Neurons and Drugs

Question 0

What are glial Cells and what are they used for?

Answer 0

Glial cells are what hold neurons in place while providing nutrients for them and absorbing toxins and wastes…. extra: glial cells outnumber neurons 10:1

Question 1

What are the 3 components of a neuron? and what are their functions

Answer 1

the three components of neuron:

1. soma (cell body .. contains nucleus of neuron)
2. Dendrites (receiving units of neuron)
3. Axon (conducts electrical impulses away from dendrite to axon terminal)

Question 2

What is the blood-brain barrier?

Answer 2

Its the barrier that prevents toxins from entering the brain… it is composed of small gaps in blood vessels and covered in a special kind of glial cell… they keep foreign substances from gaining access to the brain

Question 3

What are 2 main functions of a neuron?

Answer 3

2 main functions are:

1. To convert electricity (electrical impulses) to neuron impulses
2. Release chemicals to other parts of the body (other neurons, muscles and organs) as a form of communication

Question 4

Describe the neuron in polarization? (resting state)

Answer 4

The neuron in resting potential has a outside positive charge and an inside membrane charge of -70milliVolts. The outside is positive due to the sodium ions and the inside is negative due to large anions (this is why its polarized)

Question 5

What is going on in the gates and channels of a neuron during rest?

Answer 5

• potassium channels are open during rest and allow the flow of potassium inside and outside of the membrane
• Sodium channels are closed
• Sodium/potassium pump is open

Question 6

What happens to the channels during depolarization? and what happens to the neuron during this time?

Answer 6

Depolarization is when an electrical impulse hits the neuron. At this time, more Sodium flows inside of the membrane making it go from -70mV to +40mV

• Sodium potassium pump closes
• Potassium channels close
• Sodium channel opens

Question 7

What happens during restoration or refractory period?

Answer 7

During restoration, the neuron needs to go back to polarized state.

• Sodium channel closes
• Potassium opens
• Sodium potassium opens
• During refractory period, no action potential can be caused because the cell is undergoing restoration

Question 8

What is the all or none response?

Answer 8

All or none response is when an action potential either occurs or doesnt occur which all depends on whether or not the electrical stimulation passes a certain threshold (called the action potential threshold) … this threshold occurs anywhere between -50mV to -70mV

Question 9

What are graded potentials?

Answer 9

graded potentials are stimulations that do not pass the action potential threshold therefore do not cause depolarization. Graded potentials can however, build up in the axon terminal and can trigger a action potential if they pass the threshold

Question 10

What is a myelin sheath?

Answer 10

Myelin sheath is a white fatty layer made up of glial cells that insulates certain parts of the neuron.

Question 11

What are the parts that do not have a myelin sheath called?

Answer 11

Theyre called nodes of ranvier, they are made up of grey matter and conduct electricity very well (this is where action potential happens)

Question 12

What arises when the immune system attacks the myelin in the neurons?

Answer 12

Multiple Sclerosis. It disrupts the timing of the nerve impulses because the immune system tries to get rid of the myelin which leads too jerky movements, uncoordinated movements and eventually paralysis

Question 13

What is a synapse?

Answer 13

A synapse is a functional and not physical connection between a neuron and its target. What arises from a synpase is a synaptic cleft which is the space in between the neuron and its target

Question 14

What is the role of neurotransmitters?

Answer 14

Neurotransmitters are chemicals made in neurons that carry messages across the synaptic cleft to either excite the other neuron or inhibit it from firing.

Question 15

What are the 5 steps involved in the synaptic connection between neurons and neurotransmitters?

Answer 15

1. Synthesize —> neurotransmitters are formed as chemical molecules inside the neuron
2. Storage —-> neurotransmitters are stored in synaptic vesicles in axon terminals
3. Release –> neurotransmitters get released from their vesicles into the synaptic cleft
4. Bind –> neurotransmitters bind with receptor sites in the post synaptic neuron and either form an excitatory effect or inhibitory
5. Destruction –> neurotransmitter gets either decomposed using an enzyme or it gets reuptaked by the presynaptic neuron

Question 16

What causes a neurotransmitter to be excitatory and what causes it to be an inhibitory?

Answer 16

Excitatory neurotransmitters cause depolarization (inflow of sodium) into the post synaptic cell membrane
Inhibitory neurotransmitters release highly negative anions into the post synaptic membrane that causes hyper polarization and prevents depolarization which causes an inhibitory effect

Question 17

What are 2 ways of destruction or deactivation of a neurotransmitter?

Answer 17

1. Enzymes breaking it down in the synapse

2. Reuptake of the neurotransmitter by presynaptic neuron

Question 18

What are 2 roles of psychoactive drugs?

Answer 18

1. Mimics a neurotransmitter and binds to its receptor sites
2. Targets the steps in synthesis and release of the neurotransmitter

Question 19

What is Glutamate? Is it excitatory or inhibitory? What results in over/under activation

Answer 19

Glutamate is a excitatory neurotransmitter that is involved in learning and memory. Over activation of glutamate results in seizures

Question 20

What is GABA? Is it excitatory or inhibitory? What results in over/under activation

Answer 20

GABA is a inhibitory neurotransmitter involved in anxiety control and motor control. Underactivation of GABA results in Huntington’s disease which is tremors and loss of motor control.

Question 21

What is AcH (acetylcholine)? Is it excitatory or inhibitory? What results in over/under activation

Answer 21

AcH is a excitatory neurotransmitter that is involved in memory and muscular movement. Over activation of AcH results in muscle contractions and convulsions… Under Activation of AcH causes Alzheimer’s which is loss of memory

Question 22

What is Norepinephrine? Is it excitatory or inhibitory? What results in over/under activation

Answer 22

Norepinephrine is an excitatory and inhibitory neurotransmitter depending on where it is released. It plays a role in learning, memory, wakefulness, and eating. Over activation of norepinephrine causes panic attacks and stress.. Under Activation causes depression

Question 23

What is Serotonin? Is it excitatory or inhibitory? What results in over/under activation

Answer 23

Serotonin is an inhibitory neurotransmitter that is involved in mood, sleep, eating, arousal/pleasure/pain… underactivation causes depression, sleeping and eating disorders

Question 24

What is Dopamine? Is it excitatory or inhibitory? What results in over/under activation

Answer 24

Dopamine is both an excitatory and inhibitory neurotransmitter, it is involved in voluntary movement, emotional arousal, learning, motivation or experiencing pleasure. An over activation of dopamine causes schizophrenia and hallucinations. Under activation of dopamine causes Parkingson’s disease (loss of voluntary motor control) and depression

Question 25

What is Endorphin? Is it excitatory or inhibitory? What results in over/under activation

Answer 25

Endorphin is an inhibitory neurotransmitter that is involved in inhibition of pain impulse. Over activation of endorphins causes insensitivity to pain, and under activation to endorphins causes hypersensitivity and pain

Question 26

What are the 2 most widespread neurotransmitters?

Answer 26

GABA and Glutamate

Question 27

What happens to the body during botulism (fatal blood poisoning) and from the bite of a black widow?

Answer 27

Botulism —> blocks the release of acetylcholine which causes fatal paralysis because AcH is involved in involuntary motor control
Bite of a black widow —> Causes most release of AcH which causes violent muscle contractions and convulsions that can lead to death

Question 28

How does the antidepressant Prozac increase serotonin levels in the brain

Answer 28

It prevents the reuptake of serotonin in the synapse

Question 29

How do other anti depressants increase serotonin levels in the brain?

Answer 29

They deactivate serotonin degrading enzymes

Question 30

What do drugs like opium and morphin do to the brain and what neurotransmitter do they mimic?

Answer 30

They mimic endorphins (pain inhibitors), and they bind to the same receptor sites of endorphins and cause a painless feeling

Question 31

What are neuromodulators?

Answer 31

they are the neurotransmitters that have the most widespread and generalized influence on synaptic transmission —> they can either increase or decrease sensitivity of neurons to their transmitters and play important roles in eating, sleeping and stress

Question 32

What are agonist drugs? and what three things do they do?

Answer 32

Agonist drugs:

1) increase the synthesis, storage, and release of neurotransmitters
2) mimic the action of a neurotransmitter by binding with and stimulation post synaptic receptor sites
2) make it difficult for neurotransmitters to be deactivated by inhibiting their reuptake

Question 33

What are Antagonist drugs?

Answer 33

antagonist drugs:

1) reduce the synthesis, storage and reuptake of a neurotransmitter
2) prevent a neurotransmitter from binding to post synaptic receptor sites

Question 34

What is alcohol an example of, an antagonist drug or an agonist drug? What neurotransmitters does it have an effect on, and what results from that effect?

Answer 34

Alcohol is an agonist to GABA which depresses neural activity, and it is an antagonist to Glutamate. Together, it inhibits normal brain functions like clear thinking, emotional control and motor control

Question 35

What is caffeine an example of, an antagonist drug or an agonist drug? What neurotransmitters does it have an effect on, and what results from that effect?

Answer 35

Caffeine is an antagonist to the neurotransmitter adenosine. Adenosine inhibits release of excitatory neurotransmitters. By, not releasing adenosine, there will be excessive amounts of excitatory neurotransmitters being released in the brain which produces higher rates of cellular activity

Question 36

What is nicotine an example of, an antagonist drug or an agonist drug? What neurotransmitters does it have an effect on, and what results from that effect?

Answer 36

Nicotine is an agonist to dopamine and acetylcholine. It mimics acetylcholine and dopamine and binds to their receptor sites… this cause feelings of motivation and reward and also increases memory and learning.

Question 37

What are amphetamines an example of, an antagonist drug or an agonist drug? What neurotransmitters do they have an effect on, and what results from that effect?

Answer 37

Amphetamines are agonist to norepepinephrine and dopamine.
They release more of these neurotransmitters into the synapse and also inhibit their reuptake, therefore making them stay in the synapse longer… this causes feelings of euphoria, alertness, reward and increased muscular strength