Exam #1 Flashcards
1
Q
What are the components of a neuron?
A
soma
axon
dendrites
2
Q
neurons that transport info from
body sensors → CNS
A
sensory neurons
3
Q
neurons that connect
sensory + motor neurons, or
local connections between
brain + spinal cord
A
interneurons
4
Q
neurons that transport info from CNS →
body (effectors = muscles,
glands)
A
motor neurons
5
Q
what type of neuron is a pseudounipolar?
A
sensory neuron
6
Q
what type of neurons are multipolar neurons?
A
interneuron and motor neuron
7
Q
AXOPLASMIC TRANSPORT:
A
- Carries enzymes and proteins from the presynaptic terminal to the soma
- Uses carrier proteins (kinesins & dyneins)
- Rate of axonal transport slows with aging and in neurodegenerative diseases (e.g., Alzheimer’s, ALS)
ATP = adenosine
triphosphate
Energy-carrying molecule that supports
intracellular energy transfer
8
Q
What are the supporting cells of the CNS neurons?
A
astrocytes, microglia, oligodendrocytes
9
Q
What are the supporting cells of the PNS neurons?
A
Schwann cells
10
Q
What are the functions of glia?
A
- Myelinating
- Signaling/cleaning/nourishing
- Defending
11
Q
Anions (-)
A
- Higher concentration within cell
- Chloride (Cl-) & charged amino acids (aa-
12
Q
Cations (+)
A
- More concentrated in extracellular space
- Sodium (Na+)
13
Q
voltage-gated potassium and sodium channels are closed
A
resting potential
14
Q
local potentials summate to depolarize the membrane. Voltage-gated potassium and sodium channels remain closed.
A
slow depolarization
15
Q
when the threshold potential is reached, voltage-gated sodium channels open and sodium rushes in. The membrane quickly depolarizes to a positive membrane potential.
A
fast depolarization
16
Q
voltage-gated sodium channels are inactivated. Many voltage-gated potassium channels are open, potassium exits, taking positive charges out of the axon
A
repolarization
17
Q
voltage-gated potassium channels remain open. Potassium continues to leave the axon, restoring the polarized membrane potential.
A
hyperpolarization
18
Q
Changes in mV must reach _____ for the “all or nothing” potential to kick in
(an action potential)
A
-55mV
19
Q
the negative charge registered when the nerve is “at rest” and not
conducting a nerve impulse.
A
resting potential
20
Q
the positive electrochemical charge generated at the nerve impulse.
A
action potential
21
Q
a change from the negative resting potential to the positive action potential.
A
depolarization
22
Q
a change from the negative resting potential to a more negative potential.
A
hyperpolarization
23
Q
the change in the electrical potential from the positive action potential back to
the negative resting potential.
A
re-polarization
24
Q
local potentials that occur because of a change in ion concentration in the postsynaptic neuron
A
post-synaptic potentials
25
Depolarization =
Hyperpolarization =
1. excitatory postsynaptic potentials (EPSPs)
2. inhibitory postsynaptic potentials (IPSPs)
26
Excitatory postsynaptic potentials (EPSPs)
Occurs when neurotransmitters bind to postsynaptic
receptors
Ligand-gated channels open
Instant flow of Na+ or Ca2+ into neuron causes
depolarization
Example: neuromuscular junction
1. Binding acetylcholine (Ach) opens ligand-gated channels
2. Na+ flows into neuron
3. …
4. Contraction of muscle cells
27
Inhibitory postsynaptic potentials (IPSPs)
Occurs when neurotransmitters bind to postsynaptic receptors
Ion channels open
Local flow of Cl- in or K+ out of the neuron causes
hyperpolarization
Inhibits the generation of an action potential
Example: neuromuscular junction
1. Tetanospasmin (toxin)
2. Prevents Ca2+-dependent release of glycine, an inhibitory
neurotransmitter
3. …
4. Unopposed excitation of spinal neurons and muscle contraction
Summation
28
mimics the action of neurotransmitters
agonists
29
blocks the ability of the neurotransmitter to bend to a receptor
antagonists
30
What are the developmental stages"
Pre-embryonic
Embryonic
Fetal
31
Conception to Day 14
Pre-embryonic
32
Day 15 to End of week 8 (organs are forming)
Embryonic
33
End of week 8 to Birth
Fetal
34
Embryonic stage:
Endoderm
Mesoderm
Ectoderm
35
the developmental stage that develops into sensory organs, epidermis, and the nervous system.
ectoderm
36
the developmental stage that develops into dermis, muscles, skeleton, and the excretory and circulatory systems
mesoderm
37
the developmental stage that develops into the gut, liver, pancreas, and respiratory system
endoderm
38
Formation of the nervous system:
Phase 1: A tube forms along the back of the embryo (Neural Tube)
Phase 2: Brain formation
39
When does neural tube formation occur?
days 18-26
40
What does the thickening of the ectoderm turn into?
Neural plate
41
What are the 3 enlargements that the brain region of the neural tube expands to form?
hindbrain
midbrain
forebrain
42
What does the hindbrain become?
medulla
pons
cerebellum
In the upper hindbrain, the central canal expands to form the fourth ventricle
43
What does the midbrain become?
midbrain
“The central canal becomes the cerebral aqueduct in the midbrain, connecting the third and fourth ventricles.”
44
What does the forebrain become?
the diencephalon (thalamus, hypothalamus, subthalamus, and epithalamus) and the telencephalon which develops into the cerebrum.
45
axons (tracts) that convey information among parts of the nervous system
white matter
46
areas of the central nervous system that appear gray contain primarily neuron cell bodies
gray matter
47
groups of cell bodies in the peripheral nervous system are called
ganglia
48
in the central nervous system, groups of cell bodies are most frequently called
nuclei
49
gray matter on the surface of the brain is called
cortex
50
What are the 3 parts of the somites?
myotome
sclerotome
dermatome
51
1. an embryologic section of the somite
2. a group of muscles innervated by a segmental spinal nerve
myotome
52
The area of the somite that will become bones
sclerotome
53
1. the area of the somite that will become the dermis (skin)
2. the dermis innervated by a single spinal nerve
dermatome
54
What are the 4 structures that the diencephalon consists of?
thalamus
hypothalamus
epithalumas
subthalamus
3rd ventricle
55
structure that process emotional and some memory information, integrate different types of sensations (i.e., touch and visual information), or regulate consciousness, arousal, and attention
thalamus
56
structure that maintains homeostasis and regulates growth, the reproductive organs, and many behaviors
hypothalamus
57
structure that is part of a neural circuit that controls movement
subthalamus
58
What does the telencephalon give rise to?
cerebral hemispheres, lateral ventricles
59
What lobe plays a role in emotion?
Insula (tucked inside lateral sulcus)
60
Neuronal death:
During development as many has ½ of all neurons die
Fail to establish connection OR were not active enough
61
a cell that regulates extracellular fluid, removes waste, part of the blood-brain barrier
astrocyte cells
62
cells that are activated by infection, clean up waste
microglia cells
63
cells that cover the somas in the PNS regulate the extracellular environment
satellite cells
64
a cell that helps produce CSF (cerebral spinal fluid)
ependymal cells
65
cells that act as phagocytes to destroy bacteria
schwann cells
66
cells that:
* regulates the extracellular environment
* maintain the blood-brain barrier
* clean up debris
oligodendrocytes
67
The ependymal cells form what kind of plexus?
choroid plexus
68
Purpose of CSF:
cushion
provide nutrients
shock absorption
buoyancy (allows the brain to float)
69
divides the two cerebral hemispheres
longitudinal fissure
70
the surfaces of the cerebral hemispheres are marked by rounded elevations called _____ and grooves called _____.
gyri (singular: gyrus), sulci
71
What are the 6 lobes of the cerebral hemispheres?
frontal
temporal
parietal
occipital
limbic
insula
72
the boundary between the frontal lobe and the parietal lobe
central sulcus
73
the boundary between the parietal lobe and the occipital lobe, clearly marked only on the medial hemisphere by the
parieto-occipital sulcus
74
the division of the temporal lobe and the frontal lobe, marked by the
lateral sulcus
75
the entire surface of the cerebral hemispheres is composed of gray matter, called
cerebral cortex
76
structure that processes sensory, motor, and memory information and is the site for reasoning, language, nonverbal communication, intelligence, and personality
cerebral cortex
77
two collections of axons connecting the cerebral cortex with other central nervous system areas
corpus callosum and the internal capsule
78
bundle of axons that connects the right and left cerebral cortices
corpus callosum
79
axons that project from the cerebral cortex to sub-cortical structures and from subcortical structures to the cerebral cortex
internal capsule
80
gray matter structures in the hemispheres are
basal ganglia
amygdala (temporal lobe)
hippocampus (temporal lobe)
81
What are the 3 structures the basal ganglia consists of?
caudate
putamen
globus pallidus
82
structure that are involved in social and goal-oriented behavior, movement, and emotions
basal ganglia
83
structure involved in emotions and motivation
amygdala
84
a structure that is a part of the declarative memory system (e.g. address)
hippocampus
85
a white matter bundle that connects the hippocampus with the hypothalamus
fornix
86
Name the 4 ventricles?
lateral ventricle
3rd ventricle
4th ventricle
87
What ventricle is located in the diencephalon?
3rd ventricle
88
What ventricle is located in the cerebral hemispheres?
lateral ventricles
89
What ventricle is located posterior to the pons and the medulla?
4th ventricle
90
membranous coverings of the brain and spinal cord, are part of the cerebrospinal fluid system
meninges
91
from internal to external, what does the meninges consist of
pia mater
arachnoid mater
dura mater
92
the delicate inner layer of the meninges, which is directly attached to the spinal cord
pia matter
93
the middle layer of the meninges, which is web-like and filled with fluid to cushion the brain
arachnoid mater
94
the tough outer layer of the meninges
dura mater
95
the vertebral arteries join to for what artery?
basilar artery
96
artery and its branches supply the pons and most of the cerebellum
basilar artery
97
What arteries does the basilar artery divide to become?
posterior cerebral arteries
98
an anastomotic ring of nine arteries, which supply all of the blood to the cerebral hemispheres
Circle of Willis
99
What are the 9 arteries of the Circle of Willis?
2 anterior cerebral arteries
2 internal carotid arteries
2 posterior cerebral arteries
anterior communicating artery
2 posterior communicating arteries
100
the internal carotid artery branches into two of the major cerebral arteries
anterior and middle cerebral arteries
101
What artery does the posterior cerebral artery branch off from?
the top of the basilar artery
102
What are the 3 major cerebral arteries?
anterior cerebral artery
middle cerebral artery
posterior cerebral artery
103
What are the functional deficits that may occur with vertebrobasilar ischemia?
gait and limb ataxia
limb weakness
oculomotor palsies
oropharyngeal dysfunction
loss of vision
double vision
numbness
dizziness
headache
vomiting
104
What are the effects of anterior cerebral artery stroke?
stroke affecting the cortical branches of the anterior cerebral artery results in personality changes and cognitive changes due to frontal lobe damage (flat affect, impulsiveness, divergent thinking, fine touch/sensation, gait apraxia, etc)
105
What are the effects of middle cerebral artery stroke?
stroke affecting the cortical branches of the middle cerebral artery causing contralateral homonymous hemianopia combined with contralateral hemiplegia and hemisensory loss ( aphasia, neglect, spatial relationships, nonverbal communication, ect)
106
What are the effects of posterior cerebral artery stroke?
stroke affecting the midbrain branches of the posterior cerebral artery causes eye movement paresis or paralysis affecting the muscles innervated by the oculomotor nerve due to damage of the oculomotor nerve, the oculomotor nuclei, or neurons descending from cortical eye movement centers (agnosia, contralateral hemiparesis, etc)
107
What artery supplies blood to the corpus callosum, frontal lobe, parietal lobe, etc?
anterior cerebral artery
108
What artery supplies blood to the diencephalon, thalamus, and occipital lobe?
posterior cerebral artery
109
What artery supplies blood to the internal capsule, caudate, etc?
middle cerebral artery
110
What are the 4 main components of a neuron?
* Dendrites
* Soma
* Axon
* Presynaptic terminals
111
branchlike extensions that serve as the main input sites for the neuron. They are specialized to receive information from other neurons at synapses, the term used to describe communication sites between a neuron and another cell.
dendrites
112
the cell body of the neuron
soma
113
projections that are the transmitting elements of the neuron that release neurotransmitters, chemicals that bind to receptors on the target cell at the synapse.
presynaptic terminals
114
a process extending from the soma that serves as the output unit of the cell, specialized to send information to other neurons, muscle cells, or glands
axon
115
What are the 3 different types of neurons?
* Multipolar
* Bipolar
* Pseudounipolar
116
the most common type of neuron in the vertebrate nervous system
multipolar neuron
117
a neuron that has two primary processes that extend from the cell body:
* Dendritic root
* Axon”
bipolar neuron
118
a neuron that has a single projection from the cell body that divides into two axonal roots and has no true dendrites.
pseudounipolar neuron
119
What are the most common pseudounipolar neurons that bring information from the body into the spinal cord?
sensory neurons
120
What are the four types of membrane channels necessary for the
transmission of information by neurons.
* Ligand-gated ion channels
* Voltage-gated ion channels
* Modality-gated ion channels
* Leak channels
121
when a neuron is not transmitting information, the difference in the electrical potential between the interior and the exterior of the neuron is called the _______
resting membrane potential
“the interior of the neuron is more negatively charged than the extracellular fluid”
122
when the potential becomes less negative (more positive) than the resting potential
depolarization
123
the potential becomes more negative than the resting potential
hyperpolarization
124
The initial change in membrane potential is called a __________because it spreads only a short distance along the membrane before dissipating due to the activity of leak channels and the Na+/K+ pump. Can be either depolarizing or hyperpolarizing
local potential
125
a large depolarizing signal that is actively propagated along an axon by repeated generation of a signal. Because they are repeatedly regenerated, they transmit information over longer distances
action potential
126
Steps of an action potential:
1. Rapid depolarization due to opening of the voltage-gated Na+ channels
2. A decrease in Na+ conduction due to inactivation of the Na+ channels
3. Rapid repolarization due to the opening of voltage-gated K+ channels
127
Explain the two structural adaptations in axons that promote faster conduction velocity.
a larger axon diameter and myelination; a larger diameter reduces resistance to current flow, while myelin acts as an insulator, allowing for faster signal transmission by concentrating the electrical signal at specific nodes along the axon (called nodes of Ranvier)
128
neurons that relay commands in the opposite direction from the CNS to muscles and glands of the body
efferent neurons
129
neurons that carry sensory information from the body toward the central nervous system (CNS)
afferent neurons
130
describe the functions of glial cells in the central nervous system (CNS).
* Oligodendrocytes are found in the CNS, and each one myelinates parts of several axons from different neurons
* regulates the extracellular environment
* maintain the blood-brain barrier
* clean up debris
131
describe the functions of glial cells in the peripheral nervous system (PNS).
* Schwann cells are found in the peripheral nervous system (PNS) and can only myelinate one axon at a time
* Schwann cells act as phagocytes, ingest and destroy bacteria and other cells. After injury, Schwann cells provide trophic factors for repair of axons.
132
Guillain-Barré syndrome:
1. PNS affected
2. muscle weakness/sensory issues
3. all ages
133
Multiple Sclerosis:
1. CNS affected
2. fatigue, coordination/balance problems, memory issues, and blurred vision
3. 20-40 years of age
134
Comparisons of Guillain-Barré syndrome and Multiple Sclerosis.
1. demyelination
2. autoimmune
135
What are the 3 components of a synapse?
1. presynaptic terminal: where neurotransmitters are released
2. postsynaptic terminal: which contains receptors that bind the neurotransmitters
3. synaptic cleft: synaptic communication between neurons can occur
136
Discuss the events at chemical synapses resulting in synaptic communication:
* an action potential arriving at the presynaptic terminal triggers the release of neurotransmitters from synaptic vesicles
* which then diffuse across the synaptic cleft and bind to receptors on the postsynaptic neuron,
* causing a change in its membrane potential and potentially initiating a new action potential
137
depolarizing postsynaptic potentials that occur when neurotransmitters bind to postsynaptic ligand-gated ion channels, allowing a local, instantaneous flow of sodium (Na+) or Ca2+ into the neuron.
excitatory postsynaptic potentials (EPSPs).
138
hyperpolarizing postsynaptic potentials that reduce the possibility of an action potential
inhibitory postsynaptic potentials (IPSPs)
139
acetylcholine (ACh)- excitatory:
loss of ACh-expressing neurons and nicotinic receptor-expressing neurons in the brain is a hallmark of Alzheimer’s disease
140
norepinephrine (NE)- inhibitory/excitatory:
Excessive levels of NE can produce panic disorder and increased heart rate
141
dopamine (DA): "excitatory"
Parkinson’s disease is characterized by motor dysfunction and is due in large part to inadequate dopamine levels
142
serotonin: "excitatory/inhibitory"
Low: depression, anxiety
Excess: obsessive-compulsive disorder, schizophrenia
143
γ-aminobutyric acid (GABA)- "inhibitory"
Low levels can cause neural overactivity, leading to seizures, unwanted skeletal muscle contractions, and anxiety
144
glutamate "excitatory"
Overactivity of NMDA receptors may cause epileptic seizures.15 Changes in glutamate transmission are associated with chronic pain, Parkinson’s disease
145
glycine "inhibitory/excitatory"
unwanted skeletal muscle contractions (spinal cord) and impaired learning and memory (brain)
146
“ beta blockers prevent activation of __________ beta receptors to prevent sympathetic system activation in stressful situations.”
norepinephrine
147
L-dopa is a __________ replacement agent that increases _________ neurotransmission in the brain to control bradykinetic symptoms of Parkinson's disease.
dopamine
148
AChE inhibitors are drugs that increase ________ levels by blocking the action of enzymes that break down ACh to treat Alzheimer’s Disease symptoms like memory.
acetylcholine
149
Selective serotonin reuptake inhibitors (SSRIs) are a class of drugs that treat depression and other conditions by increasing _______ levels in the brain
serotonin
150
Benzodiazepines are drugs that increase _______ levels at the GABBA A receptors to decrease anxiety and allow the body to relax after stressful situations.
GABBA
151
phencyclidine prevents the overexcitation of NMDA receptors that causes changes in ________ transmission that's associated with Parkinson’s disease
glutamate
152
Strychnine is responsible for inhibiting postsynaptic _______ receptors causing painful involuntary skeletal muscle spasms.
glycine
153
Describe the closing of the neural tube:
occurs when the edges of the neural folds meet at the dorsal midline of the embryo fuse together and form a closed tube that will eventually develop into the brain and spinal cord
154
Why does the adult spinal cord end at the L1–L2 vertebral level?
as the fetus matures, the spinal column grows faster than the cord
155
neurons that die are probably those that failed to establish optimal connections with their target cells or that were too inactive to maintain their connection (happens to half the neurons that are formed during the development of some brain regions)
neuronal death
156
axonal retraction
157
Explain why neural damage that occurs in utero may not be evident until a year or more after the damage occurred
the brain is still actively developing during pregnancy and early infancy, meaning the full impact of the damage may not become noticeable until the affected brain regions are supposed to be actively functioning in more complex behaviors and skills, which often develop later in the first year of life
158
a movement and postural disorder caused by abnormal brain development or permanent, nonprogressive damage to a developing brain. The brain lesion interferes with signals descending from the brain to the lower motor neurons
cerebral palsy
159
Malformations associated with spina bifida occulta:
neural tube defect that results when the inferior neuropore does not close
160
Malformations associated with spina bifida meningocele:
protrusion of the meninges through the bony defect
161
Malformations associated with spina bifida myelomeningocele:
neural tissue and meninges protrude outside the body
162
Malformations associated with spina bifida myeloschisis:
most severe defect, consisting of a malformed spinal cord open to the surface of the body, which occurs when the neural folds fail to close
163
What does the CSF system include?
Ventricles
Meninges
CSF fluid
164
Describe the flow and function of the cerebrospinal fluid system:
1. The CSF system regulates the extracellular milieu and protects the central nervous system
2. CSF is formed primarily in the ventricles and then circulates through the ventricles and into the subarachnoid space (between the arachnoid and the pia mater) before it is absorbed into the lymph circulation.
3. CSF supplies water, certain amino acids, vitamins, proteins (e.g., brain-derived neurotrophic factor, a protein that promotes neuron growth), and specific ions to the extracellular fluid and removes metabolites from the brain.
165
Where are the lateral ventricles located?
both cerebral hemispheres (C-shaped)
166
Where is the 3rd ventricle located?
narrow slit in the midline of the diencephalon; thus its walls are the thalamus and the hypothalamus
167
Where is the 4th ventricle located?
a space posterior to the pons and medulla and anterior to the cerebellum
168
What is the function of the ventricles?
supplies water, certain amino acids, vitamins, proteins (e.g., brain-derived neurotrophic factor, a protein that promotes neuron growth), and specific ions to the extracellular fluid and removes metabolites from the brain.
169
a canal through the midbrain, the ________ that connects the 3rd and 4th ventricles
.
cerebral aqueduct
170
PAD- abbreviation for the meninges:
pia mater
arachnoid mater
dura mater
171
a system that helps maintain brain homeostasis and eliminates waste
glymphatic system
172
Glymphatic flow:
1. CSF flows into the brain
2. CSF and interstitial fluid mix
3. CSF and solutes flow into channels surrounding veins and cranial nerve tracts
4. CSF drains into cervical lymph vessels
173
an enlargement of the ventricles caused by CSF circulation being blocked and pressure building up (present at birth)
congenital hydrocephalus
174
an enlargement of the ventricles caused by CSF circulation being blocked and pressure building up (from a disease or injury)
acquired hydrocephalus
175
in this type of hydrocephalus, the ventricular system is intact (communicating), and a blockage exists beyond the fourth ventricle
communicating hydrocephalus
176
in this type of hydrocephalus, the blockage is within the ventricular system itself, most often the cerebral aqueduct
non-communicating hydrocephalus
177
What is the function of the blood-brain barrier?
to prevent pathogens from entering the CNS (drugs and protein antibodies)
