Week Three - Neurotransmission & Introduction to Psychopharmacology

Question 1

What do Nerve cells generate?

Answer 1

Electrical signals in order to transmit information

Question 2

Neurons generate what?

Answer 2

A negative potential called the resting membrane potential

Question 3

What does an action potential do?

Answer 3

It abolishes the negative resting potential and makes the transmembrane potential positive

Question 4

What are neurons separated by?

Answer 4

Extracellular fluid which is composed mainly of water

Question 5

What is the cell membrane made up of?

Answer 5

lipid molecules

Question 6

What does the cell membrane do?

Answer 6

Regulates the concentration of salts and other chemicals on either side

Question 7

What are the 3 factors that influence the movements of ions in and out of the cells?

Answer 7

1. Concentration Gradient
2. Voltage Gradient
3. Structure of the membrane

Question 8

Describe the Concentration Gradient

Answer 8

Describes the relative difference in the concentration of a substance at different locations in space when the substance is not evenly dispersed

Question 9

Define the Voltage Gradient

Answer 9

A measure of relative concentrations of electrical charge. Ions will move down a voltage gradient from an area of high charge to an area of low charge

Question 10

What occurs during equilibrium?

Answer 10

One side will be positively charged, while the other will be negatively charged.

Question 11

What are SALTS?

Answer 11

Molecules that separate into two parts when dissolved in water, with one part carrying a positive charge and the other part carrying a negative charge. These charged particles are collectively called IONS

Question 12

What 4 ions charge contributes to the negative charge on the inside of the cell membrane?

Answer 12

sodium, chloride, potassium and large protein anions

Question 13

How do ions flow across the cell membrane?

Answer 13

1. Ligand-gated channels
2. Mechanically-gated channels
3. Voltage-gated channels
4. Leakage channels
5. The Na+ /K+ Pump

Question 14

What are ion transporters and ion channels responsible for?

Answer 14

Ionic movements across neuronal membranes

Question 15

Explain Ligand-gated Channels

Answer 15

Basically a lock and key. Neurotransmitter binds to the channel and opens it, allowing the ions to move in response to gradient

Question 16

What are mechanically-gated channels?

Answer 16

They open when there is a force that activates.

Question 17

What direction does sodium and potassium move?

Answer 17

Sodium = in
Potassium = out

Question 18

What are voltage-gated channels?

Answer 18

When there is a change in voltage, it opens an allows ions through

Question 19

What are leakage channels

Answer 19

Leakage channels randomly open and allows a certain amount of leakage across the concentration gradient

Question 20

Explain the Sodium & Potassium pump

Answer 20

The process of moving sodium and potassium across the cell membrane

it will pump 3 Na ions outside of the cell for every 2 potassium ions pumped inside of the cell

Question 21

The equilibrium potential can be predicted by what formula?

Answer 21

The Nernst equation

Question 22

What is the equilibrium potential?

Answer 22

The voltage at which the ions no longer want to move across the membrane

Question 23

What does the Nernst equation help do?

Answer 23

Calculate equilibrium potential of one ion

Question 24

What can the Goldman equation do?

Answer 24

Calculate equilibrium potential of multiple ions

Question 25

What are postsynaptic potentials?

Answer 25

Graded potentials in the dendrites of a neuron that receives synapses from other cells

Question 26

Excitatory Postsynaptic Potential (EPSP)?

Answer 26

These are depolarisations and increase the likelihood of a neuron firing.

it causes the membrane potential to move toward threshold.

Question 27

Inhibitory postsynaptic potential (IPSP)?

Answer 27

These are hyperpolarisation and decrease the likeliness of a neuron firing.

it causes the membrane potential to move away from threshold.

Question 28

How are EPSP and IPSP transmitted?

Answer 28

decrementally from the site of input, becoming smaller as it stretches across the membrane

Question 29

Where do changes in voltage that produce an action potential come from?

Answer 29

A large influx of Sodium ions and a efflux of potassium ions

Question 30

What is an action potential?

Answer 30

a brief (about 1 ms) change from negative to positive in the trans-membrane potential.

Question 31

AP is said to be all-or-none because?

Answer 31

it occurs fully or not at all.

Question 32

What is the movement of an AP along an axon called?

Answer 32

A nerve impulse

Question 33

What is the resting membrane potential of a cell?

Answer 33

-70mV

Question 34

The mode of conduction is called what?

Answer 34

Saltatory conduction

Question 35

Why is the nerve impulse produced?

Answer 35

Because each AP propagates another AP on an adjacent part of the axon membrane.

Question 36

Where are the neurotransmitters stored before the AP?

Answer 36

In vesicles within the terminal buttons

Question 37

What are neuromodulators?

Answer 37

Like neurotransmitters but do not meet all criteria

Question 38

What are the properties of a neurotransmitter?

Answer 38

be synthesized and stored in the presynaptic neuron.

be released into the synapse when the neuron fires

cause a post-synaptic effect after it interacts with a receptor

there must be some mechanism for degradation or reuptake

Question 39

How are neurotransmitters synthesised?

Answer 39

from precursors under the influence of synthesising enzymes

Question 40

Released NT molecules bind to what?

Answer 40

postsynaptic receptors

Question 41

What are the 2 major types of postsynaptic receptors?

Answer 41

Ionotropic and metabotropic

Question 42

What are second messengers?

Answer 42

intracellular signalling molecules released by the cell in response to exposure to extracellular signalling molecules (i.e., the first messengers)

Question 43

What do agonistic drugs do?

Answer 43

Increases synthesis of NT
Increases no. of NT molecules
Increases release of NT
Binds to autoreceptors and blocks their inhibitory effect
Binds to postsynaptic receptors and either activates or increases effect

Question 44

What do antagonistic

Answer 44

Blocks, inhibits and reduces the role and function of NT

Question 45

What do amino acid transmitters do?

Answer 45

Provide both the majority of excitatory and inhibitory NT in the NS

Question 46

What is the major excitatory NT?

Answer 46

Glutamate

Question 47

What is the major inhibitory NT?

Answer 47

GABA

Question 48

Where does GABA uptake occur?

Answer 48

In neurons and glial cells

Question 49

Define all concepts of Acetylcholine (ACh)

what does it do

what affects it

Answer 49

The first neurotransmitter ever discovered

controlling heart rate, acetylcholine plays an important role in motor movement, as it is the neurotransmitter released from motor neurons onto muscle fibres to make them contract. Role in memory - Alzheimer’s disease involves a degeneration of acetylcholine neurons in the basal forebrain – drugs that increase ACh availability are used for treatment.

Toxins such as botulism, nerve gas, and black widow spider venom interfere with acetylcholine transmission and produce paralysis.

Question 50

What are Norepinephrine, Epinephrine, Dopamine, Serotonin known as?

Answer 50

Catecholamines

Question 51

Define all concepts of Norepinephrine

what does it do

what affects it

Answer 51

Norepinephrine is distributed throughout the central and peripheral nervous systems.

The noradrenergic neurons originate in the pons of the brainstem in a region called the locus coeruleus.

They form an excitatory pathway to the cortex known as the reticular activating system (RAS).

This system is primarily responsible for maintaining cortical arousal.

Structures that are innervated by NE include the thalamus, the hypothalamus, and virtually all other limbic structures.

NE is involved in controlling attention, emotion, and eating.

Noradrenergic neurons also play important roles in the peripheral nervous system regulating organs such as the heart.

Deficiencies in norepinephrine activity are linked to depression and to attention deficit disorders.

Question 52

What 2 pathways is dopamine located?

Answer 52

The nigrostriatal pathway begins in the brainstem area called the substantia nigra. The primary function of these structures involves voluntary movement. Deficiencies in dopamine in the nigrostriatal pathway result in Parkinson’s disease.

The second major dopamine pathway originates in the ventral tegmental area (VTA), with a major involvement in reward and motivation. The mesolimbic system innervates the nucleus accumbens, the septum, the amygdala, and the hippocampus. Other axons from the VTA, the mesocortical system, form the third pathway and project to the frontal cortex.

Question 53

Define the concepts of Serotonin?

Answer 53

Is distributed throughout the brain and spinal cord and is involved in the control of the sleep/wake cycle, mood, impulsive behaviour, and appetite.

Serotonin neurons originate in the brain stem in a region of cell bodies called the dorsal raphe nucleus and the median raphe nucleus. Axons from these cells travel throughout the cortex and other important areas.

has been implicated in numerous behavioural problems including sleep disorders, aggression, obesity, anorexia, and depression.