43 terms

Chapter 8 - Nuerons

Physionlogy Chapter 8
STUDY
PLAY
...
How is information from action potentials encoded?
...
...
Why can't an action potential flow backwards?
...
...
If an axon's diameter is increased, how will this affect the speed of an action potential?
...
...
What is Saltatory Conduction of Action Potentials?
...
...
What has gone wrong in people with multiple sclerosis?
...
...
What is Hyperkaleia?

What are it's implications?
...
...
What is Hypokaleia?

What are it's implications?
...
...
Where can you find electrical synapses?
...
...
What is another name(s) for the axon terminal?
Presynaptic terminal

Synaptic bouton
...
Why are callcium currents ESSENTIAL for chemical synaptic transmission?
...
...
Describe the steps for an action potential causing a response in a postynaptic cell.
...
...
Describe the re-cycling cycle of acetylcholine
...
...
What are four basic characteristics of Action Potentials?
...
...
What are 3 different fates of released neurotransmitters?
...
What is Electrical Synaptic Transmission?
Pre-synaptic and post-synaptic neurons (or other cell types) are connected by Gap Junctions. Electrical and some chemical signals can flow from one cell to the other without crossing a cleft
What are Neurocrines?

What are the different types and how are they different?
signaling molecules that are secreted by neurons


There are 3 different groups of neurocrine molecules - these divisions are based on their modes of action:

1.) Neurotransmitters: act locally & rapidly

2.) Neuromodulators: act locally but more slowly because more steps are involved (2nd messenger signaling)


3.) Neurohormones: act at greater distances & more slowly. Time is required for bloodstream to deliver the molecule to distant target cells. Many steps may be involved in producing responses.
...
Some examples of Neurocrine Molecules:
...
What are the two basic types of receptors for Neurocrine Molecules?
1.) IONOTROPIC RECEPTORS

These contain an integral (built-in) ion channel that is part of the same protein as the receptor. Also known as Receptor Channels or Ligand-Gated Ion Channels.

2.) METABOTROPIC RECEPTORS

These do NOT contain an integral ion channel. Linked to intracellular signaling pathways. May influence ion channels indirectly.
Give an example of an ionotropic and metabotropic receptors for Acetylcholine (ACh)
1.) Nicotinic ACh Receptors (nAChRs) are ionotropic.

- activated by nicotine in tobacco.

2.) Muscarinic AChRs (mAChRs) are metabotropic.

- activated by muscarine from mushrooms.
- coupled to heterotrimeric G proteins
- activate intracellular 2nd messenger pathways.
EPSPs
Excitatory Post-Synaptic Potentials

A transient change in membrane potential that makes post-synaptic neuron more likely to fire an AP
IPSPs
Inhibitory Post-Synaptic Potentials

A transient change in membrane potential that makes post-synaptic neuron less likely to fire an AP
Synaptic Plasticity
Defined as a transient or permanent change in the effectiveness (efficacy) of synaptic transmission

It can be:

Short-term (transient) synaptic plasticity:
May last for seconds or minutes or hours.

or

Long-term synaptic plasticity:
May last for days, weeks, months, years or for the lifetime of the organism (e.g., in learning).
What are two forms of Synaptic Plasticity?
Synaptic Inhibition or Depression:
Makes the post-synaptic neuron less likely to fire an AP.



Synaptic Facilitation or Potentiation:
Makes the post-synaptic neuron more likely to fire an AP
What are two diseases of Synaptic Transmission discuses in class?
Myasthenia gravis: an autoimmune disease in which a person's body produces antibodies that bind to and result in the destruction of the nicotinic acetylcholine receptors (nAChRs) at neuromuscular junctions.

Lambert-Eaton Myasthenic Syndrome (LEMS): an autoimmune disease in which a person's body produces antibodies that bind to and result in the destruction of voltage-gated calcium channels (VGCCs), which are essential for synaptic transmission. The loss of VGCCs results in less calcium influx into presynaptic terminals and reduced neurotransmitter release.
...
Which would produce the faster rescponse:

Ionotropic Receptoors or Metabotropic receptors?
...
...
What are three fates of a neurotransmitter?
...
...
Differentiate between divergent and convergent neural pathways.

What do call branched axons?
...
...
How many synapses can a single neuron cell form from with presynaptic terminals?
...
...
What does a Perkinje neuron look like?
...
...
What is Synaptic Integration?
...
...
Synamptic inibition
...
...
What is Temporal Summation?
...
...
What do dendritic spines look like?
...
...
What are some important features of dendritic spines?
...
...
Where does presynaptic inhibition occur?
...
...
Where does postysnaptic Inhibition occur?
...
...
What is Long-Term Potentiation (LTP)
...
...
What are the steps involved in LTP?

Use Glutamate as an example
...
Drugs often exert their main effects by Altering Synaptic Transmission.

What does Xanax (Alprazolam) effect?
potentiates GABA-mediated synaptic transmission.
Drugs often exert their main effects by Altering Synaptic Transmission.

What does Hydrocodon, Oxycontin effect?
synthetic opiates that bind opioid receptors (GPCRs)
Drugs often exert their main effects by Altering Synaptic Transmission.

What does Marijuana effect?
binds Cannabinoid Receptors (GPCRs)
Drugs often exert their main effects by Altering Synaptic Transmission.

What does Heroin effect?
binds opioid receptors (GPCRs)
Drugs often exert their main effects by Altering Synaptic Transmission.

What do Anti-depressants effect?
block reuptake of 5-HT.