Term
| What are 2 control systems in the body? |
|
Definition
| Nervous and endocrine systems |
|
|
Term
| Which system uses chemical and electrical signals (neurotransmitters) |
|
Definition
|
|
Term
| This is the master control system of the body |
|
Definition
|
|
Term
| In this major system, responses are fast and specific (also called a "wired" system) |
|
Definition
|
|
Term
| This system communicates only by chemical signals (hormones) |
|
Definition
|
|
Term
| This major system has slower but long-lasting responses (also considered to be "wireless" |
|
Definition
|
|
Term
| This system interacts with the nervous system to coordinate and integrate the activity of body cells |
|
Definition
|
|
Term
| what are the 3 functions of the nervous system? |
|
Definition
| sensory input, integration, and motor output |
|
|
Term
| The central nervous system is composed of? and the function is? |
|
Definition
| brain and spinal cord; Integration and control center of the body |
|
|
Term
| The peripheral nervous system is composed of? and the function is? |
|
Definition
Composed of all nervous structures outside of the CNS
(Cranial nerves (originate from the brain)
Spinal nerves (originate from the spinal cord)
Ganglia (groups of nerve cell bodies in the PNS)
Plexuses (intermingling of nerve cell processes)
The function is: Communication lines between the CNS and rest of the body |
|
|
Term
| This is a collection of neuronal axons found in the PNS |
|
Definition
|
|
Term
| What do somatic afferent fibers do? |
|
Definition
| carry impulses from skin, skeletal muscles, and joints to the CNS |
|
|
Term
| What do visceral afferent fibers do? |
|
Definition
| transmit impulses from visceral organs to the CNS |
|
|
Term
| What does the Sensory (afferent) division of the PNS do? |
|
Definition
| conveys sensory information to the CNS |
|
|
Term
| What does the motor (efferent) division of the PNS do? |
|
Definition
| Transmits impulses from the CNS to effector organs (muscles and glands) |
|
|
Term
| What are the 2 functional divisions of the PNS? |
|
Definition
| Sensory (afferent) division and motor (efferent) division |
|
|
Term
| What are the 2 main parts of the motor division? |
|
Definition
| somatic and autonomic nervous system (SNS/ANS) |
|
|
Term
| This motor division is voluntary and is where you have conscious control of skeletal muscles |
|
Definition
|
|
Term
| this motor division is composed of visceral motor nerve fibers, regulates smooth muscle, cardiac muscle, and glands of internal organs; has 3 subdivisions (sympathetic, parasympathetic, and enteric nervous system);and this is involuntary actions |
|
Definition
| autonomic nervous system (ANS) |
|
|
Term
| what are 2 principle types of cells in the nervous tissue? |
|
Definition
| neurons and support cells |
|
|
Term
| these are the basic structural and functional units of the nervous system (makes up 10% of cells in the CNS) fully differentiated, non-dividing cells, and excitable cells that transmit electrical signals |
|
Definition
|
|
Term
| also called neurolglia or glial cells |
|
Definition
|
|
Term
| non-excitable cells, provide metabolic and physical support to neurons, make up 90% of cells but only 50% of volume, capable of cell division (brain tumors caused by uncontrolled division of these) |
|
Definition
|
|
Term
| Characteristic: high metabolic rate; totally dependent on aerobic pathway to make ATP (need O2 and glucose);fully differentiated |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| receive info from other neurons and signal toward cell body |
|
|
Term
| transmit signals to other neurons or cells |
|
Definition
|
|
Term
| action potentials generated here |
|
Definition
| axon hillock (or initial segment) |
|
|
Term
| release neurotransmitters onto other neurons or cells |
|
Definition
|
|
Term
| direction of signal transmission in a neuron? |
|
Definition
| dendrites->cell body->axon or dendrites-> cell body -> axon hillock -> axon terminal |
|
|
Term
| 3 or more processes extending from the cell body (neuron) |
|
Definition
|
|
Term
| how many processes extend from a bipolar neuron's cell body |
|
Definition
|
|
Term
| 1 process extending from the cell body of a neuron |
|
Definition
|
|
Term
| What is the most abundant neuron type in the body? (unipolar, bipolar, multipolar) |
|
Definition
|
|
Term
| where are bipolar neurons found? |
|
Definition
| retina and olfactory mucosa |
|
|
Term
| Where are unipolar neurons found? |
|
Definition
| PNS; dorsal root of ganglia of spinal cord; sensory ganglia of cranial nerves |
|
|
Term
| what are the functional classes of neurons |
|
Definition
| sensory/afferent neurons(input);interneurons(integration);motor/efferent neurons(output) |
|
|
Term
| what are sensory neurons? (unipolar, bipolar, multipolar) |
|
Definition
| most unipolar, all bipolar, no multipolar |
|
|
Term
| what is the function of an interneuron and where is it found |
|
Definition
| integration, lies between sensory and motor neurons in neural pathways (CNS)(99%)(multipolar) |
|
|
Term
| function of motor/efferent neurons and where they are found |
|
Definition
| transmit information from CNS to effector organs (somatic/autonomic) commonly multipolar |
|
|
Term
| do neurons always work alone or in large groups? |
|
Definition
| in large groups of functionally-related neurons that run in parallel |
|
|
Term
| what are bundles of axons called in the PNS and the CNS |
|
Definition
|
|
Term
| The membrane that surrounds the whole group of nerves is called? |
|
Definition
|
|
Term
| the membrane that covers a group of nerves contained in the epineurium is called? |
|
Definition
|
|
Term
| covering the axon and myelin sheath is the? |
|
Definition
|
|
Term
| Characteristic: mixed(contain both sensory and motor nerve fibers);purely sensory(rare, e.g. CN I % II); purely motor(rare, e.g. CN III); cranial nerves (originate from the brain); spinal nerves (originate from spinal cord) |
|
Definition
|
|
Term
| Characteristic: either sensory or motor; common origin & destination |
|
Definition
|
|
Term
| 4 components in a spinal nerve |
|
Definition
| somatic afferent, visceral afferent, somatic efferent, visceral efferent |
|
|
Term
| also known as "support cells" or "glue", remains mitotic, and is non-excitable |
|
Definition
|
|
Term
| name the cell based on the function: provide physical support for neurons, provide nutrition to neurons, insulation(form myelin that wraps around axons), regulation chemical environment of neurons(composition of the ECF) |
|
Definition
|
|
Term
| What does excitable mean? |
|
Definition
| the ability to initiate or conduct electrical signals |
|
|
Term
| these cells surround neuron cell bodies in the PNS |
|
Definition
|
|
Term
| these cells myelinate all PNS axons-covers 1 axon |
|
Definition
|
|
Term
| axons can be myelinated or unmyelinated. myelin-forming cells can cover about 1mm of axon length. the gaps inbetween are called? |
|
Definition
|
|
Term
| the most abundant neuroglia, supports the CNS, make exchanges between neurons and capillaries, and regulates the chemical environment around neurons (cleans up leaked k+ and released neurotransmitters) |
|
Definition
|
|
Term
| modified immune cells, monitor health and perform defense functions for neurons (in CNS) |
|
Definition
|
|
Term
| these cells line the central cavities of the brain and spinal cord, forms a permeable barrier between cerebrospinal fluid(CSF) and interstitial fluid of the CNS, beats the cilia to help circulate the CSF, and germinative centers of the CNS, contain neural stem cells |
|
Definition
|
|
Term
| form myelin sheaths around CNS axons, each covers a portion of up to 40 axons. |
|
Definition
|
|
Term
| definition of neurophysiology |
|
Definition
| study of nervous system function |
|
|
Term
| how do neurons communicate with other cells |
|
Definition
| via electrical and chemical signals |
|
|
Term
| what is an electric potential across a cell membrane? and what are the units? |
|
Definition
| membrane potential(Em); milivolts(mV) |
|
|
Term
|
Definition
| the measure of electrival potential between two points |
|
|
Term
|
Definition
| movement of electrical charge from one point to another- flow of ions (not free electrons) |
|
|
Term
|
Definition
| the hindrance to the movement of electrical charge through the material(in the body, the resisitance to current flow is provided by the cell membrane) |
|
|
Term
|
Definition
|
|
Term
| when does membrane potential arise? |
|
Definition
| when there is a difference in electrical charge on the 2 sides of a call membrane |
|
|
Term
| what is the membrane potential measured at resting state called? |
|
Definition
| resting membrane potential(RMP) |
|
|
Term
| What is the range and average voltage of the resting membrane potential of a neuron |
|
Definition
|
|
Term
| membrane potential develops due to: |
|
Definition
| differences in ionic composition(na+ and K+) of intracellular fluid(ICF) and the extracellular fluid(ECF) (K+ higher inside cell) (Na+ higher outside cell); differences in membrane permeability(K+ more permeable) |
|
|
Term
| where is K+ higher and Na+ higher? and how are the concentrations maintained? |
|
Definition
| K+ higher inside the cell/Na+ higher outside the cell; maintained by the Na+-K+ pump |
|
|
Term
| is the plasma membrane permeable to cytoplasmic proteins? |
|
Definition
|
|
Term
| what is responsible for resting membrane potential |
|
Definition
| The resting membrane potential depends mainly on K+ concentration gradient across the plasma membrane and a selective permeability of the plasma membrane to K+ through K+ leak channels |
|
|
Term
| what is the difference between K+ leak channels and voltage-gated K+ channels? |
|
Definition
| k+ channels are always open, voltage-gated K+ channels only open in response to membrane potential changes (depolarization) |
|
|
Term
| what are 2 forces that influence the diffusion of ions across the cell membrane and their definition? |
|
Definition
| electrical force(determined by the Em) chemical force(determined by the ion concentration gradient between the ECF and ICF) both forces act on each individual ion(may work in same or opposite direction of eachother) the total force is the "electrochemical gradient(force)" |
|
|
Term
| the electrochemical gradient represents the combination of 2 influences: |
|
Definition
| electrical force(or electrical gradient) across the membrane; chemical force( or concentration gradient) for that ion. |
|
|
Term
| when there is no net movement of K+ across a membrane, the membrane potential at which this equilibrium is reached is called the? and for Na+ |
|
Definition
| K+ equilibrium potential (Ek); Na+ equilibrium potential(Ena) |
|
|
Term
| The Resting Membrane Potential is Close to but not Equal to K+ Equilibrium Potential. why? |
|
Definition
| Because the plasma membrane is not just permeable to K+, it is also very slight permeable to other ions (e.g. Na+) |
|
|
Term
if the membrane is permeable only to k+, what is the membrane potential?
if the membrane is permeable only to Na+, membrane potential is?
what happens if the membrane is permeable to multiple ion species?
why is the membrane 75 times more permeable to K+ than Na+? what is the resting membrane potential closer to, Na+ or K+? |
|
Definition
If the membrane is permeable only to K+, membrane potential = EK = -90 mV.
If the membrane is permeable only to Na+, membrane potential = E Na = +60 mV.
If the membrane is permeable to multiple ion species, the most permeable ion would have the greatest influence on membrane potential.
At rest, the membrane is about 75 times more permeable to K+ than Na+ because the presence of K+ leak channel. K+ has greater influence on the resting membrane potential than Na+. Thus, resting membrane potential is close to EK. |
|
|
Term
| how do ligand-gated ion channels open? |
|
Definition
| they open when a chemical (e.g. neurotransmitter) binds to its receptor (also known as chemically gated ion channels) |
|
|
Term
| how do voltage-gated ion channels open? |
|
Definition
| open and close in response to changes in membrane potential. (e.g. voltage-gated Na+ channels open in response to membrane depolarization) |
|
|
Term
| how do stretch-activated ion channels open? |
|
Definition
| mechanosensitive channels open in response to physical deformation of the channels |
|
|
Term
| How can the RMP (Em = -70 mV) be Changed |
|
Definition
| A change in Em can be produced by any stimulus that changes permeability of membrane to certain ions (due to opening or closing of ion channels). |
|
|
Term
| what does overshoot mean? |
|
Definition
| overshoot refers to a reversal of the membrane potential polarity |
|
|
Term
| what does repolarization mean? |
|
Definition
| repolarization is when the membrane potential returns to its resting value (RMP) |
|
|
Term
|
Definition
| Resting Membrane Potential |
|
|
Term
|
Definition
| a cell is "polarized" because its interior is more negative than its exterior |
|
|
Term
| what does hyperpoarization mean? |
|
Definition
| hyperpolarization is when the membrane potential becomes more negative than the RMP |
|
|
Term
| what does depolarization mean? |
|
Definition
| depolarization is when the membrane potential becomes less negative than RMP |
|
|
Term
| in which two ways do changes in membrane potential occur? explain what they are. |
|
Definition
| graded potentials:transmit information only over short distance; action potential: transmit information over very long distance |
|
|
Term
| Are graded potentials signals over short or long distances? |
|
Definition
|
|
Term
| what is the meaning of decremental? |
|
Definition
| the decrease in magnitude with increasing distance from the site of origin (graded potentials) |
|
|
Term
| True or false: Graded potentials can not be depolarization or hyperpolarization. |
|
Definition
| false. Graded potentials can be depolarization or hyperpolarization. |
|
|
Term
| Where do graded potentials occur? |
|
Definition
| at the receptor region of a sensory neuron (known as receptor potentials) and the dendrites and cell body of an interneuron or a motor neuron (known as synaptic potentials) |
|
|
Term
| what is action potential? |
|
Definition
| action potential is a brief change in membrane potential that can propagate along the surface of excitable cells. |
|
|
Term
| what is the difference between action potential and graded potential? |
|
Definition
| action potential involves voltage-gated ion channels; graded potentials involve chemically-gated ion channels or stretch-activated ion channels. |
|
|
Term
| what are cells called that generate action potentials? |
|
Definition
| excitable cells (e.g. neurons, muscles, and gland cells) |
|
|
Term
| what is occuring with the voltage-gated Na+ and K+ channels and the leak channels during resting state? |
|
Definition
| voltage-gated Na+ and K+ channels are closed, leak channels are open maintaining resting membrane potential. |
|
|
Term
| in the depolarizing phase, what happens? |
|
Definition
| initial depolarization(graded potential), which causes few voltage-gated Na+ channels to open. Na+ rushes into the cell and causes more channels to open, causing a large influx of Na+ to occur. |
|
|
Term
| What happens in the repolarizing phase? |
|
Definition
| with some delay, voltage-gated K+ channels begin to open(sometimes called delayed K+ channels) K+ ions flux out of the cell, which helps the membrane repolarize rapidly. |
|
|
Term
| what happens in hyperpolarization? |
|
Definition
| slowly the voltage-gated K+ channels close, Pk remains above resting levels, causing tansient membrane hyperpolarization (called after-hyperpolarization); voltage-gated Na+ channels being to reset back to closed states. |
|
|
Term
| what does the Na+/K+ pump do? |
|
Definition
| restores ionic composition of the ICF and ECF |
|
|
Term
| when are Action potentials produced? |
|
Definition
| they are produced when graded potentials reaching the "trigger zone" (the initial segment of the axon) depolarize the membrane to a critical level. |
|
|
Term
| True or false: can graded potentials be subthreshole or suprathreshold? |
|
Definition
| true. graded potentials can be subthreshold or suprathreshold |
|
|
Term
| what is a threshold stimulus? |
|
Definition
| when the initial stimulus is just large enough to evoke an action potential. |
|
|
Term
| what is a subthreshold stimuli and a subthreshold potential? |
|
Definition
| an initial stimuli that is too weak to produce an action potential; a subthreshold potential is what occurs after these weak depolarizations. |
|
|
Term
| What happens if the stimulus is larger than the threshold stimulus? |
|
Definition
| The action potential is the same as if it was caused by the threshold potential. (action potentials either occur maximally or not at all-allornone) |
|
|
Term
| what is an absolute refractory period? |
|
Definition
| during a period of action potential, a second stimulus, no matter how strong, will not produce a second action potential. (the channels cannot reopen unless closed, but the channels are already open or in the inactivated state) |
|
|
Term
| what is relative refractory period? |
|
Definition
| the period of time following absolute refractory period. during this time a second action potential can occur only if its a larger than threshold stimulus. some Na+ channels have returned to the closed state and can be re-opened. membrane is hyperpolarized because K+ channel is still open. larger magnitude of stimulus is needed to reach threshold. |
|
|
Term
| true or false? all action potential amplitudes are alike. |
|
Definition
| true, the amplitude of action potential is independent of stimulus intensity. although a strong stimuli can generate action potentials more often than weaker in a given time interval. |
|
|
Term
| where are action potentials generated? |
|
Definition
| at the axon hillock (junction between neuronal cell body and axon)--has a high concentration of voltage-gated Na+ channels |
|
|
Term
| what 2 things determine the speed at which action potential propogates along an axon? |
|
Definition
| axon diameter (larger>smaller) and axon myelination (myelinated>unmyelinated) |
|
|
Term
| true or false? in unmyelinated axons, action potential is not generated continuously along the axonal membrane. |
|
Definition
| false. in unmyelinated axons, action potentials are generated continuously along the axonal membrane (continuous conduction) |
|
|
Term
| what are the gaps called between myelin-forming cells on axons? |
|
Definition
|
|
Term
| is there a high density of voltage-gated Na+ channels found at the nodes of Ranvier? |
|
Definition
| yes. there is a high density |
|
|
Term
| what is it called when action potential jumps from node to node during propagation (nodes of Ranvier) |
|
Definition
|
|
Term
| what happens to someone with multiple sclerosis? |
|
Definition
| demyelination in the CNS. autoimmune disease. |
|
|
Term
| what happens when a person has Guillain Barre syndrome? |
|
Definition
| demyelination in the PNS. autoimmune disease. usually triggered by an actute infectious process. |
|
|
Term
| what is the purpose of type A fibers? |
|
Definition
| transmit sensory information on position, balance, and delicate touch & pressure sensation from skin. They also carry motor commands to skeletal muscle |
|
|
Term
| what is the purpose of type B and C fibers? |
|
Definition
| transmit sensory info on temperature, pain, general touch & pressure sensations, instructions to smooth & cardiac muscle, visceral sensation |
|
|
Term
| which types of fiber have myelination (A, B, C) |
|
Definition
| A, and B. type C does not have myelination. |
|
|
Term
| in which order of size do the fibers go (type A, B, C) |
|
Definition
| type A is the largest, then B, and type C is the smallest. |
|
|
Term
|
Definition
| blocks voltage-gated Na+ channels, used as a local anesthetic. |
|
|
Term
| what does tetrodotoxin and where is it found? |
|
Definition
| a neurotoxin found in the internal organs of puffer fish which blocks voltage-gated Na+ channels. |
|
|
Term
|
Definition
| a synapse is the junction that mediates info transfer from one neuron to the next or from a neuron to an effector cell |
|
|
Term
| what does a presynaptic neuron do? |
|
Definition
| a presynaptic neuron sends information toward the synapse |
|
|
Term
| what does a postsynaptic neuron do? |
|
Definition
| a postsynaptic neuron receives information |
|
|
Term
| what is the difference in function between an electrical synapse and a chemical synapse |
|
Definition
| in an electrical synapse, information is passed by electrical current (less common); in a chemical synapse, information is passed by chemicals called neurotransmitters. common in the nervous system. |
|
|
Term
| what are the 3 types of synapses? |
|
Definition
| axodendritic synapses, axosomatic synapses, and axoaxonal synapses |
|
|
Term
| where are axodendritic synapses? |
|
Definition
| between the axon and dendrite |
|
|
Term
| where are axosomatic synapses? |
|
Definition
| between the axon and cell body |
|
|
Term
| where are axoaxonal synapses? |
|
Definition
|
|
Term
| what type of synapse corresponds to gap junctions in non-nervous tissue, is made of connexin molecules, has rapid transmission, is one-way or two-way, provides a simple means of synchronization, and is more abundant in embryotic NS than the adult |
|
Definition
|
|
Term
| what happens in a chemical synapse and what is its structure? |
|
Definition
info is transmitted by chemical messengers called neurotransmitters (NTs) that diffuse across the synapse. the structure is
presynaptic axon terminal
synaptic cleft (~30-50nm)
postsynaptic membrane |
|
|
Term
|
Definition
| the time required for neurotransmitter release, diffusion across the synaptic cleft, and binding to receptors (usually lasts .3-.5ms) rate limiting step in neutral transmission because active potential much faster along axon (up to 150m/s) |
|
|
Term
| What chemical does a cholinergic synapse release? what breaks it down? and where is it found? |
|
Definition
| acetylcholine (ACh); acetylcholinesterase; neuromuscular junctions (NMJs) and many synapses in CNS and PNS |
|
|
Term
| the postsynaptic membrane responds to the release of neurotransmitters in one of two ways... |
|
Definition
| excitatory synapse, the postsynaptic membrane is depolarized, bringing the membrane potential closer to threshold; inhibitory synapse, the postsynaptic membrane is hyperpolarized, bringing the membrane potential farther away from threshold |
|
|
Term
|
Definition
| excitatory synapse and excitatory postsynaptic potential-at excitatory synapse, binding of neurotransmitters usually opens ligand-gated cation channels, Na+ influx is greater than K+ efflux through the channel, net effect is rapid depolarization. EPSP is graded potential. its function is to bring the membrane potential closer to threshold |
|
|
Term
|
Definition
| inhibitory synapse and inhibitory postsynaptic potential; at inhibitory synapses, binding of neurotransmitters opens Cl- or K+ channels, causes a flux of Cl- into, or K+ out of, the postsynaptic cell, which results in membrane hyperpolarization. graded potential. its function is to bring the membrane potential further away from threshold. |
|
|
Term
| These are graded potentials that spread decrementally from point of origin to axon hillock |
|
Definition
|
|
Term
| true or false: a single EPSP is sufficient to trigger action potential in a postsynaptic neuron. |
|
Definition
| false. a single EPSP is insufficient to trigger action potential in postsynaptic neurons. the magnitude becomes much smaller and cannot reach threshold at axon hillock. no ap is generated. in combination with other EPSPs at the same postsynaptic neuron, may trigger an AP |
|
|
Term
| what is synaptic integration? |
|
Definition
| a postsynaptic neuron receives thousands of synaptic inputs(convergence). some excitatory(EPSP) and some inhibitory(IPSP). postsynaptic neuron must integrate potentially conflicting incoming signals. temporal and spatial summation. |
|
|
Term
| what is temporal summation? |
|
Definition
| when two or more stimuli are applied in close succession, graded potential produced by the second stimulus sums on top of the first, producing composite potential to reach threshold. (both EPSP and IPSP can undergo temporal summation) |
|
|
Term
| what is spatial summation? |
|
Definition
| the two stimuli are received simultaneously at two close locations. graded potentials produced by the two separate events sum together to reach threshold. both EPSP and IPSP can undergo spatial summation |
|
|
Term
| what is the meaning of synaptic integration? |
|
Definition
| both EPSPs and IPSPs summate, EPSPs also summate with IPSPs. if EPSPs are dominate, membrane potential reaches threshold, and ap is generated. if IPSPs are dominate, membrane potential can't reach threshold, AP wont be generated. even if summation yields subthreshold depolarization, postsynaptic neuron is more easily excited by successive depolarizaiton-facilitation |
|
|
Term
| transmission of signals across synapses can be one of 2 things(modulation of synaptic transmission is the topic) |
|
Definition
| attenuated or enhanced via natural pre-wired mechanisms (presynaptic inhibition/facilitation) or via drug, toxin, poison effects |
|
|
Term
| what is presynaptic inhibition and what type of synapse is it? |
|
Definition
| release of neurotransmitter from one neuron is inhibited by the activity of another neuron; axoaxonic synapses;Decreases the amount of Ca2+ that enters presynaptic nerve terminal following AP |
|
|
Term
| what is presynaptic facilitation and what type of synapse is it? |
|
Definition
| release of neurotransmitters from one neuron is enhanced by the activity of another neuron;axoaxonic synapses; Increases the amount of Ca2+ that enters presynaptic nerve terminal following AP |
|
|
Term
| true or false: drug/toxin can't interfere with neurotransmitter synthesis |
|
Definition
| false. drug/toxin can interfere with NT synthesis |
|
|
Term
| Can drugs/toxins increase or block neurotransmitter release(not the same drug/toxin for both) |
|
Definition
| yes. increase(amphetamine) block(botulinum toxin) |
|
|
Term
| Can drugs/toxins prevent neurotransmitter inactivation? |
|
Definition
|
|
Term
| can drugs/toxins prevent neurotransmitter reuptake? |
|
Definition
|
|
Term
| can drugs/toxins both stimulate and prevent neurotransmitters from binding to the receptor? |
|
Definition
| yes. stimulate(agonist) prevent(antagonist) |
|
|
Term
| What classifications are neurotransmitters? |
|
Definition
| acetylcholine, biogenic amines(norepinephrine, dopamine, serotonin), amino acids(glutamate, GABA, glycine), neuropeptides(endorphine, tackykinins, substance P, etc.), purines(ATP), and dissolved gases(NO, CO, H2S) |
|
|
Term
| what are specific neurotransmitters of particular interest? |
|
Definition
| acetylchoine(ACh), norepinephrine(NE), glutamate, gamma aminobutyric acid (GABA), endorphine |
|
|
Term
| what are 2 types of acetylcholine receptors? |
|
Definition
|
|
Term
| explain nicotinic receptor for acetylcholine |
|
Definition
| NMJ in somatic NS, autonomic ganglia, CNS;excitatory |
|
|
Term
| explain muscarinic receptors for acetylcholine |
|
Definition
| visceral effectors and in CNS;either excitatory or inhibitory depending on receptor subtype |
|
|
Term
| What happens to the ACh level in CNS during alzheimer's disease? |
|
Definition
| the ACh level is significantly reduced |
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Term
| where and by what is acetylcholine synthesized? |
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Definition
| synthesized in presynaptic nerve terminal by choline acetyltransferase |
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Term
| where and by what is acetylcholine degraded by? |
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Definition
| degraded in synaptic cleft by acetylcholinesterase |
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Term
| Where is norepinephrine (NE), what does it do, and is it excitatory or inhibitory? |
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Definition
| Found in CNS and sympathetic NS; both excitatory and inhibitory, depending on receptor; in brain, functions in emotions and feelings of well being. decrease in NE (and dopamine) in certain brain region leads to depression; in periphery, NE stimulates heart and constricts blood vessels(cocaine blocks re-uptake of NE which leads to a "good-feeling", but also causes over stimulation of the heart (potential for lethal arrhythmias)) |
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Term
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Definition
| major excitatory neurotransmitter in CNS. often opens non-selective cation channels and produces EPSP, important in learning and memory. excessive release produces excitotoxicity and neuronal death, implicated in stroke |
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Term
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Definition
| gamma aminobutyric acid; primary inhibitory neurotransmitter in CNS, opens Cl- channels and produces IPSP, anti-anxiety drugs of the bensodiazepine class (e.g. valium) works by binding to GABAa receptors and opening Cl- channels. this inhibits pathways that produce anxiety. |
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Term
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Definition
| primary inhibitory neurotransmitter in CNS. often opens Cl- channels and produces IPSP. |
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Term
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Definition
| divers groups of neurotransmitters. endorphins are natural opiates that inhibit pain, substance P mediated pain transmission. |
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Term
| what are neurotransmitter receptors? |
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Definition
| actions of neurotransmitters are mediated by their receptors. receptors are classified into 2 categories:channel-linked receptors; g protein-coupled receptors (GPCRs) |
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Term
| what are channel-linked receptors? |
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Definition
| chemically-gated ion channels, ligand-gated ion channels, or ionotropic receptors. mediate direct, fast synaptic responses(i.e. fast EPSP, fast IPSP) |
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Term
| what are G-protein couple receptors? |
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Definition
| linked to g proteins, cause the productin of intracellular second messengers(eg cAMP), the second messengers regulate ion channels, activate enzymes, or regulate gene function; synaptic responses mediated by GPCRs are slow (slow EPSP/IPSP); also called metabotropic receptors |
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Term
| what is the difference between general and special senses? |
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Definition
| general- conscious awareness of touch, pressure, vibration, proprioception, temperature, and pain; special-vision, hearing, smell, taste, equilibrium |
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Term
| true or false: activation of any specific receptor will produce many types of sensation, no matter how it is activated. |
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Definition
| false. activation of any specific type of receptor always produces one type of sensation, no matter how it is activated. |
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Term
| what is the classification of sensory receptors by stimulus type? |
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Definition
Mechanoreceptors
sense touch, pressure, vibration, and stretch
Thermoreceptors
sense temperature change
Photoreceptors (in retina of the eye)
sense light
Chemoreceptors
respond to chemicals in solution (e.g. taste bud)
Nociceptors
respond to potential damaging stimuli that result in pain
e.g. extreme heat or cold, excessive pressure, and inflammatory chemicals
the potential damaging signals stimulate subtypes of thermo-, mechano- and chemoreceptors |
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Term
| what is the classification of sensory receptors by location? |
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Definition
Exteroceptors
sensitive to stimuli arising outside the body
include receptors in the skin (e.g. touch, pressure, pain, temperature), and receptors for special senses (vision, hearing, equilibrium, smell, taste)
Interoceptors
also called visceroceptors
monitor the changes of internal environment
Include receptors that sense internal temperature, chemical changes, tissue stretch, etc.
Proprioceptors
respond to internal stimuli located at restricted regions (skeletal muscles, joints, tendons, ligaments, connective tissues coverings of bones and muscles)
monitor body movement |
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Term
| what is the classification of sensory receptors by structural complexity? |
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Definition
Simple receptors
modified dendritic endings of sensory neurons
for general sensation
Complex receptors
sense organs (contain receptor cells, sensory neurons and other supporting cells)
for special sensation |
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Term
| does stimulus energy need to be converted to action potential in order to be sent to the CNS? |
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Definition
| yes. the stimulus energy does need to be converted to ap in order to be sent to the CNS |
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Term
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Definition
stimulus energy is converted into receptor potential(graded potential)
receptor potential triggers aps in sensory nerve fibers, which are sent to CNS for processing |
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Term
| what is receptor potential? |
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Definition
| a type of graded potential |
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Term
| where are sensory neurons for general senses that are unipolar neurons are found? |
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Definition
| dorsal root ganglia of spinal cord and sensory ganglia of cranial nerves. |
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Term
| all APs are all or nothing, are sensory stimuli the same thing? |
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Definition
| no, sensory stimuli vary in intensity. |
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Term
| what is the definition of adaption? |
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Definition
| reduction in response (number of APs) to the continuous presence of a stimulus; helps prevent sensory overload. |
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Term
| what is the speed of phasic receptors in adaption? |
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Definition
| fast adapting; generating burst of APs at the beginning and end of the stimulus. act to report changes in the internal or external environment. (e.g.) pacinian and meissner's corpluscles) |
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Term
| what is the speed of tonic receptors in adaption? |
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Definition
| slow adaption, generating APs during the stimulus. provide a sustained response. (e.g. nociceptors and most proprioceptors) |
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Term
| what are your somatic senses? |
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Definition
| touch, pressure, proprioception, temp, pain. |
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Term
| where much afferent info reach to discriminate quality, intensity, and location of stimulus? |
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Definition
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Term
| what are the locations of the 1st, 2nd, and 3rd order neurons? |
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Definition
| 1st-dorsal root ganglia/crandial ganglia; 2nd-spinal cord or brainstem/ axons across over to the opposite side of the CNS(decussation); 3rd-thalamus/conduct impulses to primary sensory cortex of the cerebral hemisphere |
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Term
| how does somatosensory information travel to the CNS? |
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Definition
| cranial nerves(head/some parts of neck) and spinal nerves(rest of body) |
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Term
| what has 12 pairs, the CN1 and 2 are purely sensory and others are mixed, convey sensory info from the head and some areas of the neck |
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Definition
|
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Term
| characteristics of spinal nerves(4) |
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Definition
| 31 pairs, all are mixed nerves, named according to which vertebra they are associated with, each supplies a specific body region. |
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Term
| what is the definition of dermatomes? |
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Definition
| the skin region innervated by a single spinal nerve |
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Term
| what are the names of the 2 roots that merge to form the spinal nerve? |
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Definition
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Term
| what is the function of a dorsal root in a spinal nerve? |
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Definition
| it carries sensory info from peripheral sensory receptors to the spinal cord, cell bodies are in dorsal root ganglia |
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Term
| what is the function of the ventral root in the spinal nerve? |
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Definition
| motor neuron axons, cell bodys in ventral horn and lateral horn. |
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Term
| what is gray matter in the spinal cord? |
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Definition
| contains neuronal cell bodies; dorsal horn, ventral horn, and lateral horn |
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Term
| what does white matter consist of? |
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Definition
| myelinated and unmyelinated axons forming ascending and descending tracts. |
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Term
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Definition
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Term
| what is contained in gray matter? (3 horns and what they contain) |
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Definition
| dorsal horn(cell bodes of interneurons on which some afferent neurons synapse) lateral horn(cell bodies of autonomic pre-ganglionic efferent neurons) ventral horn(cell bodies of somatic efferent neurons) |
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Term
| what are contained in white matter? |
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Definition
| myelinated and unmyelinated axons, organized into columns or funiculi, each column consists of distinct bundles of axons called tracts, each tract composed of axons having similar origin, destination, and function |
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Term
| what are ascending tracts composed of? |
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Definition
| Composed of axons of 1st and/or 2nd order neurons carrying sensory info up to the primary somatosensory cortex. High degree of segregation of modalities into specific tracts! |
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Term
| what are descending tracts composed of? |
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Definition
| Composed of axons of motor neurons that carry signals from various parts of brain down spinal cord. Synapse on motor neurons in lateral & ventral horns of spinal cord . They are axons of “Upper motor neurons”. |
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Term
| what is the definition of decussation? |
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Definition
| crossing over (like somatosensory info in the brain from left to right or the opposite) |
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Term
| what are 3 major ascending pathways on each side of the spinal cord? |
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Definition
Dorsal column pathway (fasciculus gracilis, fasiculus cuneatus)
Spinothalamic tracts (anterolateral pathway)
Spinocerebellar tracts (anterior and posterior) |
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Term
| what sensations does the dorsal column pathway sense and what are the names of the tracts? |
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Definition
| fine touch(discriminative touch), pressure, vibration, conscious proprioception; fasciculus gracilis(transmits sensation from lower limbs and inferior body trunk) and fasciculus cuneatus(transmits sensation from upper limbs, upper trunk and neck;not present in spinal cord below T6) |
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Term
| no idea how to make a question :( |
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Definition
Central axons of 1st order neurons enter spinal cord and ascend in dorsal column (fasciculus cuneatus and fasciculus gracilis) on same side without synapsing.
These axons synapse with 2nd order neurons in nucleus gracilis and nucleus cuneatus in Medulla oblongata of the brain stem.
Axons of 2nd order neurons cross to opposite side (decussation), ascend in medial lemniscal tract, and synapse with 3rd order neurons in thalamus.
Thalamic neurons project to primary somatosensory cortex. |
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Term
| where can you find the fasciculus cuneatus in the spine? |
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Definition
|
|
Term
| where can you find the fasciculus gracilis in the spine? |
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Definition
|
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Term
| what senses does the spinothalamic (anterolateral) pathway sense and in what tracts is it found? |
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Definition
| anterior (ventral) spinothalamic tract(crude touch and pressure) and lateral spinothalamic tract(pain and temp) |
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Term
| how does the lateral spinothalamic tract work? |
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Definition
Central axons of 1st order neurons enter spinal cord and synapse with 2nd order neurons (interneurons in dorsal horn) at the same level.
Axons of 2nd order neurons cross to opposite side (decussation), and ascend in lateral spinothalamic tract.
Axons of 2nd order neurons synapse with 3rd order neurons in thalamus.
Thalamic neurons project axons to primary somatosensory cortex |
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Term
| how does the anterior spinothalamic tract work? |
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Definition
Central axons of 1st order neurons enter spinal cord and synapse with 2nd order neurons (interneurons in dorsal horn) at the same level.
Axons of 2nd order neurons cross to opposite side, and ascend in anterior spinothalamic tract |
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Term
| what are the tracts and what is the function of the spinocerebellar pathway? |
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Definition
Tracts
Anterior spinocerebellar tract
Posterior spinocerebellar tract
Function:
Convey subconscious proprioceptive information about muscle or tendon to the cerebellum.
Do not contribute to conscious sensation.
Info is used to coordinate skeletal muscle activity
Remember that the conscious proprioception is mediated by the dorsal column pathway.
Transmits subconscious proprioceptive info from trunk and lower limb only
Posterior spinocerebellar pathway (does NOT decussate)
Anterior spinocerebellar pathway (decussate immediately in S.C.)
Fibers will cross back in brainstem
Send to the same side of cerebellum
No 3rd order neurons |
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Term
| What is phantom limb pain? |
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Definition
| pain experienced in amputated limb, may persist or recur, caused by activity in sensory neurons or interneurons in spinothalamic pathway, neurons involved once monitored conditions in the intact limb |
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Term
| what is the convergence theory (or referred pain)? |
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Definition
| pain felt in uninjured part of body, but actually originates in another part of the body (most commonly sensed in skin when internal organ affected) mechanism not fully understood. |
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Term
| where do motor neurons from the CNS go? |
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Definition
| to the somatic and autonomic nervous system. |
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Term
| what 2 motor neurons does the somatic motor pathways involve? |
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Definition
| upper(located in the brain, synapses on lower, facilitates or inhibits lower motor neuron) lower(located in ventral horn of spinal cord, innervates skeletal muscle, activation triggers contraction in innervated muscle, only the axon of lower extends outside CNS, damage to lower eliminates voluntary and reflex control over the innervated motor unit |
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Term
| what are the 2 major descending pathways? |
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Definition
| pyramidal system(direct system-ventral(anterior) tract and lateral corticospinal tract) extrapyramidal system(indirect system) |
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Term
what is this called?
Originate with the pyramidal neurons (upper motor neurons) in the primary motor cortex
Impulses are sent through the corticospinal tracts and synapse with lower motor neurons in ventral horn of spinal cord
Stimulation of lower motor neurons activates skeletal muscles
regulates fast and fine movements (voluntary motor control)
what decussates in pyramids of medulla?
what decussates at spinal cord? |
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Definition
| pyramidal system (corticospinal pathway);Lateral corticospinal tracts;Ventral (Anterior) corticospinal tracts |
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