Term
| resting membrane potential: |
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Definition
| determined by ionic concentration (electrochemical) gradients and selective ionic permeability. |
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Term
| receptor/synaptic potential; |
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Definition
| usually generated in dendrites, can be hyperpolarizing or depolarizing, graded, small and passively conducted |
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Term
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Definition
| action potential invades nerve ending leading to Ca2+ neurotransmitter release |
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Term
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Definition
- support cells for CNS and PNS
Oligodendrocytes/Schwann Cells
Astrocytes/Satellite cells
Microglia
Ependymal cells |
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Term
| astrocytes control the local environment in the ___. they have foot processes that interact with neurons, synapses, and blood vessels in the CNS. have transporters for ions and neurotransmitters. |
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Definition
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Term
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Definition
| - remove remanants of damaged cells by phagocytosis |
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Term
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Definition
| - line ventricles and produce CSF from choroid plexus |
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Term
| Blood brain barrier: in the CNS endothelial cells form ___ junctions around ___. ___ processes and ___ surround the capillary |
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Definition
- tight junctions
- capillaries
- astrocyte
- pericytes |
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Term
| with the blood brain barrier ___ soluble things can freely diffuse across, but ___ soluble things must have ___ or ___ transport. |
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Definition
- lipid soluble
- water soluble> facilitated or active transport |
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Term
| circumventricular organs lack a functional ___ ____ ___, and instead have a ___vasculature that allow blood borne moleucles to enter brain bypassing the blood brain barrier. |
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Definition
- blood brain barrier
- fenestrated
Sensory CVOs – subfornical organ (SFO), organum vasculosum of the lamina terminalis (OVLT), area postema (AP), subcommissural organ (SCO)
Motor CVOs – median eminence (ME), posterior pituitary (PP), Pineal (P)
- hypothalamus
- vomit centers |
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Term
| action potentials do or do not decrease in strength over distance. |
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Definition
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Term
| action potentials are all or none and are ___ conducted. |
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Definition
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Term
| initial stimulus of an action potential: |
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Definition
| a graded depolarization of axon hillock large enough (10 to 15 mV) to change resting potential (-65 to -70 mV) to threshold level of voltage-regulated sodium channels (—60 to —55 mV |
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Term
| an action potential is a change in membrane ___ due to a change in membrane ___. |
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Definition
- potential
- permeability |
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Term
| refractory period goes in what direction: |
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Definition
| - from trigger zone to axon terminal |
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Term
| continuous propogation happens in ____ axons. |
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Definition
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Term
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Definition
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Term
| what kind of propogations is slower? |
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Definition
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Term
| continous propogations affects ___ segment of the axon at a time. |
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Definition
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Term
| with continous propagation, each generated action potential ___ ___ adjacent segmemts of the membrane due to ___ spread. These local currents bring adjacent segments to threshold and a new action potential is generated |
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Definition
passively depolarizes
electronic spread |
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Term
| With continous propagation, an ___ refractory period forces the action potentials to be propagated how? |
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Definition
- absolute
- in one direction |
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Term
| absolute refractory period: |
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Definition
- sodium channels are open/ inactivated
- no action potential possible |
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Term
| relative refractory period: |
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Definition
- membrane potential almost normal
- very large stimulus can cause another action potential |
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Term
| with continuous propogation, the distance of electronic spread is related to ___ ___. |
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Definition
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Term
| larger diameter axons have larger length constant allowing signal to travel along further. Larger axons have a ___ conduction velocity. |
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Definition
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Term
| in unmyelinated axons, nerve conduction velocity ___ as axon diamter ___. |
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Definition
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Term
| gaps where myelination is lacking: |
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Definition
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Term
| myelination changes the passive membrane properties of the axon, such as: |
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Definition
- increases the length constant
- decreases its capacitance
- signal travels further along with less decay |
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Term
| myelination causes the __ __ __ channels to be clustered in nodes, and the ap can only be generated here. |
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Definition
| - voltage gated sodium channels |
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Term
| the node clusters formed by myelination lack ___ channels so that the ap lack a hyperpolarizing afterpotential. |
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Definition
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Term
| with salutatory propagation the action potential jumps from where to where? |
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Definition
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Term
| so with myelinated fibers, an action potential is regenerated at each __ ___ ___ and then is ___ conducted along the myelinated portion of the fibers. |
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Definition
- node of ranvier
- passively |
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Term
| saltatory conduction is ___ and uses less ___ than continous propagation. it also has a greater ___ ___. |
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Definition
faster
less energy
greater conduction velocity |
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Term
| axons are classified based on: |
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Definition
- diameter
- myelination
- speed of action potential |
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Term
| Type A motor axons are ___ myelinated, have very ___ conduction and are present in ___ and __ ___ __. |
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Definition
- heavily
- fast
- extrafusal and intrafusal muscle fibers |
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Term
| Type B motor axons have ___ myelination, ___ conduction speed, and are found in ___ ___. |
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Definition
- intermediate
- medium
- autonomic preganglion |
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Term
| Type C motor axons are ___ myelinated have ___ conduction and are ___ ____. |
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Definition
- not
- slow
- autonomic postganglionic |
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Term
| Type IV/ C sensory axons are __ myelinated have __ conduction and are found in ___. |
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Definition
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Term
| Type A III sensory axons are heavily myelinated have fast conduction and are in sharp pain nociceptors |
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Definition
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Term
| how does local anesthesia work? |
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Definition
- binds inside pore of voltage gated Na+ channel (open channel blocker)
- tends to block smaller fibers (A, B, and C) better than large diameter A fibers |
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Term
| demyelinating myelopathy: |
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Definition
| - Multiple Sclerosis (CNS) |
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Term
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Definition
Guillain-Barre Syndrome
Saxitioxin/shellfish poisoning
Organophospahte poisoning (insecticide or nerve gas)
Diabetes Mellitus |
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Term
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Definition
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Term
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Definition
- most common neurological disease in young adults
- no known cause
- scattered areas of demyelination with axonal damage
- variety of symptoms
- episodic and progresive |
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Term
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Definition
- demyelinating polyneuropathy
- loss of motor and sensory function due to immune response
- symmetric weakness starts with legs and arms, progressive, can lead to death if effects swallowing or breathing
- nerve conduction tests show slowing or faillure of sensory and motor nerve conduction |
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Term
| sensory transduction> propagation> synaptic release |
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Definition
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Term
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Definition
| - environmental energy acting through a receptor |
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Term
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Definition
| event that acts on receptor |
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Term
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Definition
| effect of stimulus on organsim |
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Term
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Definition
| process for stimulus to produce response |
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Term
| most receptor potentials are __, and if they reach threshold, then an __ __ will be fired. |
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Definition
- depolarizing
- action potential |
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Term
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Definition
| weakest stimulus that can generate an action potential |
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Term
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Definition
| change in the way a receptor responds to continous or prolonged stimulation, allows receptors to signal different kinds of information |
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Term
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Definition
| - discrete region on body where stimulation effects the activity of a primary sensory neuron |
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Term
| action potential are all or none and are all alike in terms of ___ |
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Definition
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Term
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Definition
| how nervous system converts action potential into sensory experience |
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Term
| Primary sensory neurons encode information about the stimulus through these mechanisms: |
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Definition
Sensory Modality - Intensity
Frequency - Spatial location
Duration - Threshold |
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Term
| sensory modality is determined by pathways activated. they can be cutaneous or non-cutaneous, list examples: |
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Definition
- cutaneous: touch, vibration, cold, hot, pain
- noncutaneous: vision, audition, position, smell, taste |
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Term
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Definition
| any activation of the receptor leads to sensory specific experience |
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Term
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Definition
Information from a specific receptive field is represented in a neural map.
Somatotopic map – cutaneuos sensation
Retinotopic map – vision
Tonotopic map – audition |
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Term
| the somatotopic map is in the ___ ___ cortex |
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Definition
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Term
| stimulus frequency increases with stimulus ___. |
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Definition
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Term
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Definition
Can also be encoded by the number of receptors activated
Strong stimulus activates more of the same types of receptors
Strong stimulus activates/recruits different types of receptors
Weak – mechanoreceptors
Strong – mechanoreceptors + pain receptors |
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