Exam 2 Flashcards
(317 cards)
1
Q
define nerves
A
a tissue; collections of neurons and associated cells (glial cells)
2
Q
define neurons
A
excitable cells capable of receiving input stimuli from other cells (or the environment), integrating the signal, transmitting it long distances and relaying the signal to a downstream cell
3
Q
parts of the Central Nervous System (CNS)
A
- brain and spinal cord
- cerebral spinal fluid
4
Q
parts of the Peripheral Nervous System (PNS)
A
- nerves
- afferent and efferent divisions
5
Q
Afferent Division
A
transmission of signal to the central nervous system from sensory and visceral stimuli
6
Q
Efferent Division
A
transmission of signals to respond to the original stimulus (voluntary or involuntary)
7
Q
difference between neurons and nerves
A
neurons are the cells responsible for the actual transmission signal. nerves are the main tissues involves with receiving and sending signals (collection of neurons and glial cells).
8
Q
glial cells
A
non-neuronal cells that support or protect neurons
9
Q
examples of glial cells
A
- Schwann cells
- Oligodendrocytes
- Asctocytes
- Microglial
10
Q
microglial cell
A
immune cell (glial cell)
11
Q
asctocytes
A
encases vasculature and keeps neurons close to blood vessels, homeostasis (glial cell)
12
Q
Schwann cell
A
myelinated neurons in PNS (glial cell)
13
Q
Satellite cell (neural tissue)
A
extra support and protection in PNS (glial cell)
14
Q
oligodendrocytes
A
myelinated CNS axons (glial cell)
15
Q
ependymal cells
A
produce cerebral spinal fluid (CNS glial cell)
16
Q
Efferent branch division
A
somatic and autonomic nervous system
17
Q
somatic nervous system
A
controls motor neurons (skeletal muscle)
18
Q
autonomic nervous system division
A
- sympathetic
- parasympathetic
- enteric
19
Q
sympathetic nervous system
A
fight or flight response
20
Q
parasympathetic nervous system
A
rest and digest response
21
Q
4 structural regions of neurons
A
- dendrites
- soma (cell body)
- axon
- synapses
22
Q
dendrites
A
major site of synaptic input from other neurons
23
Q
soma
A
cell body of a neuron, major site of integration of synaptic potentials
24
Q
axon
A
conduction component of a neuron, can be very very long
25
synapses
the output of a neuron, can alter activities of other cells
26
presynaptic
passing the signal
27
post synaptic
recipient of the signal
28
multipolar neuron
main type, multiple poles from the cell body
29
bipolar neuron
2 poles coming out of the cell body
30
unipolar/pseudounipolar neuron
singular branched neuron
31
PNS glial cells
- Schwann cells
- satellite cells
32
gray matter
dense collection of cell bodies
33
white matter
more axonal tracks (myelinated axons are fatty making it have a lighter appearance)
34
fascicle (nerve)
many axons bundled together in connective tissue
35
endonerium
connective tissue around the individual axon
(endo=inside)
36
perineurium/perimysium
connective tissue around a fascicle
37
epinerium
connective tissue around the entire nerve
38
describe the organization of a nerve
a nerve consists of a group of fascicles enclosed by a connective tissue covering (axon, covered by myelin sheath, covered by endonerium, all axons packed into a fascicle, faciscle covered by perineurim, multiple fascicles packed together and covered by epinerium)
39
what does it mean to be excitable?
excitable cells can undergo rapid changes in their membrane potentials
40
membrane potential
the separation of charges across a plasma membrane
41
average membrane potential
-70mV
42
is the inside the cell more negative or positive when there is a membrane potential?
negative charges
43
is the outside the cell more negative or positive when there is a membrane potential?
positive charges
44
the greater the concentration gradient, the _______________ the diffusion
more rapid
45
the concentration gradient is particularly important for determining the ________________________
rate of ion movement
46
electrolytes and polar solutes can ONLY move through the membrane IF ______________
their channels and transporters allow
47
how do electron gradients occur?
from concentration gradients when they are separated by selectively permeable membrane (contributes to membrane potential)
48
Is Na more concentrated on the inside or outside the cell?
outside the cell
49
Is K more concentrated on the inside or outside the cell?
inside the cell
50
electro-chemical gradients
movement of ions across the membrane is dependent on concentration gradient AND the charge across a membrane
51
membrane potential is established primarily by the relatively leakiness of which ions?
Na and K
52
How is the average membrane potential maintained?
Na/K ATPase pumps
(3 Na out of the cell, 2 K into the cell)
53
K+ is ________ times more permeable than Na
25
54
leaky ion channels
open all the time
55
gated ion channels
induced to open
56
sensory input
sensory receptors detect some sort of stimuli
57
integration
nervous system processes the sensory input and decides what should be done about it
58
motor output
the response that occurs when your nervous system activates certain parts of your body
59
2 main parts of the nervous system
- central nervous system
- peripheral nervous system
60
what is a greater make up in the nervous system; neurons or glial cells?
glial cells (10:1)
61
3 things all neurons have in common
1. some of the longest lived cells in the body
2. are irreplaceable
3. high metabolic rate (25% of calories per day are consumed by the brain activity)
62
role of an axon
transmit electrical impulses away from the body to other cells
63
sensory neurons
transmit impulses from sensory receptors to the CNS (afferent neurons) ex=unipolar neuron
64
motor neurons
impulse moves from CNS to the rest of the body (efferent neurons) ex=mostly multipolar neuron
65
interneurons
impulse moves between sensory and motor neurons (mostly multipolar neurons)
66
somatic nervous system
carries motor and sensory information, responsible for voluntary movement, processes external stimuli (hearing, touch, sight)
67
primary reason a membrane potential forms
due to excess outflow of K+ relative to the inflow of Na+
68
graded potential
localized changes in a cells membrane potential
69
can graded potential vary in magnitude?
YES, the potential change is proportional to the signal
(weak signal=minor change, strong signal=major change)
70
in graded potentials, the more neurotransmitters bound the _____________ the amount of local ion movement across the membrane
greater
71
can graded potentials be hyperpolarized or depolarized?
yes
72
depolarization
membrane potential is less negative (more positive)
73
hyperpolarization
membrane potential is more negative
74
in a graded potential, the magnitude __________ with distance from the site of origin
diminishes
75
where do graded potentials occur?
dendrites and soma
76
the size and duration of membrane potentials is determined by _________________________________
the size and duration of inputs
77
excitatory inputs
increase positive charges, bring closer to threshold, depolarize
78
inhibitory inputs
increase negative charges, further away from threshold, hyper polarize
79
in a graded potential, if there is a stronger stimulus it will release more neurotransmitters which will open more ion channels causing a greater change to the _____________________
membrane potential
80
threshold value
the membrane potential level that will induce an action potential
81
how does graded potential spread?
passive current flow
82
define passive current flow
ions flow between the active area to the inactive areas around it to spread, when the receptor closes the spread will stop
83
decremental
current flow dissipates from the original source
84
is graded potential decremental?
YES
85
summation in post-synaptic (graded) potentials
graded potentials in neurons can enhance or counteract one another id the occur nearly simultaneously or if repeated stimulations arrive in rapid sequence
86
temporal summation
repeated signals are capable of having a more pronounced effect than the individual signal alone
87
what does temporal summation look like on a graph?
the original signal gets a larger signal added onto it
88
spatial summation
stimulation occurs at the same time in different parts of the neuron
89
what does spatial summation look like on a graph?
- will either combine the signals to create just one larger one
- cancels out the signal completely (excitatory + inhibitory)
90
if summation (additive depolarization) occurs to reach threshold value an ____________________ will occur
action potential
91
axon hillock
where the initiation of an action potential occurs in an axon (where the soma and axon connect)
92
average threshold value
-55 mV
93
it is the _________________ of multiple graded potentials that can initiate an action potential
cummulative action
94
action potential
large charges in the distribution of charges across a membrane that occurs rapidly, but last a short amount of time
95
how long is an action potential?
1-2 ms
96
are action potential decremental?
NO - the intensity of the signal will be the exact same throughout the entire axon
97
what does it mean that the action potential is an all or nothing phenomenon?
if threshold is reached an action potential will occur with the same frequency, if threshold is not reached it will not occur
98
explosive __________________ takes place at threshold
depolarization
99
repolarization
occurs after depolarization, makes the membrane potential more negative
100
rapid changes in the membrane potential from a neuron reaching threshold is from the sequential opening and closing of which voltage gated ion channels?
Na and K
101
what ion depolarizes the membrane potential?
Na+ influx
102
what ion causes repolarization of a membrane potential?
K+ efflux
103
which voltage gated ion channel opens at threshold?
Na channels
104
when are Na+ channels INACTIVATED during and action potential?
the peak of the action potential
105
what is the difference between the K and Na channels?
Na is faster and more complicates (can inactivate) while K is much slower
106
when do the voltage gated K channels finally open?
peak of an action potential
107
what causes hyperpolarization?
the K channels are slow, so they close past the average membrane potential causing the membrane potential to become more negative
108
resting membrane potential: Na and K voltage gated channels
- Na+ = closed
- K+ = closed
109
rising phase: Na and K voltage gated channels
- Na+ = open
- K+ = closed
110
falling phase: Na and K voltage gated channels
- Na+ = inactivated
- K+ = open
111
Pk or Pna meaning
the permeability of the ions through the membrane
112
what reestablished and maintains the membrane potential after hyperpolarization of an action potential?
Na/K ATPase
113
absolute refractory period
period of time when another action potential can NOT be generated (Na+ channels are inactive and cannot be opened)
114
relative refractory period
an action potential can be generated but it requires a stronger than normal stimuli
115
why is propagation of an action potential in one direction?
Na channels need time to recover so it cannot go backwards.
The action potential at one location on an axon initiates an action potential at a neighboring location, by repeating this process, a signal can travel longdistances (e.g. 1m) along an axon without any decrease in amplitude.
116
myelin sheaths
layers of cell membranes from neuron-associated cells that are wrapped around the axon
117
how do myelin sheaths generally help neurons?
their presence supports and helps propagate action potentials moving down the axon
118
unmyelinated axons
in the PNS, Schwaan cells will support the axon but there will be no insulating myelin sheath
119
action potentail propogation in unmyelinated axons
a series of rolling action potentials that occur down the action potential
120
saltatory propagation
action potentail propogation in myelinated axons
121
how does myelinated action potential differ from unmyelinated?
- myelinated axons have a faster conduction velocity then unmyelinated axons
- action potential occurs between the nodes
122
nodes of ranvier
space between myelin sheath, where the voltage gated ion channels are located
123
action potential conduction velocity is affected by
- myelination
- axon diameter
124
how does axon diameter affect conduction velocity?
the larger the diameter of the axon, the faster the conduction velocity
125
GP vs AP: can be depolarizing and hyperpolarizing
graded potential
126
GP vs AP: always lead to depolarization of membrane and reversal of the membrane potential.
action potential
127
GP vs AP: Amplitude is proportional to the strength of the stimulus.
graded potential
128
GP vs AP: Amplitude is all-or-none; strength of the stimulus is coded in the frequency
action potential
129
GP vs AP: small amplitude
graded potential
130
GP vs AP: large amplitude (about 100 mV)
action potential
131
GP vs AP: duration of few ms to sec
graded potential
132
GP vs AP: short duration of 3-5 ms
action potential
133
GP vs AP: Ion channels responsible for potentials may be ligand-gated, mechanosensitive, or temperature sensitive channels, or may be channels that are gated by cytoplasmic signaling molecules.
graded potential
134
GP vs AP: Voltage-gated Na+ and voltage-gated K+ channels are responsible for the neuronal action potential.
action potential
135
GP vs AP: The ions involved are usually Na+, K+, or Cl−
graded potential
136
GP vs AP: The ions involved are Na+ and K+
action potential
137
GP vs AP: No refractory period
graded potential
138
GP vs AP: Absolute and relative refractory periods are important aspects
action potential
139
GP vs AP: can be summed over time (temporal summation) and across space (spatial summation).
graded potential
140
GP vs AP: Summation is not possible (due to the all-or-
none nature, and the presence of refractory periods).
action potential
141
GP vs AP: travel by passive spread (electrotonic spread) to neighboring membrane regions.
graded potential
142
GP vs AP: propagation to neighboring membrane regions is characterized by regeneration of a new potential at every point along the way.
action potential
143
GP vs AP: decremental
graded potential
144
GP vs AP: non-decremental
action potential
145
GP vs AP: brought about by external stimuli (in sensory
neurons) or by neurotransmitters released in synapses
graded potential
146
GP vs AP: triggered by membrane depolarization to
threshold
action potential
147
GP vs AP: potentials can occur in any region of the cell
plasma membrane: in neurons, they occur in specialized regions of synaptic contact with other cells or membrane regions involved in receiving sensory stimuli.
graded potential
148
GP vs AP: Occur in plasma membrane regions where voltage-gated Na+ and K+ channels are highly concentrated.
action potential
149
synapses
areas that are well defined specific regions where downstream neurotransmitters are delivered
150
The Synapse
where the neuron passes its signal to an elector cell
151
presynaptic terminal
where action potential occurs, carries vesicles of neurotransmitters using microtubules and neurofilaments to the post synaptic element
152
post synaptic element
receives neurotransmitters (using receptors) from the presynaptic terminal
153
synaptic cleft
the space between the presynaptic terminal and post synaptic element, enzymes are here to hydrolyze neurotransmitters
154
steps of the chemical synapse
1. AP reaches presynaptic terminal
2. depolarization opens ion channels letting Ca2+ in
3. Ca2+ triggers release of NT from vessicles
4. NT binds to receptors on postsynaptic membrane
5. postsynaptic gets a membrane potential
6. AP propagates through the next cell
7. NT are inactivated
155
what triggers the release of neurotransmitters in the synapse?
Ca2+
156
how are neurotransmitters inactivated?
hydrolyzed by enzymes in the synaptic cleft OR transported back into the presynaptic terminals and package into vesicles by proteins
157
what is the area called where synaptic vesicles will release?
| (_________zone)
active zone
158
post synaptic densities
accumulation of neurotransmitter receptors and other proteins that will support them
159
what is responsible for docking the vesicles of neurotransmitters to help fuse them to the membrane?
v-snares and t-snares
160
what induces vesicle fusion with the membrane, but docking of vesicles can occur in its absence?
Ca2+
161
what happens if v-snares and t-snares get damaged in synapses and they cannot interact?
neurotransmitters will not release
162
what can cause damage to t-snares and v-snares allowing for neurotransmitters to no longer release?
toxins (botulism, tetanus)
163
examples of small molecule neurotransmitters
- acetylcholine
- norepinephrine
- epinephrine
164
examples of neuropeptides
- enkephalin
- oxytocin
(AA and peptides)
165
how are neuropeptides made?
synthesized in the rough ER and then cleaved from larger peptides
166
how are small molecule neurotransmitters produced?
enzymatic pathways, processed in the Golgi
167
do neuropeptides have fast or slow axonal transport?
fast (400 mm/day)
168
do small molecule neurotransmitters have fast or slow axonal transport?
slow (0.5-5 mm/day)
169
why are small molecule neurotransmitters transported much slower than neuropeptides?
they do not have to be replaced as often
170
small molecule: synthesis site
axonal terminal or varicosity (neuromuscular junction)
171
neuropeptide: synthesis site
nucleus/ER as a propeptide
172
small molecule: vesicle
small, clear
173
small molecule: release
low frequency stimulation
174
small molecule: inactivation
reuptake or enzymes
175
neuropeptide: vesicle
large, dense
176
neuropeptide: release
| (high or low frequency)
high frequency stimulation
177
neuropeptide: inactivation
extracellular peptidases
178
ionotropic receptors
ion channels that open when a ligand attaches
179
metabptropic receptors
g-protein coupled receptor
180
ionotropic: receptor
ligand gated channel receptor
181
ionotropic: structure
4-5 subunits around an ion channel
182
ionotropic: molecular action
opens ion channel
183
ionotropic: 2nd messenger?
NO
184
ionotropic: gating of ion channel
direct
185
metabptropic: receptor
g-protein coupled receptor
186
metabptropic: structure
no channel, 7 transmembrane segments
187
metabptropic: molecular action
activate g-protein
188
metabptropic: 2nd messenger?
YES
189
metabptropic: gating of ion channel
indirect
190
metabptropic: type of synaptic effect
| (slow or fast)
slow post synaptic potential
191
ionotropic: type of synaptic effect
| (fast or slow)
FAST excitatory and inhibitory post synaptic potential
192
acetylcholine receptors
- nicotinic = ionoropic
- muscarinic = metabotropic
193
norepinephrine receptor
- alpha = metabotropic
- beta = metabotropic
194
Central Nervous System
brain and spinal cord
195
Peripheral Nervous Sytem
all neural tissue but the brain and spinal cord, afferent and efferent divisions
196
afferent division
receives sensory and visceral stimuli and sends information to the CNS
197
efferent division
the output of CNS, broken into somatic and autonomic
198
somatic nervous system
voluntary (ex: skeletal muscle)
199
autonomic nervous system
sympathetic vs parasympathetic vs enteric
200
sympathetic nervous system
fight or flight
201
parasympathetic
rest and digest
202
how many pairs of spinal nerves do humans have?
31
203
how are the spinal nerves named?
according to the region of the vertebral column to which they are connected
204
order of the vetebral column
top- cervical, thoracic, lumbar, sacral -bottom
205
ganglion
a collection or group of neuron cell bodies in the PNS
206
afferent fibers enter through the ________ root and efferent fibers exit through the _________ root
dorsal, ventral
207
does sensory information come in through the ventral or dorsal side of the spinal nerves?
dorsal
208
does motor information come out through the ventral or dorsal side of the spinal nerves?
ventral
209
neurotransmitter associated with the sympathetic nervous system
norepinephrine (and acetylcholineis used for pre ganglia)
210
neurotransmitter associated with the parasympathetic nervous system
acetylcholine
211
define excitable tissue
they can propagate changes in membrane potentials which cause action potentials that cause contraction (muscle)
212
3 types of muscle
skeletal, cardiac, smooth
213
striated muscle
skeletal and cardiac
214
unstriated muscle
smooth
215
voluntary muscle
skeletal
216
involuntary muscle
cardiac and smooth
217
define striated
a repeated pattern along the length of the muscle composed of aligned contractile fibers
218
what regulates skeletal muscle?
completely depends on signaling from the nervous system to work/contact because it is voluntary
219
what regulates cardiac and smooth muscle?
the nervous system can influence them but they respond to other stimuli within the body because they are involuntary
220
myoblasts
muscle cells
221
what does skeletal muscle look like?
striated, tubular, multinucleated
222
what does smooth muscle look like?
spindle shaped, non-striated, unicellular
223
what does cardiac muscle look like?
striated, branched, unicellular
224
where is cardiac muscle located?
walls of the heart only
225
myofibril
contractive units packed into a muscle fiber with mitochondria and nuclei
226
skeletal muscle: muscle fiber
a typical cell packed with myofibrils that push the nucleus to the side
227
skeletal muscle: endomysium
covering of the muscle fiber
228
skeletal muscle: fascicle
collections of muscle cells
229
skeletal muscle: perimysium
covering of fascicles
230
skeletal muscle: muscle
collection of fascicles
231
skeletal muscle: epimysium
covering of the entire muscle
232
skeletal muscle: tendon
attached the muscle to bone
233
A band (coloring)
dark
234
I band (coloring)
light
235
how are skeletal muscles innervated?
by motor neurons, it must come from the ventral side and attach to individual fibers
236
skeletal muscle: a weak contraction means a ______ motor units are contracting, while a strong contraction means _______ motor units are contracting
few, a lot
237
how is skeletal muscle formed?
the fusion of myoblasts (why there are multiple nuclei)
238
what muscle can fatigue?
skeletal muscle
239
sarcoplasm
muscle cell cytoplasm
240
sarcoplasmic reticulum
muscle endoplasmic reticulum
241
sarcolemma
muscle cell membrane
242
2 types of myofilaments in skeletal muscle
actin and myosin
243
what is contraction in skeletal muscle?
shortening of myofibrils due to actin filaments sliding over myosin filaments, the length of the filaments remains the same
244
A band
- thick myosin filament
- dark
- contains the H zone
245
what protein anchors myosin?
M-line
246
H zone
ONLY myosin, no overlap of actin
247
more contraction, ______________ the H zone
smaller
248
I band
- thin actin filament
- light
249
what protein anchors actin?
Z-disc
250
sarcomere
contractile unit (from z-disc to z-disc)
251
how do t-tubules support contraction?
as an action potential sweeps across the sarcolemma, it will travel down the t-tubules which allows for the action potential to move down into the muscle cell
252
t-tubules
extensions of the sarcolemma deep into the muscle fibers
253
sarcoplasmic reticulum
huge organelle that drapes around myofibrils, STORES Ca2+!!
254
what ion is critical of contraction?
Ca2+
255
terminal cisternae
relays information to get Ca2+ released
256
what sites are on the motor head group of myosin?
- actin binding site
- ATP binding site
257
what orientation does myosin lay?
they lay tail to tail with motor heads on the ends
258
tropomyosin
prevents myosin from binding to actin in the absence of Ca2+
259
troponin
calcium binding protein
260
what happens when calcium binds to troponin?
when Ca is bound, it shifts the position of tropomyosin exposing the myosin binding site so that contraction can occur
261
why are there so many mitochondria between the myofibrils?
contraction is an ATP dependent process
262
within the myofibril, each filament is surrounded by _____ light filaments
6
263
how many nuclei in each cardiac muscle cell?
one or two
264
why are cardiac cells connected by intercalated disks?
- contains gap junctions
- connected by desmosomes and adherent junctions
265
why is cardiac muscle auto-rhythmic?
it is involuntary, however the nervous system can have influence
266
which muscle shows branching?
cardiac
267
how does cardiac muscle avoid fatigue?
able to completely rest between contractions
268
how many nuclei are in a smooth muscle cell?
one
269
dense bodies
what actin is attached to in smooth muscle
270
caveolae
folds in the cell membrane that contain aggregates of receptors and ion channels
271
where is smooth muscle found in the body?
walls of hollow organs, vessel walls, erector pili muscles of skin, iris
272
how does smooth muscle avoid fatigue?
it has slow contractions that can be sustained for long periods of time
273
what parts of the nervous system can modulate smooth muscle?
autonomic (sympathetic and parasympathetic)
274
are there gap junctions in smooth muscle?
yes
275
how does smooth muscle contract?
dense bodies are drawn in together and actin moves over myosin
276
how are single unit smooth muscles able to contract together in a single unit?
membranes are adhered together at multiple points so excitation is able to sweep through all the muscle through gap junctions
277
where are single unit smooth muscles found?
organ walls and blood vessels
278
multi unit smooth muscle
contracts independently from one another and innervated by a single nerve ending
279
how does multi unit smooth muscle contract separately?
they are separated physically by connective tissue and must be innervated by a single nerve ending
280
where are multi unit smooth muscle found
iris and erector pili
281
in blood vessels, contraction __________ diameter, while relaxation ____________ diameter
decreases, increases
282
how does the cardiovascular system use smooth muscle to control blood flow?
it can contract and relax smooth muscle to restrict or allow blood flow to different capillary beds
283
what is the purpose of smooth muscle being organized circular and longitudinal?
it is able to constrict the organ in multiple directions
284
common features of all three muscle types
- generate movement/tension through contraction
- myosin and actin to generate force
- calcium used to trigger contraction
285
skeletal muscle signal
from somatic motor neuron
286
cardiac muscle signal
- arises from the heat itself
- some autonomic influence (but not initiate)
287
smooth muscle signal
multiple sources (internal, local, external)
288
neuromuscular junction
a synapse that comes into contact with multiple muscle fibers to stimulate them
289
neuromuscular junction: neurotransmitter
acetylcholine
290
how does and an action potential at the cells surface reach the myofibrils in the center of the cell to stimulate contractions in skeletal muscle?
t-tubules and their close relationship with the sarcoplasmic reticulum and terminal cisternae
291
In skeletal muscle: T-tubules and sarcoplasmic reticulum are complexed together throughout the fibers in _____________
triads
292
dihydropyridine receptor (DHPR)
a voltage dependent calcium channel found between tubules in skeletal muscle, has a relationship with the ryanodine receptor
293
function of dihydropyridine receptor (DHPR)
triggers intracellular calcium release from the sarcoplasmic reticulum for excitation-contraction coupling of actin and myosin
294
ryanodine receptor (RYR)
calcium releasing channel in the sarcoplasmic reticulum, has a relationship with the dihydropyridine receptor
295
function of ryanodine receptor (RYR)
triggering of the DHP receptor causes the ryanodine receptor to open releasing calcium into the cytoplasm from the sarcoplasmic reticulum
296
What occurs between the RYR and DHPR when depolarization occurs?
DHPR changes conformation allowing RYR to release calcium into the cytoplasm
297
What occurs between the RYR and DHPR when repolarization occurs?
they return to their original conformation and calcium can no longer exit the RYR
298
What happens to calcium in order to relax the cell in skeletal muscle?
- RYR is blocked from releasing calcium
- SERCA Pump returns Ca into the SR
299
SERCA (Sarcoplamic/Endoplasmic Reticulum Ca2+-ATPase) Pump
attached to the membrane of the sarcoplasmic reticulum, uses ATP to move calcium in the cell back into the sarcoplasmic reticulum
300
What is ATP needed for during a muscle twitch?
- contraction
- relaxation
301
What is another name for contraction of cardiac muscle?
calcium-induced calcium release
302
how does contraction of cardiac muscle differ from skeletal muscle?
there is no physical interaction between the sarcoplasmic reticulum and t-tubules in cardiac muscles (no triads)
303
2 sources Ca2+ uses to flood into cardiac muscle for contraction
1. cytoplasm (voltage gated Ca2+ channels)
2. sarcoplasmic reticulum (Ca2+ induces Ca2+ to release through the RYR)
304
How is calcium removed from the cell for relaxation in cardiac muscle?
sodium calcium exchanger (an anti porter transporter protein)
305
what amount does the sodium calcium exchanger move in and out of the cell?
- 1 Ca out
- 3 Na in
306
a single cross-bridge cycle uses _____ molecule of ATP and moves the actin filament about _______ nm
- 1 molecule of ATP
- 10 nm
307
myosin-actin cross bridge cycle
1. bind (rebind)
2. ratchet (motor head moves actin by changing conformation)
3. let go (cycle will continue is Ca is present)
308
Roles of ATP in the Cross Bridge Cycle
1. provide energy for the process
2. responsible for detachment
309
define rigor
the motor head is attached to actin but there is no ATP present (after death) do detachment cannot occur so the myosin cannot release actin
310
interneuron
a connection point in the CNS that is a connection point between sensory and motor pathways
311
dorsal root ganglion
a collection of soma in the PNS
312
is the afferent nervous system dorsal or ventral?
dorsal
313
is the efferent nervous system dorsal or ventral?
ventral
314
does the somatic nervous system have ganglion?
NO, all myelinated and fast
315
does the sympathetic and parasympathetic nervous system have ganglion?
YES, pre ganglion = myelinated and post ganglion = unmyelinated and works slower
316
which system is faster, the somatic or autonomic nervous system?
somatic
317
what is the purpose of the autonomic ganglia?
relay information
