereare Ach receptors in the membrane of the postysynaptic cell. In order to synthesize Ach it isbased on the amount/availability of choline. |
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What type of neurons are involved in movement, mood, attention, and visceral function. |
catecholaminergic neurons |
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The 3 catacholamine neurotransmitters are |
dopamine, norepinephrine, and epinephrine, |
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WHat is the precursof for three amine neurotransmitters ? |
tyrosine |
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What is the sussuession of the chatecholaminergic neurons? |
Tyrosine-->L-Dihydrosyphenylanine--> dopamine--->norepinephrine---> epinephrine |
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wshat is the amine neurotransmitter for serotonergic neurons? |
seotonin aka 5-HTP |
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serotonine/5HTP is derived from |
tryptophan |
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The Serotonergic neurons regulate.... |
mood, emotional behavior, and sleep |
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how do SSRI's serotonin blockers work? |
THey block serotonin transporter in the presynaptic cell. There is no reabsorption of serotonin so the serotonin will stay in the synapse longer- reduction of anxiety and depression |
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What is the key enzyme in GABA synthesis? |
Glutamic acid decarboxylases (GAD) |
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What is the major source of synaptic inhibition in the CNS? |
GABAergic neurons |
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What are the major source of synaptic excitation in the CNS? |
Glutamatergic neurons |
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what chemical reaction creates GABA |
Glutamate decarboxylase catalyzes the glutamate and it produces GABA |
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endocannabinoids are naturally produced. WHy do we have a receptor for drug cannabis? |
Theyfound that we do produce those similar kind of compounds= endocannabinoid. Oneexample is anendomeda-calming/blissful effects |
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Communication from post topresynaptic terminals is called? |
retrograde signalling |
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endocaccabinoid is a ______ messenger |
retrograde |
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what type of channels have fast synaptic transmission, sensitive detectors of chemicals and voltage, regulate flow of large currents, differentiate between similar ions |
transmitter gated channels |
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what is the basic structure of transmitter gated channels? |
pentameer: 5 protein subunits form a pore |
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glutamate receptors are unique from ACh, GABA, and Glycine receptors because??? |
form a hairpin
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The AMPA receptors are selective for??? |
sodium and potassium, more sodium gets in then potassium leaves the cell and they have an exciatory post synaptic potential |
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_______ receptors openingwill add to the excitatory post synaptic potential (EPSP)- they have theentrance of sodium and calcium |
NMDA |
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NMDA receptors are voltage dependant meaning? |
when the membranes at restMg2+ is blocking the central poor Inorder for post synaptic potentials we have to have a depolarization of themembrane. Membrane potential needs to become less and less negative or more andmore positive. Once that happens Mg will get kicked out of the central pore andCa and Na will get in the cell. It is a voltage-dependent channel |
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what mediates most synaptic inhibition in CNS? |
GABA |
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What mediates non-GAVA synaptic inhibition? |
glycine |
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G protein soupled receptors and effectors 3 steps in transmission |
1. binding of the neurotransmitter to the receptor protein
2. activation of G proteins 3. activation of effector systems |
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what is the basic structure of g-protein coupled receptors |
single polypeptide with 7 embrane spanning alpha helices |
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Structure of G-Protein-Coupled Receptors Atrest the g-protein is composed of three subunits alpha, beta, gamma. Alpha iscoupled with GDPOncewe have a neurotransmitter, binds to receptor, alpha subunit exchanges GDP forGTP. The complex then separates and the G alpha will stimulate an effector protein. Theother portion will have an effect in other proteins. Then the activated portionis able to terminate its own process through exchanging Gtp toGDP+PO4 |
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5 steps in G-protein operation |
•Inactive (resting state): 3 subunits—a, b,and g—“float” in membrane (a bound to GDP) •Active: bumps into activated receptor(receptor has a transmitter molecule bound to it) and exchanges GDP for GTP •Ga-GTP andGbg—influence effector proteins•Ga inactivates by slowly converting GTP toGDP.•Ga and Gbg recombine to start the cycle again. |
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why would the g protein take the shortcut pathway? |
because there are no second messengers |
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explain shortcut pathway |
Whenthey bind alpha exchanges GDP for GTP And the Beta Gamma will couple with areceptor (in this case a potassium channel) the binding of the beta, gamma willthen open the channel. Ifpotassium channel is open potassium leaves the cell and |
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Second messenger cascades |
Neurotransmitterà alpha subunit will become activated withGTP the alpha subunit with GTP will bind to several enzymes. That enzyme willactivate other effector proteins or second messengers. |
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PUsh pull method (different g-proteins stimulate or inhibit adenylyl cyclase) |
WhenNE binds to different receptors, different things can happenGs= stimulatory Gi= inhibitory Gs These ones stimulate adenylyl cyclasewhich transforms ATP from cytosol to cAMP. Activates protein kinase A whicheventually will either open or close the receptorsGi- the alpha portion inhibits adenylylcyclaseWehave these so we could regulate the amount of neurotransmitter in the synapticcleft. |
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some cascades branch |
–G-proteinactivates PLC-->generates DAGand IP3-->activate different effectors |
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what changes the confromation and biological activity of signal cascades ? |
phosphorylation and dephosphorylation |
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The gunction of signal cascades is the signal amplification by _______ coupled receptors |
G-protein |
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we have the opportunity to activate many receptors. t/f |
true |
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–Onetransmitter activates more than one receptor subtype ---> cause more than one type of postsynapticresponse or one transmitter binds to different receptors |
divergence |
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Different transmitters converge to affect same effector system or multiple neurotransmitters bind to receptors and make an effector system |
convergence |
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most synaptic connections are point to point t/f |
true. this restricts synaptic communication |
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the secretory hypothalamus is releaseing hormones in the blood stream. THose affect several things in the body |
info |
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What is a network of neurons that regulate different effectors, muscles, organs |
autonomic nervous system |
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neurons in the brain stem regulates different parts of the brane |
diffuse modulatory systems |
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hypothalamus defects often ... |
cause fatal disruption to the body functions because it integrates somatic and visceral responses |
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The dorsal thalamus defects causes discrete ____ or ____ deficit |
ensory or motory
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all sensory information except olfactory passes through the ____ |
thalamus |
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–Regulatoryprocesses: regulates body temperature and blood composition |
homeostasis |
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what type of hypothalamus commands happen in cold weather to humans |
shiver, goose bumps, t urn blue |
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hypothalamus commands that happen in hot weather? |
turn red and sweat
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the hypothalamus wants to keep balance. what are the phases of this |
1. stimulus produces change in variable 2. receptor detects change 3. input: information sent along afferent pathway to control center 4. output information sent along efferent pathway to effector 5. response of effector feeds back to reduce the effect of stimulus and return variable to homeostatic level |
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what zone of the hypothalamus does this 1. Suprachiasmatic nucleus that receiveretinal innervation and synchronize circadian rhythms with daily light-darkcycles; 2. control ANS; 3. neurosecretoryneurons that sends inputs to pituitary gland |
periventricular zone |
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what are two neurohormones ? |
oxytocin (lactation)
vasopressin (regulates blood volume and salt concentration) increase blood volume and bloood pressure when blood pressure is too low |
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when vasopressin realizes that your thirst it will? |
constrict blood vessels and the body will retain water/reduction of urine
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oxytocin can be secreted when the female is in labor or stimulation of nipples. explain the action potentials |
after mechanical stimulation action potentials are conducted by sensory neruons from the uterus and breast to the spinal cord and up ascending tracts to the hypothalamus. Action potentials are conducted by axons of oxytocin sereting neurons of the hypothalamohypohysial tract to the posterior pituitary where they increase oxytocin secretion. Oxy enters the circulation increasing contractions of the uterus and milk ejection from the lactating breast |
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explain how vasopressin works when you're thirsty |
Whenthirsty you have less water and salt concentration has increased so thehypothalamus have specific receptors that detect that change. It willsendaction potentials to the posterior pituitary that will release ADH/vasopressinin the blood. That will act in the kidneys reducing the production of urine inorder to retain more water. The kidneys will then start to produce Renin. Thatis an enzyme that will catalyze the reaction and it will take the inactivehormone, Angiotensinogen (inactive), transform it to other hormones,angiotensin I (inactive) which then produces angiotensine II (Active hormone) will causevasoconstriction which will increase the blood pressure. That will stimulatethe thirst center. It is doing so through the inputs through activation ofanother region in the brain named subfornical organ. That is the organ that will giveus the sensation of thirst. This is negative feedback which causes reduction ofthe release of ADH. |
