C2.2 Neural Signaling

Question 1

The resting membrane potential of a neuron is ____ millivolts

Answer 1

-70

Question 2

Identify which ion plays a key role in generating an action potential.

Answer 2

Sodium (Na+)

Question 3

An R^2 value closer to 1 represents..

Answer 3

a strong, positive correlation

Question 4

An R^2 value closer to -1 represents..

Answer 4

a strong, negative correlation

Question 5

During the resting potential, the inside of the neuron is negatively charged due to a higher concentration of
_________ ions inside the cell.

Answer 5

potassium

Question 6

A larger axon diameter leads to ____ conduction speed.

Answer 6

faster

Question 7

The junction between two neurons is called a ____.

Answer 7

synapse

Question 8

Identify the name for a junction between a neuron and a muscle fibre.

Answer 8

neuromuscular junction

Question 9

Excitatory neurotransmitters cause the postsynaptic membrane to become more ____ by allowing the entry of _____ ions.

Answer 9

positive, sodium

Question 10

Acetylcholine released from the presynaptic membrane travels to the postsynaptic membrane through the process of _____.

Answer 10

diffusion

Question 11

C. ____ potential arrives at presynaptic membrane.
B. Ca2+ diffuses into the ____ knob.
A. Voltage-gated Ca2+ channels ____.
D. Vesicles containing _____ move towards the presynaptic membrane.
F. Vesicles fuse with the ______ membrane.
E. Neurotransmitter is released in the synaptic ____.

Answer 11

action, presynaptic, open, acetylcholine, presynaptic, cleft

Question 12

During depolarisation
______
ions flood inside the neuron.

Answer 12

sodium

Question 13

An action potential is generated from the axon hillock only if the impulse crosses the threshold potential.

Answer 13

t

Question 14

The conduction of an impulse through a myelinated neuron is called ____ conduction.

Answer 14

saltatory

Question 15

Exogenous substances ________.

Answer 15

originate outside the body.

Question 16

Cocaine affects the brain since it blocks the reuptake of ____.

Answer 16

dopamine

Question 17

Inhibitory postsynaptic potentials increase membrane permeability of
______ ions into the cell.

Answer 17

chloride

Question 18

What would cause action potential to be generated in the postsynaptic neuron?

Answer 18

In the presynaptic neuron, depolarisation at the axon hillock exceeds the threshold for excitation.

Question 19

Summation takes into consideration both the ___ and _____ impulses.

Answer 19

excitatory, inhibitory

Question 20

Identify the receptors for fine, discriminative touch and vibration in human skin.

Answer 20

Meissner corpuscles

Question 21

________ is a shift in membrane potential toward a more positive state, whereas ______ is the return of the membrane potential to its resting state after depolarisation.

Answer 21

depolarisation, repolarisation

Question 22

The rapid conduction of an action potential in myelinated nerve fibres is known as _______ .

Answer 22

Saltatory conduction

Question 23

_____ is the process by which an action potential travels along a nerve fibre or axon.

Answer 23

Nerve impulse propagation

Question 24

What do dendrites, axon and cell body do in a neuron?

Answer 24

dendrites: receive sensory information from environment
axon: long extension that carries electricals signal to the axon terminal
cell body(soma): contain nucleus/other organelles

Question 25

Define membrane potential.

Answer 25

voltage created by the imbalance in charges(ions) between the inside and outside of the cell membrane

Question 26

Define resting potential.

Answer 26

active transport by the sodium potassium pump allows neuron to establish membrane potential of -70 millivolts

Question 27

Outline three mechanisms that together create the resting potential in a neuron.

Answer 27

inside neuron: relatively negative (-70 millivolts) - sodium ions outside of cell - action performed by sodium potassium pump

Question 28

State the voltage of the resting potential.

Answer 28

-70 (millivolts) mV

Question 29

Outline the six steps of sodium-potassium pump action.

Answer 29

1.) gets 3 sodium from inside the cell 2.) ATP gives phosphate group 3.) pump changes shape & release sodium into extracellular space 4.) 2 potassium bind to pump 5.) Phosphate leaves 6.) pump returns to former shape & potassium enters cell

Question 30

Define nerve impulse.

Answer 30

a signal transmitted along a nerve fiber. It consists of a wave of electrical depolarization that reverses the potential difference across the nerve cell membranes. -happen in one direction

Question 31

Define action potential.

Answer 31

a rapid sequence of changes in the voltage across a membrane.

Question 32

Explain the difference in nerve impulse speed for myelinated and unmyelinated fibers.

Answer 32

- ONLY myelinated CAN do saltatory conduction - impulse can jump from node to node instead of going in/out including myelin sheath

Question 33

State the correlation between conduction speed of nerve impulses and animal size. ​

Answer 33

larger animals: slower reflex - neurons need to travel farther

Question 34

Saltatory conduction allows the impulse to travel much _____ than in an unmyelinated axon of the same diameter.

Answer 34

faster; (50 times)

Question 35

Define synapse, synaptic gap and effector.

Answer 35

space between 2 neurons where the communicate, the space in between the axon of one neuron and the dendrites of another and is where the electrical signal is translated to a chemical signal, nerve cells that respond to a stimulus according to the instructions sent from the nervous system (mainly muscles)

Question 36

List examples of effector cells.

Answer 36

Neutrophils, eosinophils, and basophils

Question 37

A signal can only pass in _______ across a typical synapse and the role of neurotransmitters is _________.

Answer 37

one direction, chemical messenger that carry out info. at the synapse

Question 38

______ functions as a chemical signal triggering _____ of neurotransmitter from a presynaptic cell.

Answer 38

Calcium, exocytosis

Question 39

Acetylcholine is one of the most _____ neurotransmitters in both invertebrates and _____ and is used as the neurotransmitter in many synapses including between neurons and ___ fibers.

Answer 39

common, vertebrates, muscle

Question 40

In a postsynaptic cell, neurotransmitters are released into the synaptic gap through the process of ______.

Answer 40

exocytosis, diffusion

Question 41

In a cell each neurotransmitter has a specific _____ it can bind to. This ligand gated channel often causes the opening of ____ in the postsynaptic membrane.

Answer 41

receptor, ion channel

Question 42

Gated ion channels: _______

Answer 42

allow positive ions to come in which cause depolarization - more likely to fire action potential

Question 43

The minimum millivolts to fire an action potential is _____.

Answer 43

threshold potential

Question 44

Outline the digestion of acetylcholine by acetylcholinesterase.

Answer 44

acetylcholinesterase breaks it into acetate and choline

Question 45

An action potential is only initiated if the ______ potential is reached.

Answer 45

threshold (-50 mV)

Question 46

Define depolarization.

Answer 46

positive voltage from sodium ions in the cell

Question 47

Outline the mechanism of depolarization during an action potential using voltage gated sodium channels.

Answer 47

-threshold potential exceeds -50

Question 48

Define repolarization.

Answer 48

The efflux(move out) of potassium (K+) ions results in the falling phase of an action potential.

Question 49

Outline the mechanism of repolarization during an action potential using voltage gated potassium channels.

Answer 49

potassium leaves the cell, repolarizing the cell and making it negative

Question 50

depolarization and repolarization are both examples of ______.

Answer 50

facilitated diffusion

Question 51

A wave of depolarization and repolarization cause ______ to open along the length of an axon

Answer 51

ion channels

Question 52

Describe the movement of sodium ions in a local current.

Answer 52

The influx of sodium ions generates the action potential, which then triggers neighboring regions to depolarize and propagate the signal down the axon.

Question 53

Local currents cause each _____ part of the axon to reach the threshold potential.

Answer 53

successive

Question 54

Explain how the movement of sodium ions propagates an action potential along an axon.

Answer 54

The influx of sodium ions generates the action potential, which then triggers neighboring regions to depolarize and propagate the signal down the axon.

Question 55

Outline the cause and consequence of the refractory period after depolarization.

Answer 55

action potential absolutely cannot fire again due to all of the voltage-gated sodium channels being inactivated -cell has positive charge

Question 56

Outline the use of oscilloscopes:

Answer 56

Measures membrane potential using electrodes

Question 57

Annotate an oscilloscope trace to show the resting potential, action potential, threshold potential, and refractory period

Answer 57

{view graph}

Question 58

In myelinated neurons, the Na+ and K+ ion channels are clustered down the axon at ________.

Answer 58

nodes of Ranvier

Question 59

Outline the effects of neonicotinoids on synaptic transmission.

Answer 59

-bind to acetylcholine receptors -depolarization in cell doesn't occur; action potential doesn't fire - irreversible change affects insects by causing death

Question 60

Outline the effects of cocaine on synaptic transmission.

Answer 60

synaptic transmission promoter- -blocks the reuptake of dopamine into brain -too many dopamine messages into postsynaptic neuron -feelings of happiness/euphoria -forget other important messages the brain is sending "don't jump off the cliff"

Question 61

exogenous substances ______.

Answer 61

originate from outside of the body

Question 62

Sensory neurons respond to pain by sending signals to the ________________. If enough excitatory neurotransmitters are released _________________

Answer 62

central nervous system

Question 63

State the term that describes the accumulative effect of multiple releases of neurotransmitters to trigger an action potential.

Answer 63

summation

Question 64

Excess acetylcholine in the synaptic space is broken down into choline and acetate by acetylcholinesterase. What happens to the choline?

Answer 64

The choline is reabsorbed back into the presynaptic neuron.