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Biology 2312 Test 1 > Chapter 43- The Nervous System > Flashcards

Chapter 43- The Nervous System Flashcards

(93 cards)

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1
Q

Sensory receptors

A

Detect stimulus

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2
Q

Motor effectors

A

Responds to stimulus

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3
Q

Sensory neurons (afferent neurons)

A

They carry impulses to the central nervous system

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4
Q

Motor neurons (efferent neurons)

A

They carry impulses from the central nervous system to the effectors (muscles and glands)

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5
Q

Interneurons (association neurons)

A

They provide more complex reflexes and associative functions (learning and memory)

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6
Q

What supports the neurons both structurally and functionally?

A

The Neuroglia

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7
Q

What produce myelin sheaths surrounding the axons?

A

Schwann Cells and oligodendrocytes

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8
Q

What is bundled in the peripheral nervous system to form nerves?

A

Myelinated axons

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9
Q

What form white matter in the central nervous system?

A

Myelinated axons

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10
Q

Membrane potential

A

A voltage across the cell’s plasma membrane

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11
Q

What is the membrane potential of a neuron not sending signals?

A

The resting potential

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12
Q

What ion concentration is the highest inside the cell?

A

K+

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13
Q

What ion concentration is the highest outside the cell?

A

Na+

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14
Q

How are these K+ and Na+ gradients maintained?

A

The sodium-potassium pumps use the energy of ATP to maintain them

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15
Q

Where is chemical potential converted to electrical potential?

A

In the opening of ion channels in the plasma membrane

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16
Q

In a resting neuron, the currents of K+ and Na+ are what?

A

Equal and opposite

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17
Q

Graded potentials

A

Small continuous changes to the membrane potential

Selective

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18
Q

Action potential

A

A massive change in membrane voltage
With depolarization, it brings a neuron closer to the threshold
Hyperpolarization does the opposite

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19
Q

Why do action potential arise?

A

It is due to voltage-gated channels opening or closing

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20
Q

Why do changes in membrane potential occur?

A

It is due to neurons contain gated ion channels that open and close in response to stimuli

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21
Q

Voltage-gated channels lead to what?

A

They lead to action potentials

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22
Q

Ligand-gated channels lead to what?

A

They lead to graded potentials

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23
Q

Ligand gated channel

A

They are hormones or neurotransmitters

Induce opening and cause changes in cell membrane permeability

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24
Q

Hyperpolarization

A

An increase in magnitude of the membrane potential

Makes the membrane more positive

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25
Depolarization
A reduction in the magnitude of the membrane potential | Makes the membrane more negative
26
The diffusion of K+ out, making the inside of the cell more negative is an example of what?
Hyperpolarization
27
Na+ channels open and Na+ diffuses into the cell is an example of what?
Depolarization
28
Integration of EPSPs (depolarization) and ISPSs (hyperpolarization) occurs on what?
Neuronal cell body
29
What are the two ways that the membrane can reach the threshold voltage?
Spatial and temporal summmation
30
Spatial summation
Many different dendrites produce EPSPs
31
Temporal summation
One dendrite produces repeated EPSPs
32
What is a refractory period?
It is a result of a temporary inactivation of the Na+ channels and a second action potential cannot be initiated
33
Negative pole is located where?
Cytoplasmic side
34
Positive pole is located where?
Extracellular fluid side
35
What does a sodium-potassium pump do?
It brings two K+ into cell for every three Na+ it pumps out
36
What does ion leakage channels do?
They allow more K+ to diffuse out than Na+ to diffuse in
37
What are the two major forces that act on ions in establishing the resting membrane potential?
Electrical potential and concentration gradient
38
Electrical potential is produced by what?
It is produced by unequal distribution of charges
39
Concentration gradient is produced by what?
It is produced by unequal concentrations of molecules from one side of the membrane to the other.
40
Which concentration is higher? The K+ or Na+?
K+
41
Equilibrium potential
Balance between diffusional force and electrical force
42
What is summation?
The ability of graded potentials to combine
43
Voltage-gated Na+ Channels
Activation and inactivation gate At rest, activation gate closed, and inactivation gate open Transient influx of Na+ causes the membrane to depolarize
44
Voltage-gated K+ channels
Single activation gate that is closed in the resting state K+ channel opens slowly Efflux of K+ repolarizes the membrane
45
What are the three phases of action potential?
Rising, falling, and undershoot
46
Action potentials are always ___________
"separate, all-or-none events with the same amplitude."
47
In the rising phase of the action potential, what does it reflect?
Each reflects a reversal in membrane polarity.
48
What causes the positive charge to depolarize the adjacent region of the threshold?
Na+
49
What are the two ways to increase velocity of conduction?
The axon has to have a large diameter or it has to be myelinated
50
How does the Axon having a large diameter increase the velocity of conduction?
There would be less resistance to the current flow
51
How does the Axon being myelinated help increase the velocity of conduction?
It causes the impulse jumps from node to node and it is a saltatory conduction
52
Synapses
"Intercellular junctions with the dendrites of other neurons, with muscle cells, or with gland cells"
53
What cell transmits the action potential and what cell receives it?
Presynaptic cell transmits while postsynaptic cell receives it.
54
Electrical synapses
They involve direct cytoplasmic connections between the two cells formed by gap junctions.
55
Chemical synapses
The have a synaptic cleft between the two cells | End of the presynaptic cell contains synaptic vesicles packed with neurotransmitters
56
What does the chemical synapse's action potential trigger?
It triggers an influx of Ca2+
57
What are the steps to chemical synapses?
The synaptic vesicles fuse with cell membrane Neurotransmitterr is released by exocytosis Diffuses to other side of cleft and binds to chemcial- or ligand-gated receptor proteins Produces graded potentials in the postsynaptic membrane Neurotransmitterr action is terminated by enzymatic cleavage or cellular uptake
58
What are the function(s) of Acetylcholine (ACh)?
It binds to the receptor in the postsynaptic membrane It causes ligand-gated ion channels to open It produces a depolarization called an excitatory postsynaptic potential (EPSP) It stimulates muscle contraction
59
What is gluttamate?
It is a major excitatory neurotransmitter in the vertebrate CNS (Central nervous system)
60
Name the inhibitory transmitters and define what they do
Glycine and GABA (y-aminobutyric acid) | They open ligand-gated channels for Cl- and produce a hyperpolarization called an inhibitory postsynaptic potential
61
Which biogenic amines are responsible for the "fight or flight" response?
Epinephrine (adrenaline) and norepinephrine
62
Which biogenic amine is used in some areas of the brain that control body movements?
Dopamine
63
Which biogenic amine is involved in the regulation of sleep?
Serotonin
64
What is released from sensory neurons when activated by a painful stimuli?
Substance P
65
What perceives the intensity of pain?
Enkephalins and endorphins
66
What gas causes smooth muscle relaxation?
Nitric oxide
67
Habituation
Prolonged exposure to a stimulus may cause cells to lose the ability to respond to it
68
What does Cocaine affect?
Affects neurons in the brain's "pleasure pathways" (limbic system) Binds dopamine transporters and prevents the reuptake of dopamine
69
What does Nicotine affect?
Bind directly to a specific receptor on postsynaptic neurons of the brain Binds to a receptor for acetylcholine
70
What major phylum does not have nerves?
Sponges
71
What are the three basic divisions for all vertebrate brains?
Hindbrain or rhombencephalon Midbrain or mesencephalon Forebrain or prosencephalon
72
What are the two elements of the forebrain?
The diencephalon and the telecephalon
73
What is the purpose of the diencephalon?
Thalamus - integration and relay center | Hypothalamus - participates in basic drives and emotions, controls pituitary gland
74
What does the telencephalon do?
It is devoted largely to associative activity | Called the cerebrum
75
What is the right and left cerebral hemispheres connected by?
They are connected by a tract called the corpus callosum
76
What are the hemispheres divided into?
The frontal, the parietal, the temporal, and the occipital lobes
77
Cerebral cortex
Outer layer of the cerebrum | Highly convoluted surface
78
What does the primary motor cortex control?
Movement
79
What does the primary somatosensory cortex control?
Sensory
80
What does the association cortex control?
Higher mental functions
81
Basal ganglia
Aggregates of neuron cell bodies | Participate in the control of body movement
82
What is the limbic system responsible for?
Emotional response
83
Reticular-activating system
Controls consciousness and alertness
84
Electroencephalogram (EEG)
Records electrical activity
85
What are the two proposed causes to Alzheimer disease?
Nerve cells are killed from the outside in | Nerve cells are killed from the inside out
86
Inner zone of the spinal cord
Gray matter | Consists of the cell bodies of interneurons, motor neurons, and neuroglia
87
Outer zone of the spinal cord
White matter | Contains cables of sensory axons in the dorsal columns and motor axons in the ventral columns
88
Somatic Nervous System
Stimulate the skeletal muscles to contract
89
Automatic Nervous System
Composed of the sympathetic and parasympathetic divisions, plus the medulla oblongata Has 2 neurons: Preganglionic neuron and postganglionic neuron
90
Preganglionic neuron
Exits the CNS and synapses at an autonomic ganglion
91
Postganglionic neuron
Exits the ganglion and regulates visceral effectors
92
Sympathetic division
Preganglionic neurons originate in the thoracic and lumbar regions of the spinal cord Most axons synapse in two parallel chains of ganglia right outside the spinal cord
93
Parasympathetic division
Preganglionic neurons originate in the brain and sacral regions of spinal cord Axons terminate in ganglia near or even within internal organs

Biology 2312 Test 1 (2 decks)

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