Neuroscience Exam 1 Flashcards
(293 cards)
1
Q
The brain’s three parts are
A
the cerebrum, cerebellum, and the brain stem
2
Q
Why should SLPs learn Neuroscience?
A
diagnosis & treatment of speech/language/communication/swallowing disorders correlates with neuropathology
3
Q
What are 4 initial/embryonic divisions of the central nervous system? What do they become?
A
prosencephalon (forebrain/cerebrum/thalamus), mesencephalon (midbrain/upper brainstem), rhombencephalon (hindbrain/pons/medulla/cerebellum), and spinal cord
4
Q
What further specialization takes place in the CNS in embryonic development?
A
the prosencephalon splits into the telencephalon (cerebrum/hemispheres) and the diencephalon (thalamus - sensory relay station and hypothalamus); the rhombencephalon divides into the metencephalon (pons & cerebellum) and the myelencephalon (medulla)
5
Q
What are the two main divisions of the peripheral nervous system? What do they do?
A
the autonomic nervous system (involuntary systems - organs, glands, blood vessels); and the somatic nervous system (voluntary systems - motor/sensory)
6
Q
What are the divisions of the autonomic PNS?
What do they do?
A
sympathetic nervous system (fight or flight); parasympathetic nervous system (return to rest; homeostasis)
7
Q
Where is the central nervous system and how is it protected? How is this different than the PNS?
A
it is housed w/in bony structure (skull/vertebral col) and covered with protective tissue/membranes (meninges divided into three layers, pia mater, arachnoid mater, dura mater) The PNS does not have this bony protection
8
Q
What is meant by interconnectivity?
A
there is a functional organization: L & R hemis communicate via corpus collosum, association areas (mainly in the parietal lobe) different modalities come 2gether (ex. writing uses motor, lang, and visuals); basic reflexes (patella reflex, hot stove) - don’t require brain, just travel to spinal cord, complex reflexes (lifting a light box, like its a heavy box), may req brain involvement, but both use the brain to store in memory, sensory and motor areas must work together
9
Q
How does the CNS control everything?
A
it integrates all incoming and outgoing info, creates responses (volitional and reflexive- spinal cord); no two parts of the PNS communicate w/o the CNS
10
Q
What is the hierarchy of complexity and organization?
A
in the embryonic nervous system there is an increase in complexity as we move superiorly: spinal cord; brain stem & diencephalon (autonomic, visceral systems - consciousness, bl press, respiration, sleep/wake cycles); cerebrum - complex sensory/motor integration, cognitive function
11
Q
What is meant by laterality?
A
even though the two cerebral hemispheres are almost symmetric anatomically, there is hemispheric specialization: left controls language and analytic skills; right controls emotion, prosody, big picture/gestalt, pragmatics
contralateral sensorimotor control
12
Q
What are the three sensory methods of organization of the cerebrum?
A
somatotopic - sensory/motor organization based on region of the body (somatosensory cortex is just post central sulcus; primary motor cortex is just pre central sulcus);
tonotopic organization of the auditory cortex/Heschel’s gyrus (org based on sound)
retinotopic organization of the visual cortex; certain locations of objects trigger certain parts of the occipital lobe;
13
Q
What are Broadman’s Areas?
A
specific areas of cell depth related to certain funcs; defined by cytoarchitecture
14
Q
How is the brain organized generally?
A
executive functions/higher level planning/cognition - housed in frontal lobes & other general lobes for cognition
specific sensory and motor maps (homunculus)
specific areas for special sensory processes
general areas for language - left lobes for cognition
basic things, carefully mapped out
more complex things, have general areas, but we don’t know precisely
15
Q
What is cytoarchitecture?
A
the cell structure, the way Broadmann divided the brain; 6 layers of the cortex, differ in density and architecture
16
Q
What is meant by brain plasticity?
A
it can change over time: change in organization (cell connectivity; cell function); response to internal/external changes: recovery from brain damage; amputation; motor practice; it decreases w/ age; groups of neurons changing jobs
17
Q
What is the afferent pathway?
A
pathway from the body to the brain (sensory pathway)
18
Q
What is the efferent pathway?
A
pathway from the brain to the body (motor)
19
Q
How do you divide the brain into front and back?
A
take a coronal/frontal slice
20
Q
How do you divide the brain into left and right pieces? What if they are halves?
A
sagittal; midsagittal
21
Q
How do you divide the brain into top and bottom pieces? Parallel to the floor
A
horizontal (transverse is another term in the brain, but in the spinal cord, transverse is different)
22
Q
What is a gyrus/convolution?
A
a bump or hill of the brain
23
Q
What is a sulcus or a fissure?
A
a groove or valley of the brain (fissure is a really deep group)
24
Q
What is a cortex?
A
the outer surface/layer of brain; literally means bark
25
What is a neuron cell?
primary nervous system tissue, send signals to other neurons, muscles, organs, glands, etc.
26
What are glial cells?
support cells of nervous system, provide structure and protection
27
What is a nerve?
bundles of neuron extensions (axons), mostly found in the peripheral nervous system
28
What percent of the brain is glial cells?
90%, neurons are the additional 10%
29
What are astrocytes?
type of glial cells that provide structure for the brain; connected neurons to capillaries; supply nutrients to neurons; create the blood-brain barrier
30
What are oligodendrocytes and Schwann cells?
types of glial cells which insulate axons by creating myelin
31
What are microglia?
types of glial cells which are phagocytes - eater cells
32
What are ependymal cell?
glial cells which make good lining for cerebral spinal fluid
33
What are dentrites?
part of the neuron that are afferent, which pick up information and transmit it to the cell body
34
What are axons?
the part of the neuron which is efferent, passing the signal along to the next neuron
35
What is a synapse?
the juncture between one neuron to the next
36
What is gray matter?
the cortex/outer surface of the cerebrum; made up of cell bodies and dendrites
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What is white matter?
the axons/axon tracts that extend from the cell bodies of the cortext; covered by myelin, which is fatty
38
What are nuclei? What are ganglia?
gray matter - collection of cell bodies; CNS cell bodies: nucleus (except the Basal Ganglia, triangular grey matter in the center of the brain); PNS cell bodies: ganglion
39
What are subcortical structures?
cell bodies that are deep to the cortical structures
40
What is a fasciculus/tract?
groups of axons (CNS: tract; PNS: fasciculus); in the PNS are more bundled and are nerves, but as they spread the
41
What is a commissure?
band of connecting fibers; connect the right and the left hemispheres; corpus callosum is the largest in the brain; anterior commissure is for olfactory connection; posterior commissure is for visual connection
42
What is the major sulcus which divides the anterior and posterior halves of the brain?
the central sulcus (sulcus of Rolando); more difficult to see
43
What is the major sulcus which divides the left and right hemispheres?
sagittal sulcus (longitudinal fissure)
44
What is the line which makes the little arm in the brain (separating the temporal lobe and the frontal and parietal)? The thumb of the boxing glove brain
the Sylvian fissure (or lateral sulcus)
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What are the 4 major lobes of the brain? What are the 2 extras?
1 frontal, 2 parietal, 3 occipital, 4 temporal (All are paired! Divided by the sagittal sulcus)
bonus: insular; limbic (system and lobe)
46
What is the frontal pole?
the tip of the frontal lobe; most anterior point
47
What are the 3 gyri of the frontal lobe?
superior, middle and inferior, rough divisions, not clearly demarcated
48
What are the 3 areas in the inferior horizontal frontal gyus?
BA 44 - pars opercularis (most posterior)
BA 45 - pars triangularis (most inferior)
BA 11 pars orbitalis (lies right above the orbit of the eye, most anterior)
44 & 45 very imp for lang processing: BROCA'S AREA
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What are the landmarks of the the frontal lobe?
the pre-central gyrus BA 4 - where the motor homunculus is;
| the supplementary motor area BA6 and premotor area BA8 imp for movement planning
50
What are the two sections of the parietal lobe? What are they divided by?
the superior and inferior; the intraparietal sulcus
51
What are three other important areas of the parietal lobe? What is they important?
the angular gyrus (at the posterior end of the sylvian fissure) & the supramarginal gyrus (superior & anterior to the angular) - important for reading and writing (lang comprehension; post-central gyrus - sensory strip of the body
52
What is the anterior most boundary of the temporal lobe?
the temporal pole
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What is the purpose of the superior temporal gyrus? What are the areas called?
hearing and language; Heschel's gyrus - primary auditory processing area- mostly contralateral response/bilateral anatomically; Wernicke's area (posterior to Heschel's gyrus) - primary language comprehension area, only in the Left hemisphere; area
54
What structures are on the inferior surface of the temporal lobe?
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the uncus (very important to the limbic system, very medial)
the parahippocampal gyrus (just superficial to the hippocampus and medial to the inferior temporal gyrus); fusiform gyrus (extension of the parahippocampus; functions in recognizing things)
```
55
Where is the hippocampus? What does it look like? What does it do?
deep/medial in the temporal lobe; squiggly; seahorse shaped; transforms short term into long term memory
56
What are the two sulci that divide the occipital lobe?
the parieto-occipital fissure/sulcus; calcarine sulcus/fissure (demarcates the primary visual cortex
57
What are other important landmarks of the medial brain? 7
corpus callosum; cinulate gyrus; septum pellucidum; thalamus; hypothalamus; anterior and posterior commissure; infundibulum pituitary/hypophysis
58
Where is corpus callosum? What does it do?
major brain of fibers that connect the right and left hemispheres - made of axons/white matter
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Where/what is the cingulate gyrus?
immediately superior to corpus callosum; associate w/ the limbic system
60
What are the basal gangli?
collection of structures; bilateral that regulate motor functions, muscle tone, action execution, cognition; groups of cell bodies, where processing takes place
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What are the three sections of the basal gangli?
the caudate nucleus; putamen; globus pallidus
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Where/what is the septum pellucidum?
inferior to the corpus callosum; thin tissue which divides the r/l lateral ventricles
63
Where is the hypothalamus? What is the function?
inf and anterior to the thalamus; autonomic - fight or flight response; endcrine - hormone regulation; circadian rhtyhms; body temp, blood volume, intake/output, drive and emotion; cyclical things
64
Where is the thalamus? What is it made of? What does it do?
inf to the septum pellucidum; third ventricles divides the two thalami; consists of multiple nuclei; sensory relay to cortex; also SOME speech/language functions; sense of smell does NOT stop here, but everything else does;
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What shape is the caudate nucleus?
c-shaped
66
Where is the putamen?
lateral to the caudate
67
Where is the globis pallidus?
deep/internal to the putamen
68
What is the subthalamic nucleus?
a small lens-shaped nucleus; part of the basal ganglia system;
69
What does substantia nigra mean? What does it do?
black substance, darker than the surrounding tissue; where dopamine made
70
Where are the anterior and posterior commissure?
axon tracts that connect the two hemispheres at the front and back end of the corpus callosum
71
What is the massa intermdia/thalamic adhesion?
connection of the r/l thalami; 70-80% of people this is present;
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Where is the pituitary? What does it do?
inferior primary gland that controls the secretion of hormones
73
What are the different sections/nuclei of the thalamus? 2
medial geniculate body (auditory) lateral geniculate body (visual system) & others
74
What is the brain stem?
the connection between the brain and the spinal cord; it monitors all brain outputs; automatic control system; heart/breath rate controlled here, connects to the basal ganglia/thalamus/cerebellum
75
What are the 3 sections of the brain stem?
the midbrain, the pons, and the medulla oblongata (becomes the spinal cord)
76
What are cerebellar peduncles?
large tracts of axons (white matter) entering/exiting the cerebellum; connectors between pons/brainstem and cerebellum
77
What starts the impulses to the head & neck from the brain stem?
cranial nerve nuclei (collections of cell bodies) - relay stations; cell bodies of neurons (nerves) that innervate the head and neck
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What gray matter/ exists in the brain stem?
the longitudinal fiber tracts
79
What is the corticobulbar tract?
motor tract that start in the cortex ends in the brain stem
80
What is the corticospinal tract?
motor tract that start in the cortex ends in the spinal cord
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What is a pyramidal tract?
one set of tract that traverses the brain stem
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What is the reticular formation?
part of the brain stem/ neurons that connect the thalamus and spinal cord; regulates inhibit, facilitates, modifies all cortical function; integrated w/ the autonomic nervous system (fight or flight and return to homeostasis) (influences signal up or down)
83
What is the reticular activating system?
responsible for cortical arousal and consciousness (sleep/wake control), respiration, swallowing (influences the cortex)
84
What is the reticular formation? What does it do?
circuitry connecting thalamus & spinal cord, inhibit, facilitate, modify, regulate all coritcal func
85
What is the corpora quadrigemina? Where is it?
four bumps on the dorsal/posterior of the midbrain; the superior colliculus (regulates visual reflexes, integrates head & eye movements, reflexive eye mvts); inferior colliculus (hearing - point on the pathway to the temporal lobe
86
What dos the pons contain? (3) Where is it?
descending motor & ascending sensory tracts, reticular formation, middle cerebellar peduncle; inferior to the midbrain, superior to medulla
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What are the internal features of the medulla? 5
1. reticular formation, 2. cardiac center (regs h.beat), 3. vasomotor center (regs bl vessel dilation), 4. respiratory ctr (regs breathing), 5. fiber tracts (pyramidal decussation - 80-90% of motor neurons crossover here); really important part of the brain!
88
What do the cranial nerves do? Where do they enter/leave the brain?
they innervate the head/neck (motor and sensory) and provide special senses (taste, smell, vision); the cranial nerve axons enter/leave from the brain or brain stem
89
What is the function of hte cerebellum? What are its extensions?
it modifies motor signals/coordinates movement; extensive connections to the motor cortex; basal ganglia; and spinal cord
90
What are the features of the cerebellum? 4
the gyri are called folia (b/c they are tiny, lots more surface area than the cerebrum); the vermis is the (midline structure), it has two hemispheres, flocculonodular lobe (inferior extension)
91
What is the spinal cord?
a bi-directional pathway for axons; it houses reflex arcs;
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How long is the spinal cord? How wide?
16-18 inches long; 1 cm diameter
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How many pairs of spinal nerves are there? What is their break down?
31 pairs; 8 cervical; 12 thoracic; 5 lumbar; 5 sacral; 1 coccygeal
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What is the h-shaped/butterfly shaped structure in the spinal cord made of? What is the surrounding structure made of?
cell bodies; axons (reversed from the brain)
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What is the lower tip of the spinal cord? What is below it?
the conus medullaris;the filum terminale (fiber extending down to connect to the coccyx) and the cauda equina (tail of nerves exiting to innervate lower extremities)
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What are the two "horns" of the spinal nerve cells?
the dorsal horns (sensory exiting); ventral horn (mostorentering)
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Where do the fibers exit/enter the spinal cord?
the intervertebral foramina
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The dorsal and ventral fibers combine and become ___
spinal nerves
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What are the fiber tracts of the white matter of the spinal cord called?
funiculi/fasciculi; can be labeled for where they connect, or what they do
100
How does they spinal cord change in size as it descends?
there are fewer nerves as you reach the bottom, there is more gray matter near the limbs, more white matter rostrally, w/ sensory, more and more is added as the cord ascends, the gray matter increases in percentage at the sacral region because all of the motor neurons for the lower limbs must exit there.
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What is the ventricular system?
the set of the cavities and canals, which are filled with cerebrospinal fluid (CSF); the ventricles are all connected
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How many ventricals are there in the brain?
4: 2 lateral ventrals and two midline ventricles (3rd ventricle, 4th ventrical)
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What are the meninges?
the protective membranes surrounding the CNS (cover brain and spinal cord, create space to hold the CSF);
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What are the three layers of the meninges?
1 dura mater; 2 arachnoid membrane; 3 pia mater
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What are projection fibers?
fibers that leave the brain (the corticobulbar, corticospinal fibers examples)
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What are association fibers?
stay w/in a hemisphere
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What are commissural fibers?
connect the two hemispheres (unilateral)
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What are the two types of association fibers?
short (connections that don't stretch too far); long (ex. superior longitudinal fasiculus - sup to corpus collosum (frontal to occipital); inferior longitudinal fasciculus (temporal & occipital connection); uncinate fasciculus (inferior frontal to the temporal lobe); cingulum (deep in the cingulate gyrus, immediately superior to the corpus callosum)
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What are commissural fibers? What is the largest?
connect the r/l hemispheres; corpus callosumis the lgest, made of 300-400 million fibers; connect homolog areas (same areas on opposite sides), but does not primary motor and sensory ares (incl A/V) does not connect this way: they connect via association areas; the anterior commissure (olfactory info), the posterior commissure (visual info)
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What are the parts of the corpus callosum?
rostrum (head); genu (bend); body (main portion) splenium (posterior portion); information carried is related to where it is.
111
What are neurotransmitters?
chemical signals
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What percentage of the nervous system is neurons? What % is glial cells?
10%; 90%
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What is the PNS equivalent to astrocytes?
satellite cells - surround cell bodies and protect & scaffold
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What is the PNS equivalent to the oligodendrocytes?
schwann cells - create myelin
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What is another names for the cell body of the neuron?
soma, perikaryon
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What is the afferent part of a neuron? What is the efferent?
dendrite; axon
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Where does the axon leave the cell body?
the axon hillock; may split into collateral branches;
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What are the tiny packets of chemicals found at the end of an axon?
synaptic vesicles (filled w/ synaptic vesicles) also mitochondria down here (creates energy for the cell)
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What is the cytoskeleton?
structural proteins that give the cell its shape (composed of microtubules neurofilaments, and microfilaments that run the length of the axon: they continue down axons and create "roadways" for transporting proteins and organelles
120
What are tau proteins?
important proteins for microtubules
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Most of the neurons are covered with ___. What does this do?
myelin; it's a fatty substance that increases the speed of signals travelling down the axons
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What are nodes of Ranvier?
portions of the axon that are not covered by myelin, jumping points
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What is a nerve fiber?
a myelinated axon
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What are nerves?
bundles of nerve fibers
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What is the myelin sheet?
fatty tissue created by either schwann cells or oligodendrocytes (it speeds up neural conduction)
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How are Schwann cells different than oligodendrocytes?
each Schwann cell creates one packet of myelin; but oligodendrocytes create multiple myelin packets (also Schwann is in PNS, oligodendrocytes are in CNS)
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How much faster is myelinated axons than unmyelinated?
10 m/s to 120 m/s
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What is myelogensis?
the development of myelin, begins during fetal development; rate/timing matches sensori-motor & cognitive development; continues into adulthood
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The point of communication between two neurons or between the neuron and the muscle is the ____
synapse
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Is there physical contact at a synapse?
no.
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What are the components of the synapse? 3
the axon terminal; the synaptic cleft and the receptors/receptor sites
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What are the steps in the sending of a message?
dendrites receive a chemical message and send it to the soma/cell body; the soma gest the msg from the dendrites, sends electrical msg down the axon; axon transports electrical msg to axon terminal; axon terminal sends chemical signal through the synapse to the next neuron (usually through a dendrite)
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What are the two types of signals a cell body can send?
excitatory ("go" signal) or inhibitory ("stop" signal); both can be sent, whichever has more is going to win (be passed on)
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What are tau proteins?
important proteins for microtubules
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Most of the neurons are covered with ___. What does this do?
myelin; it's a fatty substance that increases the speed of signals travelling down the axons
136
What are nodes of Ranvier?
portions of the axon that are not covered by myelin, jumping points
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What is a nerve fiber?
a myelinated axon
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What are nerves?
bundles of nerve fibers
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What is the myelin sheet?
fatty tissue created by either schwann cells or oligodendrocytes (it speeds up neural conduction)
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How are Schwann cells different than oligodendrocytes?
each Schwann cell creates one packet of myelin; but oligodendrocytes create multiple myelin packets
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How much faster is myelinated axons than unmyelinated?
10 m/s to 120 m/s
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What is myelogensis?
the development of myelin, begins during fetal development; rate/timing matches sensori-motor & cognitive development; continues into adulthood
143
The point of communication between two neurons or between the neuron and the muscle is the ____
synapse
144
Is there physical contact at a synapse?
no.
145
What are the components of the synapse? 3
the axon terminal; the synaptic cleft and the receptors/receptor sites
146
What are the steps in the sending of a message?
dendrites receive a chemical message and send it to the soma/cell body; the soma gest the msg from the dendrites, sends electrical msg down the axon; axon transports electrical msg to axon terminal; axon terminal sends chemical signal through the synapse to the next neuron (usually through a dendrite)
147
What are the two types of signals a cell body can send?
excitatory ("go" signal) or inhibitory ("stop" signal); both can be sent, whichever has more is going to win (be passed on)
148
What are the two types of signals that can be sent?
1. electrical signal (w/in a neuron, has to do with Na and K moving in and out of the cell from soma to axon terminal) 2. chemical signal (neuro transmitter function transferring a signal from one neuron to another or muscle cell)
149
What are the three shapes of nerve cell? What are examples of each?
unipolar (T-shaped, one extension from soma divides into axon and dendrite; spinal sensory neurons), bipolar (1 dendrite & 1 axon; retina, inner ear), or multipolar neuron (many dendrites & 1 axon; CNS, motor system; most common: found in Purkinje cells in the cerebelum)
150
What are 3 different classifications systems of neurons?
shape, size, and function
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What are the two classifications of size of neurons?
Golgi type I (sensory/motor tracts) Golgi type II (interneurons - connect adjacent cells)
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What are the three functions of neurons?
sensory (afferent); motor (efferent); interneurons (cerebral neurons, other neurons of the brain)
153
Where does an axon terminate?
ends in terminal bouton/axon terminal
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What does the termination contain? 2
ctns synaptic vesicles filled w/ neurotransmitters and the terminal bouton also contains mitochondria
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What are the three sections of the synapse?
1 the presynaptic neuron; 2 synaptic clef 3 post-synaptic neuron
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What are the three types of synapses?
1 axodendritic (axon connects to dendrite of the post-synaptic neuron) 2 axosomatic (axon attaches to the cell body) 3. axoaxonic - axon attaches to the axon of the post synaptic nueron)
157
How do synapses work in the PNS?
they attach at the neuromuscular junction
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Motor neurons extend out from the ____ of the spinal cord.
ventral body
159
What are the presynaptic neurons steps (3)?
1 msg sent down axon to terminal, 2 neurotransmitters released from vesicles in axon terminal, 3 neurotransmitters spill into synaptic gap
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What are the postsynaptic neuron steps (3)?
1 neurotransmitter binds to receptors on dendrite, 2 responds to presence of neurotransmitter, 3 sends message to next neuron
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How do electrical signal work?
called action potentials or nerve impulses, they are sent w/in a neuron, ion channels & ion pumps make this happen (Na, K, and Ca)
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How do chemical signals work?
at the synapses, neurotransmitters (dopamine, norepeniphrene)
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What is the resting state of a neuron characterized by?
it is not conducting a signal/impuls, and the membrane potential is polarized (it is negative inside, positive outside the cell membrane); lots of sodium outside, some potassium, chloride ions, and negatively charged proteins inside the cell. The inside of the cell is -70 mV relative to the outside (cell is polarized)
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What are the ions involved in electrical signal transmission?
Sodium (Na+), Potassium (K+), Chloride (Cl-), Calcium (Ca++)
165
What are the two membrane potential gradients in the neuron?
membrane potential (concentration gradient: ion concentration gradiate means that there is more one kind of ion outside than inside; electrical gradient - the difference in the charge (-70mV);
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What are ion channels?
openings for free ion movement (sodium will move inside and potassium will move outside the cell to balance the ion concentration)
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What are ion pumps?
energy-powered pumps to move ions in/out (used to recreate the gradient found in the resting state - pump potassium in and sodium out)
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What are leak channels?
allow ions to just flow in and out (allow potassium to leave cell, allow chloride in, they do not affect the electrical charge/gradient)
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How do the membrane potential and the sodium-potassium pump work?
the membrane potential is the fact the Na and Cl are high outside the cell and K is greater inside the cell and the sodium-potassium pump restores this gradient using energy
170
What is neuron excitability?
its potential for creating an impulse to send to the next neuron or cell
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What is another name of action potential?
nerve impulse
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Are there levels of action potentials?
no, they are all or nothing
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What are the steps of the action potential sequence? 3
```
1 depolarization (opens Na channels)
2 repolarization (closes Na, opens K channels)
3 return to resting state (closure of K channels)
```
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What is hyperpolarization?
increased internal negativity; less able to conduct action potential; Inhibitory Post-Synaptic Potential (IPSP)
175
What is the excitatory post-synaptic potential and how is it started?
decreased negativity, which requires a 5-10 mV change from resting potential
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What is it called when an action potential moves down a myelinated axon?
Saltatory conduction (AP jumps down the axon)
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How does saltatory conduction work?
the changes in gradients only happen at the nodes of Ranvier
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What happens when the action potential reaches the axon terminal?
instead of sodium channels opening, Calcium (Ca++) channels open; which flows in b/c there's less Ca inside, which causes exocytosis
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What is exocytosis?
synaptic vesicles fuse w/ presynaptic membrane and release the neurotransmitter into the synaptic cleft
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What happens when the neurotransmitters enter the synaptic cleft?
it binds to the receptors, if it is excitatory, it will open the sodium channels and become depolarized, creating an excitatory post-synaptic potential (EPSP); if it is inhibitory, it creates hyperpolarization or inhibitory post-synaptic potential (IPSP)
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What are EPSP neurotransmitters?
ACh, Glutamate, Dopamine, and Seratonin
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What is an IPSP neurotransmitter?
GABA, also barbituates and "downers"
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What happens after the neurotransmitter finishes binding? 2 options
it releases and re-enters the synaptic cleft and some go through reuptake enter the axon terminal and can be rebound for the next and others can be consumed by enzymes.
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What are the rules governing an action potential? 3
1 initiated when depolarization reaches the threshold 2 it is all or nothing 3 it is the same magnitude each time
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What is the absolute refractory period?
a period after an action potential, when sodium channels are inactivated/locked w/ strong depolarization, this prevents new AP until repolarization occurs
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What is a relative refractory period?
the hyperpolarized state, -80 mV; needs a bigger stimulus to fire (need more work, more EPSPs to fire)
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What is summation?
the addition of charges, which determines if the EPSPs or IPSPs are greater
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What is spatial summation?
the location of the greatest charge is localized and as a result, causes an AP
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What is temporal summation?
if one neuron fires repeatedly, can over come another neuron's firing (IPSP or EPSP)
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The timing of action potentials can reflect the ____ of the stimulus.
intensity
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Many inhibitory synapses are either ____ or ___.
axoaxonic or axosomatic
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An excitatory impulse will ____ activity in the post synaptic neuron.
increase
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An inhibitory impulse will ____ activity in the post synaptic neuron.
decrease
194
What are the small molecule neurotransmiters? 6
1 Acetylcholine (ACh); 5 Monoamines (produced in the brainstem): Dopamine (DA), Norepiniphrine (NE), Serotonin (5-HT), Glutamate (Glu), Gaba-aminobutyric acid (GABA),
195
What is acetylcholine?
common in the PNS, primary Ntx found at the neuromuscular junction
196
What is acetycholine esterase?
an enzyme that breaks down ACh at synapse and allows repittive neve impulses; allows muscle repolarization
197
How does Myasthenia Gravis affect ACh function?
an autoimmune disease that causes antibodies to interfere with ACh receptors at neuromusclar junction, affects the muscles over time (speech will be come slurred as the pt speaks); swallow will get weaker and weaker over time
198
How does Alzheimer's Disease affect ACh function?
it affects the cholinergic (ACh releasers) projections to frontal cortex & hippocampus
199
Where is Dopamine found? What can result in a lack of DA?
found in the circuits in the basal ganglia (Parkinson's) also found in cortex (affects motivation, cognition, and Schizophrenia)
200
Where is Norepinephrine (NE)? What does it do?
noradrenergic cells release it in the brainstem, thalamus, cortex, and limibic system. Associated with the sympathetic: fight or flight response: adrenaline rush; primary PNS Ntx
201
Where is Serotonin (5-HT) found? What does it do?
95% is found in blood platelets & GI tract; it is also found CNS various areas: imbalances affect sleep cycles, depression, and modulates pain input (more or less sensitive to pain)
202
What/where is GABA?
the primary inhibitory Nt, GABA is spread thru-out the CNS - cortex, hippocampus, and cerebellum, it can fast inhibitatory transmission or slow modulatory effects (slows activity more broadly)
203
For what can drugs that increase the effectiveness of GABA be used?
treat epilepsy, anxiety, insomnia, and Huntington's Chorea (caused by loss of GABA-ergic neurons in basal ganglia)
204
Where is Glutamate found?
in CNS, synaptic vesicles
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What does Glutamate do? What's the deal?!
it is the primary excitatory Ntx in the CNS, most neurons will have receptors to Glutamate so that they can responds to it wherever it's released. it is toxic to the external cell membrane if it escapes (this is called excitotoxicity- where it escapes and there is too much excitation in a system, damage between) - one of the reason for neuropathologies in nearby areas to trauma.
206
What types of neuronal circuits are there? 4
divergent circuit - signal from 1 neuron to may neurons (amplifies impulse)
convergent circuits - many inputs (from 1 or many neurons) into 1 post-synaptic neuron, focusing impulses;
lateral inhibition - sending an EPSP to a target cell and IPSPs to neighboring cells; amplifies 1 by shutting down the others
reverberating circuit - self-propagating system
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___ makes 1 signal stand out; IPSP of neighboring cells, amplifies 1 by shutting down the others
lateral inhibition
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A self propagating system of neuronal circuit is called a ____.
reverberating circuit
209
How do drugs modify actions of neurotransmitters? 3
1 a blocking effects, 2 simulating effect (mimic ntx), 3 prolonging effects
210
A ____ blocks post-synaptic receptors.
receptor antagonist
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What are two types of receptor antagonists (inhibitors)?
1 curare: binds to ACh receptors at neuromuscular junction; paralysis;
2 Atropine: blocks ACh at synapse in pupil, prevents constriction of pupil so the pupil dilates
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A ____ mimics a neurotransmitter.
receptor agonist
213
What is an example of a receptor agonist?
nicotine: mimics ACh, binds to ACh receptors and activate post-synaptic neuron
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What are the two ways that neuropharmcologists can prolong the effects of an axon firing?
by blocking breakdown or blocking re-uptake: leads more Ntx in the synaptic cleft, block the enzymes and the block re-uptake
215
What is an example of a prolonging effect neuropharmacology?
the blocking of acetylcholinesterase, making ACh survives longer in the synaptic cleft (used for treating Myasthenia Gravis)
216
What does CNS do in response to damage?
not very good at repairs: 2 actions can be taking:
axonal (retrograde reaction): degeneration up axon to soma (axotomy);
Wallerian (anterograde) degeneration: degeneration distally to axon terminal
217
How quickly does Wallerian degeneration happen? When does Myelin degeneration take place?
begins 12-20 hrs post-injury; denervation of muscles w/in 2-3 days; myelin degeneration 7 days to 6 months
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What happens to the soma after injury? 5
1 the organelles begin to swell, 2 Nissl substance degenerates, 3 chromatolysis (9-10 days after injury- shrinking of the nucleus) degeneration of the cell body btw axon hillock & nucleus; 4 pyknosis (condensation of chromatin in the nucleus of a cell undergoing necrosis), 5 nucleus moves away from the center of the soma
219
What does the CNS do to try to maintain the axon?
general neuronal changes: increased in RNA and protein synthesis (regenerate severed axon & prevent cell body death) if the response works: the chromatolysis process stops;
generalized changes: Edema (swelling) begins - maximal 90-100 hrs post-injury; glial cells migrate to the area; caused by changes to blood-brain barrier; masks gray/white matter boundaries
220
What are the glial cell processes response to injury? 4
hyperplasia - migration to injury; incr in #
hypertropy - growth in size
nutrophils - scavenger white blood cells that fight infection
breakdown of the BBB (blood brain barrier)
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What does hypertrophy in the brain cause?
increased intracranial pressure (which slows down function of the brain) (can be pushed down towards the foramen magnum)
222
What are the longer term process of the glial cells in response to injury? 4
1 necrotic tissue liquefies; 2 microglia, astrocytes, other macrophages migrate to site and phagocytize the tissue (may cause pre-/post-synaptic terminals become displaced); 3 cystic cavity - (resulting from a large lesion, fluid filled); 4 gliosis (result of a small lesion, basically a scar)
223
What are the steps of axonal regeneration in the PNS?
it begins 3-4 days post injury; can be surgically cleaned/re-attached;
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What cells assist in PNS regeneration and how? 3 steps
schwann cells: 1 fill space btw proximal/distal ends; 2 create tube to guid growth of proximal end; 3 can re-connect to wrong distal end
225
How widespread is re-growth re-connection in the CNS?
minimal
226
What limits regrowth in the CNS?
oligodendrocytes actions and inflammation
227
What is multiple sclerosis? (meaning and process)
sclerosis means scarring, and it is an autoimmune disease attacking the myelin; glial cells proliferate and form plaques/scars which disrupts function and slows nerve conduction over time; the immediate affect is slowing of function
228
What are the signs and symptoms of MS (early)?
muscle weakness, spasticity/tone, numbness in limbs; loss of vision; double vision; vertigo, loss of balance
229
What are the difference between signs and symptoms?
```
symptoms = pt reported
signs = doctor observed
```
230
What are the later signs and symptoms of MS?
tremor (rapid muscle contraction) /ataxia (incoordination - affecting the cerebellum); dysarthria (speech disorder of incoordination); dizziness
231
What is the relapsing/remitting pattern of MS?
some people will have periods where things seem to get better, and then things seem to get worse: oligodendrocytes decide to help create new myelin for a while, then stop and relapse can cause axon death (permanent damage)
232
What are the Pt characteristics of MS?
2:1 female to male ratio; more comon in northern/colder climates; 30-60 cases/100,000
233
How widespread is re-growth re-connection in the CNS?
minimal
234
What limits regrowth in the CNS?
oligodendrocytes actions and inflammation
235
What is multiple sclerosis? (meaning and process)
sclerosis means scarring, and it is an autoimmune disease attacking the myelin; glial cells proliferate and form plaques/scars which disrupts function and slows nerve conduction over time; the immediate affect is slowing of function
236
What are the signs and symptoms of MS (early)?
muscle weakness, spasticity/tone, numbness in limbs; loss of vision; double vision; vertigo, loss of balance
237
What are the difference between signs and symptoms?
```
symptoms = pt reported
signs = doctor observed
```
238
What are the later signs and symptoms of MS?
tremor (rapid muscle contraction) /ataxia (incoordination - affecting the cerebellum); dysarthria (speech disorder of incoordination); dizziness
239
What is the relapsing/remitting pattern of MS?
some people will have periods where things seem to get better, and then things seem to get worse: oligodendrocytes decide to help create new myelin for a while, then stop and relapse can cause axon death (permanent damage)
240
What are the Pt characteristics of MS?
2:1 female to male ratio; more comon in northern/colder climates; 30-60 cases/100,000
241
What are the characteristics of myasthenia gravis?
chronic auomimmune disease; progressive weakness w/ continued muscle use; loss of ACh receptors - neuromuscular junction (antibodies bind to ACh receptors (prevent ACh function); later will destroy receptors); muscles receive only a
242
The onset of Myathenia Gravis is ____
gradual
243
females are more affected by Myasthenia Gravis ______ years old.
before 30
244
males are more affected by Myasthenia Gravis ______ years old.
after 30
245
The disease progression of Myasthenia Gravis can be _____.
slowly progressive; remission periods can be long
246
What are symptoms of Myasthenia gravis? 3 primary, 4 secondary
increasing weakness: diplopia (double vision) ptosis (drooping eyelids); weak respiration; cranial nerve involvement (facial expression; dyphagia; hypernasality; dropped jaw
247
What is diagnosis and treatment of Myasthenia Gravis?
use of anticholinesterase drugs: inhibit acetylcholinesterase, ACh lasts longer
248
What is ALS?
Amyotropic Lateral Sclerosis (Lou Gherig's disease)- degeneration of muscles; scarring and location of spinal tracts; motor neurons afftected
249
What are pt's characteristics of ALS?
greater among males than females; 40-60 yo onset; 90+% idiopathic; associated w/ traumatic brain injury
250
What is the progression of ALS?
slowly progressive, but can progress rapidly; symptoms include muscle twitching, cramping, stiffness, muscle weakness in arms/legs, gradually spreads to both head/neck and body; cognition affected, but later in the disease
251
Who are famous people with ALS?
Lou Gherig, Stephen Hawking
252
What are the components of the diencephalon?
thalamus, hypothalamus, epithalamus, subthalamus, and the optic tract (anterior extension of the diencephalon)
253
What are the functions of the hypothalamus?
mediates endocrine/metabolic states
254
What are the functions of the epithalamus?
diurnal/autonomic body functions
255
What are the functions of the thalamus?
sensory relay to the cortex, movement coordination, speech/language functions; and emotions
256
The thalamus is consists of multiple ______ or _____.
nuclei or cell bodies
257
The _____ or ____ connects the R/L thalami. It is present in 70-80% of people.
massa intermedia or thalmic adhesion
258
What are the three primary functions of thalamus and where does this happen?
relay sensory info to cortex (gross sensory processing, mostly unconscious); integrate motor info (from basal ganglia, cerebellum, limbic system to primary and pre-motor cortex); regulates cortically-mediated cognitive functions (inputs to/from brainstem reticular formation)
259
What are some connections to the thalamus?
the thalamo-cortico-thalamic loop (reverberating circuit- keeps sending signals unless stopped by some external input; projects and retains info); there are as many as 120 thalamic nuclei: specific (bi-directional connections target specific cortical areas - sensorimotor & cog processes) non-specific (no direct connection to cortex, connected to brainstem arousal system)
260
Where are the medial (mediodorsal) nuclear complex and what does it do?
conx from mamillary glands, hippocampus, cortical areas; output to cortical association areas, prefrontal, orbitofrontal, limbic, hippocampus, hypothalamus:
involved with MOOD, EMOTION, COGNITION, PERSONALITY
261
Development of emotion, judgement/reasoning, memory, language; integrates visceral info w/ affect, emotion, thought processes, personality and judgement, regulates mood based on sensory input & stored experiences and sensory and motor learning is located _____
in the medial (mediodorsal) nuclear complex
262
Where is the lateral nuclear complex and what does it do?
conx from the cingulate to percuneus (visceral-sensory integration), from other thalamic nuclei to parietal (integrate sensory modalities for cognition); SENSORY INTEGRATION
263
Visceral-sensory integration and multiple sensory modalities (complex sensory integration) is located in ____.
the lateral nuclear complex
264
Where is the pulvinar and what does it do?
conx from the visual cortex, superior colliculus, midbrain visual reflex ctr, inferior parietal and output to inferior parietal, angular & supramarginal gyri; FUNCTIONS IN READING AND WRITING
265
Language formulation and processing, reading, writing and visual reflexes is located in ___
the pulvinar (the pillow)
266
Where are the ventral anterior and ventrolateral nuclear complexes and what do they do?
conx from globus pallidus, substantia nigra, motor cortex, and the cerebellum; imp for MOTOR INTEGRATION/COORDINATION
267
Regulation of volitional movement (body position, muscle tone, and mvt coordination) and coordination of motor info (cortex, basal ganglia, cerebellum) and implicated in dystonias (mvt disorders) is located in ______
ventrolateral and ventral anterior nuclear complexes
268
Where do the ventral posterior lateral and ventral posterior medial receive info from? What kind of info?
from the body, primary sensory information (goes to parietal lobe)
269
____ receives primary sensory info from the head and neck.
the ventral posterior medial nucleus of the thalamus
270
_____ receives primary sensory info from the body and also plays a role in the primary motor signals.
the ventral posterior lateral of the thalamus
271
The _____ is part of the visual tract and receives fibers from the CN II or ____, which sends to the occipital lobe.
lateral geniculate body; optic nerve
272
The _____ is part of the auditory tract and receives fibers from the CN VIII or ____, which sends to Heschel's gyrus of the superior temporal gyrus of the temporal lobe.
medial geniculate body; auditory nerve
273
____ has connections to the mamillary body to the cingulate gyrus and plays a role in emotion and visceral functions (digestive, respiratory systems).
anterior nucleus of the thalamus
274
_____ receives info from motor areas (cortex/basal ganglia) and influences cortical excitability.
centromedian and intralaminar nuclei of the thalamus
275
The ___ connects to/from the cortex diffusely and plays a role in attention and wakefulness. It covers the thalamus.
reticular nucleus of the thalamus
276
What are 2 important parts of the epithalamus?
the habenular nucleus and the pineal gland
277
______ is connected to the hypothalamus, limbic system, orbitofrontal cortex, reticular formation that plays a role in emotion, drive, smell and memory/smell systems. It is named after a horse's reins.
habenular nucleus
278
____ is an endocrine system gland which secretes melatonin, and influences gonadal systems, sleep/wake cycles and Seasonal Active Depression.
pineal gland
279
_____ is connected with the motor system, the basal ganglia, globus pallidus, and superior colliculus. Anatomically related to the thalamus.
subthalamus
280
How many nuclei have been counted in the hypothalamus?
up to 30
281
What roles does the hypothalamus play in the body? 4
autonomic - of the ANS; endocrinic - hormones, regulatory (body temp, blood vol, intake (fluid/food), circadian rhythms, drive & emotion (limbic system)
282
What do lesions of the hypothalamus cause? 5
```
1 temperature reg malfunction
2 ANS malfunction
3 diabetes insipidus
4 thirst response
5 obesity/anorexia
```
283
What are structures near the hypothalamus?
optic chiasm, infundibular stem/pituitary stalk, and the pituitary (hypophysis)
284
What are teh connections in and out of the hypothalamus (afferent 3, efferent 5)
aff 1 hippocampus/limbic sys; 2 olfactory sys; 3 amygdala;
| eff 1 brainstem (parasympathetic sys); 2 reticular formation; 3 thalamus, 4 cingulate, 5 pituitary gland
285
What are the neural and hormonal connections and functions of the hypothalamus? 3
1 control center for ANS
2 controls endocrine system
3 regulates body temperature; food/water intake; sugar metabolism; sex beh; emotional state
286
What are the general cognitive functions of the thalamus? 4
1 sensory-motor functions
2 cognitive functions
3 language, speech functions
4 influences cortical alertness, information flow to cortex
287
What is paraphasia?
word errors involving substituting one word or sound for another
288
What is anomia?
word finding difficulties and difficulties naming objects
289
What do lesions of the thalamus cause? 5
1 paraphasias, 2 anomia, 3 jargon, w/ 4 intact comprehension and repetition; 5 and motor speech disorders (such as dysarthria)
290
Stimulation of parts of the thalamuscan help with ____ recall, ___ retrieval, and can influence ____ behaviors.
verbal recall, lexical retrieval, and stuttering behaviors
291
_____ is disfunction which is marked by altered threshold for sensation (touch, pain, temperature), with contralateral input, Pain is poorly localized, can have an increased pain threshold, but increased pain response above threshold OR decreased pain threshold.
Thalamic syndrome
292
What are some characteristics of Thalamic syndrome? 4
altered threshold to pain/temperature (increased or decreased)
2 altered perception of sensation (parasthesias)
3 speech/lang disorders (dysarthria, reading writing disorders)
4 altered emotional responses (inappropriate laughter crying)
293
What are 3 large molecule ntx?
3 Large molecule Ntx (peptides): enkephalin, endorphins, substance P
