1. Agenda 5/2 Nervous System Quick Recap Mock Exam Score ‘meetings’
MC Reflection/exam study guide
Homework: Independent Studying
Turn in: Nothing
*Place phones in folders*

2. Falling phase of the action potential 3
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
The raised voltage opened many more potassium channels than usual, and some of these do not close right away when the membrane returns to its normal resting voltage. Hence, there is an undershoot or hyperpolarization that persists until the membrane potassium permeability returns to its usual value.
Time
OUTSIDE OF CELL
Sodium channel
Potassium channel
INSIDE OF CELL
Inactivation loop 1
Resting state 5
Undershoot 2

3. Calcium gated channels in the synaptic knob
Note the structural features that allow the cell to cell communication to occur in the synaptic region:
Calcium gated channels in the synaptic knob
Sodium channels in the post-synaptic membrane
Fluidity of the lipid bi-layer allows for exocytosis of the neurotransmitter
The transfer of information that occurs at the synapse is a classic example of cell to cell communication. The membrane is specifically adapted for this task. The synaptic knob membrane contains voltage gated Ca2+ channels, the post synaptic membrane contains receptor-bearing sodium, Na+ channels, and the fluidity of the membrane allows for the fusion of vesicles.

4. Cell To Cell Communication Events
Action potential depolarized the membrane of synaptic terminal, this triggers an influx of Ca2+.
That causes synaptic vesicles to fuse with the membrane of the pre-synaptic neuron.
Vesicles release neurotransmitter molecules into the synaptic cleft.
Neurotransmitters bind to the receptors of ion channels embedded in the postsynaptic membrane.

5. The process of contraction requires the input of ATP to “reset” the myosin head of the thick filament. This is why muscles consume large amounts of energy.

6. Ask them to think about what they would say if they were narrating this video clip.

7. Point out that the contraction requires the presence of calcium ions to expose the myosin binding sites.