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Nervous
Tissue Activities
1) Make clay models of or draw the various structural
types of neurons (K).
2) Draw the human body and label various
organs/structures including: eyes, heart, bladder, leg muscles, arm
muscles, fingertips. Utilizing the various scenarios below draw nerve
impulse pathways and label which nervous system divisions are involved
in each scenario and pathway (K, V).
a) A person sees a lion
approaching and heart rate increases.
b) A person sees a lion
and runs away.
c) The bladder fills with
urine and sends message “urinate.”
d) A person touches a
cactus and pulls hand away.
e) Make up your own
scenario.
3) Membrane potential simulations. (K, V).
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Draw a multipolar neuron on a large piece
of paper or use the one in lab.
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Draw active pumps and passive diffusion
channels (more for K+ and fewer for Na+). In the
lab neuron, these are drawn in the cell body, though they would be found
throughout the neuron.
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Draw acetylcholine (ACh) receptors on the
dendrites; These also might be found on other parts of neurons, such as
the cell body.
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On the axolemma, draw voltage-regulated
gates (VRGs) for Na+ and K+. On the lab neuron, K+
VRGs are on one side and Na+ VRGs on the other, but in
reality, these would be interspersed throughout that axolemma.
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Utilize the chips provided to represent Na+
= yellow and K+ = red or use different coins for each ion.
Move these chips in response to gates opening and closing.
Resting Membrane Potential (RMP)
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Move 3 Na+ out and 2 K+
in at the active pumps in the cell body. Repeat 3-4 times.
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Allow diffusion of the K+ and Na+
down their concentration gradient with more K+ out than Na+
because there are more passive K+ channels. However,
concentrations won’t equalize because K+ is going against an
electrical gradient.
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Observe the unequal distribution of Na+
and K+ found with RMP.
Local depolarization (AKA
postsynaptic potential if ACh released from another neuron)
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Use a bead or another coin to represent ACh.
Release the ACh from the presynaptic neurons into the synaptic cleft,
and attach to the ACh receptors on the dendrites.
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Na+ now rushes in to cause
depolarization. The more ACh binds with receptors, the more Na+
rushes in and if strong enough depolarization occurs all the way to the
axon hillock.
Action potential
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If enough Na+ flows in toward
the axon hillock, then the axolemma there depolarizes and if membrane
potential reaches -55 mV, then the VRGs start to open.
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The Na+ VRGs open first and Na+
rushes in. The adjacent axolemma depolarizes. This causes the next Na+
gates to open, and so on. Not all gates are opened at once
because once, some gates are opening, the gates behind it are closing.
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Next, K+ VRGs open and the cell
repolarizes and then hyperpolarizes before K+
gates close.
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Once both gates are closed, the membrane
potential is restored as described in RMP.
Central
Nervous System
Brain
Tour - You are a tour guide for a tourist
attraction called the Amazing Human Brain.
Draw the brain with its different parts and write a tour brochure of the
brain with highlights on function and anatomy. (R,V)
Take someone else on that tour (A, K).
back to 2113 VARK
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