Test 1 Analysis EndoGlucoseThermoNeuroShort Answer HikingOverall Avg Stdev Median Max

This Week in Physiology Class Finish Chapter 6 D Nervous System Do Chapter 7 Sensory Physiology Lab Visual System Part 1 – PPT is posted to password protected website – Text p Sensory Physiology – Cutaneous sites sensitive to four modalities

Anatomy of an Electrical Synapse (aka Gap Junction) Comparison to Chemical Synapses Directionality Response time Sign inversion? Uncommon in human CNS. Common in cardiac muscle and some smooth muscle. S 8 S 1

Figure 6.28 EPSPs :which ion moving in which direction? Duration of PSP vs AP Synaptic delay Some ion Channels that allow flux of Na+ and K+ simultaneously e.g. nicotinic Acetylcholine Receptor (nAChR) S 2 Exercise, Hypokalemia, and Sports Drinks Exercise, Hypokalemia, and Sports Drinks

Figure 6.29 IPSPs :which ion moving in which direction? Some IPSPs result in no change in membrane potential by opening Chloride channels that stabilize membrane potential at resting value (Nernst Potential for Cl- = -70mV) or in cells that actively transport Cl- out. E K+ S 3

Figure 6.33 Presynaptic Facilitation Presynaptic Inhibition Who Cares? Mechanism: vary Ca++ entry in presynaptic terminal B. Size of PSP is Variable! S 4

Figure 6.31 Summation and Synaptic Integration Different timesDifferent locations Challenge question: Suppose each IPSP hyperpolarizes by 5 mV and each EPSP depolarizes by 5 mV. If 4 inhibitory synapses are active at the same time, how many excitatory synapses must be active simultaneously to exceed threshold (-55 mV) if the resting membrane potential is -70mV? S 5

Synapses cover the dendrites and cell body of CNS Neurons What could be conjugated with a red fluorescent marker to reveal synapses? What is gray matter? What is white matter? S 6

Figure 6.24 Section C: Synapses and Synaptic Transmission S 7

Synapses named for NT used: -ergic Examples: Cholinergic Adrenergic Serotonergic GABAergic Peptidergic S 8

Pharmacological agents intended to act in brain must be able to cross blood-brain barrier. Who Cares? Parkinsons Disease Treatments for Parkinsonism: a) tablets of L-Dopa (which crosses the BBB) unlike Dopamine (which would have widespread effects) b) neuronal transplants (self, fetal, stem cell, pig), c) electrical stimulation NIH Stem Cell Information NIH Stem Cell Information S 9