The Nervous System Flashcards
1
Q
Which layer forms nervous system?
A
The outer layer - the ectoderm
2
Q
The nervous system can
be divided into:
A
1) The Central Nervous
System (CNS)
- brain (encephalon)
- spinal cord
- retina
2) The Peripheral Nervous
System (PNS)
3
Q
The retina forms the….
A
…optic nerve
4
Q
What does the sensory component of the Peripheral nervous system (PNS) do?
A
- The 5 senses (sight, sound, smell, taste, touch).
5
Q
How does the sensory component work?
A
- A nervous information is
travelling from the periphery to be processed in the brain. - Thus, the information is
arriving to the brain (afferent)
6
Q
How does the motor component of the PNS work?
A
A nervous information is
travelling from the brain
to the periphery (i.e.
muscles)
Thus information is leaving (exit) the brain (efferent).
7
Q
The motor component of
the PNS is then further
subdivided into:
A
- Somatic (voluntary
actions/movements) - Autonomic (involuntary
actions/movements; ANS)
8
Q
The Autonomic Nervous
System (ANS) is then,
again, further sub-divided
into:
A
- the parasympathetic
nervous system - the sympathetic nervous system
9
Q
The brain is part of the …
A
… CNS
10
Q
THe correct terminology for the brain is…
A
…encephalon.
11
Q
Dorsal side means …
A
…the top
12
Q
Frontal lobe is responsible for:
A
Actions
Senses
Movement
Reason
Emotions
13
Q
The parietal lobe is responsible for:
A
touch and motor.
14
Q
The temporal lobe is responsible for:
A
- Memory
- Visual
- Language
- Emotions
15
Q
The occipital lobe is responsible for?
A
- Visual
Its sole purpose is to encode visual images.
16
Q
Function of the insular lobe:
A
Only one main function:
- Processing taste
17
Q
Where is insular lobe found in the brain?
A
Deeply folded between frontal lobe and temporal lobe
18
Q
The spinal cord is part of the…
A
… CNS
19
Q
White matter is organised into 3 parts, the …
A
…posterior columns, lateral columns, and the anterior columns (ventral columns)
20
Q
Central canal is for…
A
…fluid to circulate into
21
Q
Central canal is neither…
A
…grey or white matter. It is a transparent liquid.
22
Q
Gray matter organised into …
A
…posterior horn, lateral horn, and anterior (ventral) horn.
23
Q
Called gray matter due to…
A
…dna within the nuclei which will impede light infraction and so appears darker under a microscope.
24
Q
White matter: located…
A
… ‘outside’, fibers
25
Gray matter: located...
...‘inside’, neuronal nuclei + cell bodies
26
THe dorsal and anterior horns are...
...gray matter
27
The columns are ...
...white matter
28
Staining the spinal cord causes it to appear...
...purple
29
Fibres =
matter
30
Fibres are grouped...
...together depending on information type
31
the amount of gray matter depends on...
...the amount of neurons in that particular\ area.
32
The cranial nerves are all part of the PNS apart from 3 of them whcih are:
- olfactory
- optic (retina!)
- trigeminal
33
olfactory meaning:
Having to do with the sense of smell.
34
The cranial nerves emerge from...
...the base of the brain
35
Soem cranial nerves are purely ...
... sensory
36
Some cranial nerves are purely sensory, some are purely...
...motor
37
Some cranial nerves are purely sensory, some are purely motor, others are...
...mixed
38
What nerve is motor only?
nerve XII (hypoglossal)
39
WHat nerve is sensory only?
nerve I (olfactory)
40
What nerve is mixed (motor and sensory)?
- nerve X (vagus)
- or nerve V (trigeminal)
41
Cranial nerves are often contrasted with...
...spinal nerves
42
Spinal nerves contain both ...
...motor and sensory fibers
43
Spinal nerves belong to the...
...PNS
44
Types of spinal nerves?
- Cervical nerves
- Thoracic nerves
- Lumbar nerves
- Sacral nerves
- Coccygeal nerves
45
How many pairs of cervical nerves?
8 pairs of cervical nerves
46
How many pairs of thoracic nerves?
12 pairs of thoracic nerves
47
How many pairs of lumbar nerves?
5 pairs of lumbar nerves
48
How many pairs of sacral nerves?
5 pairs of sacral nerves
49
How many pairs of coccygeal nerves?
1 pair of coccygeal nerves
50
Spinal nerves have paramount roles in...
...reflex arc
51
These responses (motor response following a sensory input) are ...
uncontrolled (involuntary) & of maximum strength.
52
Responses of reflex arc can be tested in...
the clinic, part of the routine “Neuro Exam”
53
Examples of the neuro exam?
1. Patellar reflex (knee jerk)
2. Biceps reflex
3. Triceps reflex
4. Ankle reflex (Achilles reflex)
5. Extensor digitorum reflex
54
What is a functional unit?
a single cell capable of assuming the entire function of an organ.
55
What are neurons?
functional units of the Nervous System
56
Examples of neurons:
- Purkinje neurons
- Pyramidal neurons
57
What are Purkinje neurons?
Major neuron type in the cerebellum
58
What are pyramidal neurons?
Major neuron type in the cortex
59
The main function of the nervous system is:
- To detect information
- To process information
- To respond to this information (transmit) if needed
60
How many neurons in the nervous system?
86 billion neurons
61
Neurons do not...
...divide
(except in a very specific region: dentate
gyrus of the hippocampus)
62
Once we are born, neurons cannot be ...
replaced in cases of neuronal damage/loss/death.
63
Transmission of information:
neurons and synapses
64
Neurons are organized into...
... circuits / networks
65
Cell-to-cell communication in the nervous system (transmission of information) is crucial to...
...maintain adequate functioning
66
neurons need to be able to send signals: this is done by...
... transmitting electric signals
from cells to other cells.
67
neurons need to be able to send signals: this is done by transmitting electric signals from cells to other cells. This is done by ...
...generating Action Potentials. This is a multi-step process.
68
When a stimulus is detected, the membrane potential will...
... rise (increase) slightly.
69
If the stimulus is not strong enough...
...nothing else will happen and the membrane will return to its resting state (“failed initiations”).
70
If the stimulus is strong enough...
...the membrane potential will rise
until reaching the -55 mV threshold.
71
the -55 mV threshold is a trigger for ...
...some specific channels to open
72
the -55 mV threshold is a trigger for some specific channels to open which are...
... Voltage-dependent Sodium Channels.
73
Voltage-dependent Sodium Channels can be opened by...
... the difference of potential across
the membrane. When it reaches -55mV, the channels will change
conformations
74
Slide 51 - slide 61
75
Action potentials can only be generated at a very specific location in neurons:
the Axon Hillock
76
Action potentials can only be generated at a very specific location in neurons: the Axon Hillock.
This region is also called the ...
... Initial segment (i.e. the initial segment ‘of the axon’).
77
Neurons cannot survive without...
...support cells.
78
Neurons cannot survive without support cells:
These support cells are called...
...Neuroglia (glial cells)
79
What are astrocytes?
- Star shaped cells.
- Biochemical support
- Regulation of cerebral blood flow
- Maintenance of the brain-blood barrier
- Maintenance of ion balance.
80
What are microglia?
Immune cells of the brain. These are considered the brain’s resident macrophages
81
What are oligodendrocytes?
- Provide electric insulation.
- Produce myelin sheaths.
- Oligodendrocytes in the CNS
- Schwann cells in the PNS
82
What are ependymal cells?
- Produce the CerebroSpinal Fluid
(CSF).
- A transparent liquid similar to plasma but has no proteins.
83
The CNS can be divided into two types of matter:
- Grey matter
- White matter
84
What is grey matter made from?
Made of the neurons cell bodies (nuclei of neurons)
85
What is white matter made from?
Made of axons (fibers)
86
Myelin increases the...
...velocity of action potentials
87
Membranes wrap around the...
...axon
88
Myelin is produced by...
...support cells
89
Myelin is produced by support cells:
- Oligodendrocytes in the CNS
- Schwann Cells in the PNS
90
Function of myelin?
- Electric insulation of axons
- Conduction speed
91
Whats the direction of conduction?
from Hillock --> Terminals
92
Arriving at the axon terminals:
the synapse.
93
What is the synapse?
The synapse is a small void (space) between two neurons. There are two types.
94
WHat are the two types of synapse?
- The electrical synapse (also called ‘electronic’).
- The chemical synapse
95
Vesicles contain...
...neurotransmitters
96
Neurons can be classified according to...
...shape and neurotransmitter
97
Examples of neurotransmitter?
dopamine neurons
adrenaline neurons
noradrenaline neurons
serotonin neurons
histamine neurons
endorphin neurons
acetylcholine neurons
glutamate neurons
GABAneurons (γ-amino butyric acid)
98
Slide 91
99
Neurotransmitters are classified in two major categories:
- Excitatory:
Glutamate, Kainate, Aspartate, Nitric oxide
- Inhibitory:
GABA, Glycine, Serotonin, Dopamine
- Mixed:
Acetylcholine, Noradrenaline
100
Ligand-gated channels versus G-protein-coupled receptors
- which provides the fastest communication?
Ligand-gated channels
101
Ligand-gated channels are known as...
...ionotropic channels
102
what channels are called ionotropic channels?
Ligand-gated channels
103
G-protein-coupled receptors are known as...
... metabotropic channels
104
metabotropic channels are...
...G-protein-coupled receptors
105
G-protein-coupled receptors:
E: excitatory
I: inhibitory
106
Two types of summation:
- Temporal
- Spatial
107
Different number of ‘connexions’ in neural networks are:
- monosynaptic (muscle stretch reflex),
- disynaptic (Golgi tendon reflex),
- trisynaptic (hippocampus),
- polysynaptic (most circuits).
108
What is plasticity?
“1. the quality or state of being plastic. especially : capacity for being molded or altered. 2. the ability to retain a shape
attained by pressure deformation. 3. the capacity of organisms with the same genotype to vary in developmental pattern, in phenotype, or in behaviour according to varying environmental conditions."
109
Neural plasticity, also known as neuroplasticity or brain plasticity, can be defined as...
...the ability of the nervous system to change its activity in response to intrinsic or extrinsic stimuli by reorganizing its structure, functions, or
connections.
110
What was the model organism used for the plasticity of the nervous system?
Aplysia californica (see snail).
111
What was found out about plasticity in Aplysia californica?
- As an identical stimulus is applied there is a decreased response
- This is a typical example of neuroplasticity (response modulation)
- Reversible mechanism
112
define homeostasis
regulation of the internal environment. In other words: maintaining an adequate equilibrium.
113
If there is a disturbance in the system (whether anatomical or physiological), the result is...
...pathology (due to abnormal homeostasis).
114
Homeostasis is maintained (almost exclusively) by...
...the Autonomic Nervous System (ANS).
115
Higher organisms (including humans) maintain homeostasis by...
... constant feedback from the ANS (loops).
116
As we have seen earlier, the ANS is divided into two components:
- the sympathetic nervous system
- the parasympathetic nervous system
117
Sympathetic is responsible for...
FFF response = fight-flight-freeze
118
Parasympathetic is responsible for...
RR response = rest-relax
119
Physico-chemical properties of the CSF:
Clear
Colorless
Almost similar to plasma
120
The CNS is surrounded by fluid called...
... Cerebro-Spinal Fluid (CSF)
121
Where is cerebro-spinal fluid (CSF) produced?
Produced by the Choroid Plexus in:
- the lateral ventricles
- the third ventricle
- the fourth ventricle
122
Functions of the CSF?
Buoyancy
Protection
Homeostasis
Clearing “waste”
123
What are the meninges?
The meninges are a set of protective membranes that surround and support the central nervous system, which includes the brain and spinal cord. There are three layers of meninges, each with its own structure and function
124
What are the 3 layers of the meninges?
1. Dura mater
2. Arachnoid mater
3. Pia mater
125
What is dura mater?
The dura mater is the toughest and most durable layer of the meninges. It is a thick, fibrous membrane that lines the inside of the skull and forms a protective covering around the brain and spinal cord
126
The dura mater contains ...
blood vessels and nerves and serves to provide mechanical support and protection to the underlying neural tissues. It also helps in containing and circulating the cerebrospinal fluid (CSF).
127
What is Arachnoid mater?
The arachnoid mater is a delicate, web-like membrane that lies beneath the dura mater. It is named after its spiderweb-like appearance
128
The space between the dura mater and arachnoid mater is called ...
... the subdural space
129
The primary function of the arachnoid mater is to ...
...protect the underlying delicate neural structures and to provide a barrier against pathogens. It also helps in the circulation of CSF through its projections, known as arachnoid villi, which allow CSF to be reabsorbed into the bloodstream.
130
What are the projections of the arachnoid mater called?
arachnoid villi
131
What is pia mater?
The pia mater is the thin, delicate and innermost layer of the meninges, and it directly adheres to the surface of the brain and spinal cord.
132
The pia mater contains...
...numerous blood vessels that supply nutrients to the underlying neural tissues.
133
An additional function of the pia mater is...
...to anchor and stabilize the brain and spinal cord within the skull and spinal column, respectively.
134
Collectively, the meninges serve several important functions:
1. Protection: The meninges provide a physical barrier and cushioning to protect the brain and spinal cord from mechanical shocks and trauma.
2. Support: They provide structural support and stability to the delicate neural tissues, helping to maintain their position within the skull and spinal column.
3. Barrier: The meninges act as a barrier between the central nervous system and the surrounding tissues, helping to regulate the exchange of substances and preventing the entry of harmful pathogens.
4. Circulation of Cerebrospinal Fluid (CSF): The meninges play a role in the production, circulation, and reabsorption of CSF. CSF is a clear fluid that surrounds and nourishes the brain and spinal cord, as well as providing buoyancy and removing waste products.
