Lesson 5: Neurotransmitters
Soma (cell body) & Axon terminal
Most neurons also do get a smaller number of synapses that don't come through the dendrites, but come through the?
Endorphins
Natural, opiatelike neurotransmitters linked to pain control and pleasure
Structural neuroplasticity
Neuroplasticity can occur at the level of entire cells where the total # of synapses between a neuron and its target cell are changed. This we call?
Synaptic neuroplasticity
Neuroplasticity that happens at a synapse is called?
Acetylcholine
Neurotransmitter that enables muscle action, learning, and memory
Norepinephrine
Neurotransmitter that helps control alertness and arousal
Dopamine
Neurotransmitter that influences movement, learning, attention, and emotion
Glutamate
Neurotransmitter that's involved in memory, but an over-supply can wig out the brain and cause seizures and migraines
Excitatory or Inhibitory
Neurotransmitters can be?
Serotonin, Histamine, Dopamine, Epinephrine, & Norepinephrine
The 5 monoamine neurotransmitters that are most important include?
Glutamate, GABA, & glycine
The 3 types of amino acid neurotransmitters are?
Multiple sclerosis
A chronic, typically progressive disease involving damage to the (myelin) sheaths of nerve cells (neurons) in the brain and spinal cord
Growth hormone
A hormone that stimulates growth in animal or plant cells, secreted by the pituitary gland
Serotonin
A neurotransmitter that affects your mood, hunger, and sleep
Alzheimer's
A progressive neurological deterioration that can occur in middle or old age, due to generalized degeneration of their acetylcholine in the brain
Catecholamines
A subgroup of the monoamines are called the?
End-feet
In the CNS, covering most of the synapses are the _____ of the astrocytes
Acetylcholine
Another important neurotransmitters that are not part of the amino acid, monoamine, or peptide categories are?
Adrenal glands
Are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. Help trigger fight-or-flight response
Synapses
Are where neurons contact and communicate with their target cells
Blood vessels to secrete substances into the bloodstream, called hormones
Besides synapsing with another neuron, a muscle cell, or a gland cell, which is the other example it can synapse with?
Epinephrine (adrenalin), norepinephrine, and dopamine
The 3 catecholamine neurotransmitters are?
Hormones
Chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues. Some are chemically identical to certain neurotransmitters. Affect our moods, arousal, circadian rhythm, regulate our metabolism, monitor our immune system, signal growth, and help with sexual reproduction.
Synaptic Neuroplasticity is a strengthening or weakening of signal transmission due to an increase or decrease in receptors. These changes may happen over short or long periods of time. Structural Neuroplasticity is a strengthening or weakening of signal transmission due to an increase or decrease in the number of axon terminals and dendrites. These changes typically occur over a long period of time.
Compare Synaptic with Structural Neuroplasticity.
Both of these catecholamines play a key role in controlling alertness and wakefulness. Norepinephrine is known for having local effects as a neurotransmitter, whereas Epinephrine is more known for acting as a hormone and being secreted by the Adrenal Medulla.
Compare the effects that Epinephrine and Norepinephrine have.
1. Re-uptake Pumps. These may be located on the pre-synaptic neuron and astrocyte end feet. They will actively pump neurotransmitters out of the synapse. 2. Diffusion. Neurotransmitters may simply float out and away from the synapse. 3. Enzymes. Some enzymes actively break down neurotransmitters in the synapse.
Describe how each of the following may help clear out neurotransmitters from the synaptic cleft. 1. Re-uptake Pumps 2. Diffusion 3. Enzymes
Monoamines have a single amine group, aromatic group, and a two carbon link between the two.
Describe the key structural characteristics of monoamines.
Slow frequency
Diffusion removal of a neurotransmitter from a synapse only works if the action potential is firing at a?
(D) Norepinephrine, anxiety and mania Low levels of Norepinephrine are associated with depression; high levels are associated with Anxiety and Mania.
Fill in the blanks: Low levels of ________________ are associated with depression; high levels are associated with ____________________. (A) Epinephrine, bipolar disorder (B) Norepinephrine, bipolar disorder (C) Epinephrine, anxiety and mania (D) Norepinephrine, anxiety and mania
(B) Electrical, Chemical Electrical Synapses are common in both smooth muscle and in cardiac muscle to coordinate contraction; Chemical Synapses are most often seen in the Nervous System.
Fill in the blanks: ____________ Synapses are common in both smooth muscle and in cardiac muscle to coordinate contraction; ___________ Synapses are most often seen in the Nervous System. (A) Electrical, Electrical (B) Electrical, Chemical (C) Chemical, Electrical (D) Chemical, Chemical
Chemically-gated channels
In these channels, we're talking about receptors, so when the neurotransmitters gap with it they can open it up, which can move us towards or away from an action potential
Brain
GABA is the most common inhibitory neurotransmitter in the?
Spinal cord
Glycine is the most common inhibitory neurotransmitter in the?
A) Enzymatic deactivation Neurotransmitters bind to specific receptors on the postsynaptic membrane, and are removed from the membrane in a specific way. When the structure of a neurotransmitter is changed, it is not recognized by the receptor. Acetylcholine is deactivated by acetylcholinesterase, which is an enzyme that breaks down acetylcholine into choline and acetate.
How is acetylcholine removed from the postsynaptic membrane? A) Enzymatic deactivation B) Diffusion C) Reuptake pumps D) Astrocyte pumps
(D) I, II and III Each of the following are symptoms to expect if Calcium could not be cleared from cells: I. Increased Neurotransmitter release II. Increased Protein Hormone Secretion III. Increased Muscle Contractions (initially)
Imagine that someone has a defect in Calcium pumps that made them non-functional, leaving Calcium inside the cell for extended periods of time. Which of the following symptoms would you expect? I. Increased Neurotransmitter release II. Increased Protein Hormone Secretion III. Increased Muscle Contractions (initially) (A) I only (B) I and II only (C) I and III only (D) I, II and III
Gap junctions
In electrical synapses, there are special channels called _____ that actually let the inside of the neuron communicate with the inside of the target cell
Chemical synapses
In humans, are the chemical or electrical synapses more common?
Sprouting, Pruning
In structural plasticity, potentiation can lead to something called _____ when dendrites and axon terminals get longer and more branched or depression can lead to something called ___ where parts of a neuron can be lost
Increased, Decreased
In synaptic neuroplasticity, potentiation can lead to a ____ response and depression can lead to a ____ response
Long-term potentiation
Is a persistent strengthening of synapses based on recent patterns of activity by addition of receptors. These are patterns of synaptic activity that produce a long-lasting increase in signal transmission between two neurons
Glutamate
Is the most common excitatory neurotransmitter of the nervous system
Presynaptic vesicles
Just on the inside of the presynaptic membrane are vesicles, which are little membrane-enclosed bubbles inside the cytoplasm of the neuron, and these are called?
Schizophrenia
Linked to excessive amounts of dopamine. A long-term psychiatric disorder of a type involving a breakdown in the relation between thought, emotion, and behavior. Also addictive and impulsive behavior.
Depression
Low amounts of serotonin are linked to?
Receptors
On the postsynaptic membrane there are _____ that are specific for the neurotransmitter that are in presynaptic membrane
A) Serotonin
One specific type of antidepressant medication works by blocking the removal of neurotransmitters. Which of the following neurotransmitters is most likely the target of the antidepressant medication? A) Serotonin B) GABA C) Acetylcholine D) Dopamine
Neuroplasticity
Referes to how the nervous system changes in response to experience. Changes in synapses or other parts of neurons that affect how information is processed and transmitted in the nervous system
Adrenal glands, pancreas, thyroid glands, parathyroid glands, testes, ovaries, hypothalamus, and pituitary gland
Some important hormone brewing glands of the endocrine system include?
Potentiation & Depression
The 2 directions in which neuroplasticity can go is?
Calcium (Ca2+)
The action potential travels down the axon and reaches the pre-synaptic terminal depolarizing the membrane in the pre-synaptic terminal. The depolarization causes the voltage-gated ____ channels to open allowing the influx of ____ that signals the release of neurotransmitter into the synaptic cleft
Endorphins/Opioids
The common peptide neurotransmitter that plays a role in our perception of pain are the?
Surface area
The dendrites are branched so they could have more _____ to form more synapses
Synaptic cleft
The gap between the chemical synapse is called a?
Development of the nervous system
The level of neuroplasticity is the highest during?
Attention, cognition, and emotion
The monoamines have important functions in the brain such as handling our?
GABA & Glycine
The most common inhibitory neurotransmitters of the nervous system are?
Pituitary gland
The most important of the endocrine glands that controls the function of most of the other glands and is sometimes called the master gland is the?
Hypothalamus
The part of the brain that controls the pituitary gland
Growth hormone and oxytocin
The pituitary gland secretes?
Depression
The strength of information flowing through a particular part of the nervous system decrease, which we call?
Potentiation
The strength of information flowing through a particular part of the nervous system increase, which we call?
Presynaptic membrane
The structure on the axon terminal that's before the synaptic cleft is called the?
Postsynaptic membrane
The structure that's located after the synaptic cleft is called the?
Dendrites
The synapses first come into contact with the?
Neurotransmitters
The synaptic vesicles inside of the presynaptic membrane carry?
Electrical synapse The cytoplasm of the 2 are connected and ions can flow directly from the neuron into the target cell. Also have gap junctions
The type of synapse that doesn't have a gap and the cells are physically connected is called a?
Chemical synapse Because it releases molecules, or chemicals, at the synapse that cross from the axon terminal to the membrane of the target cell
The type of synapse that has a gap is called a?
Amino acids, Peptides, & Monoamines (& other)
The types of neurotransmitters include?
(D) Mg2+ The Chief Cells in the Parathyroid Gland use Magnesium cations to trigger vesicular release, because of its similar structure.
There are certain types of cells which will not rely upon Calcium to trigger Vesicular Release, like the Chief Cells in the Parathyroid Gland that would release Parathyroid Hormone (which increases Calcium). Which molecule would you expect these cells to use to trigger Vesicular Release? (A) K+ (B) Na+ (C) Cl- (D) Mg2+
A) Metabotropic neurotransmitter receptors move more slowly than ionotropic neurotransmitter receptors. Ionotropic neurotransmitter receptors are the type of receptor that directly allows ions to pass through the membranes. Metabotropic neurotransmitter receptors are the type of receptor that activate a second messenger inside the neuron. Metabotropic neurotransmitter receptors move more slowly than ionotropic receptors, but their results may be larger and more widespread.
There are two main types of neurotransmitter receptors. Which of the following statements about receptors accurately describes how they function? A) Metabotropic neurotransmitter receptors move more slowly than ionotropic neurotransmitter receptors. B) Ionotropic neurotransmitter receptors activate a second messenger inside the neuron. C) Ionotropic neurotransmitter receptors move more slowly than metabotropic neurotransmitter receptors. D) Metabotropic neurotransmitter receptors directly allow ions to pass through the membrane.
Acetylcholine & Dopamine
These 2 neurotransmitters can be either excitatory or inhibitory
Voltage-gated channels
These channels are important in the transmission of the action potential
Leak channels
These channels are used with sodium and potassium and establishes the resting potential
Excitatory
These type of neurotransmitters let sodium in to start depolarizing to trigger an action potential
Inhibitory
These types of neurotransmitters allow potassium out or chloride in and they're stopping a message from being sent
Pancreas
This endocrine gland consists of two major hormones which are insulin, which acts to lower blood sugar, and glucagon, which acts to raise blood sugar
Thyroid gland
This endocrine gland secretes hormones that affects metabolism.
Parathyroid Gland
This endocrine gland secretes hormones that help regulate levels of calcium in blood
Catechol group
This is a part of a catecholamine, which is the?
Endocrine System
This system is the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream
False. The amount of neurotransmitter released into the synaptic cleft is dependent on the frequency of action potentials being fired down the axon of the neuron. Remember, action potentials are all-or-none signals that do not have varying strengths. A higher action potential frequency will cause more openings of the calcium channels to open, more calcium will flow in, and the increased concentration of calcium will cause a greater amount of neurotransmitter release.
True or False? The amount of neurotransmitter released into the synaptic cleft is dependent on the intensity of the action potential that went down the axon.
True. Each of the three major Catecholamines play key roles in experiencing emotions.
True or false? Each of the three major Catecholamines play key roles in experiencing emotions.
True. The Calcium mechanisms that are used to trigger neurotransmitter release from vesicles can also be used for most Protein Hormones stored in vesicles.
True or false? The Calcium mechanisms that are used to trigger neurotransmitter release from vesicles can also be used for most Protein Hormones stored in vesicles.
Leak, voltage-gated, and chemically-gated channels
What are the 3 channels involved in a neuron?
Diffusion, Enzymes, Reuptake pumps (Active transport channels), & Astrocyte end-feet pumps
What are the ways that a neurotransmitter can be removed from a synapse?
They're fast, but there's no control
What is good and then bad about electrical synapses?
Ca2+ will signal to the synaptic vesicles to fuse with the pre-synaptic membrane, and release their neurotransmitters into the synapse.
What is the role of Ca2+ in the release of neurotransmitters?
Calcium will flow INTO the membrane, since it is at a higher concentration outside than inside.
When an action potential comes down an axon and reaches the axon terminal, the action potential will change the membrane potential at the axon terminal and open Ca2+ gated voltage channels. Will calcium flow into the membrane or out?
A) Ca2+
Which of the follow voltage-gated channel is present at the axon terminal that aids in neurotransmitter release? A) Ca2+ B) Ca+ C) K+ D) Na+
(B) Electrical Electrical synapses have gap junctions between its axon terminal and the membrane of the target cell, directly causing depolarization.
Which of the following best describes a synapse that has gap junctions between its axon terminal and the membrane of the target cell, directly causing depolarization? (A) Potential (B) Electrical (C) Chemical (D) Kinetic
(D) I and II only While all three amino acids are neurotransmitters, only I and II describe them correctly with their function. Glutamate is mostly excitatory. GABA and Glycine are mostly inhibitory.
Which of the following correctly matchs the type of amino acid neurotransmitter with its function. I. Glutamate - Excitatory II. GABA - Inhibitory III. Glycine - Excitatory (A) I only (B) II only (C) II and III only (D) I and II only
(C) Chemical
Which of the following describes a synapse that has a gap between it's axon terminal and the membrane of the target cell? (A) Potential (B) Electrical (C) Chemical (D) Kinetic
C) Action potentials ultimately result in more calcium leaving the target cell at the post synaptic membrane. Action potentials determine how much information is released into the synaptic cleft. Action potentials also determine how long information is present in the synaptic cleft. Action potentials open voltage gated calcium channels, which results in calcium flowing into the axon terminal. Action potentials do not result in calcium leaving the target cell at the post synaptic membrane.
Which of the following statements about action potentials and information transmission in the synaptic cleft is false? A) Action potentials ultimately result in more calcium entering the neuron at the axon terminal. B) Action potentials determine the duration that neurotransmitters are released into the synaptic cleft. C) Action potentials ultimately result in more calcium leaving the target cell at the post synaptic membrane. D) Action potentials determine the amount of neurotransmitters that are released into the synaptic cleft.
A) Structural depression Depression refers to neuroplasticity that results in activity and response growing weaker. Potentiation refers to neuroplasticity that activity and response growing stronger. Synaptic refers to neuroplasticity that occurs at a synapse. Structural refers to neuroplasticity that affects whole neurons or groups of neurons. In this example, the loss of entire neurons due to inactivity would refer to structural depression.
Which of the following terms describes the type of plasticity that occurs when entire neurons are lost due to decreased activity? A) Structural depression B) Synaptic potentiation C) Synaptic depression D) Structural potentiation
Because allowing Chlorine to enter the neuron will decrease the membrane potential, this would be an Inhibitory Neurotransmitter. This one would function a lot like GABA!
You have just discovered a new neurotransmitter, and you want to see what it does! After many blocking experiments, you see that this neurotransmitter specifically allows Chlorine to enter the neuron. Would this be an Excitatory or Inhibitory Neurotransmitter?
Reuptake
is the reabsorption of a neurotransmitter by a neurotransmitter transporter located along the plasma membrane of an axon terminal (i.e., the pre-synaptic neuron at a synapse) or glial cell after it has performed its function of transmitting a neural impulse