Neurons Flashcards

1
Q

Glia Cells

A

-non-neuronal cells
-supportive, homeostasis, regulation

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2
Q

Neuron function

A

Reception, integration, transmission, and transfer of information

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3
Q

Bipolar Neurons

A

-1 dendrite, cell body and 1 axon
-sensory

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4
Q

Pseudounipolar Neurons

A

Dendrites, axon and cell body on side
-motor

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5
Q

Multipolar Neurons

A

Multiple dendrites
-interneurons
-most common

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6
Q

Macroglia

A

-larger supporting cells
-Astrocytes
-Oligodendrocytes
-Schwann Cells

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7
Q

Microglia

A

-immune for CNS
-phagocytes

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8
Q

Astrocytes

A

-macroglia cells in CNS
-support, signal, nutrtients

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9
Q

Oligodendrocytes

A

-macroglia cells in CNS
-create myelin

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10
Q

Schwann Cell

A

-PNS macroglia
-support PNS and make myelin
-does all the job

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11
Q

Local Potential

A

-small, graded
-occurs in receptor or synapse
-spreads passively

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12
Q

Action potential

A

Large “all or none”
-depolarizing

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13
Q

Resting Membrane Potential

A

-70mV

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14
Q

Ion Cell Distribution at Rest

A

More Na+ outside, more K+ inside
-Extracellular positive charge outside
-Intracellular negative charge inside
-more permeable to K+M

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15
Q

Movement of K+ during AP

A

-diffuses down concentration gradient and towards negative charges
-chemical gradient force out, electrical gradient force in

2K+/3Na+

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16
Q

4 Membrane Ion channels

A

Leak (non-gated): small amount leak, K+

Modality-gated: Sensory neurons only; mechanical, temp or chemicals

Ligand-gated: opens when stimulated by neurotransmitters

Voltage-gated: opens when reaction; Ca+

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17
Q

Movement of Na+ during AP

A

-moves through leaky channels and then voltage gated negative charges

2K+/3Na+

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18
Q

Spatial Summation

A

I…..I……I……I

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19
Q

Temporal Summation

A

AP combine to form a large AP.
-Build up of multiple excitatory waves merging

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20
Q

Depolarization

A

-voltage gated channels release Na+ into cell
- polarity becomes positive

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21
Q

Repolarization

A

-Na+ channels close, K+ voltage channels open and release to the outside of the cell

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22
Q

Hyperpolarization

A

K+ gates remain open and cause hypo
-90mV

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23
Q

Absolute Refractory Period

A

completely unresponsive to stimuli
-Na+ has not reset yet

24
Q

Relative Refractory Period

A

May respond to higher stimuli
-Most Na+ resets

25
Q

Factors Influencing AP

A

-diameter of axon, larger=faster
-myelin, more=faster
-temperature, warm=faster

26
Q

Nodes of Ranvier

A

-site of saltatory conduction
-location of AP generation and depolarization
-high density of voltage gated ion channels

27
Q

Conduction Speeds of fibers

A

large myelinated: PNS sensory and motor

Thin unmeylinated:
-short axons in grey matter in CNS
-visceral ANS axons
-pain fibers

28
Q

Muscle Cell AP

A

-90mV RMP
-AP 1-5msec
-18x slower than neuron

29
Q

Presynaptic Terminal

A

-neuron conducting impulse toward synapse
-feet
-release neurotransmitters/neuromodulators

30
Q

Postsynaptic terminal

A

-dendrite or cell body receiving neurotransmitter

31
Q

Axosomatic Synapse

A

-synapse that binds to cell body of another nerve
-local membrane potential

32
Q

Axoaxonic Synapse

A

-synapse that binds to axon of another nerve
-1st neuron activates second
-presynaptic effects

33
Q

Axodendritic

A

-synapse that binds to dendrite of another nerve
-local membrane potential

34
Q

Steps of Synaptic Transmission

A
  1. AP comes to presynaptic terminal
  2. Presynaptic membrane depolarizes and releases Ca+
  3. Ca+ causes vessicles to exocytose neurotransmitters
  4. Neurotransmitter binds to postsynaptic receptor
  5. Postsynaptic receptor opens ion channel or triggers intracellular messengers
35
Q

Excitatory Postsynaptic potential (EPSP)

A

-local depolarization with Na+ or Ca+ into neuron
-facilitates AP generation
-common throughout CNS and PNS

36
Q

Inhibitory Postsynaptic Potential (IPSP)

A

-local hyperpolarization with K+ out of neuron

37
Q

Presynaptic Facilitation

A

-1st presynaptic neuron (Axoaxonic) releases neurotransmitters that attaches to 2nd neurotransmitter (axosomatic) and slightly depolarizes it to releases Ca+

38
Q

Presynaptic Inhibition

A

-1st presynaptic neuron (axoaxonic) causes slight hyperpolarization to decreased Ca+ released from 2nd neuron (axosomatic)

39
Q

Neurotransmitters

A

-fast
-released from synapse
-EPSP and IPSP
-ms to mins

40
Q

Neuromodulators

A

-extracellular space
-alter gene expression, open iono channels, change metabolism, affects many neurons
-mins to days

41
Q

Ligand-Gated Ion Channels

A

-fast response
-aka ionotropic receptor
-some excitatory and inhibitory
-inactivate due to lack of neurotransmitter and resorption

42
Q

Guanine Nucleotide Binding Protein Activation of Ion Channels

A

-alters electrical excitability or neurons
-Neurotransmitter being to G protein and alter the shape
-Internal subunit breaks away and binds to membrane ion channel to change shape and open
-slower than ligand

-Mood disorders, Parkinson’s, Alzheimer’s

43
Q

Agonist

A

-drugs the bind to receptors and copy actions of neurotransmitter

44
Q

Antagonists

A

-drugs that block postsynaptic neurotransmitter
-drugs that inhibit release of neurotransmitter in presynaptic neurons

45
Q

Acetylcholine (Ach)

A

-Neurotransmitter produced in basal forebrain above eyes and midbrain (at top of brainstem)

-Skeletal Muscles: Ach for neuromuscular junctions for muscle contraction. Blocking: causes weakness, fatigue, paralysis

-Autonomic NS: slows HR, constricts pupils

-Brain: Arousal, pleasure, cognitive function, movement and attention. Pleasure seeking behaviors and alzheimers

46
Q

Glutamate

A

-amino acid principal fast neurotransmitter of CNS
-Neural changes w/ learning and development (neuroplasticity)

Excessive:
-excitotoxiciity and neuron death
-seizures

Associated with
-chronic pain, Parkinson’s, schizophrenia, neuron death, stroke

47
Q

GABA

A

-Glycine and y-aminobutyric acid
-animo acid primary inhibitory neurotransmitter that prevent excessive neural activities in CNS (downers)

Glycine: inhibits postsynaptic in brainstem and SC

Low Levels:
-seizure, involuntary muscle contractions, anxiety

48
Q

Huntington’s Disease

A

-causes loss of neurons that use GABA
-causes jerky, involuntary movements and cognitive decline

49
Q

Dopamine

A

-amine neurotransmitter produced in substantia nigra of the brain
-affects motor function, cognition, and behavior, reward seeking behaviors (good for eating, bad for addiction)
-2nd messenger systems

Abnormalities seen in:
-Parkinson’s: not enough dopamine; bradykinesia, treat with precursor
-Schizophrenia: signalling pathways, treat with drugs that prevent binding

Excessive:
-drug abuse by preventing reuptake of presynaptic terminals

50
Q

Norepinephrine

A

-amine neurotransmitter produced in brainstem, hypothalamus, and thalamus
-released by neurons of ANS and adrenal glands
-fight or flight

Excessive:
-fear, panic, PTSD
-beta blockers to treat

Low:
-sleeping
-depression

51
Q

Serotonin

A

-amine neurotransmitter involved with mood, pain, arousal, and motor acitivities

High
-alert and during REM

Low
-depression

52
Q

Opioid Peptides

A

-endogenous: endorphins, enkephalins, dynorphins
-produced in NS and bind to receptors for opium
-receptors in SC, hypothalamus, brainstem to inhibit pain

53
Q

Substance P

A

-peptide that stimulates nerves at injury site

Neurotransmitter: acts on CNS to cary info to brain

Neuromodulator:
-pain syndromes
-hypothalamus and cerebral cortex during long duration excitation
-modulate immune activity during stress

54
Q

Ways to Restrict of # Receptors

A

-internalize receptor
-inactivate receptor

55
Q

Increase of # receptors

A

-infrequent activate
-low levels of neurotransmitters

56
Q

Lamber-Eaton Syndrome

A

-antibodies damage Ca channels in presynaptic membrane
-no Ach release
-muscle weakness

57
Q

Myasthenia Gravis

A

-antibodies damage receptors on muscle cells
-Ach released but cannot bind
-muscle fatigue
-life threatening