NEURO LEC 2: SYNAPSES Flashcards
What are the 3 parts of a synapse?
Pre-synaptic terminal
Synaptic Cleft
Post-synaptic terminal
If a synapse is ______, the presynaptic effect occurs
axoaxonic
a strong excitatory stimulus in the presynaptic terminal leads to ____________.
more ________ leads to larger amount of neuro transmitter released
More action potentials
action potentials
IPSP means what?
Inhibitory post synaptic potential
Local hyperpolarization that occurs with the influx of **Cl- or K+ OUT of neuron **
Remember: Na Ca (NASA) flows in (during EPSP), whereas CL K clocks out! (During IPSP)
Summation of (EPSP OR IPSP) determines whether or not an action potential is generated?
EPSP
What is pre synaptic facilitation
When the 1st presynaptic neuron causes slight local depolarization of a 2nd neurons presynaptic terminal
When an AP arrives, the duration is increased allowing for more CA2+ influx
What is presynaptic inhibition
1st presynaptic neuron causes a 2nd to have local hyperpolarization
therefore when an AP arrives, the duration is decreased allowing less CA2+ influx
What has a longer duration, Neurotransmitters or neuromodulators
Neuromodulators.
Neuromodulators last for **mins to days **whereas neurotransmitters last for milliseconds to Mins
Which of the following use EPSP and IPSP as their method of action.
Neuromodulator or Neurotransmitter
Neurotransmitter
What is the method of action of neuromodulators?
Alter gene expression
open ion channels
change metabolism
affects many neurons
Neurotransmitters act in the synapse whereas neuromodulators act in the ___________
Extra cellular space
Neuro messengers can function as a neuromodulator or neurotransmiter depending on…
If they’re released in the synapse or the extracellular space
The effect of a neurotransmitter is related to
A. Type of receptor
or
B. Type of chemical that the neurotransmitter is
A. type of receptor
Some neurotransmittors can be excitatory in some places and inhibitory in other places
At rest, ligand gated ion channels are _____
Closed
What is a G-Protein?
Guanine Nucleotide binding protein
A protein that alters the electrical excitability of neurons, can activate ion channels
What is faster, a G protein activated channel or a Ligand gated ion channel
Ligand gated
Drug that binds to receptor and copies the action of neurotransmitters
Agonist
Acetylcholine, Glutamate, and GABA are all….
Amino Acids
Dopamine, Norepinephrine, and seratonin are all considered…
Amine
Substance P is considered a…
Peptide
Where is acetylcholine produced
produced in Basal forebrain and midbrain
All neurons that synapse with skeletal muscles use _____ to elicit a fast acting effect on muscle membranes. It’s an excitatory neurotransmitter found in muscle junctions
Acetylcholine (Ach)
Blocking ____ receptors causes weakness, fatigue, and paralysis
Acetylcholine
Acetylcholine effects the Autonomic nervous system by
Slowing HR
Constricting Pupils
and Increases smooth muscle contractions/ digestion
Acetylcholine effects the brain by
Stimulating arousal, pleasure, and cognitive function
Acts as a slow neuromodulator in control of movement and attention
______ is the principal fast excitatory neurotransmitter of the CNS in virtually every brain region and related to neural changes with learning and development
Glutamate
“Glutamate is the most exciting and that’s why he’s our mate”
Glutamate levels must be closely regulated, excess levels can lead to
Excitotoxicity/neuron death
epileptic seizures
______ is the primary inhibitory neurotransmitter in the CNS. Especially with interneurons in the spinal cord
GABA
Alcohol, barbiturate, anticonvulsants, and baclofen mimic what neurotransmitter
GABA (Inhibitor to CNS)
______ inhibits postsynaptic membranes mostly in the brainstem and spinal cord
Glycine
Huntington’s disease causes loss of neurons in the striatum that use _____ with jerky and involuntary movements and cognitive decline
GABA
Dopamine is produced in the _____ of the brain
Substantia Nigra of brain
All receptors of dopamine are _______
Secondary messengers
What disease is associated with a lack of dopamine?
Parkinson’s disease
Secondary messenger systems are typically (faster or slower)
Slower
Excessive ______ levels are seen in cocaine or amphetamine abuse by preventing reuptake by presynaptic terminals
dopamine
Where is norepinephrine produced?
Brainstem, hypothalamus, and thalamus
What neurotransmitter is released by neurons of the autonomic nervous system and secreted by adrenal glands, which is responsible for “fight or flight”
Norepinephrine
Excessive ______ is found in people with PTSD
Norepinephrine
______ is involved in mood, pain perception, arousal, and motor activity
Low levels seen in depression
Lowest during REM sleep
Seratonin
_______ stimulates nerve endings at injury sites
acts as a neurotransmitter carrying CNS information from spinal cord to brain
Substance P
What neurotransmitter can also act as a neuromodulator in pain syndromes, and modulates immune system during times of high stress
Substance P
Lambert Eaton syndrome is….
Antibody damage to volatage gated Ca2+ in presynaptic terminal of neuromuscular junction
-Decreased release of neurotransmitters
-decreased muscle excitation
-muscle weakness
How i will remember: Lambert Eaton needs to eat more calcium because his muscles are weak”
Myasthenia Gravis is…
Antibodies (autoimmue) cause damage to AcH receptors on muscle cells. (You still have plenty of AcH)
-Causes fatigue
-can be life threatening
When a pre-synaptic terminal depolarizes, the voltage gated ____ channels open
Ca+
EPSP means what?
Excitatory Post Synaptic Potential
-The local depolarization that occurs with the flow of Na+ and Ca2+ into the neurons
A summation of EPSP’s facilitates Action Potential generation
When stimulation duration is _____ in the presynaptic cell, the series of action potentials is longer
longer
If a synapse is _____ , _____ or ______ , the ions flow through the ligand-gated channels to cause local membrane potential
Neuromuscular, axosomatic, or axodendritic
(not axoaxonic)
Define a synapse
Where a neuron transfers information to 1 or more neurons/muscle
specialized zone of contact
Receptors for opiod peptides are mainly found where?
Spinal cord, hypothalamus, and brainstem in areas that inhibit pain perception
What are 2 causes of an increase in the number of receptors for a specific neuro transmitter
Infrequent activation or low levels of neurotransmitter
Overstimulation of post synaptic receptors can cause…
A decrease in the number of receptors available
What are two ways that the body restricts the number of receptors available
Inactivate receptors
or Internalize receptors into cell body
What is the 1st and 2nd messenger in the G-Protein second messenger system
1st- Neuromodulator
2nd- Chemical produced inside neuron
What are the 3 steps of a G protein activation of ion channels
- Receptor Protein alters shape and internal G protein is triggered
- G protein subunits break away and bind to ion channels
- Ion channels open
Myasthenia graves destroys what receptors
L
Ach
