APHY 101 Ch 12: Nervous System and
Nervous Tissue Ivy Tech
1. Absolute Refractory Period - ANS-During this period the membrane cannot respond to
further stimulation.
2. Action Potential - ANS-If the graded potential reaches threshold at the axon hillock, it
triggers this potential in the excitable membrane of the axon. It is an electrical event that
is due to sequential opening and closing of sodium and potassium voltage-gated
channels. It spreads along the surface of an axon toward the axon terminals.
3. Action Potentials - ANS-Propagated changes in the membrane potential that, once
initiated, affect an entire excitable membrane. This potential depends on voltage-gated
channels.
4. adequate stimulus - ANS-Stimulus to which a nerve receptor is most sensitive. Touch for
touch receptors, light for photoreceptors, stretch for stretch receptors, etc.
5. Afferent Fibers - ANS-Axons that carry sensory information to the CNS.
6. All or None Principle - ANS-A given stimulus either triggers a typical action potential by
reaching threshold voltage, or it does not trigger one at all.
7. Astrocytes - ANS-These cells maintain the blood-brain barrier. They also provide
structural support within neural tissue; regulate ion, nutrient, and dissolved gas
concentrations in the interstitial fluid surrounding the neurons; absorb and recycle
neurotransmitters that are not broken down or reabsorbed at synapses; and form scar
tissue after CNS injury.
8. at the nodes of Ranvier - ANS-In myelinated axons, action potentials take place (at the
dendrites, at the nodes of Ranvier, at the cell body)
9. Autonomic Nervous System - ANS-(ANS) Automatically regulates smooth muscle,
cardiac muscle, glands, and adipose tissue.
10. Axolemma - ANS-A specialized portion of the plasma membrane that surrounds the
cytoplasm (axoplasm) of the axon.
11. Axon - ANS-Carries information away from the cell body and toward other cells. Can
convey action potentials due to the presence of voltage-gated channels.
12. Axon Hillock - ANS-Origin of the axon from the cell body.
13. Axon Terminals - ANS-The axon ends at this terminal, which is also known as synaptic
terminals, where the neuron communicates with other cells. Synaptic vesicles containing
neurotransmitter are present.
14. axons - ANS-Many neurons have thin extensions along which action potentials can
travel quickly and over long distances. These extensions of the neuron are called (nerve
cells, axons, dendrites).
15. before the voltage-gated potassium channels - ANS-During an action potential,
voltage-gated sodium channels open (before the voltage-gated potassium channels,
, after the voltage-gated sodium channels, at the same time as the voltage-gated
potassium channels).
16. Bipolar Neurons - ANS-These neurons have two distinct processes- one dendritic
process that branches extensively at its distal tip, and one axon with the cell body
between the two. These neurons are rare, but occur in special sense organs, where they
relay sensory information about sight, smell, or hearing from receptor cells to other
neurons.
17. Blood-Brain Barrier - ANS-A barrier that isolates the CNS from the chemicals and
hormones circulating in the blood.
18. calcium - ANS-During an action potential, at the synaptic knob (chloride, calcium,
magnesium) ions enter the terminal to initiate vesicle release.
19. Cell Body (Perikaryon) - ANS-Contains the nucleus and other organelles. Biosynthetic
center of neuron that synthesizes proteins, membranes, and other chemicals. Part of
receptive region and can convey graded potentials to axon hillock due to presence of
ligand-gated channels.
20. Central Nervous System - ANS-(CNS) Consists of the brain and spinal cord. It is
responsible for integrating, processing, and coordinating sensory data and motor
commands.
21. Chemical - ANS-_______________________ synapses transmit signals from one
neuron to another using neurotransmitters.
22. Chemical Gradient - ANS-Difference in solute concentration across the plasma
membrane.
23. Chemical Synapses - ANS-Synapses that rely on neurotransmitter release, are far the
most abundant type of synapse.
24. Continuous Propagation - ANS-The action potential appears to "move" along the
axolemma of an axon as it sequentially opens the voltage gated channels.
25. Dendrites - ANS-Receptive region of the neuron along with the cell body. Receive stimuli
from the environment or from other neurons. Highly branched. Typically covered with
ligand-gated ion channels. Convey incoming messages toward cell body as graded
potentials (short distance signals).
26. Depolarization - ANS-Any shift from the resting potential toward a more positive value.
This applies to changes in potential from -70mV to smaller negative values (toward 0
mV) as well as to membrane potentials above 0 mV.
27. depolarized (less negative) - ANS-An action potential is produced when the membrane
reaches 'threshold,' which is (hyperpolarized (more negative), depolarized (less
negative), neutral) with respect to resting membrane potential
28. Diffusion - ANS-Neurotransmitter crosses the synaptic cleft by
______________________.
29. Effectors - ANS-Target organs (muscles or glands) whose activities change in response
to neural commands.
30. Efferent Fibers - ANS-Axons that carry instructions from the CNS to peripheral tissues.
31. Electrical (Ephatic) Synapse - ANS-At this synapse, the presynaptic and postsymaptic
membranes are locked together by gap junctions. As a result, changes in the membrane
potential of one cell will produce local currents that affect the other cell as if the two
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller LegitPage. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.99. You're not tied to anything after your purchase.
