The Nervous System (Nerves and Action Potentials) Flashcards
(86 cards)
1
Q
The nervous system works in conjunction with the _________ system to respond to both internal and external environmental change
A
Endocrine
2
Q
The nervous system works with the endocrine system to maintain ___________ within the body
A
Homeostasis
3
Q
The nervous system responds via _______________ messages relayed from the brain
A
ELECTROCHEMICAL
4
Q
The endocrine responds via ________ messages relayed through the bloodstream (hormones)
A
CHEMICAL
5
Q
What are the two types of nerve cells found in the nervous system?
A
- Glial Cells
- Neurons
6
Q
nerve cells used for structural and nutritional support
A
GLIAL CELLS
7
Q
nerve cells that conduct nerve impulses throughout the body and are supported by Glial Cells
A
Neurons
8
Q
What is the basic unit of the nervous system?
A
Neurons
9
Q
Branches which accept nerve impulses from other neurons and carry them towards the cell body
A
Dendrites
10
Q
longer branches which carry nerve impulses away from the cell body
A
Axons
11
Q
surrounds each axon, insulating the neuron and SPEEDS UP the rate of impulse transmission
A
Myelin Sheath
12
Q
A TYPE OF GLIAL CELL, are responsible for producing the myelin around each axon
A
Schwann Cells
13
Q
small gaps in the Myelin Sheath of a nerve fiber that allow electrical signals to move quickly.
A
Nodes of Ranvier
14
Q
what is it called when action potentials that travel down the axon “jump” from node to node?
A
Saltatory Conduction
15
Q
Once the electrical signal reaches the ____ ________, it is passed on to the dendrites of an adjoining neuron
A
Axon Terminal
16
Q
the process of creating a fatty, insulating sheath around nerve cells in the brain and spinal cord.
A
Myelination
17
Q
(TRUE OR FALSE) The Myelination of Neurons is vital for proper signal transduction within the nervous systems.
A
TRUE
18
Q
What are the characteristics of Myelinated Neurons?
A
- Make up WHITE matter of your brain, which is responsible for conducting nerve impulses
- CAN regenerate after injury
19
Q
What are the characteristics of Unmyelinated Neurons?
A
- Make up GREY matter of your brain, which is responsible for processing information and generating nerve impulses
- CANNOT regenerate after injury
20
Q
(TRUE OR FALSE) Myelinated Neurons make up white matter
A
TRUE
21
Q
(TRUE OR FALSE) Myelinated Neurons cannot regenerate
A
FALSE
22
Q
(TRUE OR FALSE) Myelinated Neurons are responsible for conducting nerve impulses
A
TRUE
23
Q
(TRUE OR FALSE) Unmyelinated Neurons make up the grey matter of your brain
A
TRUE
24
Q
(TRUE OR FALSE) Unmyelinated Neurons cannot regenerate
A
TRUE
25
(TRUE OR FALSE) Unmyelinated Neurons are responsible for processing information and generating nerve impulses
TRUE
26
What are the three main types of neurons that carry signals to and from the brain?
1. Sensory Neurons
2. Interneurons
3. Motor Neurons
27
What type of Neuron is this?
- Afferent (moving towards the central nervous system)
- Gather information from sensory receptors (i.e. touch/sight/sound/taste receptors) and transmit these impulses to the brain
Sensory Neurons
28
What type of Neuron is this?
- Process and integrate incoming sensory information from sensory neurons and relay outgoing information to motor neurons
Interneurons
29
What type of Neuron is this?
- Efferent (moving away from the central nervous system)
- Transmit information from the brain to the muscles (effectors), GLANDS, and other organs
Motor Neurons
30
A neural circuit that passes through interneurons in the spinal cord for immediate response
REFLEX ARC
31
______ ___
- simplest nerve pathway
- neural circuit through the spinal cord
- reflexes are involuntary & unconscious (no brain coordination)
REFLEX ARC
32
What are the 5 essential components for a Reflex Arc?
1. Receptor
2. Sensory Neuron
3. Interneuron (in spinal cord)
4. Motor Neuron
5. Effector
33
What are the two things the Speed of an Impulse along the nerve fiber dependant on?
1. Myelin
2. Diameter of Axon
34
Why is the speed of an impulse along the nerve fiber dependant on Myelin?
myelinated axons send impulses faster than non-myelinated axons because the impulse jumps from node to node along the adon
35
Why is the speed of an impulse along the nerve fiber dependant on the Diameter of Axon?
bigger = faster
36
(TRUE OR FALSE) A nerve impulse or ACTION POTENTIAL has both a chemical and electrical component
TRUE (hence the term electrochemical impulse)
37
what are the four stages of a nerve impulse?
1. Polarized/Resting State
2. Depolarization
3. Repolarization
4. Refractory Period
38
The difference in charge across the membrane of a resting neuron is called resting ________ _________
membrane potential
39
At resting state, the inside of a neuron had a slight ________ charge at rest, whereas the outside has a slight ________ charge.
This results in a resting potential of -70mV
negative, positive
40
At rest __+ ions are found mostly outside the axon membrane and _+ ions are found mostly within the axon, along with larger negatively charged ions that cannot pass through the membrane
Na+ ions, K+ ions
41
At rest, membrane is impermeable to which ions?
Na+ ions
42
(TRUE OR FALSE) At rest, membrane is slightly permeable to K+ ions so some K+ ions leak out
TRUE
43
At rest, is the inside of the membrane relatively positive or negative
Negative
44
The sodium-potassium pump along the membrane surface maintains the electrical potential difference by transporting 3 Na+ ions out of the cell and _ K+ ions inside the cell
2
45
(TRUE OR FALSE) At rest, an excess of positive charge accumulates outside of the cell membrane
TRUE
46
Which stage of nerve impulse is this?
- Action potentials occur when a neuron is stimulated by an electrical impulse
2) Depolarization
47
During Depolarization, an impulse causes sodium gates to fully ____, thus allowing Na+ to diffuse freely across the membrane.
OPEN
48
During Depolarization, __+ rushes into the cell (down their concentration gradient), leading to a slight positive charge on the inside relative to the outside
Na
49
(TRUE OR FALSE) Once the membrane is depolarized, the membrane potential (mV) is decreased
FALSE (it increases from -70mV to +40mV)
50
Once the membrane is Depolarized and Na+ reaches equilibrium, the membrane becomes impermeable to them again and the gates _____
close
51
An action potential is considered to be an "all-or-none" event because any stimulus that fails to achieve a membrane potential of at least ___mV will have no effect
-55mV
52
(TRUE OR FALSE) Increasing stimulus strength increases the impulse strength
FALSE!! (a neuron will either fire or not fire)
53
The intensity of a stimulus is experienced as an increased _________ (number) of nerve impulses
FREQUENCY
54
Which stage of nerve impulse is this?
- Once an action potential has peaked, Na+ gates close, and K+ gates open so K+ rushes out of the axon
3) Repolarization
55
During Repolarization, it restores the positive charge outside the membrane; however Na+ and K+ are briefly ________ compared to at the resting state (Na+ is higher inside the membrane)
reversed
56
The sodium-potassium pump kicks in and exchanges Na+ for K+, restoring the initial resting potential of -70mV. This process is called ______________.
Repolarization
57
Repolarization occurs in a wavelike motion down the ____
Axon
58
During the Refractory Period, so much __ rushes out of the cells that the membrane potential overshoots -70mV and the cell becomes hyperpolarized (-90mV)
K+
59
During the Refractory Period, the ______ _________ ____ restores the membrane potential to -70mV
SODIUM MEMBRANE PUMP
60
Until the resting potential of the neuron has been properly restored, a second action potential cannot be conducted along the axon; this is referred to as the __________ ______
Refractory Period
61
(TRUE OR FALSE) During the Refractory Period, the membrane cannot be made permeable to Na+, so the second wave of Depolarization CANNOT OCCUR
TRUE
62
(TRUE OR FALSE) The stronger the impulse, the longer it takes for the nerve to recover
TRUE
63
Once the impulse has traveled down the entire length of the axon, it reaches the ____ ________
Axon Terminal
64
The Axon terminal is in close contact with the _________ of another neuron
Dendrites
65
For the signal to move to the next neuron, it must cross the space between the axon terminal and the dendrites of the subsequent cell; this space is referred to as the...
SYNAPSE (aka Synaptic Cleft)
66
required to help "carry" the electrical impulse from one neuron to another
Neurotransmitters
67
Neurotransmitter Release
1. An action potential reaches the ____ ________
Axon Terminal
68
Neurotransmitter Release
2. Calcium channel "gates" within the axon terminal open, causing calcium ions to flow into the cell and trigger the movement of neurotransmitter vesicles toward the _________ membrane
Prehaptic
69
Neurotransmitter Release
3. Vesicles fuse to the membrane and _________________ are released into the synapse
Neurotransmitters
70
Neurotransmitter Release
4. Neurotransmitters diffuse across the Synaptic Cleft (synapse) to the ____________ membrane
Postsynapse
71
Neurotransmitter Release
5. Once Neurotransmitters have reached the Postsynaptic membrane, they bind with _________ embedded in the membrane
Receptors
72
Neurotransmitter Release
6. Binding induces or inhibits an Action _________ in the corresponding neuron
Potential
73
Neurotransmitter Release
7. Neurotransmitters are then released by the receptors and either return to the ___________ Neuron or are broken down by an enzyme on the Postsynaptic membrane
Postsynaptic
74
What are the two types of Neurotransmitters?
1. Excitatory
2. Inhibitory
75
Which type of Neurotransmitter is this?
- Causes Na+ channels of the Postsynaptic membrane to open, resulting in Depolarization and continuing the action potential
Excitatory
76
an Excitatory Neurotransmitter found in muscle cells; causes contraction of muscle fibre
Acetylcholine
77
the enzyme required to break down Acetylcholine after the action potential has occurred
Cholinesterase
78
Which type of Neurotransmitter is this?
Trigger K+ channels to open, causing K+ to flow out and thus lowering the membrane potential
Inhibitory
79
(TRUE OR FALSE) Inhibitory Neurotransmitters lead to Hyperpolarization, making it more difficult to generate an action potential
TRUE
80
Problems with ____ are often associated with epilepsy and Huntington's disease
GABA (gamma-aminobutyric acid)
81
Produced by adrenal glands during flight or fight response. Can be Excitatory or Inhibitory (ie. increase blood glucose levels, decrease digestion rate)
Norepinepherine
82
A single action potential and, thus neurotransmitters, from one neuron is usually too small to trigger an action potential in the ____________ neuron
Postsynaptic
83
(TRUE OR FALSE) Most neurons have many synapses on their dendrites from many neurons
TRUE
84
the effect produced by the accumulation of Neurotransmitters from two or more neurons on the Postsynaptic neuron
Summation
85
(TRUE OR FALSE) An excitatory transmission can be enhanced with more excitatory transmissions (to produce an action potential)
TRUE
86
(TRUE OR FALSE) An Inhibitory transmission cannot delete the effects of an excitatory transmission (and prevent an action potential)
FALSE (they can!)
