Announcements

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Announcements

• Pick up keep Quiz 1 from piano
• Pick up copy of Androstenedione paper for Lab
  next week
• Monday Quiz on Endocrine Chapter and Case
  Studies Lab
• Check email website over weekend for updates

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Ch 6 Nervous System Part A and B

• Ch 6 Part A Basic terms
• Cell types of Nervous Tissue
• Components of a neuron
• Components of a reflex arc
• Axonal regeneration
• Ohms Law
• Origin of resting membrane potential
• Equilibrium Potentials (Nernst potentials)

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Important Terms (well know these and many more
as we move through Chapter 6
Cell Body (soma)
Afferent Neuron
Astrocyte Astroglia
Axon Terminal
Myelin
Dendrite
Microglia
Node of Ranvier
Neurotransmitter
Schwann cell
Interneuron
Axon with axon hillock
Oligodendrocyte
Synapse
Ependymal cell
Axonal pathfinding
Efferent Neuron
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Nervous tissue Neurons (for electrical
signalling) and Glial cells (for..)
Know relative numbers (neuronsglia) and various
functions of CNS Glial cell types.
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Membrane Potential Structure make Neurons good
Electrical Communicators
ligand-gated ion channels in membranes of
dendrites and soma. Graded potentials
receiving
Axon hillock integrates. Decremental conduction
in dendrites and somatic membranes Unidirectional
Non-decremental conduction in axons
sending
voltage-gated ion channels in membrane of axon
hillock and axon..Action potentials
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Fig. 06.02
Nodes of Ranvier 1mm apart
Not all axons are myelinated, although all axons
are enveloped by Schwann cells in CNS or
Oligodendrocytes in PNS What are the advantages
of myelination?
In PNS
In CNS
Lightly myelinated axon
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Communication in The Vertebrate NS
Reflexes require some part of the CNS (i.e. frog
lab)
Blood pressure Blood gases and pH Muscle stretch
Skin temperature Hair movement Light Taste Odor To
uch Pain Etc.
Peripheral nerves are mixed (have sensory
motor axons)
Signalling over short and long distances
Dimensions of neurons
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Nodes of Ranvier are 1 mm apart. How many
Schwann cells to myelinate the 2 meters of a
sensory axon from hoof to dorsal root ganglion
near spinal cord?
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Fig. 06.03
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Axonal Transport

• Orthograde Anterograde from soma to terminals
• slow1-2 mm/day
• fast ..200-400 mm/day (kinesin)
• Retrograde from terminals to soma
• fast.200-400 mm/day (dynein)
• What gets transported and why?
• Axonal transport is too slow for rapid
  signalling, so

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Who Cares?
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Alayna Davis

• October 1992 Age 5

October 1998
October 31, 1992
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Regeneration in CNS?