1. 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 & website over weekend for updates

2. 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
Ohm’s Law
Origin of resting membrane potential
Equilibrium Potentials (Nernst potentials)

3. Important Terms (we’ll 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
Interneuron
Schwann cell
Axon with axon hillock
Oligodendrocyte
Synapse
Ependymal cell
Axonal pathfinding
Efferent Neuron

4. Nervous tissue = Neurons (for electrical signalling) and Glial cells (for…..)
06.06.jpg
Know relative numbers (neurons:glia) and various functions of CNS Glial cell types.

5. 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

6. Lightly myelinated axon
Fig
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
06.02.jpg
In CNS
Lightly myelinated axon

7. 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
Touch
Pain
Etc.
Peripheral nerves are “mixed” (have sensory & motor axons)
Signalling over short and long distances
Dimensions of neurons

8. Descending neurons (interneurons) from brain to spinal cord
Sensory (afferent) neurons from hoof to brain
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?

9. Fig
06.03.jpg

10. Axonal Transport Orthograde = Anterograde = from soma to terminals
slow……1-2 mm/day
fast … mm/day (kinesin)
Retrograde = from terminals to soma
fast… mm/day (dynein)
What gets transported and why?
Axonal transport is too slow for rapid signalling, so…

11. Who Cares?

13. Alayna Davis
October Age 5
October 1998
October 31, 1992

15. Regeneration in CNS?