Transcript bio 342 human physiology

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
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)
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
Nervous tissue = Neurons (for electrical signalling) and Glial cells (for…..)
Know relative numbers (neurons:glia) and
various functions of CNS Glial cell types.
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
Nodes of Ranvier ~1mm apart
In PNS
Not all axons are
Fig. 06.02
myelinated, although all
axons are enveloped by
Schwann cells in CNS or
Oligodendrocytes in PNS
What are the advantages
of myelination?
In CNS
Lightly myelinated axon
Communication in The Vertebrate NS
Reflexes require
some part of the
CNS (i.e. frog lab)
Peripheral nerves are
“mixed” (have sensory &
motor axons)
Blood pressure
Blood gases and pH
Muscle stretch
Skin temperature
Hair movement
Light
Taste
Odor
Touch
Pain
Etc.
Signalling over short and long distances
Dimensions of neurons
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?
Fig. 06.03
Axonal Transport
• Orthograde = Anterograde = from soma
to terminals
– slow……1-2 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…
Who
Cares?
Alayna Davis
October 1992 Age 5
October 31, 1992
October 1998
Regeneration in CNS?