Synapses Flashcards
What is the function of synapses
Send information to another cell or target
Pre-synaptic part of the synapse
Axon
Post-synaptic part of the synapse
Dendrite
What are the types of synapses?
- Axo-somatic
- Axo-dendridic
- Axo-axonal (right by presynaptic terminal)
Do synapses with different locations have different functions?
The axo-somatic and axo-dendridic synapses send information. Axa-axonal synapses modulate how much neurotransmitter is released by the second neuron.
What type of ion channels do APs open in the presynaptic terminal?
Voltage-gated calcium ion channels
What happens when calcium enters the presynaptic terminal?
Calcium activates a series of proteins and enzymes, which moves the vesicles to the presynaptic terminal and releases neurotransmitters into the synaptic cleft
What determines how much neurotransmitter is released?
The amount of calcium that enters the presynaptic terminal (more calcium = more neurotransmitter); determine by how many and how long voltage gated-ion channels are opened
What ion channels are involved in EPSPs?
Na and Ca ion channels
What ion channels are involved in IPSPs?
K and Cl ion channels
In the nervous system, EPSPs can summate to generate an action potential. What kinds of summation are used to do this?
Temporal and Spatial; usually need summation to fire AP
Do you need summation at the NMJ to produce EPSP in the muscle to produce a muscle contraction?
No, an AP in the motor neuron is sufficient
What happens when there are both EPSPs and IPSPs at a postsynaptic neuron?
Summation is important here - depends on which potential summation is stronger
With presynaptic facilitation, the synapses are axon-______. An [inhibitory/excitatory] synapse neuron (1) makes an action potential in the 2nd neuron last [longer/shorter] and [increases/decreases] the number of calcium ions that enter the presynaptic terminal.
Axo-axonal; excitatory; longer; increases
{Depolarization}
With presynaptic inhibition, an action potential in the 2nd neuron last [longer/shorter] and [increases/decreases] the number of calcium ions that enter the presynaptic terminal.
shorter; decreases
{Hyperpolarization}
Collection of neuorns in one region that communicate among themselves to process things
Local circuits
Generalized information that goes from one point to wide-spread regions of the nervous system; i.e., level of arousal, sympathetic nervous system
Diffuse systems
Transmit specific information from one point to another; i.e., making your thumb move
Relay systems
What are the two receptors for ACh?
- Nicotinic
2. Muscarinic
What makes acetylcholine? what breaks it down?
Choline acetyltransferase (CAT); Acytlcholineesterase (AChE)
What are the type of receptors at the NMJ that bind ACh? What is its function?
Nicotinic; contraction of muscles
What are the type of receptors in the autonomic nervous system that bind ACh? What is its function?
Muscarinic (target) and nicotinic (postganglionic neuron); Regulate visceral function
What are the type of receptors in the central nervous system that bind ACh? What is its function?
Nicotinic and muscarinic; autonomic regulation and selection of objects of attention
What are the main neurotransmitters of central nervous system?
Amino acids (aspartate, glutamate, glycine, GABA)
