NURS 2090 Lecture Notes - Peristalsis, Basal Ganglia, Major Depressive Episode

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Published on 16 Apr 2013
School
Dalhousie University
Department
Nursing
Course
NURS 2090
Altered Neuronal Transmission
Neuron Components:
1. Cell body/ Soma: filled with cytoplasm + nucleus
2. Dendrites: branched ends that transmit impulses to the cell body
3. Axon: carry impulses away from cell body
Functional Types:
1. Sensory/Afferent: carry impulses from receptors in periphery of brain + SC → CNS
2. Motor/Efferent: carry impulses away from brain + SC → target in body that regulates
activity
3. Interneuron: most abundant, are connections btw neurons, transmitting signals btw
afferent/efferent
Supporting cells:
1. Glia: provides support + nutrition, maintain homeostasis and form myelin that covers
neurons in the brain.
2. Oligodendrocytes: myelin segments around multilayered axons in the brain (CNS)
3. Schwann Cells: myelin on single axon in PNS
Membrane Potential: Difference in electrical charge between the inside and outside of the cell
Action Potential: * polarized at rest! (inside = more negative, difference = -70mV)
1. Resting membrane potential: state of tension inside CM
2. Depolarization phase: rapid movement of Na into cell through Na channels in CM
3. Repolarization phase: efflux of K+
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Neural Communication: Flow of information across a synapse
1. Electrical: through gap junctions, fast and direct, multidirectional
2. Chemical: neurotransmitters between nerve cells/excitable cells, unidirectional
Synapse structures
1. Presynaptic terminal
2. Synaptic cleft
3. Postsynaptic membrane
Action Potential
Hypopolarization: towards threshold (more positive, less negative)
Hyperpolarization: away from threshold (more negative) ** promotes inhibition
Interruption of NT:
1. Reuptake
2. Diffusion
3. Enzymatic Breakdown
Types of NT:
1. Amino acids: glutamic acid, GABA
2. Peptides: endorphins, Substance P
3. Monoamines: Serotonin, dopamine, NE
Neuromodulators:
Can alter effects of NT
Are released from axon terminals
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Nervous System Organization
Central Nervous System
Lobes: are divided by sulci (fissures), and gyri (convolutions)
Hemispheres: R/L
Spinal cord: central to control reflex response
1. Ventral horns: (Anterior extensions)
Efferent motor neurons leaving cord (via ventral roots)
2. Dorsal horns: (Posterior extensions)
Sensory neurons receiving afferent impulses (via dorsal roots)
Spinal Cord Structures Dorsal root: of each spinal nerve is
specialized to carry incoming sensory
info.
Dorsal root ganglia: are swellings in
the dorsal root just before they enter the
cord which contains cell bodies of
sensory neurons
Ventral root: carries info from CNS to
muscles/glands.
Ascending tracts: take sensory info to
the brain (dorsal/external lateral part)
Descending tracts: carry mostly efferent (motor) signals from the brain to the cord
(ventral/interior lateral portion of white matter)
Frontal: reasoning, planning, speech and
movement
Parietal: perception of touch, pressure,
temperature and pain
Temporal: perception, memory, and
recognition of auditory stimuli
Occiptal: vision
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Document Summary

Altered neuronal transmission: cell body/ soma: filled with cytoplasm + nucleus, dendrites: branched ends that transmit impulses to the cell body, axon: carry impulses away from cell body. Supporting cells: glia: provides support + nutrition, maintain homeostasis and form myelin that covers neurons in the brain, oligodendrocytes: myelin segments around multilayered axons in the brain (cns, schwann cells: myelin on single axon in pns. Membrane potential: difference in electrical charge between the inside and outside of the cell. Neural communication: flow of information across a synapse: electrical: through gap junctions, fast and direct, multidirectional, chemical: neurotransmitters between nerve cells/excitable cells, unidirectional. Synapse structures: presynaptic terminal, synaptic cleft, postsynaptic membrane. Hyperpolarization: away from threshold (more negative) ** promotes inhibition. Interruption of nt: reuptake, diffusion, enzymatic breakdown. Types of nt: amino acids: glutamic acid, gaba, peptides: endorphins, substance p, monoamines: serotonin, dopamine, ne. Lobes: are divided by sulci (fissures), and gyri (convolutions) Parietal: perception of touch, pressure, temperature and pain.

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