FOM 7.5.1 Flashcards
Name the three types of synapses and describe their morphology.
Axosomatic, axodendritic, axo-axonic
What are the two different synaptic signaling in the axon?
Electrical and Chemical
Describe the chemical synapse.
Vesicle cluster. Clear space b/t membranes (pre- and postsynaptic)
Describe the electrical synapse.
Very close apposition of membranes (Gap junctions), dense material in contact area
What is the sequence of events at the chemical synapse? (10 steps)
1) Neurotransmitter stored in synaptic vesicles 2) Action potential 3) Depolarization, opening of volatage-gated Ca channel 4) Influx of Ca 5) Ca leads to synaptic vesicle fusion 6) NT into synaptic cleft 7) Bind receptor on postsynaptic membrane 8) Open/close postsynaptic channels 9) Change in exitability 10) Retrieval of vesicular membrane, endocytosis using clathrin
What is the name of the 3 SNARE proteins found in the synapse? What are involved in?
Synaptobrevin, Snap-25, syntaxin Synaptic vesicle fusion
What cleaves SNARE proteins resulting in inhibition?
Clostridial toxins (Botulinum toxins - BOTOX)
Is electrical or chemical synaptic transmission faster?
Electrical
Which is larger the neuromuscular junction or hippocampal synapse?
NMJ. Much larger
What are the two autoimmune neuromuscular dz’s? What are the Ab’s targeting in each?
Myasthenia Gravis: postsynaptic acetylcholine receptors Lambert-Eaton Syndrome: Ca channels
What two NT are solely inhibitory?
GABA (CNS) and Glycine (Spinal Cord)
What are three main NT’s that can be both excitatory and inhibitory?
Acetylcholine, Glutamate, Dopamine
What NT is affected in Parkinson’s?
Dopamine
What is responsible for the difference b/t excitatory and inhibitory actions of a particular NT?
Differences in the ligand-gated receptor
Describe the large scale propagation of an action potential.
Sensory signals, motor signals, muscle signals
Describe the shape of an action potential.
Look at picture
What pump is responsible for setting the resting membrane potential?
Na-K pump
Where is Na high and K high?
Na high outside K high (Nah get out, K come in)
What are the two types of driving forces for a potential?
Chemical (concentration) and Electrical
Once the threshold of a potential is reached, which voltage-gated channel opens first? Which one closes last?
Na-gated opens first K-gated closes last
In a nerve cell, where is the action potential generated?
The axon initial segment
What synapses work on the nerve? (hint: they counteract one another)
Excitatory: excitatory postsynaptic potential (EPSP) - depolarization Inhibitory: Inhibitory postsynaptic potential (IPSP) - hyperpolarization
How many axons can one Schwann cell wrap around?
One
What is the name of the junction b/t Schwann cells?
Node of Ranvier
What wraps around multiple axons in the CNS?
Oligodendrocyte
Describe saltatory conduction.
The action potential jumps down the axon. Must cause action potential at the nodes of ranvier.
What is MS?
Multiple Sclerosis; A disease of the central nervous system characterized by a variety of clinical problems arising from multiple regions of demyelination and inflammation along axonal pathways.
