Chapter 1 : Studying the Nervous system + Anatomy appendix Flashcards
1
Q
Neuroscience is the study of…
A
how the nervous systems of humans are organized, how they develop and how they function to generate behaviour
2
Q
Neural circuits are…
A
subsets of neurons and glia
3
Q
Neural systems are made of…
A
many neural circuits
4
Q
The three types of neural systems are:
A
SAM: sensory, associational, motor
5
Q
Sensory neural systems report…
A
sensory information about the state of organism and environment (external/internal sensory info)
6
Q
Motor neural systems…
A
organize and generate actions
7
Q
Associational neural systems provide…
A
higher-order brain functions such as PA-MELT: perception, attention, memory, emotions, language, thinking
8
Q
A gene comprises which DNA sequences?
A
Coding DNA sequences and regulatory DNA sequences
9
Q
Genomics is…
A
the analysis of complete DNA sequences (both coding and regulatory)
10
Q
Genomics provided insight on what?
A
How nuclear DNA helps determine the assembly and operation of the brain and rest of nervous system
11
Q
True or false: A single gene can encode information for a variety of protein products
A
True
12
Q
True or false: The mutation of a single gene can lead to neurological or psychiatric disorders.
A
True
13
Q
The central nervous system is made of…
A
The brain and the spinal cord
14
Q
The peripheral nervous system is made of
A
Sensory neurons, somatic motor division, autonomic motor division
15
Q
What theory did Golgi support?
A
The reticular theory
16
Q
The reticular theory states that
A
all neurons formed a single, continuously connected network
17
Q
What theory did Ramon y Cajal support?
A
The neuron doctrine
18
Q
The neuron doctrine states that
A
neurons communicate at specialized contact points rather than trough physical continuity
19
Q
What did Sherrington do?
A
He identified the points of communication between neurons as synapses
20
Q
What scientific development provided the ultimate proof of the neuron doctrine and how?
A
The development of electron microscopy (1950s) because it allowed us to visualize synapses and confirm that neurons were discrete entities
21
Q
What are the primary cells of the brain?
A
Neurons and glia
22
Q
What are the roles of neurons?
A
- process information
- sense environmental changes
- communicate changes to other neurons via electrical signaling
- control bodily responses
23
Q
What are the roles of glia?
A
- support the signaling functions of neurons
- insulate, nourish, repair neurons
24
Q
What is an action potential?
A
All or nothin change in electrical potential across the neuronal cell membrane
25
True or false: dendrites convey information
True
26
True or false: axons integrate information coming from dendrites and convert it to an electrical signal
True
27
True or false: axons only innervate one unique post-synaptic site
False: axons can branch to innervate multiple post-synaptic sites on multiple neurons
28
What are neurotransmitters and what do they do?
Specialized molecules that are released from the presynaptic terminal, cross the synaptic cleft, and bind receptors in the post synaptic density
29
What are nodes of Ranvier?
Gaps in the myelination of axons where action potentials are generated/regenerated
30
Glia is greek for what word?
glue
31
What are the 6 functions of glia?
- MAINTAINING the ionic milieu of neurons
- MODULATING the rate of action potential propagation
- MODULATING synaptic transmission by regulating neurotransmitter uptake at the synaptic cleft
- REGULATING recovery from neural injury
- INTERFACE between brain and immune system
- FACILITATING flow of interstitial fluid through the brain during sleep
32
What are the types of glia?
SAMOSA: Schwann cells, Astrocytes, Microglia, Oligodendrocytes, (Glial) Stem Cells
33
Where are the astrocytes and oligodendrocytes located?
Central nervous system (brain and spinal cord)
34
What is the equivalent of oligodendrocytes in the PNS?
Schwann cells
35
Where are Schwann cells located?
PNS
36
What is the role of oligodendrocytes?
Lay down myelin around axons, regulate speed of transmission of action potentials
37
What is the role of Schwann cells?
Provide myelin in the PNS
38
What is the role of astrocytes?
Maintain appropriate chemical environment for neuronal signaling, including formation of the BBB
39
True or false:
Recent evidence suggests astrocytes secrete
substances to influence construction of new synaptic
connections
True
40
What is the role of microglia?
- They are primarily scavenger cells that remove cellular debris from sites of injury or cell turnover
- They also secrete signaling molecules, particularly cytokines (immune signaling molecules)
41
What is the role of glial stem cells?
Proliferate and generate additional precursor cells or differentiated glia or neurons
42
What is the role of afferent neurons?
Carry info toward the CNS
43
What is the role of efferent neurons?
Carry info away from CNS
44
What is the role of interneurons?
Participate in local aspects of circuit function
45
Divergent neural circuit...
spread information
46
Convergent neural circuit...
integrate information
47
What are the two types of electrophysiological recordings?
Extracellular recording and intracellular recording
48
What is extracellular recording?
An electrode is placed near a neuron and detects temporal patterns of action potetial activity
49
What is intracellular recording?
An electrode is placed inside the neuron and detects smaller, graded changes in electrical potential that trigger action potentials
50
What is calcium imaging?
Recording of transient changes in the concentration of calcium ions that are associated with action potential firing to infer changes in neural activity
51
What are optogenetics?
- Can assess physiology of neural circuits based on activity of neuronal populations
- Inject bacteria (opsins) that , when they have a light on them, react bu transducing light energy into a chemical signal that activates channel proteins
52
What is the role of sensory neural systems?
acquire and process information from the internal and external environment
53
What is the role of motor systems?
respond to information by generating movement
54
What is the role of association systems?
lie between input and output systems
55
What are the 3 characteristics of neural systems?
- unity of function
- orderly representation of specific information at various levels
- division of the function of the system into subsystems that are relayed and processed in parallel
56
What are topographic maps?
Topographic maps reflect a point-to-point correspondence between the sensory periphery and neurons within CNS
57
What is gray matter?
cell bodies in the brain, appear grey in freshly dissected brain
58
what is a cortex?
thin sheet of neurons, usually at the brain's surface
59
what is a nucleus?
clearly distinguishable mass of neurons, usually deep in the brain
60
what is substantia?
related neurons but with less distinct boundaries than a nucleus
61
what is a locus?
small, well-defined group of cells
62
what is a ganglion?
collection of neurons in the PNS. There is only the basal ganglia that is present in the CNS
63
What is a nerve?
a bundle of axons in the PNS. Only nerve in the CNS is the optic
nerve
64
What is white matter?
generic term for collection of axons; appear white from
| myelination
65
What is a tract?
collection of CNS axons having common origin and destination
66
what is a bundle?
collection of axons that run together but do not necessarily have a
common origin/destination
67
what is a capsule?
axon collection that connects cerebrum with brainstem
68
what is a commissure?
axon collection that connects one side of the brain to the
| other
69
what is a leminiscus?
a tract that meanders through the brain like a ribbon
70
What is the genetic analysis of the neural system?
Involves studying the genetic variation that shapes structure and function of the NS
71
What are genome wide association studies (GWAS)>
```
Large scale population
studies that assesses
statistical correlation
between genetic variation
and frequency of
clinically diagnoses
conditions to identify ‘risk
locus’ for a particular
condition
```
72
What did Henry Molaison lose after the ablation of his hippocampus?
HM lost the ability to form new lasting autobiographical memory.
73
What is tract tracing?
Consists of injecting a tracer that allows detailed assessments of connections between brain regions
74
What are the two types of tract tracing?
Retrograde: you see where information comes from
Anterograde: you see where information goes
75
What are the ways to do a functional analysis of neural systems?
Electrophysiological recording and functional brain imaging:
| EEG, TMS, CT, fMRI
76
What is the role of the cerebrum?
Generally receives and sends information to the contralateral side of the body
77
What is the role of the cerebellum?
Also called tiny brain, it contains as many neurons as the cerebrum. It's responsible for movement control
78
What is the role of the brain stem?
It is a relay between cerebrum/cerebellum and spinal cord. It is responsible for basic vital functions such as breathing.
79
How does sensory information travel to the spinal cord?
It is carried by afferent axons of the spinal nerves and enters the spinal cord via the dorsal roots
80
How do motor commands leave the spinal cord?
They are carried by efferent axons and leave the spinal cord via the ventral roots
81
What is inside the spinal cord?
The interior of the cord is formed by gray matter, surrounded by white matter
82
What is the role of cervical and lumbosacral enlargements>
```
They enlargements accommodate
the greater number of nerve cells and connections
required to process
information from upper and
lower limbs
```
83
What are the 3 parts of the white matter of the spinal cord?
LVD (Louis Vuitton Dior): dorsal, lateral and ventral columns
84
What do dorsal columns carry?
Ascending information from somatic mechanoreceptors
85
What do lateral columns include?
Axons that travel from the cerebral cortex to interneurons and motor neurons in the ventral horns
86
What do ventral columns carry?
Both ascending information about pain and temperature AND descending motor information from the brainstem and motor cortex
87
What are the 2 parts of the gray matter of the spinal cord?
Dorsal and ventral horns
88
What do neurons of the dorsal horns receive?
Sensory information that enters via the dorsal roots of the spinal nerves
89
What do the ventral horns contain?
They contain the cell bodies of motor neurons that send axons via the ventral roots of spinal nerves to striated muscles
90
What is the brainstem and cranial nerves?
Midbrain and pons & medulla
91
What are the 3 fundamental functions of the brainstem and cranial nerves?
1. Target and source cranial nerves that deal with sensory and motor function of head & neck
2. A throughway for (ascending sensory tracts, head&neck, descending motor tracts from forebrain, local pathway linking eye movement centers)
3. regulating levels of consciousness through extensive forebrain projections
92
Structure of Brainstem and cranial nerves
- brainstem structures are tightly packed
- cranial nerve nuclei in brainstem are the target of cranial sensory nerves and the source of cranial motor nerves
- there is a seperation of sensory and motor nuclei in the brain stem (sensory nuclei - laterally) (motor nuclei - medially)
93
Lateral surface of the brain
Lateral fissure separates temporal lobe from frontal & parietal lobes
• Central sulcus separates frontal and parietal lobes
• Parieto-occipital sulcus separate parietal and occipital lobes
94
Lateral surface of the brain (ii)
* Precentral gyrus locates motor cortex
* Postcentral gyrus locates somatic sensory cortex
* Insula cortex is hidden beneath frontal and temporal lobes
95
Dorsal and ventral surfaces of the brain
- Bilateral symmetry of cerebral hemispheres
- Corpus callosum bridges the two hemispheres, carrying axons originating from:
- neurons in cerebral cortex of each hemisphere to
contact target neurons in the opposite cortical region
96
Midsagittal surface of the brain
* Calcarinesulcuslocates primary visual cortex
* Cingulate gyrus is part of limbic system
* Corpuscallosum
97
Components of the diencephalon
* Components of diencephalon:
* Thalamus- relay of sensory and motor signal to relevant primary cortical cortex and also distributer of high order signals from one part of cortical area to another.
* Hypothalamus- homeostatic and reproductive functions
98
The thalamus: a cortical relay
- The sensory pathways from the eye, ear, and skin all relay in the thalamus before terminating in the cerebral cortex
- ~50 nuclear subdivisions maintain distinct inputs & outputs
99
How does the thalamus receive input?
• Receives input from throughout brain and spinal cord
• Sends axons to different cortical areas
◼ Sends information back to brain stem via internal capsule and basal ganglia
100
Explain the internal anatomy of forebrain
- Amygdala located in front of hippocampus
- Basal ganglia: caudate, putamen & globus pallidus
- Anteriorcommissure- axon tract connecting the two hemispheres
- Internalcapsule-major pathway linking cerebral cortex to brain & spinal cord
101
What causes major blood vessels to be damaged?
- Damage to major blood vessels by trauma or stroke results in combinations of functional deficits caused by
- Local cell death
- Disruption of axons passing through area of vascular
damage
- Neurons are highly sensitive to oxygen (& glucose) deprivation because they have a high metabolic rate
102
What happens if major blood vessels are damaged?
- Even brief loss of blood supply (ischemia) can cause cellular changes that may end in cell death
- Prolonged loss of blood supply leads to cell death & degeneration
- A ‘stroke’ refers to the death or dysfunction of brain tissue that follows compromised blood supply
103
What is the role of the blood brain barrier? (BBB)
- BBB protects the brain from toxins & fluctuations in ionic milieu
- Interface between walls of capillaries and surrounding tissue are observed throughout the body
- In the brain, tight junctions form between capillary endothelial cells that are not seen elsewhere in the body
104
How do molecules enter the brain?
- To enter the brain, molecules must move through endothelial membranes:
- Lipid soluble
- Actively transported e.g. glucose
105
What are the the two meniges?
1. Aranchinoid membrane
| 2. Pia mater
106
What is the arachinoid membrane?
middle layer of the menige with a web like consistency from the greek word 'spider'
107
What happens if blood vessels pass between the dura and arachnoid membranes?
- can cause subdural hematomas
| - fluid build here is dangerous because it puts pressure on CNS
108
What is the Pia mater?
inner layer adheres closely to the brain and includes many vessels; latin for 'gentle mother'
separated from the arachnoid by the subarachnoid space containing cerebrospinal fluid (CSF)
109
What are ventricles?
- canals through the brain filled with cerebrospinal fluid
| (CSF)
110
What is CSF - cerebrospinal fluid?
- CSF is produced by the choroid plexus, special tissue lining the ventricles of the brain
- CSF turnover multiple times daily
- flows into the subarachnoid space by small openings along the dorsal midline of the forebrain, where it is absorbed by subarachnoid villi into the blood
111
What is the Glymphatic system of the brain?
* The brains waste clearance system
* CSF passes from arterial perivascular space through the substance of the brain
* The CSF rinses metabolic waste and discarded proteins
* The waste-carrying CSF passes out of the brain via the perivascular space surrounding veins
* CSF flow increases during sleep when extracellular spaces expand
