Topic.5.TheNeuron.powerpoint.5.2.Neuronal.Functioning

Question 1

What increases the conduction potential of AP, aka speed neurons transmit signals?

Answer 1

Having a larger diameter

Question 2

Nerve fiber

Answer 2

axon and dendrite of a nerve cell

Question 3

List the the four types of nerve fibers from lease to greatest conduction potential of

Answer 3

c-nerve fiber, A-delta nerve fiber, A-beta nerve fiber, A-alpha nerve fiber

Question 4

A-alpha nerve fibers carry
information related to

Answer 4

muscle sense(proprioception)

Question 5

A-beta nerve fibers carry
information related to

Answer 5

touch

Question 6

A-delta nerve fibers carry
information related to

Answer 6

pain and
temperature

Question 7

C-nerve fibers carry information
related to

Answer 7

pain, temperature and
itch

Question 8

Another contribution besides diameter that contribute to C-nerve fiber’s extremely low speed in transmitting neurons is…

Answer 8

not myelinated

Question 9

What two creatures have a large diameter axons? Why?

Answer 9

Squids and earthworms; fast conduction=fast response aka muscle contraction for escape response

Question 10

using a large-diameter water hose. Fill in :
Larger diameter – lower___faster
____

Answer 10

lower internal resistance, faster
conduction

Question 11

Cable theory is used to understand ___ by calculating the flow of ___

Answer 11

conduction velocity, electric currents along an axon

Question 12

In the Cable theory, what two things are taken into account in order to calculate conduction velocity?

Answer 12

-capacitances
-resistance

Question 13

Capacitance refers to___

Answer 13

stored electrical charge

Question 14

What causes capacitance in the cable theory?

Answer 14

electrostatic forces that
act through the phospholipid
bilayer

Question 15

What causes resistance(longitudinal or membrane resistance) in the cable theory?

Answer 15

resistance is due to the
cytosol’s significant resistance
to movement of electric charge
Ex: organelle

Question 16

Explain what this teaches us:
2λ, it will be 37% of the size it was at 1 λ,

Answer 16

λ (length constant), a measure of
how far the voltage travels down the axon before it decays to 37% of its size(1/3)

Question 17

if you apply a voltage of 90mV at a specific spot on the axon, at the distance of 1 λ, the voltage would be ____
At a distance of 2λ, the voltage would be about ____

Answer 17

~30mV;10mV.

Question 18

if you have a length constant of 1 mm, that means at____ away from the cell body in an axon, ___% of
the voltage magnitude remains.

Answer 18

1 mm;37%

Question 19

How does have a larger length constant relate conduction velocity? Why?

Answer 19

A larger length constant gives greater conduction velocity.
-Can reach threshold further down axon each time the AP is generated.
-AP doesn’t have to be regenerated as many times

Question 20

What is the equation that shows lambda is dependent on resistance?

Answer 20

λ= sqrt(rm)/(rl)
rm = resistance of
membrane
rl = longitudinal
resistance/cytosol resitance

Question 21

Using the lambda equation, how can I increase the amount of current that will remain inside the cytosol to travel longitudinally along the neuron

Answer 21

Asking about how to increase lambda, you will increase the membrane resistance(rm)

Question 22

How does myelin relate to conduction velocity?

Answer 22

Myelin increases rm and speeds conduction velocity. Ions can’t leave the axon in areas covered by myelin, so those ions with travel to regenerate the action potential at the next nodes of Ranvier.

Question 23

Chemical synapses:

Answer 23

Allow neurons to receive inputs from
numerous axon terminals at the same time.

Question 24

neurotransmitters:

Answer 24

small signal molecules secreted by
the presynaptic nerve cell to relay the signal to the postsynaptic nerve cell.

Question 25

What are the two types of neurotransmission at the chemical synapse?

Answer 25

Direct and indirect

Question 26

What is the difference between a direct and indirect neurotransmission

Answer 26

1.Direct neurotransmission: -Neurotransmitter binds directly to a ligand-gated ion channel -Quick (0.2msec) -Ionotropic receptors form an ion channel pore 2. Indirect Neurotransmission -Neurotransmitter first binds to G-protein coupled receptors on postsynaptic membrane to activate a second messenger pathway -Slower (100msec) -metabotropic receptors: indirectly linked with ion channels on the cell plasma membrane through signal transduction mechanisms, often G proteins

Question 27

In neurotransmission, information at the post-synaptic end is ___ resulting in a ___ or ___ effect

Answer 27

integrate, inhibitory effect ,stimulatory effect

Question 28

What is the acronym to remember all the direct neurotransmitters?

Answer 28

A Gray Grumpy Gorilla Named Dave Sings.

Question 29

Acetylcholine

Answer 29

neurotransmitter between nerves and muscles; found in the brain (memory, attention, learning); and in the heart Ex: Alzheimer Disease

Question 30

GABA (gamma aminobutyric acid)

Answer 30

inhibitor of neurotransmission through increase Cl- influx

Question 31

Glycine

Answer 31

inhibitor of neurotransmission through increase Cl- influx

Question 32

Glutamate

Answer 32

involved with learning and memory; generally excitatory

Question 33

Norepinephrine and epinephrine (adrenaline)

Answer 33

duel roles as hormones and neurotransmitters; involved in attention and mental focus, can be excitatory or inhibitory Adhd

Question 34

Dopamine

Answer 34

Neurotransmitter/neurohormone. Behavior and cognition voluntary movement, motivation and reward, lactation Ex: Parkinson’s

Question 35

What 3 neurotransmitters are derived from tyrosine?

Answer 35

Norepinephrine, epinephrine, dopamine

Question 36

Serotonin

Answer 36

derived from tryptophan, regulates intestinal movements, involved in mood, appetite, sleep

Question 37

Indirect neurotransmitters are called

Answer 37

Neuropeptides

Question 38

What is the acronym to remember indirect neurotransmitters?

Answer 38

"Every Evening, Sarah Cooks Noodles

Question 39

Endorphins: (“endogeneous morphines”)-

Answer 39

released during pleasurable experience, reduce the perception of pain, work on PNS

Question 40

Enkephalins:

Answer 40

subset of endorphins, work in CNS, modulate pain response

Question 41

Substance P:

Answer 41

released by spinal cord, increase the perception of pain

Question 42

Dissolved carbon monoxide:

Answer 42

regulates the release of hormones from the hypothalamus

Question 43

Dissolved nitric oxide

Answer 43

learning, muscle movement. Relaxes smooth muscle in the walls of blood vessels, causes dilation

Question 44

Synaptic vesicles

Answer 44

store neurotransmitters in cytoplasm of axon terminal

Question 45

Explain steps of neurotransmission at a chemical synapse

Answer 45

1. action potential arrives at the axon terminal of the presynaptic neuron 2. Voltage-gated Ca2+ channels open, and influx 3. Synaptic vesicles, fuse with the membrane and release neurotransmitters (exocytosis) into synaptic cleft 4.Neurotransmitter binds to post-synaptic receptor and open ligand-ion-gated channels 5.stimulate or inhibit the generation of an action potential in the post synaptic cell

Question 46

How does neurotransmission end? Steps?

Answer 46

1. stimulus subsides, no action potentials are generated, voltage-gated Ca2+ channels close 2.Ca2+ is pumped outside of the axon terminal, vesicles no longer fuse with the membrane 3. remaining neurotransmitters in the cleft diffuse away or are broken down

Question 47

What does it by: neurotransmitters can stimulate the generation of an action potential in the post synaptic cell?

Answer 47

Na+ channels open, Na+ enters, the cell membrane depolarizes, action potential threshold is reached

Question 48

EPSP

Answer 48

excitatory post synaptic potential: change in membrane potential that moves the neuron closer to threshold

Question 49

What is inhibition in neurotransmission?

Answer 49

K+ exits membrane becomes hyperpolarized, no action potential in the post synaptic cell)

Question 50

IPSP

Answer 50

inhibitory post synaptic potential: change in membrane potential that pushes the membrane farther from threshold

Question 51

EPSPs and IPSPs are ___ EPSPS and IPSPS have no ____

Answer 51

EPSPs and IPSPs are graded potentials EPSPS and IPSPS have no refractory periods

Question 52

Graded potential:

Answer 52

is an increase or decrease in membrane potential that is below threshold, so it does not trigger an action potential.

Question 53

Graded potentials can occur in

Answer 53

Graded potentials can occur in a sensory cell when a sensory stimulus excites it, or in a postsynaptic cell when a chemical neurotransmitter binds to it.

Question 54

EPSPs (Graded potentials) are the precursors

Answer 54

to Action Potentials.

Question 55

Information is received as changes in ___ Information is transferred over distance by ___

Answer 55

potential: graded potentials; action potentials

Question 56

What is reuptake?

Answer 56

When remaining neurotransmitter are broken down, a molecule goes back to the pre-synaptic cell to start making the neurotransmitter again

Question 57

If a person has early Alzheimer what might we give them?

Answer 57

Aricept: Acetylcholinesterase Inhibitor, treat it by keeping acetylcholine in the synapse longer

Question 58

What are SSRI?

Answer 58

Selective serotonin reuptake inhibitors Antidepressants prevent it from being repackaged

Question 59

SSNRIs

Answer 59

selective serotonin- norepinephrine reuptake Inhibitors Anti depressants

Question 60

graded potential characteristics

Answer 60

-size dependent on stimulus intensity or amount of transmitter -can be depolarized/hyperpolarized -decrease with distance -rise and fall not instantaneous -responses can sum

Question 61

Are graded potential different from action potential?

Answer 61

Graded have no all or nothing decreases with distance. Also doesn't depend on frequency but rather amount of neurotransmitters. Slower not instantaneous and responses are summed

Question 62

Graded Potentials: what are the two types of responses that can sum?

Answer 62

temporal summation: summation of more than one EPSP produced by successive firing of a single presynaptic neuron over a short period of time. Spatial summation: summation of EPSPs produced by the firing of different presynaptic neurons