Exam 1 Flashcards
1
Q
define nucleus
A
aggregation of dendrites and nerve cell bodies in the CNS
2
Q
define ganglion
A
aggregation of dendrites and nerve cell bodies in the PNS
3
Q
define nerve
A
bundle of fibers in the PNS
4
Q
define tract
A
bundle of fibers in the CNS
5
Q
define commissure
A
tract in the CNS that crosses from one side to another
6
Q
define white matter
A
areas of myelinated axons
7
Q
define gray matter
A
areas of unmyelinated axons, cell bodies, and dendrites
8
Q
when does the formation of the nervous system occur
A
at the end of the second week to the end of the eighth week
9
Q
what are the developmental stages of the neural tube
A
neural plate
neural folds
neural tube
10
Q
what are the three major subdivisions of the nervous system
A
CNS
PNS
ANS
11
Q
what are the main components of the CNS
A
brain and spinal cord
12
Q
what are the main components of the PNS
A
cranial nerves and spinal nerves
13
Q
what are the main components of the ANS
A
sympathetic and parasympathetic divisions
14
Q
define anencephaly
A
the failure of the cranial end of the neural tube to close
15
Q
define holoprosencephaly
A
the failure of the prosencephalon to divide into two cerebral hemispheres
16
Q
what is spina bifida occulta
A
the failure of the inferior neuropore to close, however spinal cord function is normal
17
Q
what is spinal bifida cystic
A
the presentation of a sac like cyst at the caudal end of the spine
18
Q
what are the characteristics of meningocele
A
only the meninges are found in the sac
spinal cord function may be impaired
19
Q
what are the characteristics of meningomyelocele
A
both meninges and spinal cord are found in the sac abnormal growth of spinal cord lower extremity paralysis bowel and bladder dysfunction loss of sensation to lower limbs
20
Q
what are the characteristics of myeloschisis
A
failure of caudal neural folds to close
most severe of the defects
21
Q
what are the characteristics of arnold chiari deformity
A
hydrocephalus
malformation of lower cranial nerves
medulla and pons are small and deformed
22
Q
define epithalamus
A
habenular nuclei involved in responses to odor
23
Q
define thalamus
A
a relay station for info to and from the brain
24
Q
define hypothalamus
A
mammillary bodies involved in olfactory reflexes and responses to odors
25
define superior colliculi
visual reflexes
26
define inferior colliculi
auditory and olfactory reflexes
27
what are the functions of the cerebellum
coordinate skeletal muscle movements
maintain equilibrium and posture
synergic control of muscle activity
28
define axon cell body
the part of the neuron that encloses the nucleus and other organelles to maintain the neuron
29
define dendrites
branches of the cell body that carry info to the cell body
30
define axon
the part of the neuron that carries info to another cell
31
what 2 branches do spinal nerves divide into
dorsal primary ramus
| ventral primary ramus
32
what does each spinal nerve in the thoracolumbar region give off before branching into primary rami
white ramus communicans
| gray ramus communicans
33
define paravertebral ganglia
site of cell bodies of postganglionic sympathetic nerves
site of synapses between preganglionic myelinated sympathetic neurons and postganglionic non myelinated sympathetic neurons
34
define prevertebral ganglion
site of synapses between preganglionic myelinated sympathetic neurons and postganglionic non myelinated sympathetic neurons
35
define splanchnic nerve
a nerve supplying viscera
36
define reflex arc
a pathway that leaves from and returns to the CNS
37
define afferent pathways
carry info to CNS
38
define efferent pathways
carry info to muscles
39
define interneuron
modulate interaction between afferent and efferent pathways
40
what are the components of a synapse
presynaptic membrane
synaptic cleft
postsynaptic membrane
41
define somatosensory axis
the sequence of structures involved in the transmission of a sensory signal from peripheral receptors to higher brain centers
42
what are the components of the somatosensory axis pathway
```
peripheral receptors
afferent neurons
spinal cord or brainstem
reticular substance
cerebellum
thalamus
somesthetic areas of cerebral cortex
```
43
define primary afferent neurons
synapse in the poster horns of spinal cord or sensory nuclei in the brain
44
define secondary afferent neurons
synapse in the thalamus
45
define tertiary afferent neurons
synapse in the somesthetic areas of cerebral cortex
46
define skeletal motor nerve axis
refers to the sequence of structures involved in the transmission of an action potential from the higher brain centers to skeletal muscles
47
what are the skeletal motor nerve components
motor cortex of cerebrum
efferent pathways
effectors: skeletal muscles
48
define decremental conduction
the gradual loss of the potential as the depolarization spreads from the site of initiation
49
define electronic conduction
direct spread of electrical current by ion conduction in the dendritic fluid without generating an action potential
50
define excitatory state
the summated degree of excitatory drive to the neuron
51
define firing rate
the threshold that the neuron must remain above in order to fire repeatedly
52
what determines firing rate
normal excitatory rate
| the changes in excitatory rate due to superimposition
53
define synaptic delay
refers to the time it takes to transmit a signal from a presynaptic neuron to postsynaptic neuron
54
what factors contribute to synaptic delay
time it takes to release the neurotransmitter
time it takes to diffuse across membrane
how it acts on postsynaptic membrane
time it takes for receptor to increase membrane permeability
time it takes for the inward diffusion of sodium
55
what two sources supply blood to the brain
vertebral arteries
| internal carotids
56
what is the circle of willis
a pentagonal shaped circle of arteries on the ventral surface of the brain that unites the two internal carotid arteries
57
what are the components of the circle of willis
```
posterior cerebral arteries
posterior communicating arteries
internal carotids
anterior cerebral arteries
anterior communicating artery
```
58
what are the components of the telencephalon
cerebral hemispheres
olfactory bulb
basal nuclei
59
what are the functions of the occipital lobe
integrates eye focusing movements
correlates visual images with visual memory
involved in conscious perception of vision
60
what are the functions of the parietal lobe
understanding speech
somatesthetic interpretation
formulating words to express thoughts and emotions
61
what are the functions of the frontal lobe
```
voluntary motor control
motivation
aggression
mood
personality
cognitive processes
verbal communication
```
62
what are the functions of the temporal lobe
receives/interprets olfactory and auditory sensations
| responsible for storage of memory related to auditory and visual experiences
63
what are the functions of the insula lobe
involved with memory
| highest levels of brain function
64
what are the functions of the epithalamus
involved in emotional and visceral responses to odors
65
what are the functions of the pineal body
secretes melatonin
66
what are the function of the thalamus
relays all sensory information except smell to the cerebral cortex
provides crude awareness
initial autonomic response of the body to intense pain
interpretation center for crude pain, temperature, light touch, and pressure
plays a role in arousal and alerting
plays a role in complex reflex movements
67
what are the functions of the reticular activating system
modulates sensation of pain
modulates certain postural reflexes and muscle tone
helps control breathing and heartbeat
regulates level of brain arousal and consciousness
made up of diffuse aggregations of cells
68
what are the three types of neurons
granular
fusiform
stellate
69
what is the function of layer 4 of the cerebral cortex
termination of most incoming specific sensory signals
70
what is the function of layers 5 and 6 of the cerebral cortex
origin of most output signals
| fibers to thalamus from 6
71
what is the function of layers 1,2,3 of the cerebral cortex
intracortical association functions
72
define primary motor areas
direct connections with specific muscles
73
define primary sensory areas
detect specific sensations
74
define secondary motor areas
provide patterns of motor activity
75
define secondary sensory areas
analyze meanings of specific sensory signals
76
what are the sub areas of the parieto-occipitotemporal association area
area for analysis of spatial coordinates
wernicke's area
angular gyrus area
area for naming objects
77
what are the functions of the prefrontal association area
receives preanalyzed sensory information necessary for planning effective movements
carries out though processes in the mind
78
what are the functions of the limbic association area
concerned with behavior, emotions, motivation
79
what is the function of the broca's area
provides circuitry for word formation
| works closely with wernicke's area
80
what is the function of wernicke's area
language comprehension
81
what happens if you cut the corpus callosum
blocking of transfer of information from wernicke's area to non dominant motor cortex
prevention of the transfer of somatic and visual information from right hemisphere into wernicke's area
results in two entirely separate conscious portions of the brain
82
define declarative memory
refers to memory of various details of an integrated thought
| surrounds, time relationships, causes of experience, meaning of experience
83
define reflexive memory
associated with motor activities
84
define short term memory
lasts only as long as person thinks of number or facts
85
define intermediate long term memory
lasts many minutes or week
86
what structural changes occur in long term memory
increase in vesicle please site for secretion of transmitter substance
increase in number of transmitter vesicles released
increase in number of presynaptic terminals
changes in structures of dendritic spines
87
what are the sensory receptor types
```
mechanoreceptors
thermoreceptors
nociceptors
electromagnetic receptors
chemoreceptors
```
88
define nociceptors
free nerve endings responding to pain
89
define electromagnetic receptors
include rods and cones of the eye for vision
90
define differential sensitivity
each type of receptor is highly sensitive to one type of stimulus and is almost non responsive to other types
91
define modality
refers to each of the principal types of sensation
92
define labeled line principle
refers to the specificity of nerve fibers for transmitting only one modality of sensation
93
define adaptation
all sensory receptors adapt either partially or completely to any constant stimulus after a period of time
94
what are the mechanisms of stimulation for receptors
mechanical deformation
application of a chemical
temperature change
electromagnetic radiation
95
define receptor potential
potentials created by opening modality gated channels in response to membrane deformation caused by touch or pressure
96
describe tonic receptors
slow adapting
detect continuous stimulus strength
transmit impulses as long as stimulus is present
97
describe phasic receptors
rapidly adapting
do not transmit a continuous signal
stimulated only when stimulus strength changes
transmit information regarding rate of change
98
define spatial summation
increasing signal strength is transmitted by using progressively greater number of fibers
99
define temporal summation
increases signal strength by increasing frequency of nerve impulses in each fiber
100
define neuronal pool
neuronal area within the pool stimulated by each incoming nerve fiber
101
define discharge zone
includes all the output fibers stimulated by the incoming fiber
102
define facilitation/inhibition zone
neurons further from the discharge zone that are facilitated but not excited
103
define diverging neuronal pathways
may result in amplification of initial signal
| may allow transmission of original to separate areas
104
define converging neuronal pathways
multiple input fibers converge onto a single output neuron
105
define reverberatory circuit
caused by positive feedback within neuronal circuit
| circuit once stimulated may discharge repetitively for a long time
106
define somatic senses
collect sensory information from all over the body
107
name types of somatic senses
mechanoreceptive
thermorecptive
pain
108
define special sense
refers to vision, hearing, smell, taste, and equilibrium
109
define exteroreceptive sensation
sensation from the surface of the body
110
define visceral sensation
sensation that refers to the physical state of the body
111
define deep sensation
sensation that refers to deep pressure, pain, and vibrations
112
what are the three types of neurons that make up the ascending pathways
primary
secondary
tertiary
113
define brodmann's areas
the 50 distinct areas of the cerebral cortex
114
define refraction
the bending of light waves at an angulated surface of a transparent material
115
what does the degree of refraction depend on
the ratio of the two refractive indices of the two transparent media
the degree of angulation between the interface and the entering wave front of the light waves
116
define refractive index
the ratio of the velocity of light in air to the velocity of light traveling in the substance
117
define refractive power
a measure of how much a lens bends light waves
118
define focal point
the point through which all parallel rays of light will pass after passing through each part of the lens
119
define focal length
the distance from the center of the lens to the focal point
120
define emmetropia
refers to the normal eye with regard to depth of focus
| all distant objects can be seen clearly
121
define hyperopia
farsightedness
| usually due to an eyeball that is too short
122
define myopia
nearsightedness
| usually due to an eyeball that is
123
define visual acuity
a measure of the resolving power of the eye
124
what is the pathway of fluid flow in the eye
anterior chamber to canal of Schlemm to aqueous veins in the sclera
125
define tonometer
used to measure intraocular pressure
126
what are the parts of a photoreceptor
outer segment
inner segment
nucleus
synaptic body
127
name the layers of the retina
```
photoreceptors
horizontal cells
bipolar cells
amacrine cells
ganglion cells
```
128
describe the 3 neuron pathway for cone vision
cones
bipolar cells
ganglion cells
129
describe the 4 neuron pathway for rod vision
rods
bipolar cells
amacrine cells
ganglion cells
130
what is glutamate used for
used between rod/cone cells and bipolar cells
131
describe photoreceptors
includes rods and cones
transmits signals to outer plexiform layer
synapses with bipolar cells and horizontal cells
132
describe horizontal cells
transmits signals from rods and cones to bipolar cells
transmits signals to outer plexiform layer
output is inhibitory
133
describe bipolar cells
transmits signals from rods, cones, and horizontal cells to inner plexiform layer
synapses with amacrine and ganglion cells
134
describe amacrine cells
transmits signals directly from bipolar to ganglion cells
135
whose axons make up the optic nerve
ganglion cells
136
describe ganglion cells
transmits signals from retina to brain
| 3 types: W, X, Y
137
describe interplexiform cells
transmits from inner plexiform layer to outer plexiform layer
138
describe W ganglion cells
```
small
make up 40% of ganglion cells
transmits signals 8m/s
receive most of their excitation from rods transmitted by way of small bipolar cells and amacrine cells
have broad fields
```
139
describe X ganglion cells
medium
make up 55% of ganglion cells
transmit signals 14m/s
have small fields
140
describe Y ganglion cells
large
make up 5% of ganglion cells
transmit signals 50m/s
respond to rapid changes in visual image
141
what is the function of the dorsal lateral geniculate nucleus
receives input from optic nerve
| relays information from optic tract to visual cortex by way of optic radiation
142
define transmission gating
lateral geniculate nucleus controls how much of the signal is allowed to pass to the cortex
143
what is the source of gating control
corticofugal fibers from primary visual cortex
| reticular areas of the mesencephalon
144
define the conduction pathway sequence
tympanic membrane
auditory ossicles
oval window
145
describe oval window
stapes attaches to oval window
| oval window open into the scala vestibuli
146
describe round window
membrane covered region at the end of the scala tympani
147
describe tensor tympani
a muscle that inserts on the malleus and pull it inward
148
describe stapedius
a muscle that inserts on the stapes and pulls it outward
149
what are the components of the cochlea
scala vestibuli
scala media
scala tympani
reissner's membrane
150
what does the reissner's membrane separate
scala media and scala vestibuli
151
what does the basilar membrane separate
scala media and scala tympani
152
what is the function of the organ of corti
generates nerve impulses in response to vibration of basilar membrane
153
what do hair cells do
they stimulate nerve fibers that lead to the spiral ganglia of Corti
154
where is endolymph found
the scala media
155
where is perilymph found
the scala vestibuli and scala tympani
156
endolymph contains...
high potassium and low sodium
157
perilymph contains...
low potassium and high sodium
158
define the place principle
nervous system detects sound frequencies by determining positions along the basilar membrane that are most stimulated
159
what are the components of the nervous system pathway
```
spiral organ of corti
dorsal and ventral cochlear nuclei
superior olivary nucleus
lateral lemniscus nucleus
medial geniculate nucleus
auditory cortex
```
