Quiz 1 Flashcards
1
Q
Division of nervous system into two =
A
Peripheral nervous system (PNS)
+
Central nervous system (CNS)
2
Q
How are PNS and CNS different?
A
Axon myelination - CNS by oligodendrocytes, PNS by Schwann cells
3
Q
What is NGF?
A
nerve growth factor; an important neurotrophic factor produced by Schwann cells; helps in regrowth of PNS neurons; not present in CNS neurons
4
Q
Peripheral nerves are comprised of axons of…
A
motor, sensory, and postganglionic sympathetic motor neurons
5
Q
Cranial nerves are part of PNS except…
A
CN II (Optic nerve)
6
Q
Which cranial nerves contain parasympathetic autonomic motor fibers?
A
III, VII, IX, X – 3, 7, 9, 10
7
Q
CNS is made up of two parts, which are:
A
brain + spinal cord
8
Q
Brain is further divided into…
A
1) Cerebrum (telencephalon), 2) Cerebellum, 3) Brainstem
9
Q
The cerebrum (telencephalon) is further divided into…
A
Cortex + Diencephalon
10
Q
The diencephalon is further divided into…
A
Thalamus + Hypothalamus
11
Q
The brainstem is further divided into…
A
Midbrain + Pons + Medulla
12
Q
White matter is mostly composed of…
A
Axons
13
Q
Tracts are…
A
Bundles of axons
14
Q
Ascending tracts do what?
A
Transmit sensory info from sensory receptors to higher levels in CNS
15
Q
Descending tracts do what?
A
Transmit motor info from CNS
16
Q
Descending tracts are subdivided into…
A
Column, Fasciculus, Funiculus, Lemniscus, Peduncle, Tract (named origin to destination)
17
Q
Grey matter is composed of…
A
Cell bodies + Dendrites (e.g., cortex or specific nuclei)
18
Q
What is the term for clusters of cell bodies in the CNS?
A
Nuclei
19
Q
What is the term for clusters of cell bodies in the PNS?
A
Ganglia
20
Q
Grey matter includes what two types of neurons?
A
Projection neurons + Interneurons
21
Q
White matter is located where?
A
On the periphery in the spinal cord + Deep in the cerebrum
22
Q
Grey matter is located where?
A
On the periphery in the cortex and cerebellum + Deep in the spinal cord and brainstem
23
Q
Crossing patterns: sensory patterns - where?
A
Some level of the nervous system
24
Q
Crossing patterns: motor pathways - where?
A
As descend
25
Crossing patterns result in...
Contralateral control of brain, so deficits manifest contralateral to lesion side;
Exception: crossing patterns in cerebellum
26
Sagittal plane
Divides body into 2 halves; perpendicular to frontal (coronal) plane
27
Parasagittal plane
Divides body into two sides
28
Frontal (coronal) plane
Divides anterior from posterior; perpendicular to sagittal plane
29
Rostral direction
Towards the nose (or tip of frontal lobe)
30
Caudal direction
Towards the tail (or end of spinal cord)
31
Why use rostral + caudal terms for CNS?
The cephalic flexure results in the telencephalon (cerebrum) being at 100 degree angle to the spinal cord and brainstem
32
How many neurons are there?
20 billion in the neocortex
33
How many synapses of neurons exist?
0.15 x 10^15 synapses
34
How many glial cells are there?
39 billion in the neocortex
35
Neurons are classified by 1) shape into...
1) Multipolar, 2) Pseudounipolar, 3) Bipolar
36
Bipolar neurons are special sense organs for what senses?
Olfactory (smell), vision (sight), and hearing
37
Neurons are classified by 2) according to their connections into...
1) Sensory, 2) Motor, 3) Interneurons
38
What do sensory neurons do?
Receive info from receptors
39
What do motor neurons do?
Send info to muscles or glands; has lots of branches
40
Which constitutes the majority of neurons? Sensory, motor, or interneurons?
Interneurons
41
What defines multipolar neurons?
Has many branches (blob with a bunch of spikes, e.g., hand + fingers)
42
What defines pseudo unipolar neurons?
Dorsal root ganglion (DRG); one process is in the periphery, to body, one process centrally towards CNS
43
Anatomy of a Neuron: Cell Body is also called...
soma, perikaryon
44
Anatomy of a Neuron: Dendrites
Where the synaptic input is received
45
Anatomy of a Neuron: Spines
On dendrites to increase surface area for synaptic input; only present while active plasticity (e.g., while learning); can be resorbed (when intense learning phase is over) or built out again (when long term learning phase starts)
46
Anatomy of a Neuron: Nucleus
Has a nucleolus inside
47
Anatomy of a Neuron: Nissl substance
Rough ER; disappears if the cell is damaged
48
Anatomy of a Neuron: Axon Hillock
Connection between cell body/soma to axon
49
Anatomy of a Neuron: Axon
Myelinated
50
Anatomy of a Neuron: Myelin segments
Myelin sheaths cover myelin segments to increase speed of impulse propagation
51
Anatomy of a Neuron: Nodes of Ranvier
Gaps between myelin segments
52
Anatomy of a Neuron: Synaptic ending, bouton, terminal
Where neurotransmitters are stored in vesicles before release into the synaptic cleft to communicate with another neuron
53
Anatomy of a Neuron: Collaterals
Multiple endings of an axon; allows a single neuron to reach many targets
54
Glia in nervous system are considered neuroglia, aka...
"Nerve glue"; supports neurons since there aren't many connective tissue fibers present; prevents NS from turning into mush
55
Glia functions (x4)
1) Act as "skeleton" of CNS; 2) Help maintain electrolyte balance, nutrition, and homeostasis in CNS; 3) Participate in immune response; 4) Modulate Neurotransmission - clears NTs from synaptic cleft, secretes "modulators" such as ATP, releases glutamate (in vivo)
56
Types of Glial cells: Macroglia: Astrocytes - function
1) Perivascular end feet to help transport nutrients to far away neurons; 2) May be involved in transport of nutrients - selective absorption; 3) Forms a glial membrane (barrier) beneath the pia mater; 4) Forms glial scar after injury; 5) Has many interconnections via small gap junctions
57
Types of Glial cells: Macroglia: Astrocytes - 2 types
1) Fibrous astrocyte (white matter); 2) Protoplasmic astrocyte (grey matter)
58
Glial intracranial tumors
1) Glioblastomas (fast growing astrocytic tumor); 2) Astrocytomas (slow growing astrocytic tumor)
59
Types of Glial cells: Macroglia: Oligodendrocytes
1) Has little cytoplasm/small body; 2) Produces myelin sheaths of CNS; 3) One oligodendrocyte gives off processes (arms) to myelin ate segments of several (up to 15) different axons, but cannot myelin ate two segments of a single axon
60
Types of Glial cells: Microglia
1) Smaller than macroglia; 2) Normally inactive; 3) Active after injury, with infection; 4) Can change into macrophage for phagocytosis
61
Types of Glial cells: Ependymal Cells
Line the inner surface of the ventricles of the brain to contain CSF (cerebrospinal fluid) within the ventricles
62
Types of Glial cells: Schwann Cells
1) Glial type of the PNS; 2) Myelinates PNS axons; 3) Supports unmyelinated axons in PNS; 4) One Schwann cell myelinated one myelin segment
63
Types of Glial cells: Satellite Cells
A glial cell type of the PNS that supports the cell bodies in the DRG
64
Protein Synthesis and Transport: DNA
DNA determines which proteins are synthesized - specific to the cell (e.g., NTs and receptors) or common to all cells (e.g., proteins that make up cytoskeleton, membranes)
65
Protein Synthesis and Transport: Proteins made for use outside cell
Examples: Neurotransmitters + hormones
66
Protein Synthesis and Transport: Proteins made for use within the cell
Examples: Cytoskeleton proteins, ion channels, receptors, enzymes, proteins that support dendrites and spines
67
Protein Synthesis and Transport: Cytoskeleton: Functions (3)
1) Supports the neuron, giving rigidity and shape; 2) Holds receptors in place in the membrane; 3) Transports substances
68
Protein Synthesis and Transport: Cytoskeleton: 3 Filament Types
1) Microtubules (transport); 2) Microfilaments (support body); 3) Neurofilaments (support axon)
69
Protein Synthesis and Transport: Cytoskeleton: Transport
1) Transport anterogradely (away from cell body) and retrogradely (toward cell body); 2) Transport mechanisms can be affected in certain types of neuropathies (e.g., diabetes) because they are energy-dependent (longer/fatter neurons require greater energy)
70
What is Computerized Tomography?
CT scan that uses the principles of an X-ray machine to measure tissue density; Compiled data of single slices into one image
71
CT imaging: Appearance of tissues
1) Brighter areas - more water, grey matter, hyper-dense; 2) Darker areas - more fat, white matter, hypo-dense; 3) Grey areas - iso-dense
72
CT imaging: Hemorrhage
Determines age of hemorrhage: Acute - brighter; Subacute (2-3 weeks) - isodense; Chronic - darker
73
CT imaging: Ischemia (loss of blood flow)
1) Not good for imaging ischemia in first 6 hours; 2) After, edema visible and infarcted (dead due to lack of blood) tissue appears dark
74
MRI: Physics
Magnetic Resonance Imaging
Magnetism, properties of photons and hydrogen molecules
On/off pulses of magnets causes H molecules to give off magnetic field energy pulse, which is detected and constructed into an image
75
MRI: T1 and T2
T1 and T2 weighted images can be generated, dependent on different axes of proton spins
76
MRI: T1
Looks like an image of the anatomical brain (e.g., white matter is white, grey matter is grey)
77
MRI: T2
Looks like a photo negative
78
MRI: Ischemia
T2 can detect ischemic area a few hours after onset
79
MRI: Hemorrhage
Acute (6-24 hrs) difficult to see on both T1 and T2 b/c it appears grey and is hard to distinguish from CSF
By 3-30 days, appears white on both T1 and T2 images
80
CT vs. MRI: MRI Advantages
1) Anatomical detail and detection of small lesions; 2) Acute ischemia (within a few hours utilizing DWI [diffusion weighted imaging])
81
CT vs. MRI: CT Advantages
1) Acute hemorrhage and aging of hemorrhages; 2) Cheaper, quicker, can be done with metals in field (MRI costly, takes longer, can't be done with metals in field)
