Exam 2

Question 0

What are the terms in reference to membrane potential?

Answer 0

Polarization, depolarization, hyperpolarization

Question 1

What is the membrane potential of a neuron at rest?

Answer 1

-70Mv the inside of the cell being more negative

Question 2

What’s the difference between polarization, depolarization, and hyperlarization? (Membrane potential)

Answer 2

Polarization- membrane potential is negative (inside of neuron is more negative than outside of neuron)

Depolarization- making the membrane potential less negative, more likely to fire

Hyperpolarization- making the membrane potential more negative, less likely to fire

Question 3

What are the factors contributing to even distribution of ions when neuron is at rest (encouraging Na+ to move into neuron and make the inside less negative)?

Answer 3

Random motion: particles tend to move down their concentration gradient

Electrostatic pressure: like repels like; opposites attract

Question 4

What are the factors that factors contributing to uneven distribution of ions during when neuron is at rest?

Answer 4

Selective permeability to certain ions

Sodium- potassium pumps

Question 5

Describe distribution of Na+ and K+ ions when neuron is at rest

Answer 5

There are more Na+ ions outside the cell than inside, and more K+ ions inside than outside. (Page 79)

Question 6

What is the function of the sodium-potassium pump?

Answer 6

Use ATP force that exchanges 3 Na+ inside for 2k+ outside

Question 7

Describe the difference between EPSPs and IPSPs

Answer 7

EPSP- more likely to fire, postsynaptic depolarization, making the membrane potential less negative.

IPSP- less likely to fire, postsynaptic hyperpolarization, making the membrane potential more negative

Question 8

Describe the differences between postsynaptic potentials and action potentials

Answer 8

EPSP/IPSP= graded, decremental, fast

Action potential= all or none response, non decremental, when the threshold is reached

Question 9

In order to generate an action potential, the ______ must be reached in the ______

Answer 9

Threshold of activation, axon initial segment

Question 10

Describe the change in Na+ and K+ distribution that occurs during an action potential

Answer 10

1) voltage-activated Na+ channels open causing depolarization (less negative)
2) voltage-activated K+ channels open (rising phase)
3) Na+ channels close causing polarization
4) K+ channels close causing hyperpolarization (membrane becomes more negative)

Page 82

Question 11

Describe the types of refractory period and the effects of these refractory periods on axonal conduction

Answer 11

Axonal conduction- axon potentials travel along the axonic membrane in the same direction

Absolute- the period where it’s impossible to initiate another action potential

Relative- the period where it is possible to die the neuron again but only by applying higher-than-normal levels of stimulation. Harder to initiate another action potential

The refractory periods limit the rate of firing (based on level of stimulation)

Question 12

Describe saltatory conduction

Answer 12

Saltory conduction: the transmission of action potentials in myelinated axons

• passive conduction (instant and decremental) occurs along each myelin segment to the next node of Ranvier
• A new action potential is generated at each node
• Is faster than non-saltory conduction

Question 13

Describe the process of exocytosis

Answer 13

The process of neurotransmitter release

Exocytosis= Ca2+

• arrival of an AP at the terminal opens voltage-activated Ca2+ channels
• the entry of Ca2+ causes vesicles to fuse with the terminal membrane and release their content

Question 14

Describe the difference between iontropic and metabotropic receptors

Answer 14

Iontropic- directly associated with ligand-activated ion channels in postsynaptic membrane, induce brief EPSPs or IPSPs

Metabotropic- associated with signal proteins attached to G proteins, leads to either activation of ion channels and membrane potential charge or to production of second messenger

Question 15

What are some processes that deactivate neurotransmitter?

Answer 15

Reuptake, enzymatic degradation, recycling

Question 16

Describe processes that deactivate neurotransmitters including reuptake, enzymatic degradation, and recycling.

Answer 16

Reuptake- more common, the majority of the neurotransmitters, once released, are almost immediately drawn back into the presynaptic buttons by transporters mechanisms

Enzymatic degradation- enzymes break apart neurotransmitter in synapse

Recycling- terminal buttons recycle neurotransmitters or their breakdown products after they are released and reuptake occurs

Page 89

Question 17

Describe autoreceptors

Answer 17

• Metabotropic receptors that have two unconventional characteristics
• They bind to their neuron’s own neurotransmitter molecules
• They are located on the presynaptic.
• Their usual function is to monitor the number of neurotransmitter molecules in the synapse.

Question 18

Which of the amino acid neurotransmitters is not common in proteins we consume and how is it synthesized?

Answer 18

GABA

GABA is synthesized by a simple modification of the structure glutamate.

Question 19

Describe the steps required for synthesis of catecholamines from tyrosine

Answer 19

1) tyrosine is converted to L-dopa
2) which in turn is converted to dopamine
3) extra enzyme and neuron’s convert dopamine to norepinephrine
4) extra enzyme in neuron’s convert norepinephrine to epinephrine

(Short answer)

Question 20

How is serotonin different from dopamine, epinephrine, norepinephrine?

Answer 20

• Serotonin is synthesized from the amino acid tryptophan
• classified as an indolamines
• the other catecholamines synthesized from amino acid tyrosine

Question 21

Describe how acetylcholine is reduced in the synapse? How does this relate to Alzheimer’s disease and treatment of Alzheimer’s disease?

Answer 21

It’s one of the few neurotransmitters broken down by enzymatic degradation in the synapse by the enzyme acetylcholinesterase

Acetylcholine transmission is decreased significantly in Alzheimer’s disease. Acetylcholine inhibitors are used to treat Alzheimer’s disease

Question 22

Describe characteristics of soluble-gas neurotransmitters

Answer 22

1) unconventional neurotransmitters
2) synthesized in neural cytoplasm
3) once synthesized immediately diffuse through cell membrane into extracellular fluid and into nearby cells
4) extra enzyme in neuron’s convert norepinephrine to epinephrine

Question 23

Describe characteristics of endocannabinoids

Answer 23

• synthesized from fatty tissue in cell membrane
• released from dendrites in cell bodies immediately after they are synthesized form fatty tissues in the cell membrane
• the main psychoactive, have effects on presynaptic neuron’s in that they inhibit subsequent transmission

Question 24

What are endorphins?

Answer 24

Neuropeptides neurotransmitter that opiate-like and important for analgesia (drugs that reduce pain) and reward system of the brain

Question 25

Parkinson’s disease involves a deficiency in dopamine. Describe why Parkinson’s disease is treated with L-dopa

Answer 25

Dopamine will not cross the blood brain barrier so precursor for dopamine is used to increase dopamine

Question 26

Describe the precautions that must be taken for MRI/fMRI studies. What individuals with which conditions/characteristics are not permitted to undergo MRI?

Answer 26

It is dangerous to complete MRI if one has metal in his/her body

(ex: pacemaker, aneurysm clip)

Question 27

Which MRI technique examines white matter connections?

Answer 27

Diffuser tensor imagining (DTI)

Question 28

Do functional neural methods (ex: PET, fMRI) directly measure neural activity?

Answer 28

No, instead they measure the consequences of neural activity.

(Ex: fMRI measures the amount of deoxygenated blood which increased as a result of neural activity)

Question 29

TMS should not be used in persons with which neurological condition?

Answer 29

Epilepsy

Question 30

TMS has been found to be beneficial in treating which psychiatric condition?

Answer 30

Depression

Question 31

Which biopsychology method has been used to measure sleep stage and diagnose epilepsy?

Answer 31

(EEG) electroencephalogram

Question 32

Describe the various purposes of neuropsychological evaluation

Answer 32

1) neuropsychological evaluation assists in the diagnosis of neural disorders, particularly in cases in which brain imaging, EEG, and neurological testing have proved equivocal
2) by serving as a basis for counseling and caring for the patient
3) recommend optimal treatments. (By providing a basis for objectively evaluating the effectiveness of the treatment and the seriousness of its side effects)
4) evaluate the effects of treatment

Question 33

Which conflictive ability is though to be important for all other cognitive abilities? What technique is used to measure this ability?

Answer 33

• Attention

- digit span- test of short term memory/attention

Question 34

Describe the paired-subtraction technique used in functional neuroimaging studies

Answer 34

The use of PET or fMRI to locate constituent cognitive processes in the brain by producing an image of difference in brain activity associated with two cognitive tasks that differ in terms of a single constituent cognitive process.

Question 35

Describe the difference between skin conductance level and skin conductance response

Answer 35

Skin conductance level- SCL is a measure of the background level of skin conductance that is associated with a particular situation.

Skin conductance- a measure of the transient changes in skin conductance that are associated with discrete experiences.