SYNAPTIC PHYSIOLOGY Flashcards
(101 cards)
1
Q
A functional connection or junction between two nerve cells (neurons)
A
Synapse
2
Q
What types of cells are involved in a synapse?
A
Neurons and other types of cells
3
Q
Axon terminal synapses on the cell body (soma)
A
Axo-somatic Synapse
4
Q
Axon terminal synapses on a dendrite
A
Axo-dendritic Synapse
5
Q
The synapse between two axons
A
Axo-axonic Synapse
6
Q
Synapse between two dendrites
A
Dendro-dentritic Synapse
7
Q
- Blocked in its transmission
- Changed from a single impulse to a repetitive impulse
- Integrated with impulses of other neurons
A
How information is transmitted in the CNS mainly in the form of nerve action potentials
8
Q
[Electrical/Chemical Synapse]
Low-resistance allows current flow directly & passively from one cell to another
A
Electrical Synapse
9
Q
[Electrical/Chemical Synapse]
Fast and bidirectional
A
Electrical Synapse
10
Q
[Electrical/Chemical Synapse]
Found mostly in Central Nervous System (CNS) and ciliary ganglia in eye muscles
A
Electrical Synapse
11
Q
[Electrical/Chemical Synapse]
Unidirectional transmission
A
Chemical Synapse
12
Q
[Electrical/Chemical Synapse]
Neurotransmitter binds to receptors on post-synaptic neurons altering their membrane potential
A
Chemical Synapse
13
Q
[Neuroreceptors/Autoreceptors]
Receptors found on the presynaptic neuron
A
Autoreceptors
14
Q
[Neuroreceptors/Autoreceptors]
Produce presynaptic inhibition
A
Autoreceptors
15
Q
[Neuroreceptors/Autoreceptors]
Lessen the number of chemical messengers able to bind with the receptors in the post-synaptic neuron
A
Autoreceptors
16
Q
[Neuroreceptors/Autoreceptors]
Chemical-gated ion channels in the membrane of the cell that is receiving the nerve impulse (post-synaptic neuron)
A
Neuroreceptors
17
Q
Substance that mediates chemical signaling between neurons
A
Neurotransmitters
18
Q
Production and storage of neurotransmitters
A
Vesicles at the axon terminal
19
Q
2 Types of Neurotransmitter Receptors
A
- Ionotropic Receptors
- Metabotropic Receptors
20
Q
What leads to the release of neurotransmitters?
A
Increase in intracellular Ca2+ levels
21
Q
How is a neurotransmitter released from the axon terminal?
A
Via exocytosis
22
Q
[Ionotropic/Metabotropic Receptors]
Ionic channels themselves
A
Ionotropic Receptors
23
Q
[Ionotropic/Metabotropic Receptors]
Fast responses due to binding of ligand to receptors
A
Ionotropic Receptors
24
Q
[Ionotropic/Metabotropic Receptors]
Act indirectly on separate ion channels through a G protein and/or second messenger
A
Metabotropic Receptors
25
[Ionotropic/Metabotropic Receptors]
Slower response due to the use of 2nd messengers to relay signal
Metabotropic Receptors
26
[Ionotropic/Metabotropic Receptors]
Biochemical events will happen before the expected result comes through
Metabotropic Receptors
27
2 Types of Post-synaptic Potentials
Excitatory Postsynaptic Potential (EPSP)
Inhibitory Postsynaptic Potential (IPSP)
28
[EPSP/IPSP]
Excitatory chemical synapses generate an EPSP, which brings the membrane potential closer to threshold
EPSP
29
[EPSP/IPSP]
Usual effect is to open non-selective Na+ and K+ channels
EPSP
30
[EPSP/IPSP]
Inhibitory chemical synapses generate IPSP, which makes the membrane potential more negative
IPSP
31
[EPSP/IPSP]
Open Cl- and K+ channels
IPSP
32
- Tetanus toxin
- Prevents vesicle fusion with membrane
- Causes increased muscle contraction
Clostridium tetani
33
- Causes muscle paralysis by inhibiting neurotransmitter release
- Bacili toxin (Botulism)
- Interferes with SNARE proteins at excitatory synapses that activate muscles
Clostridium botulinum
34
What are the therapeutic uses of low doses of botulinum toxin (Botox)?
Treating facial wrinkles, severe sweating, uncontrollable blinking, and misalignment of the eyes
35
What must be removed to terminate the signal in a chemical synapse?
Neurotransmitter
36
How is the removal of neurotransmitters accomplished in a chemical response?
Through diffusion of transmitter from the cleft, degregation of transmitter by enzymes, and reuptake into the pre-synaptic cells for reuse
37
The alteration of the efficacy of synaptic transmission by fine-tuning or changing a signal from EPSP to IPSP
Neuromodulation
38
Site of ACh production and enzyme involved
Presynaptic axon and Choline Acetyl Tranferase (CAT)
39
[Intrinsic/Extrinsic]
Both from one presynaptic neuron
Intrinsic
40
[Intrinsic/Extrinsic]
Two different synaptic neurons releasing neuropeptides
Extrinsic
41
What are the two types of receptors for neuromodulators?
Muscarinic and Nicotinic receptors
42
- Modify both the presynaptic and the postsynaptic cell's responses to specific transmitters
- Tend to be associated with slower events
Neuromodulators
43
- Bring about changes in metabolic processes in neurons
- Can occur over minutes, hours or days
Neuromodulator receptors
44
What enzyme is responsible for the synthesis of acetylcholine?
Choline aceytl transferase (CAT)
45
- Released by cholinergic neurons are both found in CNS and PNS
- Acts at muscarinic (G-protein coupled) or nicotinic (ion channels) receptors
Acetylcholine
46
[Muscarinic/Nicotinic Receptors]
Mostly in the parasympathetic nervous system
Muscarinic Receptors (M1 to M5)
47
[Muscarinic/Nicotinic Receptors]
Found at neuromuscular junctions of skeletal muscles and both sympathetic and parasympathetic nervous systems
Nicotinic Receptors
48
It causes paralysis
a. Overstimulation
b. Desensitization
b. Desensitization
49
Causes uncontrolled muscle contractions
a. Overstimulation
b. Desensitization
a. Overstimulation
50
Sarin receptors
- Overstimulation
- Desensitization
51
What is the initial treatment for alleviating symptoms of Parkinson's disease?
Drug L-Dopa
52
Neurons associated with the ACh system degenerate in people with this disease
Alzheimer's disease
53
- Loss of dopamine-releasing neurons in the substantia nigra
- Not curative
Parkinson's disease
54
An experimental treatment for Parkinson's disease involving the surgical implantation of electrodes
Deep brain stimulation
55
A type of cell transplant used in experimental treatments for Parkinson's disease
Fetal/stem cell transplants
56
Which biogenic amines are involved in Parkinson's disease?
- Dopamine
- Norepinephrine
- Epinephrine
57
- Classical modulator with multiple effects
- Mainly excretory chemical inducing physical & mental arousal
- Mediates heart rate, bp, rate of glycogen
Norepinephrine and Epinephrine
58
Where is NE utilized as a neurotransmitter?
In the CNS and PNS
59
Where is Epi mainly utilized as a neurotransmitter?
Mainly in the PNS
60
What types of receptors are adrenergic receptors?
G protein coupled receptors
61
To what are adrenergic receptors generally linked?
Second messenger presetssignal transduction pathways
62
What is another name for Biogenic Amines?
5-hydroxytryptamine or 5-HT
63
Where are the majority of Biogenic Amines, specifically serotonin, found in the body?
Enterochromaffin cells in the gut (90%)
64
Besides the gut, where else are Biogenic Amines, specifically serotonin, found in the body?
Platelets and immune cells (8%)
Brain stem (1-2%)
65
Inhibits pain pathways in the spinal cord and higher regions of the nervous system and helps control mood
Serotonin
66
What is the major location of histamine in the CNS?
Hypothalamus
67
What type of actions is histamine commonly known for?
Paracrine actions
68
What is histamine involved in?
Allergic reactions, nerve sensitization, and acid production in the stomach
69
The primary neurotransmitter at 50% of the excitatory synapses in the CNS.
Glutamate
70
What is the cooperative activity of AMPA and NMDA receptors implicated in?
Long-term potentiation (LTP), a cellular process underlying learning and memory
71
What is excitotoxicity related to NMDA receptors?
Injury caused by excessively stimulating nearby neurons, leading to toxic levels of intracellular Ca2+
72
What is the main function of GABA neurons in the brain?
Dampen activity within neural circuits
73
What is the result of GABA binding to ionotropic receptors?
Increases Cl- flux into the cell, resulting in hyperpolarization of the postsynaptic membrane
74
What are some compounds that have additional binding sites on the GABA receptor?
Steroids, barbiturates, and benzodiazepines
75
How do benzodiazepine drugs like alprazolam affect the GABA receptor?
They increase Cl- flux through the GABA receptor, reducing anxiety, guarding against seizures, and inducing sleep
76
Which amino acid from inhibitory interneurons in the spinal cord and brainstem binds to ionotropic receptors on postsynaptic cells?
a. GABA
b. Glycine
b. Glycine
77
Causing convulsions and spastic contractions of skeletal muscles
Strychnine poisoning
78
Short chains of amino acids with peptide bonds are released by neurons and act on receptors throughout the CNS.
Neuropeptides
79
What are the mechanisms of action of neuropeptides?
They are released to terminals, acted upon by peptidases, and can work synergistically with classic neurotransmitters
80
What are neuropeptides known as endogenous opioids?
Enkephalins and endorphins
81
What are morphine and codeine primarily used for?
Pain relief, including anesthesia
82
What neuropeptide is released by afferent neurons involved in pain sensation?
Substance P
83
How are gases like nitric oxide released?
- Not released by exocytosis of presynaptic vesicles
- Produced by enzymes in axon terminals
84
What happens to nitric oxide once in the target cell?
Activates cGMP signaling pathways
85
What medical condition is associated with cGMP signaling pathways and nitric oxide?
Erectile dysfunction
86
Where is adenosine present?
In all pre-synaptic vesicles
87
What triggers the release of adenosine?
Ca2+ influx into the terminal
88
What kind of receptors does adenosine have?
Both presynaptic and postsynaptic receptors
89
Where can adenosine act as a transmitter?
At synapses in PNS and CNS
90
What is adenosine responsible for in small purines?
Sympathetic vasoconstriction
91
What is the function of Acetylcholine in the heart?
Inhibiting heart muscle, specifically through the vagus nerve
92
Neurotransmitters that INCREASE the likelihood of an action potential in the postsynaptic neuron.
Excitatory neurotransmitters
93
Neurotransmitters that DECREASE the likelihood of an action potential in the postsynaptic neuron.
Inhibitory neurotransmitters
94
- Released by neurons that originate in the substantia nigra
- Primarily inhibitory transmitter
Dopamine
95
What channels open when dopamine is released?
Na+ channels
96
What channels open when GABA is released?
Cl- channels
97
What happens when Na+ channels open in the neuron?
Na+ ions enter the cell
98
What happens when Cl- and K+ channels open in the neuron?
Cl- ions enter and K+ ions exit the cell
99
What happens to the charge inside the cell during depolarization?
It becomes less negative
100
What happens to the charge inside the cell during hyperpolarization?
It becomes more negative
101
A change in the membrane potential that makes it less negative, increasing the likelihood of an action potential.
Depolarization
