Lecture 3: Structure And Function Of Synapses Flashcards
What type of neurotransmitter elicits fast acting effects on muscle membrane?
Acetylcholine (ach)
Cocaine and amphetamines directly affect dopamine signaling by interfering with dopamine ________ into the presynaptic neuron
reuptake
Where a neuron and a postsynaptic cell communicate is called the _______
synapse
Each nerve cell makes and receives up to how many synaptic connections with others?
10,000
Conducts impulses toward the synapse
presynaptic neuron
Conducts impulses away from the synapse
postsynaptic neuron
There are two types of synapses; what are they?
Chemical synapse
Electrical synapse
An increase in the strength or duration of an excitatory stimulus to the presynaptic cell results in the release of _______ quantities of neurotransmitter
greater
The place between the two terminals
synaptic cleft
Chemicals that transmit information across the cleft
neurotransmitters
distance between pre and post cell membrane: 3.5 nm
gap junction
cytoplasmic continuity between pre to post synaptic cell
agent of transmission : ion current
virtually no synaptic delay
bi-directional direction of transmission
Electrical Synapses
distance between pre and post cell membrane: 20-40 nm
Synaptic cleft
NO cytoplasmic continuity between pre to post synaptic cell
agent of transmission : chemical neurotransmitter
synaptic delay of 1-5 ms or longer
uni-directional direction of transmission
Chemical Synapses
Axon to dendrite synapses are called
Axodendritic
Axon to axon synapses are called
Axoaxonic
Axon to cell body synapses are called
Axosomatic
Dendrite to dendrite synapses are called
dendrodendritic
The advantage of using neurotransmitters it that the nerve impulse can be given some more ____________
specificity
Neurotransmitters can control the operation of the nervous system by __________ or __________
inhibition
exhibition
Signal can be modulated (amplified or degraded) based on specific type of ________ ___________
synaptic connections
Local changes in ion concentration across the post synaptic membrane are called:
post-synaptic potentials
Local depolarization allowing the flow of NA+ or Ca2+ into the neuron (ex. Ach in muscle)
EPSP
excitatory post synaptic potential
Local hyperpolarization allowing the flow of Cl- into the cell or K+ out of the cell
ISPS
Inhibitory post synaptic potential
How do the multiple inputs combine to determine the output firing pattern of a neuron?
Synaptic integration: spatial and temporal summation
Released at specific synapses
act DIRECTLY on postsynaptic ion channels (ionotropic) of a neuron or activate proteins (metabotropic) inside the postsynaptic neuron
neurotransmitters
released into extracellular space
affect a group of neurons
manifest more slowly and last longer than neurotransmitters
Neuromodulators
List the types of neurotransmitters (7) (AGGDNSS)
Acetylcholine Glutamate GABA Dopamine Norepinephrine Serotonin Substance P
All neurons that synapse with skeletal muscles use _________ to elicit fast-acting effects on muscle membrane
Acetylcholine
Ach is an Excitatory neurotransmitter found in neuromuscular junctions involved in ________ ____________
muscular contractions
In the brain, Ach acts as a slow ______________ in control of movement and attention
neuromodulator
________ works on Ach receptors by mimicking Ach. It can artificially move skeletal muscles, leading to slight trembling movements
Nicotine
low levels of Ach are found in those with __________ _______
Alzheimer’s disease
What is the major, fast excitatory neurotransmitter of the CNS?
glutamate
Too much glutamate is involved in _________ _________
epileptic seizures
__________ is involved with learning and development
glutamate
The release of neurotransmitters from an axon terminal can be ___________ or _________ by the chemical action at the axoaxonic synapse
facilitated
inhibited
The most prevalent fast-acting neurotransmitters are _________ (excitatory) and ____ (inhibitory)
glutamate
GABA
When in low supply, this neurotransmitter can cause neural over-activity (ie seizures and unwanted skeletal muscle contractions) and anxiety
GABA
_______ mimics GABA
Alcohol
__________ _______ involves loss of neurons in striatum that utilize GABA
Symptoms: Jerky involuntary movements and mental deterioration
Huntington’s disease
_________, __, _________, and _________ function as slow acting neurotransmitters and neuromodulators
Dopamine
Ne
Serotonin
Histamine
Affects motor activity, cognition, and behavior
Involved in movement, attention, and learning
Also pleasure and rewarding sensations
Dopamine
Too much dopamine is involved in ____________
Schizophrenia
Parkinson’s disease: loss of ________ -producing neurons in the substantial nigra
symptoms include:
difficulty starting and stopping voluntary movements
tremors at rest
stooped posture
rigidity
poor balance
dopamine
What neurotransmitter is responsible for around and increasing attention to sensory information?
NE
Excessive levels of NE can produce _____ _______, the abrupt onset of intense terror and hallucinations combined with signs of increased sympathetic nervous system activity
panic disorder
PTSD often involves excessive ___
NE
Low levels of NE are found while sleeping and in those with __________
depression
Involved in mood, perception of pain, general arousal level, and can suppress sensory information
Serotonin
Highest levels occurs with alertness and lowest levels occur during REM sleep
serotonin
Prozac works by keeping serotonin in the _______ longer, giving to more time to exert an effect
synapse
One of the most common nucleopeptides
Substance P
In PNS, substance P stimulates nerve endings to transmit ____ messages to the brain
pain
In CNS, P acts as a ______________, producing long-duration excitation of postsynaptic cells.
neuromodulator
Modulates the immune system and neuronal activity in times of high stress
substance P
Synaptic receptors are typically named for the neurotransmitters to which they ____.
Bind
The effects of a neurotransmitter is based not one the chemical itself, but one the type of _________ to which it binds
receptor
Lock and key analogy:
_______ lock
________ Key
receptor site
neurotransmitter
Ionotropic receptors have _____ synaptic transmission, directly activating the ion channels
fast
Metibotropic receptors have ____ synaptic transmission and act through G proteins. They can cause persistent opening of membrane channels
slow
The ______ _________ ______ is responsible for some of the most profound, longest lasting changes in the nervous system
second messenger system
effect of drugs on nervous system tissues
neuropharmacology
mimics actions of naturally occurring neurotransmitters
Agonist
Impedes the effects of a naturally occurring transmitter such as preventing the release of neurotransmitter or binding to the receptors
Antagonists
Describe Myasthenia Gravis
Damage to the nicotinic postsynaptic receptors on muscle cells
Adequate Ach is being produced but few receptors are available for binding
Repetitive use of muscles leads to weakness and fatigue
Improves after periods of rest
Describe Lamber-Eaton syndrome
Damage to voltage-gated Ca2+ channels in presynaptic terminal
Decreased release of Ca2+ into neurotransmitter
Decreased excitation of muscle
Lead to muscle weakness