Chapter 43 - The Nervous System Flashcards
(113 cards)
1
Q
All animals must be able to respond to ___________
A
Environmental Stimuli
2
Q
- Detect stimulus (light, heat, touch)
- Ex. Photoreceptors, chemoreceptor
A
Sensory receptors
3
Q
- Respond to sensory receptors
- Ex. Muscle, gland
A
Motor effectors
4
Q
Consists of the brain and spinal cord
A
Central Nervous System
5
Q
Consists of sensor and motor neurons
A
Peripheral Nervous System
6
Q
Three types of neurons
A
- Sensory neurons
- Motor neurons
- Interneurons
7
Q
Carry impulses to CNS
A
Sensory neruons
8
Q
Carry impulses from CNS to effectors
A
Motor nuerons
9
Q
- Provide more complex reflexes and associates functions
- Majority of neurons
- Learning and memory
A
Interneurons
10
Q
Three parts of a nueron
A
- Cell body
- Dendrites
- Axon
11
Q
Enlarged part of neuron containing the nucleus
A
Cell body
12
Q
Short, cytoplasmic extensions that receive stimuli
A
Dendrites
13
Q
Single, long extension that conducts impulses away from cell body
A
Axon
14
Q
Supports neurons
A
Neuroglia
15
Q
Multiple layers of cell membranes wrapped around axons
A
Myelin sheath
16
Q
Two neuroglia in CNS
A
- White matter
2. Grey matter
17
Q
Myelinated axons form _____?
A
White matter
18
Q
Dendrites/cell bodies form ____ ?
A
Gray matter
19
Q
Type of neuroglia in the PNS
A
Nerves
20
Q
Myelinated axons are bundled to form ________
A
Nerves
21
Q
A potential difference exists across every neuron’s plasma membrane
A
Membrane potential
22
Q
Charge of cytoplasmic side?
A
Negative
23
Q
Charge of extracellular fluid side?
A
Positive
24
Q
Cytoplasm is negatively charged because of ____
A
Sodium -potassium pump
25
Brings two k+ into cell for every three Na+ pumped out
Sodium-potassium pump
26
- Moves away from poles (-70mv) and toward neutral (0mV)
| - Because cytoplasm is negatively charged, ___________ makes the membrane potential more posotive
Depolarization
27
Voltage change makes it extremely negative (lower than -70mv)
Hyperpolarization
28
A change in membrane potential that moves down the axon
Action potentials
29
The cycle of action potentials
1. From resting
2. To depolarization
3. To hyperpolarization
4. Back to resting
30
Action potentials are proliferated by ________
Voltage-gated ion channels
31
What are the voltage-gated ion channels?
- Na+ channels
| - K+ channels
32
_________ channels open first??
Na+ channels
33
What two things do Na+ open channels cause?
1. An influx of Na+
| 2. Depolarization
34
_________ channels open second??
K+ channels
35
What two things do K+ channels cause?
1. Cause the exist of K+
| 2. Hyperpolarization
36
When depolarization occurs, the change in charge is detected by __________
The adjacent Na+ channels
37
Once the cytoplasm is positive enough, it will cause ____
1. The next channels to open
2. Na+ to move in
3. Depolarization to move down the axon
38
The positive point in action potential is known as _______
Threshold
39
___________ follows depolarization down the axon
Hyperpolarization
40
When hyperpolarization happens, what happens to the voltage gated ion channels?
1. The K+ channels open after the Na+ ones do
| 2. This causes K+ to rush OUT
41
Comparative Chart for Na+ channels and K+ channels
Na+ Channels
1. Open quickly
2. Na+ flows into the cell
3. Open first
4. Depolarizes
K+ Channels
1. Open slowly
2. Na+ moves in
3. K+ rushes out
4. Hyperpolarizes
42
- Before an action potential
- -70mV
- Na+ moves downstream
- Contacts the voltage gated ion channel
- Raises the voltage
Resting potential
43
- First phase in action potential
- Enough Na+ can cause the voltage gated ion channel to open
- Na+ flows through the channel into the cell
- The region becomes depolarized
Rising action potential
44
- K+ voltage gated ion channels open next
- K + flows out of the cell
- Repolarizes cell to become negative
Falling action potential
45
- All the K+ causes the cell to become hyperpolarized
| - Less negative than -70 mV
Undershoot
46
After the signal moves, that area of the axon becomes reset to the _________
Resting potential
47
How does resting potential happen?
Sodium Potassium Pump
48
The signal in action potential moves down the axon until it reaches the _________
Axon terminal
49
- Intercellular junctions between neurons
| - The way action potential moves across
Synapses
50
Transmits action potential
Presynaptic Cell
51
Synapse that receives action potential
Postsynaptic Cell
52
Two types of synapses
1. Electrical
| 2. Chemical
53
Vertebrates have mostly what kind of synapses?
Chemical
54
Chemical synapses have a _____________ , which is a space between the two cells
Synaptic cleft
55
End of presynaptic axon terminal in chemical synapses contain _________
Synaptic Vesicles
56
Synaptic vesicles are packed with _________
Neurotransmitters
57
The first four steps of Transmission
1. Action potential moves down the axon
2. Synaptic vesicles fuse with cell membranes
3. Neurotransmitter is released into cleft
4. Diffuses to other side of cleft
58
What causes the first graded potential on the postsynaptic cell?
Neurotransmitters activate ligand-gated ion channels on the postsynaptic cells
59
What are closed in the normal resting cell?
Ligand-gated ion channels
60
Induce openings of the ligand-gated ion channels
Neurotransmitters
61
What do neurotransmitters do after they activate Ligand-gated ion channels?
Cause changes in cell membrane permeability
62
The process of neurotransmitters in Transmission
1. Bind to ligand-gated ion channels
2. New action potential begins on the postsynaptic cell
3. Neurotransmitter action is then terminated
63
What happens when the neurotransmitter action is then terminated?
1. Enzymatic breakdown
2. Cellular reuptake
3. Allows for repition
64
Two ways to increase velocity of conduction
1. Axon has a large diameter
| 2. Axon is myelinated
65
- Axon has less resistance to current flow
| - Found primarily in invertebrates
When axon has a large diameter
66
- Spaces between myelin sheeth
| - Action potential is only produced here
Nodes of Ranvier
67
Impulses jump from node to node
Saltatory conduction
68
When the axon is myelinated, what major thing does it contain?
Nodes of Ranvier
69
Prolonged exposure to a neurotransmitter may cause cells to love the ability to respond to it
Habituation
70
Example of habituation
Cocaine
71
How does cocaine have an effect on you?
1. Affects the brains "pleasure pathways" (limbic system)
2. Inhibits reuptake of neurotransmitter (stays in cleft)
3. Cell decreases the number of receptors to reestablish homeostasis
4. This results in decreased neuron activity in normal conditions
72
________ are the only major phylum without nerves
Sponges
73
_________ have the simplest nervous system
Cnidarians
74
- Cnidarians
| - Neurons linked to each other in a ________
Nerve net
75
What group has NO association to neurons and one big reflex machine?
Cnidarians
76
_________ are the simplest animals with associative activity
Free-living Platyhelminthes
77
Three components of Free-living Platyhelminthes nervous sytem
1. Two nerve cords run down the body
2. Permit complex muscle control
3. Rudimentary "brain"
78
All other nervous systems in other invertebrates are basically elaboration on the ________ model
Platyhelminth
79
__________ have a CNS that connect to the periphery
Earthworms
80
________ have a coordination centers in the front, and branching nerve chords
Arthropods
81
__________ have several giant axons connecting to relatively large-sized brain
Cephalopods
82
Why are the vertebrate brains different than other brains?
An enlargement of the anterior portion of the nerve cord
83
Three basic divisions of the vertebrate brain
1. Hindbrain
2. Midbrain
3. Forebrain
84
Part of the brain that processes blood flow
Hindbrain
85
Part of the brain that processes visual information
Midbrain
86
Part of the brain processes olfactory information
Forebrain
87
What part of the brain has evolved in vertebrates and become the dominant feature
Forebrain
88
The increase in brain size in mammals reflects the great enlargement of the ________
Cerebrum
89
The cerebrum is split into right and left _____, which are connected by a tract called the ________
1. Cerebral hemisphere
| 2. Corpus callosum
90
Each hemisphere in the cerebrum __________ from the opposite side
Receives sensory input
91
Hemispheres are divided into what four lobes?
1. Frontal
2. Parietal
3. Temporal
4. Occipital
92
Part of the brain that integrates visual, auditory and somatosensory information
Thalamus
93
- Integrates visceral activities
- Controls pituitary gland
- Part of limbic system
Hypothalamus
94
The hypothalamus is apart of what system?
Limbic system
95
System responsible for emotional response
Limbic system
96
A cable of neurons extending from the brain down through the backbone
Spinal cord
97
The spinal cord in enclosed and protected by the ________ and ___________
1. Vertebral column
| 2. Meninges
98
Membranes surrounding the spinal chord
Meninges
99
Two function of the spinal chord
1. Serves as the body's "information highway"
| 2. Reflexes
100
How does the spinal cord function as the body's information highway?
1. Functions to interpret simple information with interneurons
2. Relays messages between the body and the brain
101
- The knee jerk is __________
Monosynaptic (no interneurons)
102
Most reflexes in vertebrates involves a ________
Single neuron
103
What does the peripheral nervous system consist of?
1. Nerves
| 2. Ganglia
104
Bundles of axons bound by connective tissue
Nerves
105
Aggregates of neuron cell bodies
Ganglia
106
____________ stimulate the skeletal muscles to contract
Somatic Motor Neurons
107
What are somatic motor neurons in response to?
Conscious command or reflex actions
108
How many neurons do the somatic motor neurons need?
One motor neuron
109
Subconscious control
The Autonomic Nervous System
110
Motor pathway of the autonomic nervous system has how many motor neurons
Two
111
What is the process of autonomic nervous system?
1. The first neuron exits the CNS and synapses at autonomic ganglia
2. The second exist the ganglion and regulates effectors (smooth or cardiac muscle or glands)
112
Five facts about Sympathetic Division
1. FIght or flight
2. Heightened metabolism
3. Reduce digestion
4. Increase alertness
5. Increase respiration
113
Four facts about Parasympathetic Division
1. Slow heart rate and breathing
2. Increase digestive functions
3. Relaxed state
