Chapter 11.4 - Nervous System Flashcards
1
Q
soma
A
cell body of the neuron, contains nucleus
2
Q
dendrites
A
receive signals from previous neurons
3
Q
Axon
A
part of the neuron that sends signals to the axon terminal and passed onto next neuron
4
Q
Axon hillock
A
connects axon to cell body, summated graded potentials
5
Q
myelin sheaths are formed by ____ in the CNS
A
oligodendrocytes
6
Q
myelin sheaths are formed by ___ in the PNS
A
Schwann cells
7
Q
how does myelin sheath allow action potentials to travel faster down the axon?
A
insulated the axon from undergoing ion exchange, can only occur at nodes of ranvier
8
Q
saltatory propagation/conduction
A
action potential jumps from one node of ranvier to the next
9
Q
When a neuron is stimulated, it is ____ and the membrane becomes ___ ____
A
depolarized; less negative
10
Q
When a neuron is stimulated, __ ___ ___ are opened
A
Na+ gated channels
11
Q
When the threshold potential is reached,:
A
more Na+ gated channels open, membrane potential becomes more positive creating action potential
12
Q
Once the membrane potential reaches its max potential:
A
the neuron will repolarize
13
Q
How does neuron repolarize?
A
K⁺ gated channels open up, causing K⁺ outflow out of the neuron
14
Q
Hyperpolarization
A
Membrane potential goes lower than resting state, makes it more challening for another AP to fire
15
Q
refractory period can be ___ or ___
A
absolute or relative
16
Q
Absolute refractory period
A
a second stimulus cannot generate another action potential no matter how powerful it is. Na+ gated channels remain inactivated
17
Q
relative refractory period
A
sufficiently powerful stimulus can cause an action potential to occur - voltage gated sodium channels are no longer inactivated, but the neuron is still hyperpolarized
18
Q
When an AP reached the end of the presynaptic axon: (4)
A
- voltage gated calcium channels open
- Ca²⁺ ions to flow into the presynaptic neuron
- triggers synaptic vesicles to fuse with the membrane
- via exocytosis release the neurotransmitters they contain into the synaptic cleft
19
Q
EPSPs
A
generated by excitatory nt’s; cause NA+ gated gates to open, neuron fires AP
20
Q
IPSPs
A
generated by inhibitory neurotransmitters; cause K⁺ ion gates to open, which results in a K⁺ outflow, more hyperpolarized, harder to fire AP
21
Q
EPSPs and IPSPs are:
A
graded potentials
22
Q
True or false: graded potentials always cause AP to fire
A
false - they vary in magnitude.
23
Q
an action potential will fire down the axon if:
A
the sum of EPSPs and IPSPs is higher (less negative) than the threshold potential
24
Q
APs are:
A
all or nothing (either it fires or not at all)
25
which amino acids act as NTs
glutamate, GABA, glycine
26
glutamate
main excitatory NT of the CNS, most abundant in the vertebrate nervous system; NT of neuromuscular junction in invertebrates
27
GABA
inhibitory NT of the brain
28
glycine
inhibitory NT of the CNS (spinal cord, brainstem, retina)
29
Amino acid derived NT's
epinephrine, norepinephrine, dopamine, serotonin (5HT)
30
epinephrine
excitatory postsynaptic NT of sympathetic nervous system
31
norepinephrine
excitatory postsynaptic NT of sympathetic nervous system
32
dopamine
excitatory NT involved in reward motivated behavior
33
serotonin
inhibitory NT of the brain involved in mood, appetite, sleep, learning, increases contraction of GI tract in response to food intake
34
what neuropeptide can act as NTs
short chain amino acids, such as substance P, have diverse roles
35
gasotransmitter NT
nitric oxide
36
nitric oxide
NT causes smooth muscle relation, in blood vessels causes vasodilation leads to dec BP
37
true or false: nitric oxide is stored in vesicles
false - synthesized and released on demand
38
Acetylcholine
excitatory NT of neuromuscular junction in vertebrates; presynaptic NT of PNS and SNS; postsynaptic NT of PNS
39
glial cells
non-neuronal cells that nourish, support, protect the neurons by making sure the conditions are perfect for neuronal health
40
microglial cells
specialized macrophages which protect the CNS
41
macroglia
include astrocytes, Schwann cells, oligodendrocytes, satellite cells, ependymal cells
42
most abundant type of glial cell
astrocytes
43
function of astrocytes
1. help provide blood supply to CNS neurons
2. recycle neurotransmitters
3. maintain proper ion levels
4. help to form the blood-brain-barrier
44
blood-brain-barrier
selectively semipermeable membrane that covers the brain and regulates the passage of substances from the blood into the brain
45
satellite cells
similar function to astrocytes but function in the PNS - support ganglia
46
ependymal cells
create CSF for CNS
47
one oligodendrocyte can myelinate:
several neurons
48
one schwann cell can myelinate:
only a single neuron
49
during embryonic development, brain can be divided into _ areas:
3; forebrain, midbrain, hindbrain
50
forebrain develops into:
telencephalon and diencephalon
51
midbrain develops into:
mesencephalon
52
hindbrain develops into:
metencephalon, myelencephalon
53
telencephalon gives rise to:
cerebrum
54
diencephalon gives rise to:
thalamus, hypothalamus, pineal gland
55
mesencephalon gives rise to:
midbrain
56
metencephalon gives rise to:
pons, cerebellum
57
myelencephalon gives rise to:
medulla oblongata
58
frontal lobe function
- decision making, problem solving, judgement, planning for future, consequences of actions
- works with limbic system for memories and emotions
- attention/ concentration
59
temporal lobe function
speech/language, hearing
60
occipital lobe function
vision
61
parietal lobe function
spatial/visual perception, toucj/pain/temperature sensation and integration
62
somatosensory cortex function
major receptive area for touch
63
somatomotor cortex function
initiation of motor impulses
64
corpus callosum function
connects two hemispheres of the brain
65
cerebellum function
fine tuning motor inputs, balance, coordination
66
midbrain function
relays senses to higher functioning parts of brain (vision, hearing)
67
pons function
relays messages between forebrain, cerebellum, medulla; sleep and dreaming
68
medulla oblongata function
maintains vital body functions (HR, BP, breathing rate), toxin sensation, vomiting
69
thalamus function
relay center of the brain - sensory function is routed from the body to the thalamus, which directs the impulse to other areas of the brain
70
limbic system includes:
hypothalamus, hippocampus, amygdala
71
hypothalamus function
produces ADH, regulated homeostasis, thirst, hunger, temperature, ANS, controls pituitary gland
72
hippocampus function
learning/memory (long term)
73
amygdala
emotion (anger, fear, sadness), controls aggression, motivation, libido
74
sensory neurons enter and innervate the ___ ___ via __ ___
spinal cord; dorsal roots
75
motor neurons exit and send signals to the ___ via the ___ ___
muscles; ventral roots
76
mechanoreceptors
respond to a mechanical stimuli (such as touch and sound)
77
nociceptors
respond to painful stimuli
78
thermoreceptors
respond to temperature-related stimuli.
79
chemoreceptors
respond to chemical stimuli
80
Electromagnetic (light) receptors
respond to light, electricity, and magnetic stimuli
81
peripheral nervous system can be divided into:
somatic nervous system; autonomic nervous system
82
somatic nervous system
controls voluntary movement of the body, specifically the activity of skeletal muscles
83
autonomic nervous system
controls the involuntary movement of the body, such as the activity of effector organs and involuntary muscles
84
autonomic nervous system can be divided into:
SNS and PNS
85
Main effects of sympathetic nervous system
1. release of sugar
2. increase in heart rate
3. dilation of bronchi and bronchioles
4. dilation of the pupil
86
Parasympathetic nervous system
resting/relaxing - controls passive actions
1. relaxation of muscles
2. decrease in heart rate
3. maintenance of homeostasis
4. increase in gastrointestinal activity
87
ganglion
cluster of nerve cell bodies in the PNS
88
True or false: PNS and SNS have the same length of pre- and post ganglionic nerves
false - they are different
89
In the PNS, preganglionic nerves are __ and postganglionic are ___
long; short
90
Ganglia of the PNS are ___ to effector organs
close
91
In the SNS, preganglionic nerves are __ and postganglionic are ___
short; long
92
The ganglia of the SNS are typically ____ the effector organs
further away from (compared to PNS)
93
PNS uses acetylcholine for:
both preganglionic and postganglionic neurotransmitter
94
SNS uses acetylcholine for:
only as preganglionic neurotransmitter
95
SNS uses ___ and ___ for postganglionic NT
norepinephrine (NE) and epinephrine (E)
96
SNS preganglionic neurons also directly stimulate ____ to release NE/E into the blood
adrenal medulla
97
___ ___ transfers the vibrations of pulsatile sound waves from the outer ear to the middle ear
tympanic membrane
98
middle ear is composed of:
3 bones (ossicles): malleus, incus, stapes
99
__ connects to the oval window
stapes
100
oval window
membrane bound opening which separates the middle ear from the inner ear; transfers vibrations from the stapes to the cochlea
101
What happens to the vibratory signal when it reaches the oval window?
signal if amplified due to smaller surface area than tympanic membrane
102
external auditory meatus
ear canal
103
nitric oxide is a ____ that causes:
gasotransmitter; smooth muscle contraction
104
How does nitric oxide affect blood vessels?
causes vasodilation --> decreases BP
105
What is the connective tissue between the sclera and retina of the eye?
choroid
106
How many different types of taste receptor cells cover the tongue?
5 (salty, sour, bitter, sweet, umami)
107
How many different types of taste receptor cells cover the tongue?
acetylcholine; acetylcholine
108
Where does the optic nerve exit the back of the eye?
optic disc
109
What is the pathway of a sound wave?
tympanic membrane; ossicles; oval window; cochlea; auditory nerve; temporal lobe
110
Where does the optic nerve exit the back of the eye?
rods
111
What are the components of the central nervous system?
brain and spinal cord
112
The mesencephalon gives rise to which brain structure(s)?
developed midbrain
113
During which period is it impossible to fire another action potential?
absolute refractory period
114
Which of the following describes the membrane potential of a neuron during a relative refractory period?
hyperpolarized
115
Where in the neuron do graded potentials summate?
axon hillock
116
Which of the following is a function controlled by the hippocampus?
long-term memory
117
The sympathetic nervous system releases which neurotransmitter in its preganglionic synapse and which neurotransmitter in its postganglionic synapse?
acetylcholine; norepinephrine and epinephrine
118
Which part of the brain relays messages between the forebrain, cerebellum, and medulla?
Pons
119
Which of the following is another term for motor neurons?
efferent
120
When inhibitory postsynaptic potentials (IPSPs) cause chloride channels to open, what is the direction of Cl- flow?
Inflow
121
```
Which of the following is responsible for high acuity vision?
A. Pupil
B. Lens
C. Cornea
D. Fovea
```
D. Fovea
122
High acuity vision
the ability to visually discern sharp details
123
___ is the most densely packed with the highest concentration of photoreceptors (cones)
Fovea
124
The metencephalon gives rise to which brain structure(s)?
pons and cerebellum
125
What brain structures make up the brainstem?
pons, midbrain, medulla oblongata
126
```
Which of the following structures allows the cochlear membrane to expand and vibrate?
A. Oval window
B. semicircular canals
C. round window
D. stapes
```
C. round window
127
What type of membrane is the blood-brain-barrier?
semi-permeable
128
Approximately what percentage of optic nerves travel to the fovea?
50%
129
Where do the ganglia of the parasympathetic nervous system exist in relation to their effector organs?
close to the organs
130
Which brain structure connects to the vagus nerve?
medulla oblongata
131
Which of the following is directly involved in re-establishing the membrane resting potential after the refractory period?
Na+/K+ ATPases
132
What brain structure controls balance and coordination?
cerebellum
133
The activity of which of the following muscles is controlled by the somatic nervous system?
A. Cardiac muscles
B. Smooth muscles
C. Skeletal muscles
C. Skeletal muscles
134
The lens refracts incoming light to focus on which part of the eye?
retina
135
What term describes the process of conducting a mechanical signal to a nerve signal?
transduction
136
What brain structure receives signals from the thalamus to give us the conscious perception of smell?
orbitofrontal cortex
137
Which of the following accurately describes the term “cornea”?
the transparent front portion of the eye that covers the iris and pupil
138
Cataracts occur when opacities form in which part of the eye?
Lens
139
First part of the eye that light encounters
Cornea
140
___ is the transparent front portion of the eye that covers the iris and the pupil
cornea
141
___ does not contain any blood vessels or photoreceptors
Cornea
142
___ curvature cannot be altered
Cornea
143
Which part of the eye gets sliced in LASIK?
Cornea
144
After the cornea, light reaches:
iris (pupil more specifically)
145
___ controls how much light enters the eye
pupil
146
After the iris/pupil, light hits the:
lens
147
Sclera
protective connective tissue layer containing collagen and elastin (white part of the eye)
148
Choroid
connective vascular tissue between sclera and retina
149
Taste buds differ in
size, appearance, function
150
When taste receptors are stimulated, information sent to
thalamus --> gustatory cortex
151
Nasal cavity contains __ types of olfactory receptor cells
1000
152
Olfactory cortex
gives us perception of smell, sends signals to thalamus
153
___ gives us conscious perception of smell
orbitofrontal cortex
154
Pathway of smell
olfactory receptor cells --> olfactory cortex --> thalamus --> orbitofrontal cortex or amygdala
