Chapter 2 Flashcards
1
Q
The basic signaling units that transmit information throughout the nervous system.
A
Neurons
2
Q
Serve various functions in the nervous system, providing structural sup- port and electrical insulation to neurons and modulating neuronal activity.
A
Glial cells
3
Q
What are the 3 main types of glial cells in the CNS?
A
astrocytes, microglial cells, and oligodendrocytes
4
Q
Are large glial cells with round or radially symmetrical forms; they surround neurons and are in close contact with the brain’s vasculature.
A
Astrocytes
5
Q
Astrocytes make contact with blood vessels at specializations called __________.
A
end feet
6
Q
Permits the astrocyte to transport ions across the vascular wall.
A
End feet
7
Q
A barrier between the tissues of the central nervous system and the blood created by astrocytes
A
Blood brain barrier
8
Q
Restricts the diffusion of microscopic objects (such as most bacteria) and large hydrophilic molecules in the blood from entering the neural tissue, but it allows the diffusion of small hydrophobic molecules, such as oxygen, carbon dioxide, and hormones.
A
Blood brain barrier
9
Q
plays a vital role in protecting the central nervous system from blood-borne agents such as chemical compounds and also pathogens.
A
Blood brain barrier
10
Q
What happens when astrocyte activity is blocked?
A
Neuronal activity increases, supporting the notion that neuronal activity is moderated by astrocyte activity
11
Q
Glial cells also form the fatty substance called ________ in the nervous system
A
myelin
12
Q
In the central nervous system, ____________ form myelin
A
oligodendrocytes
13
Q
In the peripheral nervous system, ____________ form myelin
A
Schwann cells
14
Q
How do Schwann cells and oligodendrocytes create myelin?
A
By wrapping their cell membranes around the axon in a concentric manner during development and maturation.
15
Q
What is a good electrical insulator, preventing loss of electrical current across the cell membrane. It increases the speed and distance that information can travel along a neuron?
A
Myelin
16
Q
Are small and irregularly shaped, are phagocytes that devour and remove damaged cells.
A
Microglial cells
17
Q
_________ cells can proliferate (reproduce rapidly)
A
microglia
18
Q
__________ cells dispose of damaged cells
A
microglial
19
Q
3 main parts of a neuron
A
cell body, dendrites, and an axon.
20
Q
Cell membrane that encases the cell body in neurons; contains the metabolic machinery that maintains the neuron
A
soma
21
Q
The salty intracellular fluid that is made up of a combination of ions
A
Cytoplasm
22
Q
molecules or atoms that have either a positive or negative electrical charge
A
ions
23
Q
Are branching extensions of the neuron that receives input from other neurons.
A
Dendrites
24
Q
Specialize processes in most dendrites; little knobs are attached by small necks to the surface of the dendrites, where the dendrites receive inputs from other neurons.
A
Spines
25
A single process that extends from the cell body.
Axon
26
What travels along the length of the axon to its end, the axon terminals, where the neuron transmits the signal to other neurons or other targets?
Electrical signals
27
Transmission occurs at the __________
synapse
28
a specialized structure where two neurons come into close contact so that chemical or electrical signals can be passed from one cell to the next.
Synapse
29
Some axons branch to form __________________ that can transmit signals to more than one cell
axon collaterals
30
Along the length of the axons, there are evenly spaced gaps in the myelin
Nodes of Ranvier
31
Information that is received by the neuron at its input syn- apses passes through the cell body and then, via the axon, to output synapses on the axon terminals
neuronal signaling
32
Within a neuron, how does information move?
information moves from input synapses to output synapses through changes in the electrical state of the neuron caused by the flow of electrical currents within the neuron and across its neuronal membrane.
33
Between a neuron, how does information move?
information transfer across synapses is typically mediated chemically by neurotransmitters (signaling molecules), uses chemical synapses
34
signals between neurons travel via transsynaptic electrical currents
Electrical synapses
35
When are neurons presynaptic?
when their axon’s output synapses make connections onto other neurons or target
36
When are neurons postsynaptic?
when other neurons make a connection at input synapses onto their dendrites or elsewhere on the receiving neuron.
37
What is needed to generate signals?
energy
38
What is energy in the form of across the neuronal membrane?
electrical potential
39
The difference in voltage across the neuronal membrane or, put simply, the voltage inside the neuron versus outside the neuron.
Electrical potential
40
When a neuron is in its resting state and not actively signaling, what happens to the inside of a neuron?
the inside of a neuron is more negatively charged than the outside.
41
The voltage difference across the neuronal membrane in the resting state is typically about -70 millivolts (mV) inside.
Resting potential/ Resting membrane potential
42
a bilayer of fatty lipid molecules that separates the cytoplasm from the extracellular milieu
Neuronal membrane
43
Since the membrane is composed of lipids, what does this mean?
it does not dissolve in the watery environments found inside and outside of the neuron, and it blocks the flow of water-soluble substances between the inside and the outside. It prevents ions, proteins, and other water-soluble molecules from moving across it.
44
Maintains the separation of intracellular and extracellular ions and electrical charge that ultimately permits neuronal communication.
The lipid membrane
45
Serve as conduits for ions to move across the membrane
Transmembrane proteins
46
Are proteins with a pore through the center, and they allow certain ions to flow down their electrochemical and concentration gradients.
Ion channels
47
use energy to actively transport ions across the membrane against their concentration gradients—that is, from regions of low concentration to regions of higher concentration.
Ion pumps
48
selectively permit one type of ion to pass through the membrane.
The hydrophilic ion channels
49
What ions are the ion channels selective for?
sodium, potassium, calcium, or chloride ions
50
The extent to which a particular ion can cross the membrane through a given ion channel
Permeability
51
a property of all cells in the body; as part of cellular homeostasis, it enables cells to maintain internal chemical stability
Selective permeability
52
The neuronal membrane is more permeable to which ion(s).
K+ than to Na+ (or other) ions
53
Neurons are excitable, what does this mean?
their membrane permeability can change
54
Why can neurons' membrane permeability change?
Because the membranes have ion channels that are capable of changing their permeability for a particular ion.
55
They open or close in response to changes in nearby transmembrane voltage or to chemical or physical stimuli.
Gated ion channels
56
are unregulated, and hence always allow the associated ion to pass through, are known as nongated ion channels.
Ion channels
57
For Ion pumps under normal conditions, concentrations of what ions are greater outside the cell?
Na+ and Cl-
58
For Ion pumps under normal conditions, concentrations of what ions are greater inside the cell?
K+
59
Active transport proteins used by neurons to combat the drive toward equilibrium
ion pumps
60
What ion pump do neurons use to pump Na+ ions out of the cell and K+ ions into the cell?
Na+/K+ pump
61
Each ion pump is an enzyme that does what?
Hydrolyzes adenosine triphosphate (ATP) for energy
62
The concentration gradients create forces due to what?
unequal distribution of ions
63
The force of the Na+ concentration gradient acts to push what?
Na+ from an area of high concentration to one of low concentration (from outside to inside)
64
The force of the K+ concentration gradient acts to push what?
K+ from an area of high concentration to an area of low concentration (from inside to outside)
65
Why are the inside and outside voltages different?
The membrane is more permeable to K+ than to Na+
66
What causes an electrical gradient?
Each K+ ion carries one unit of positive charge out of the neuron as it moves across the membrane.
67
When does a negative charge build up along the inside of the membrane?
The positively charged K+ ions outside of the cell are drawn electrically back into the neuron through the same ion channels that allow K+ ions to leave the cell by diffusion
68
EPSPs occur in the ___________.
dendrite
69
Passive current conduction is called ____________________.
electrotonic conduction/ decremental conduction
70
What is passive current conduction called decremental conduction?
Because it diminishes with distance from it origin --- the synapse on the dendrites
71
The maximum distance a passive current will flow in a neuron in only about _________.
1mm
72
A rapid depolarization and repolarization of a small region of the membrane on the neuron's output via its axon caused by the opening and closing of ion channels.
Action potentials
73
How are action potentials able to enable signals to travel for meters with no loss in signal strength?
They continually regenerate the signal at each patch of membrane on the axon
74
Action potentials are able to regenerate itself because...?
voltage-gated ion channels
75
A specialized region of the neuronal soma where the axon emerges; it initiates the action potential.
Spike-triggering zone in the axon hillock
76
In myelinated axons, voltage-gated ion channels along the axon's length are restricted to the ___________________.
nodes of Ranvier
77
The membrane moves from its resting potential of about -70mV to a less negative value of approximately -55mV, then an action potential is triggered.
Depolarization
78
When the membrane reaches -55mV, leading to the fire an action potential
Threshold
79
When the threshold is reached, what happens?
Voltage-gated Na+ channels open and Na+ flows rapidly into the neuron. This influx of positive ions further depolarizes the neuron, opening additional voltage-gated Na+ channels; thus, the neuron becomes more depolarized, continuing the cycle by causing even more Na+ channels.
80
Describe the Hodgkin-Huxley cycle.
1. When a neuron reaches a certain threshold, voltage-gated sodium channels open.
2. Sodium flows into the neuron, which depolarizes it further.
3. The depolarization opens more sodium channels, which causes even more depolarization.
4. This cycle continues until the membrane potential reaches the sodium equilibrium potential.
5. Potassium channels open, allowing potassium to flow out of the neuron.
6. This repolarizes the membrane potential, returning it to its resting state.
81
The membrane potential at which there is no net flux of a given ion.
Equilibrium potential
82
What is the result of reaching the equilibrium potential?
The membrane is temporarily hyperpolarized.
83
What happens when the resting potential reaches -80mV?
the membrane potential is more negative than both the resting membrane potential and the threshold required for triggering an action potential
84
What does hyperpolarization cause?
the K+ channels to close, in response to which the membrane potential gradually returns to its resting state
85
During the transient hyperpolarization state, what happens to the voltage-gated Na+ channels?
voltage-gated Na+ channels are unable to open, and no other action potential can be generated.
86
the time after an action potential when a cell cannot generate another action potential.
Absolute refractory period
87
Follows an absolute refractory period, the neuron can generate action potentials, but only with larger-than-normal depolarizing currents.
Relative refractory period
88
What are the two consequences of the refractory period?
1. neuron's speed is limited to about 200 action potentials per second.
2. passive current that flows from the action potential cannot reopen the ion-gated channels that generated it.
89
Describe the direction of an action potential.
an action potential moves down the axon in one direction only -- from the axon hillock toward the axon terminal.
90
Acceleration and transmission of the action potential is accomplished in _________________.
myelinated axons
91
The myelin surrounding the membrane of myelinated axons causes what?
the axon super-resistant to voltage loss
92
Action potentials in myelinated axons need to occur only at where?
at the nodes of Ranvier where myelination is interrrupted
93
What is the result of action potentials only occurring at the nodes of Ranveer?
action potentials appear to jump down the axon at great speed, from one node of Ranvier to the next.
94
The rapid method by which nerve impulses move down a myelinated axon with excitation occurring only at nodes of Ranvier
Saltatory conduction
95
What disease does loss of myelination cause?
multiple sclerosis
96
Action potentials always have the same amplitude; the amplitude of the action potential does not depend on the size of the triggering depolarization as long as that depolarization reaches the threshold for initiating the action potential.
all or none phenomena
97
The intensity of a stimulus is communicated by what?
the rate of firing of the action potentials
98
Most neurons fire at a _____________ rate.
continuous baseline
99
What forms myeline around the axons of neurons?
Glial
100
The electrical gradient across a neuron's membrane results from?
the asymmetrical distribution of ions
101
The electrical difference across the membrane is the basis for what?
of the rest potential, the voltage difference across the neuronal membrane during rest
102
Where are voltage Na+ and K+ channels located and where do action potentials occur?
nodes of ranvier
103
How can postsynaptic potentials be measured?
From large populations of neurons by electrodes located some distance away, such as the scalp, as when the oscillatory signals in an EEG are being recorded.
104
The transfer of a signal from the axon terminal of one neuron to the next neuron.
Synaptic transmission
105
How do most neurons send a signal to the cell across the synapse?
by releasing chemical neurotransmitters into the synaptic cleft
106
The gap between neurons at the synapse
Synaptic cleft
107
Different neurons produce and release different neurotransmitters, and some may release more than one type at a time.
co-transmission
108
Describe the general mechanism of chemical transmission
The arrival of the action potential at the axon terminal leads to depolarization of the terminal membrane, causing voltage-gated Ca21 channels to open. The opening of these channels triggers small vesicles containing neurotransmitter to fuse with the membrane at the synapse and release the transmitter into the synaptic cleft. The transmitter diffuses across the cleft and, on reaching the postsynaptic membrane, binds with specific receptors embedded in it.
109
What are the two types of postsynaptic receptors?
ligand-gated channels, G protein-coupled receptors (GPCR)
110
Where neurotransmitter binding directly gates (opens) the ion channel
Ligand-gated ion channels
111
Biochemical signals indirectly cause the gating (opening) of ion channels
G protein-coupled receptors (GPCR)
112
Those that bind the guanine nucleotides GDP and GTP (guanosine diand triphosphate) and act as molecular switches in cells
G proteins
113
In ligand-gated ion channels, binding induces a conformational change in the receptor. What does this cause?
The change in shape opens an ion channel, resulting in an influx of ions leading to either depolarization (excitation) or hyperpolarization (inhibition) of the postsynaptic cell
114
Hyperpolarization of the postsynaptic neuron produces what?
an IPSP
115
Each type of GPCR is activated by a what?
specific signaling molecule
116
A small protein-like molecule secreted by neurons or glial cells
Neuropeptide
117
When a signaling molecule specifically binds to its GPCR, the shape change activates what?
a G protein within the cell, which in turn activates or regulates a specific target protein, typically an enzyme, which produces a diffusible molecule of some sort called a second messenger.
118
Triggers a biochemical cascade of reactions/ a specialized target protein
Second messenger
119
DIrectly gated channels mediate ________ signaling.
fast
120
GPCRs mediate _________ signaling.
slow
121
What makes a molecule a neurotransmitter?
■ It is synthesized by and localized within the pre-synaptic neuron and stored in the presynaptic terminal before release.
■ It is released by the presynaptic neuron when action potentials depolarize the terminal (mediated primarily by Ca21).
■ The postsynaptic neuron contains receptors specific to it.
■ When artificially applied to a postsynaptic cell, it elicits the same response that stimulating the pre-synaptic neuron would.
122
Aspartate, gamma- aminobutyric acid (GABA), glutamate, and glycine.
Amino acids
123
dopamine, norepinephrine, and epinephrine (these three are known as the catecholamines), serotonin, (5-hydroxytryptamine), and histamine.
Biogenic amines
124
made up of strings of amino acids
Neuropeptides
125
True or false: the rate of stimulation by the action potential can induce the release of a specific neurotransmitter.
TRUE
126
The effect of a neurotransmitter on the postsynaptic neuron is determined by the what?
Postsynaptic receptor’s properties rather than by the transmitter itself.
127
Neurotransmitters that usually have an excitatory effect include what?
ACh, the catecholamines, glutamate, histamine, serotonin, and some of the neuropeptides.
128
Neurotransmitters that are typically inhibitory include what?
GABA, glycine, and some of the neuropeptides.
129
Why are some neurotransmitters called conditional neurotransmitters?
because their action is conditioned on the presence of another transmitter in the synaptic cleft or activity in the neural circuit
130
The primary players in the balancing act between excitation and inhibition are?
Glutamate and GABA
131
___________ is released by the pyramidal cells of the cortex, the most common cortical neurons.
Glutamate
132
____________ is the most prevalent neurotransmitter and is found in most of the fast excitatory synapses in the brain and spinal cord.
Glutamate
133
What can too much glutamate (excitation) do?
it can be toxic and cause cell death and has implicated in stroke, epilepsy, and neurodegenerative diseases such as Alzheimer's and Parkinson's
134
found in most of the fast inhibitory synapses across the brain
GABA
135
Most GABA receptors open what type of channels to allow an influx of negatively charged ions into the cell, negatively shifting (hyperpolarizing) the membrane potential and, in essence, inhibiting the neuron by making it much less likely to fire?
Cl- channels
136
What does decreased levels of GABA (decreased inhibition) result in?
Seizures, increases in emotional reactivity, heart rate, blood pressure, food and water intake, sweating, insulin secretion, gastric acid, and colonic motility.
137
What does increased levels of GABA (decreased inhibition) result in?
Lead to coma
138
139
is present in the synapses between neurons and between neurons and muscles (neuromuscular junctions), where it has an excitatory effect and activates muscles. It acts as a neurotransmitter and a neuromodulator and sup- ports cognitive function
Acetylcholine (ACh)
140
Where are nicotinic ACh receptors located?
in the automatic ganglia of the sympathetic and parasympathetic nervous system.
141
_________ binds nicotinic ACh receptors and imitates the actions of ACh
Nicotine
142
Where are muscarinic ACh receptors located?
in the CNS, heart, lungs, upper GI tract, and sweat glands
143
What toxin suppressed the release of ACh at the neuromuscular junction, causing flaccid paralysis?
Botulinum
144
What toxin binds to the nicotinic ACh receptor, decreasing ACh levels, and causes muscle weakness and, in sufficient doses, flaccid paralysis of the diaphragm and death?
Curare
145
What is the ACh breakdown enzyme?
acetylcholinesterase (AChE)
146
Where are the primary sites of dopamine production?
adrenal glands, brain areas like the striatum, substantia nigra, and hypothalamus
147
What diseases are associated with deficits in dopamine systems?
Parkinson's, schizophrenia, ADHD, and addiction
148
_____________ in the brain is released largely by the neurons of the raphe nuclei, located in the brainstem.
Serotonin
149
Involved in the regulation of mood, temperature, appetite, behavior, muscle contraction, sleep, and the cardiovascular and endocrine systems.
Serotonin
150
Are used to treat clinical depression as the act on the raphe nuclei and their targets in the brain.
Serotonin
151
produced and used by neurons with cell bodies in the locus coeruleus (LC), an area of the brain involved with physiological responses to stress and located in the pons.
Norepinephrine (NE)
152
Outside the brain, how is NE released?
by the adrenal glands
153
What does NE mediate?
fight-or-flight response
154
Steroids that are synthesized in the brain and are involved in the control of various neurobiological processes.
Neurosteroids
155
The reabsorption by a neuron of a neurotransmitter following the transmission of a nerve impulse across a synapse
reuptake
156
What is the reuptake mechanism mediated by?
Active transports
157
Transmembrane proteins that pump the neurotransmitter back across the presynaptic membrane.
Active transports
158
Neuronal membranes touch at specializations called gap junctions, and the cytoplasms of the two neurons are essentially continuous
Electrical Transmission
159
In electrical transmission, communication is __________.
bidirectional
160
Useful when info must be conducted rapidly. It activates muscles quickly to get the animal out of harm's way.
Electrical synapses
161
How are electrical synapses limited?
they are much less plastic than chemical synapses, and they cannot amplify a signal.
162
How are electrical synapses different from chemical synapses?
they operate by passing current directly from one neuron (presynaptic) to another neuron (postsynaptic- tic) via specialized channels in gap junctions that connect the cytoplasm of one cell directly to the other.
163
neurons handling higher cognitive processes
Cortical neuron
164
neurons focusing on fine motor control
Purkinje neuron
165
Localized interconnected neurons form a __________.
microcircuit
166
They process specific kinds of info and can accomplish sophisticated tasks such as processing sensory info, generating movements, and mediating learning and memory.
microcircuit
167
How do axons from neurons in the cortex reach distant targets?
By descending below the cortical sheath into the white matter, traveling through long fiber tracts, and then entering another region of the cortex, subcortical nucleus, or spinal layer to synapse on another neuron.
168
macrocircuits that are made up of multiple embedded microcircuits.
neuronal networks
169
Connections between two cortical regions are referred to as _________________.
corticocortical connections
170
consists of the brain and spinal cord
CNS
171
consists of the nerves and ganglia outside of the CNS
PNS
172
the command and control center of the nervous system. It is covered in meninges.
CNS
173
a courier network that delivers sensory info to the CNS and carries motor commands from the CNS to the muscles.
PNS
174
Two subdivisions of the PNS
somatic and autonomic motor system
175
controls the voluntary muscles of the body
somatic motor system
176
controls the automated visceral functions
autonomic motor system
177
Involved in controlling the involuntary action of smooth muscles, the heart, and various glands
Autonomic nervous system
178
2 subdivisions of the autonomic nervous system
sympathetic and parasympathetic
179
Uses the neurotransmitter NE. It increases heart rate, diverts blood from the digestive tract to the somatic musculature, and prepares the body for action by stimulating the adrenal glands to release adrenaline (fight or flight)
sympathetic nervous system
180
Uses the neurotransmitter ACh. It slows heart rate, stimulates digestion, and helps the body with functions germane to maintaining itself (rest and digest)
parasympathetic nervous system
181
3 protective membranes of the CNS
meninges
182
describe the layers of the meninges from most outer to most inner?
Dura mater
Arachnoid mater
pia mater
183
What is between the arachnoid and pia membrane?
subarachnoid space, which is filled with CSF
184
What does CSF do for the brain?
the brain floats in it, which offsets the pressure and damage that would be present if it were merely sitting and scraping on the base of the skull. It also reduces shock to the brain and spinal cord
185
4 large interconnected cavities within the brain
ventricles
186
Where are the two largest ventricles located?
the two lateral ventricles in the cerebrum
187
Where is the 3rd ventricle located?
brains midline
188
Where is the 4th ventricle located?
in the brainstem below the cerebellum
189
A relatively compact arrangement of nerve cell bodies and their connections
Nucleus
190
How is the cerebral cortex arranged?
in a sheet containing several layers of neurons, folded across the surface of the cerebral hemispheres.
191
Structure of the brain that is highly layers, containing grey and white regions
Cerebellum
192
Layers of the cerebellum that is composed of neuronal cell bodies
gray matter
193
Layers of the cerebellum that consists of axons and glial cells
white matter
194
How are axons that form the white matter grouped together?
tracts that run from one cortical region to another within a hemisphere, or that run to and from the cerebral cortex to the deeper subcortical structures and the spinal cord.
195
The main commissure crossing between the hemispheres
corpus callosum
196
Why is the constant flow of blood to the brain necessary?
the brain has no way of storing glucose or extracting energy without oxygen
197
Rostal
front end
198
Caudal
back end
199
Dorsal
top of the brain, back of the body
200
Ventral
bottom of the brain, front area(belly area) of the body
201
Superior
dorsal surface of the brain
202
Inferior
ventral surface of the brain
203
Anterior
rostral area (front)
204
Posterior
caudal area (back)
205
Sagittal cut
Gives a left and right portion
206
medial sagittal cut
cut right down the middle giving the left and right hemisphere
207
lateral sagittal cut
cut to the sides of the brain, still giving you a left and right part
208
Coronal cut
separates the front and back of the brain
209
Horizontal/axial cut
separates the dorsal and ventral part of the brain (gives you a top and bottom half)
210
Supplies blood to the caudal portion of the brain
vertebral arteries
211
Supplies blood to wider brain regions
carotid arteries
212
What happens in the event of a blockage or ischemic attack?
The circulatory system can reroute blood to reduce the probability of a disruption in blood supply
213
Blood flow in the brain is tightly coupled with the metabolic demand of the local neurons. What does this cause?
increases in neuronal activity lead to a coupled increase in regional cerebral blood flow.
214
Takes info from the body's peripheral sensory receptors, relays it to the brain, and conducts the outgoing motor signals from the brain to the muscles.
Spinal cord
215
The vertebral column is divided into sections. name them?
cervical, thoracic, lumbar, sacral, and coccygeal
216
The _________ neuron carries sensory input through the dorsal root into the spinal cord.
afferent
217
The __________ neuron carries motor output through the ventral root away from the spinal cord
efferent
218
Contains the large motor neurons that project to muscles
ventral horn
219
Interneurons project to motor neurons on the what sides of the spinal cord to aid in the coordination of limb movements ?
ipsilateral and contralateral
219
Contains sensory neurons and interneurons
dorsal horn
220
an anatomical extension of the ventricles in the brain and contains CSF; grey matter surrounds it
central canal
221
3 main parts of brainstem
medulla (myelencephalon), the pons and cerebrum (metencephalon), and the midbrain (mesencephalon)
222
a relay station for sensory and motor info between the body and brain; it controls several autonomic functions; crossroads for most of the body's motor fibers
Medulla
223
main connection between the brain. It sits anterior to the medulla
Pons
224
Important for some eye movements, as well as movements of the face and mouth, responsible for generating rapid eye movement (REM) sleep
Pons
225
What are the three columns of nuclei?
raphe nuclei, parvocellular reticular nuclei, gigantocellular nuclei
226
Clings to the brainstem at the level of the pons, critical for maintaining posture, walking, and performing coordinated movements.
Cerebellum
227
What does damage to the cerebellum cause?
your movements will be uncoordinated and halting, and you may not be able to maintain balance
228
Lies superior to the pons and can be seen only in a medial view
Mesencephalon/midbrain
229
What does the dorsal portion of the mesencephalon consist of?
tectum
230
What does the ventral portion of the mesencephalon consist of?
tegmentum
231
Hosts a hub of activity that integrates incoming threatening the stimuli and outputs processing to shape behavior. It receives pain fibers ascending from the spinal cord on their way to the thalamus and is key to the modulation of descending pain signals
Periaqueductal gray
232
plays a role in perceiving objects in the periphery and orienting our gaze directly toward them, bringing them into shared view.
superior colliculus
233
used for locating and orienting toward auditory stimuli
inferior colliculus
234
involved in certain aspects of motor coordination
red nucleus
235
The larger of the diencephalon structures. It is divided into two parts. It is referred to as the gateway to the cortex because all senses, except olfactory, make synaptic relays in the thalamus before continuing to the primary cortical sensory receiving areas.
thalamus
236
recieves info from the ganglion cells of the retina and sends axons to the primary visual cortex
LGN (lateral geniculate nucleus)
237
recieves info from the inner ear, via other brainstem nuclei in the ascending auditory pathway, and sends axons to the primary auditory cortex.
MGN (medial geniculate nucleus)
238
Somatosensory info projects to the primary somatosensory cortex via what?
the ventral posterior nuclei of the thalamus
239
the posterior pole of the thalamus
Pulvinar nucleus
240
the chief site for hormone production and control. It receives input from the limbic system structures. Its job is to control circadian rhythms
Hypothalamus
241
Where does the hypothalamus project to?
prefrontal cortex, amygdala, spinal cord, and pituitary gland
242
Controls the functions necessary for maintaining the normal state of the body (homeostasis)
Hypothalamus
243
How does the hypothalamus accomplish its job?
through the endocrine system via control of the pituitary gland
244
The telencephalon is located where?
toward the front of, develops into the cerebrum.
245
an area located on the ventromedial aspect of the temporal lobe
Hippocampus
246
System of Structures for Emotional Behavior. Includes the amygdala, hypothalamus , basal ganglia, and hippocampus
limbic system
247
A collection of nuclei bilaterally located deep in the brain beneath the anterior portion of the lateral ventricles, near the thalamus
Basal ganglia
248
Receives inputs from sensory and motor areas and the striatum receives extensive feedback projections from the thalamus.
Basal ganglia
249
Are involved in a variety of crucial brain functions, including action selection, action gating, reward-based learning, motor preparation, timing, task switching, and more.
Basal ganglia
250
It is made up of a large sheet of (mostly) layered neurons, crumpled and folded on the surface of the 2 symmetrical hemisphere
Cerebral cortex
251
The infoldings of the cortical sheet are called __________ and __________.
sulci, gyri
252
the crevices of the cortical sheet
sulci
253
the crowns of the folded tissue that are visible on the surface of the cerebral cortex
gyri
254
Includes axons and axon terminals of neurons projecting to the cortex from other brain regions, such as the subcortical thalamus. It also contains blood vessels
The cortex
255
Why do underlying regions appear white?
because of their lipid myelin sheaths
256
Why does the cerebral cortex appear grayish in relation to underlying regions?
it has such a high density of cell bodies, Its composed of axons that connect the neurons of the cerebral cortex.
