The Nervous System Flashcards
1
Q
what structures are a part of the central nervous system
A
- brain
- spinal cord
2
Q
what is the function of the central nervous system
A
- take in sensory (afferent) information
- make decisions about the information
- send motor (efferent) signals to control muscles/glands of the body
3
Q
how many pairs of spinal nerves are there
A
31
4
Q
how many pairs of cranial nerves are there
A
12
5
Q
what are the two motor divisions of the nervous system
A
- autonomic nervous system
- somatic nervous system
6
Q
describe the somatic nervous system
A
- sends commands to skeletal muscles
- conscious and voluntary control
7
Q
what are the two divisions of the autonomic nervous sytem
A
- sympathetic division
- parasympathetic division
8
Q
what are the effectors of the autonomic nervous system
A
- cardiac muscle
- smooth muscle
- glands
9
Q
what are the effectors of the somatic nervous system
A
skeletal muscle
10
Q
describe the sympathetic nervous system
A
- division of the autonomic nervous system
- responsible for fight or flight reactions
11
Q
describe fight or flight responses
A
- increased heart rate
- pupil dilation
- sweating
- blood flowing to internal organs (feeling a chill)
- adrenal glands activated
12
Q
describe the parasympathetic nervous system
A
- division of the autonomic nervous system
- responsible for regulating resting and digesting functions
13
Q
are you always in either the sympathetic nervous system or parasympathetic nervous system
A
no, usually both systems are being activated at varying levels depending on the circumstances
14
Q
when are you entirely relying on the parasympathetic nervous system and not the sympathetic nervous system
A
sleeping
15
Q
is it better to be more on the sympathetic or parasympathetic side of the autonomic nervous system
A
better to be more in the parasympathetic division
16
Q
what are the 3 neuron types
A
- multipolar neuron
- bipolar neuron
- pseudo-unipolar neuron
17
Q
which neuron type is the most common
A
multipolar neuron
18
Q
describe multipolar neurons
A
- have many dendrites (up to thousands)
- have only one axon
19
Q
define the trigger zone on a neuron
A
where an action potential will begin
20
Q
where is the trigger zone located on a multipolar neuron
A
where the cell body meets the axon
21
Q
describe bipolar neurons
A
- have only one dendrite
- have only one axon
22
Q
where is the trigger zone located on a bipolar neuron
A
where the cell body meets the axon
23
Q
where are bipolar neurons found
A
- retina
- cranial nerve I (olfactory)
24
Q
describe pseudo-unipolar neurons
A
- appear to have no dendrites and one axon
- cell body only connects to the axon
- sensory receptors on a portion of the axon
25
where is the trigger zone located on a pseudo-unipolar axon
at the end of the sensory recepting portion of the axon
26
what is the general function of all glial cells
support the functioning of neurons
27
how many neurons are in the brain
100 billion
28
how many glial cells are there compared to neurons
50-100x more glial cells than neurons
29
what are the glial cell types in the CNS
- astrocytes
- ependymal cells
- microglia
- oligodendrocytes
30
what are the glial cell types in the PNS
- Shwann cells
- satellite cells
31
what are the most abundant glial cell type
astrocytes
32
what are the functions of astrocytes
- surround neurons to anchor them in place
- wrap around capillaries with perivascular feet to regulate what can leave the capillary and enter the interstitial fluid (blood-brain barrier)
33
where are ependymal cells found
- CNS
- lining ventricles of the brian
34
what is the function of ependymal cells
circulate cerebrospinal fluid in brain ventricles
35
what type of cell in the skin are microglial cells analogous to
dendritic cells (immune cells)
36
what are the functions of microglial cells
- attack pathogens found
- remove damaged/dead cells through phagocytosis
37
what is the function of oligodendrocytes
wrap around axons (myelination) to speed the travel of action potentials in the CNS
38
how many axons does each oligodendrocyte myeliante
multiple
39
what is the function of schwann cells
wrap around axons (myelination) to speed the travel of action potentials in the PNS
40
how many axons does each schwann cell myelinate
one
41
what type of neuron detects light touch in the hands
pseudo-unipolar neuron
42
which root of the spinal cord does sensory information pass through
dorsal root
43
which root of the spinal cord does motor information pass through
ventral root
44
where in the spinal cord do somatic motor neurons (controlling skeletal muscle) start
ventral horn of the gray matter in the spinal cord
45
where in the spinal cord do autonomic motor neurons (controlling cardiac muscle, smooth muscle, and glands) start
lateral horn of the gray matter in the spinal cord
46
what CNS structure makes decision when a damaging stimulus is detected
- spinal cord recognizes and reacts to damaging stimuli
- brain is not needed because it would take more time to react
47
how many somatic motor neurons are needed from the spinal cord to skeletal muscle
one
48
how many autonomic motor neurons re needed from the spinal cord to cardiac muscle/smooth muscle/glands
two
49
define the autonomic ganglion
- collection of cell bodies outside of the CNS
- where the synapse is between a motor neuron from the spinal cord and a motor neuron going to the effector
50
what do all autonomic responses go through
autonomic ganglion
51
what is the resting membrane potential of neurons
-70 mv
52
what are most neurotransmitters made from
amino acids
53
why are neurotransmitters made from amino acids
- can be easily made
- can be easily destroyed
- can be vacuumed back into the axon that released them
54
what do neurotransmitters being released and binding to gated channels cause in the cell membrane
- depolarization
OR
- hyperpoalrization
55
define depolarization
- movement of resting membrane potential towards zero
- exciting, making it more likely that an action potential will fire
56
what is the threshold for depolarization and when an action potential will occur
-55 mv
57
define hyperpolarization
- movement of resting membrane potential farther from zero
- inhibiting, making it less likely that an action potential will fire
58
define GABA
- gamma aminobutyric acid
- inhibiting neurotransmitter
- causing hyperpolarization
59
can an action potential be stopped once it hits the trigger zone
no
60
describe summation in nuerons
multiple axons firing to get the depolarization wave to reach the trigger zone at a level that will create an action potential at the trigger zone
61
describe how GABA causes hyperpolarization
- release of GABA will cause Cl- to enter the neuron
- a negative ion entering the neuron will cause hyperpolarization
62
define the refractory period in neurons
- time when another action potential cannot be fired until the first action potential has finished
- must wait for the membrane to be repolarized
- takes about 1 millisecond
63
can action potentials summate in axons
- no
- refractory period
64
what are the two parts of the refractory period of a neuron
- absolute
- relative
65
describe the absolute division of the refractory period of a neuron
- occurs first during the depolarization and repolarization phases
- nothing will happen if another action potential is fired
66
describe the relative division of the refractory period of a neuron
- occurs after the absolute division
- during hyperpolarization until the resting membrane potential reaches -70 mv
- another action potential firing will cause a weak reaction
67
describe why an action potential won't split into 2 going in opposite directions while traveling down an axon
the refractory period will be in the area right behind the action potential so the action potential cannot start moving backwards
68
define telencephalon
cerebrum
69
what surrounds the cerebrum
cerebral cortex
70
define cerebral cortex
- surrounds the cerebrum
- made of gray matter
- neuronal cell bodies and dendrites
71
describe the separation of the cerebrum
- divided into 2 hemispheres: left and right
- separated by the longitudinal fissure
72
define matencephalon
cerebellum
73
what does cerebellum literally translate to
little cerebrum
74
what are the functions of the cerebellum
- coordination of movements
- some autopilot functions communicating with the frontal lobe
75
describe the autopilot function of the cerebellum
- compares what the body is currently doing with what the brain wants it to do
- makes adjustments to get the body to do what the brain wants
76
what are the components of the diencephalon
- thalamus
- hypothalamus
- epithalamus
77
what does diencephalon literally translate to
in between brain
78
where is the diencephalon located
between the cerebrum and the midbrain
79
what are the components of the brain stem
- midbrain
- pons
- medulla oblongata
80
define sulcus
crevices in the brain
81
what is the plural of sulcus
sulci
82
define gyrus
bulge of cerebral cortex between sulci
83
what is the plural of gyrus
gyri
84
define central sulcus
- important landmark
- between the frontal and parietal lobes
85
what do brain lobes usually have the same name as
the bone that covers them
86
which brain lobe does not have the same name as the bone that covers it
insula
87
where is the insula brain lobe located
- insulated from view
- under temporal lobe
88
what does corpus callosum literally translate to
colossal body
89
describe the location of the corpus callosum
- connects the two cerebral hemispheres
- floor of the longitudinal fissure
90
what is the corpus callosum made of
white matter: tracts of axons running parallel
91
define axonal tract
- nerve-like bundle of axons running parallel
- different from a nerve in that it is confined to the CNS
92
what does the corpus callosum do
- connects the cerebral hemispheres
- sends information between hemispheres
93
what is the floor of the longitudianl fissure
corpus callosum
94
what does the epithalamus do
contains the pineal glands which makes melatonin
95
what does the thalamus do
- relay station for all sensory information entering the brain except olfaction
- directs sensory signals
96
what is the only sensory information that does not run through the thalamus
- olfaction
- goes straight to the insula
97
what does the hypothalamus do
- thermostat of the body
- hunger and thirst
- sex drive
- fight or flight
- regulates hormones of the pituitary gland
98
what does the midbrain do
responsible for the startle reflex
99
what is the most complicated reflex
startle reflex
100
what does pons literally translate to
bridge
101
what function do the pons and medulla oblongata share
controlling the rate and depth of breathing
102
what is the function of the medulla oblongata
adjusts vaso-motor tone by regulating smooth muscle lining blood vessels
103
what tells the cerebrum how the body is currently positioned
stretch receptors in skeletal muscles
104
when does the cerebellum not work as well at its autopilot functions
when someone is inebriated (drunk)
105
define basal nuclei
gray matter areas in the brain
106
what is the function of basal nuclei
modulating voluntary movement and muscle tone
107
what disease is caused by basal nuclei not working correctly or dying
Parkinson's disease
108
what are the symptoms of Parkinson's disease
- can't regulate movements and muscle tone
- shuffling gait, drooping face
109
are all areas of the brain entirely specialized to one specific function
- no, most areas of the brain have multiple responsibilities
- some areas are more specialized but not exclusively
110
what does the prefrontal area of the brian do
- makes decisions about somatic movement
- sends signals to the premotor area
111
what does the premotor area of the brain do
- receives motor signals from the prefrontal area
- middle management
- sends signals to the primary motor cortex
112
what is the precentral gyrus
- gyrus that that anterior to the central sulcus
- aka the primary motor cortex
113
what does the primary motor cortex do
- receives motor signals from the premotor area
- produces movement
- projects axonal fibers to the spinal cord to synapse with neurons that will move skeletal muscles
114
what are the lateralized areas of the brain
- broca area (motor speech area)
- wernicke area (sensory speech area)
115
where are the broca area and wernicke area usually found
lateralized: only on the left side of the brain
116
what is another name for the motor speech area of the brain
broca area
117
what does the broca area (motor speech area) do
movement of speech muscles
118
what happens if there is trauma/damage to the broca area (motor speech area)
difficulty speaking
119
where is the broca area (motor speech area) located
lateral frontal cortex on the left hemisphere
120
what is the postcentral gyrus
- gyrus that is posterior to the central sulcus
- aka the primary somatic sensory cortex
121
what does the primary somatic sensory cortex do
- receives sensory information form the thalamus
- sensory information received is from the body (somatic, NOT special senses)
122
what does the somatic sensory association area do
- receives information from the primary somatic sensory cortex
- matches the stimuli to memory to decode the stimulus
- determines what you are feeling
123
what is another name for the sensory speech area of the brain
wernicke area
124
what does the wernicke area (sensory speech area) of the brain do
- understanding of speech and language being read
- receives information from the auditory and/or visual cortexes
- decodes words to uncover meaning
125
what happens if there is trauma/damage to the wernicke area (sensory speech area) of the brain
difficulty understanding speech and language
126
what does the visual cortex do
- receives visual information from the thalamus
- puts together an image that the brain can interpret
- sends information to the visual association area
127
what does the visual association area do
- receives image information from the visual cortex
- decodes the image to determine what you are looking at
128
describe the pyramidal tracts of the brain
tracts of neurons that send information between the cerebral cortex and the spinal cord
129
define decussation of the pyramids
- crossover of the pyramidal tracts in the brain
- why sensory and motor information happens on the opposite side of the brain and body
130
what does homunculus literally translate to
little man
131
which motor areas are controlled by the medial side of the primary motor cortex
- lower limbs
- trunk
- upper limbs (not hands)
132
which motor areas are controlled by the lateral side of the primary motor cortex
- hands
- face
- mouth
133
how much of the motor neuron area in the primary motor cortex controls muscles of the hands, face, and mouth
50%
134
why does most of the primary motor cortex control muscles of the hands, face, and mouth
- places that are very demanding in terms of control of movement; requiring precision
- humans have a dependency on facial expression for communication
- humans have a dependency on hand movements to do things
135
which areas of sensory stimulus are sent to the medial side of the primary somatic sensory cortex
- lower limbs
- trunk
- upper limbs (not hands)
136
which areas of sensory stimulus are sent to the lateral side of the primary somatic sensory cortex
- hands
- face
- mouth
137
how much of the sensory neuron area in the primary somatic sensory cortex receives information from the hands, face, and mouth
50%
138
why does most of the primary somatic sensory cortex receive information from the hands, face, and mouth
- humans move in the direction of their head
- special senses are in the head
- touching and feeling with the hands is important for human functions
139
describe why it is good and bad that the delicate brain is in the hard skull
- good: protection
- bad: brain could hit against skull and be damaged
140
what is the primary function of the meninges
prevent the brain from banging against the skull and becoming damaged
141
what are the 3 layers of the meninges from superficial to deep
- dura mater
- arachnoid mater
- pia mater
142
define dura mater
- outermost meningeal layer
- most durable
- thickets
143
define arachnoid mater
- middle layer
- less durable than dura mater
144
define pia mater
- innermost layer
- least durable layer
- directly attached to the brain and not removable
145
define subarachnoid space
- space between the pia mater and arachnoid mater
- contains cerebrospinal fluid to absorb shock to lessen brain movement/damage
146
what is contained within brain ventricles
cerebrospinal fluid
147
list the ventricles of the brain in order of the movement of cerebrospinal fluid
- lateral ventricle
- third ventricle
- fourth ventricle
148
what connects the lateral ventricle and the third ventricle
interventricular foramen
149
what connects the third ventricle and the fourth ventricle
cerebral aqueduct
150
where does cerebrospinal fluid go after exiting the fourth ventricle
leaks into subarachnoid space in the brain and spinal cord
151
how many layers of the eye are there
3
152
list the 3 layers of the eye from superficial to deep
- sclera
- choroid layer
- retina
153
describe the sclera
- outermost layer of the eye
- very tough and fibrous
- the white of the eye
- melds into the cornea at the anterior end
154
describe the cornea
- at the anterior side of the eye
- major refractor and focuser of light
- sends light to the lens of the eye
155
what does the lens do in the eye
focuses light on the retina
156
describe the choroid layer
- middle layer of the eye
- very dense in blood supply
- enriches nutrient and oxygen supply to the other layers of the eye
157
describe the retina
- innermost layer of the eye
- transducer of light information to action potential information
- contains photoreceptive cells: rods and cones
158
define trasnducer
taking in sensory information and converting it to an electrical signal
159
how does the cornea get nutrients and release waste without a direct blood supply
through tears (lacrimal gland secretions)
160
how many chambers of the eye are there
2
161
what are the 2 chambers of the eye
- anterior chamber
- posterior chamber
162
describe the anterior chamber of the eye
- smaller chamber
- between the cornea and the lens
- contains aqueous humor
163
describe the posterior chamber of the eye
- larger chamber
- between the lens and the retina
- contains aqueous and vitreous humor
164
describe the texture of vitreous humor
- very viscous
- gelatinous
- goopy
165
describe the iris
- sphincter muscles made of smooth muscle
- constrict or dilate the pupil
166
describe the shape of the lens
- convex
- thicker in the middle and tapers towards the edges
167
what muscle controls the tension on the lens
ciliary body
168
describe the ciliary body
- circular muscle
- controls tension on the lens of the eye
- made of smooth muscle
169
how is the ciliary body connected to the lens
through suspensory ligaments
170
describe why the ciliary body is imporatn
allows you to keep adjustable focus on objects less than 12 feet away
171
what are the 2 types of photoceptor cells in the eye
- rods
- cones
172
what are the 3 types of cones
- red
- blue
- green
173
what wavelengths of light can rods pick up on
400-700 nm
174
do rods impart color vision
no
175
what wavelengths of light can blue cones pick up on
400-575 nm
176
what wavelengths of light can green cones pick up on
460-650 nm
177
what wavelengths of light can red cones pick up on
485-700 nm
178
at what wavelength of light are blue and green cones stimulated at about the same extent
475 nm
179
list the layers of cells that light travels through as it enters the eye
- ganglion cells (multipolar neurons)
- bipolar neurons
- rods and cones
180
what happens to light particles after they hit the back of the retina
they travel back forward until they hit the optic nerve
181
what makes up the optic nerve
axons of ganglion cells converging
182
which are more sensitive to light intensity: rods or cones
rods
183
describe the vision that is generated when rods are stimulated
- blurry
- gray-scale (no color)
184
in what light intensity are rods stimulated
- low-level light
- will become overstimulated in higher intensity light
185
in what light intensity are cones stimulated
higher light intensity
186
describe the vision that is generated when cones are stimulated
- crisp
- clear
- color vision
