1. Neurons, Synapses and Signaling

2. Dendrites Stimulus Axon hillock Nucleus Cell body Presynaptic cell
Figure 48.4
Dendrites
Stimulus
Axon hillock
Nucleus
Cell body
Presynaptic cell
Axon
Signal direction
Synapse
Synaptic terminals
Figure 48.4 Neuron structure and organization.
Synaptic terminals
Postsynaptic cell
Neurotransmitter

3. Table 48.1 Ion Concentrations Inside and Outside of Mammalian Neurons

4. Sodium- potassium pump
Figure 48.7
Key
Na K
Sodium- potassium pump
OUTSIDE OF CELL
Potassium channel
Sodium channel
Figure 48.7 The basis of the membrane potential.
INSIDE OF CELL

5. 140 mM KCl 150 mM NaCl Inner chamber  90 mV Inner chamber  62 mV
Figure 48.8
Inner chamber
 90 mV
Inner chamber
 62 mV
Outer chamber
Outer chamber
140 mM KCl
5 mM KCl
15 mM NaCl
150 mM NaCl
Cl K
Na
Cl
Potassium channel
Sodium channel
Artificial membrane
Figure 48.8 Modeling a mammalian neuron.
(a)
Membrane selectively permeable to K
(b)
Membrane selectively permeable to Na
EK  62 mV
 90 mV
ENa  62 mV
 62 mV

6. Strong depolarizing stimulus
Figure 48.10
Stimulus
Stimulus
Strong depolarizing stimulus
50
50
50
Action potential
Membrane potential (mV)
Membrane potential (mV)
Membrane potential (mV)
Threshold
Threshold
Threshold
50
50
50
Resting potential
Resting potential
Resting potential
Hyperpolarizations
Depolarizations
100
100
100
Figure Graded potentials and an action potential in a neuron. 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 6
Time (msec)
Time (msec)
Time (msec)
(a)
Graded hyperpolarizations produced by two stimuli that increase membrane permeability to K
(b)
Graded hyperpolarizations produced by two stimuli that increase membrane permeability to Na
(c)
Action potential triggered by a depolarization that reaches the threshold

7. Falling phase of the action potential 3
Figure
Key
Na K 4
Falling phase of the action potential 3
Rising phase of the action potential
50
Action potential 3
Membrane potential (mV)
Threshold 4 2
50 1 1 5 2
Depolarization
Resting potential
100
Figure The role of voltage-gated ion channels in the generation of an action potential.
Time
OUTSIDE OF CELL
Sodium channel
Potassium channel
INSIDE OF CELL
Inactivation loop 1
Resting state 5
Undershoot

8. Axon Plasma membrane Action potential 1 Cytosol Action potential 2
Figure
Axon
Plasma membrane
Action potential 1
Cytosol
Na
Action potential K 2
Na
Figure Conduction of an action potential. K
Action potential K 3
Na K

9. Nucleus of Schwann cell Axon Myelin sheath
Figure 48.13
Node of Ranvier
Layers of myelin
Axon
Schwann cell
Schwann cell
Nodes of Ranvier
Nucleus of Schwann cell
Axon
Myelin sheath
Figure Schwann cells and the myelin sheath.
0.1 m

10. Presynaptic cell Synaptic cleft
Figure 48.15
Presynaptic cell
Postsynaptic cell
Axon
Synaptic vesicle containing neurotransmitter 1
Postsynaptic membrane
Synaptic cleft
Presynaptic membrane 3
Figure A chemical synapse. K
Ca2 2
Voltage-gated Ca2 channel
Ligand-gated ion channels 4
Na

11. Figure 48.17 Summation of postsynaptic potentials.
Terminal branch of presynaptic neuron E1 E1 E1 E1 E2 E2 E2 E2
Postsynaptic neuron
Axon hillock I I I I
Threshold of axon of postsynaptic neuron
Action potential
Action potential
Membrane potential (mV)
Resting potential
Figure Summation of postsynaptic potentials.
70 E1 E1 E1 E1
E1  E2 E1 I
E1  I
Subthreshold, no summation
(a)
(b) Temporal summation
(c) Spatial summation
Spatial summation of EPSP and IPSP
(d)

12. Concentration That Blocked Naloxone Binding
Figure 48.18
EXPERIMENT
Radioactive naloxone 1
Radioactive naloxone and a test drug are incubated with a protein mixture.
Drug
Protein mixture 2
Proteins are trapped on a filter. Bound naloxone is detected by measuring radioactivity.
RESULTS
Concentration That Blocked Naloxone Binding
Figure INQUIRY: Does the brain have a specific protein receptor for opiates?
Drug
Opiate
Morphine
Yes
6  109 M
Methadone
Yes
2  108 M
Levorphanol
Yes
2  109 M
Phenobarbital No
No effect at 104 M
Atropine No
No effect at 104 M
Serotonin No
No effect at 104 M

13. Membrane potential (mV)
Figure 48.UN01
Action potential
50
Falling phase
Rising phase
Membrane potential (mV)
Threshold (55)
50
Resting potential
Figure 48.UN01 Summary figure, Concept 48.3
70
Depolarization
Undershoot
100 1 2 3 4 5 6
Time (msec)

14. Figure 48.UN03 Appendix A: answer to Figure 48.10 legend question

15. Figure 48.UN04
Figure 48.UN04 Appendix A: answer to Test Your Understanding, question 7