Exam 3 Flashcards
1
Q
anchor for thin filaments
A
Z-line
2
Q
anchor for thick filaments
A
M-line
3
Q
dark area; extends length of thick filaments
A
A-band
4
Q
light area; thin myofilaments only (Z line is center)
A
H-zone
5
Q
functional unit of skeletal system; z-line to z-line
A
sarcomere
6
Q
makes up thick myofilaments; rodlike tail and 2 globular heads
A
myosin
7
Q
makes up thin myofilaments; made of polypeptide subunits
A
actin
8
Q
contain active sites for myosin heads; G actin strung together; 2 twisting strands make up thin myofilaments
A
polypeptide subunits of actin
9
Q
in thin myofilaments; rod-shaped protein that runs along actin; blocks myosin binding sites on actin when muscle relaxed
A
tropomyosin
10
Q
in thin myofilaments; 3 polypeptide subunit complex: 1 bound to actin, tropomyosin, and calcium
A
troponin
11
Q
organelle; smooth ER of skeletal muscle; stores and regulates intercellular levels of Ca; connects to the next myofibril; tubules run longitudinally
A
sarcoplasmic reticulum
12
Q
part of sarcoplasmic reticulum; runs perpendicular to the myofibril; found at A and I band intersection
A
terminal cisternae
13
Q
perpendicular located at all A and I band junction; sandwiched between terminal cistern; lumen are continuous with extracellular space; form triads
A
T-tubules
14
Q
terminal cisternae + T-tubules; located at A and I band intersection; integral proteins sense change in membrane potential; calcium channels in membrane of sarcoplasmic reticulum
A
triads
15
Q
Sliding filament model of contraction:
Thin filaments slide past thick filaments due to __________. Myosin head of thick filaments will bind to actin of the thin filaments forming _________. Bridges pull ________ filaments towards center of sarcomere. Greater _______ of thick and thin filaments.
A
cross bridge formation
cross bridges
thin
overlap
16
Q
Sliding filament model of contraction:
I bands ______. Sarcomeres ________. H-zones _______. A bands _________ but _________. Myofilaments _________. Myofibrils and muscle fibers _______.
A
shorten shorten disappear move closer together but length is the same shorten
17
Q
How do muscles contract?
Muscle fiber stimulated by ________. Generate and propagate ________. Increase in intracellular _______ due to changes in the __________. Includes ________ and _______ systems.
A
nerve ending electrical impulses calcium sarcoplasmic reticulum muscular and nervous
18
Q
motor neuron involved in voluntary function; site where axon of motor neuron meets with skeletal muscle fiber; consists of axon terminal, synaptic cleft, motor end plate
A
neuromuscular junction
19
Q
end of axon; synaptic vesicles (contain acetycholine)
A
axon terminal
20
Q
extracellular fluid; space in between sarcolemma and muscle fiber
A
synaptic cleft
21
Q
area of muscle fiber that makes up the neuromuscular junction (meets skeletal fiber); junctional folds (have ACh receptor)
A
motor end plate
22
Q
_________ gated channels open when membrane potential changes. ________ gated channels open when a chemical (ligand) binds.
A
voltage; chemically (ligand)
23
Q
_______ flows into the neuron because of levels intracellular and extracellular; more (intracellular/extracellular)
A
calcium; extracellular
24
Q
When calcium enters the neuron it causes ______ to fuse to the motor neuron
A
synaptic vesicle
25
_________ is released into synaptic cleft via ________
achtylcholine; exocytosis
26
What occurs at the junctional folds?
ACh binds to receptors
27
difference in electrical charge across plasma membrane
membrane potential
28
Resting membrane potential is _____ mV. The inside of the cell has an overall _____ charge relative to the outside.
-70; negative
29
Muscle and nerve cells are excitable - they receive stimuli and change in ________.
resting membrane potential
30
What makes sodium and potassium channels open? What kind of channels are they? ____ exits and ____ enters.
Acetylcholine; chemically gated; potassium; sodium
31
membrane potential becomes less negative during _____
depolarization
32
a depolarization of the sarcolemma that occurs at the motor end plate
end plate potential
33
triggers voltage gated sodium channels to open; more sodium enters in the area next to junctional folds (makes even less negative)
membrane potential
34
How depolarized does a membrane potential have to be for an action potential to occur?
-55 mV
35
large, transient depolarization event including polarity reversal, that is conducted along the plasma membrane of a muscle or nerve fiber; only generated if stimulus is strong enough
action potential
36
About how long does an action potential last?
1-2 milliseconds
37
Action potentials are a(n) _______ response which means that they have the same _______ and _______
all or none; amplitude and shape
38
another stimulus cannot cause another action potential to occur during this time because the electrical and ionic conditions have not been reestablished across the plasma membrane (resting membrane potential)
refractory period
39
sequence of events whereby action potential propagation leads to sliding of myofilaments (all events from stimulus to binding of myosin and actin)
excitation contraction coupling
40
Excitation contraction coupling:
Action potential goes down the ________ and changes shape of _______. This leads to the opening of _______ of the terminal cisternae, then goes into the ________.
T-tubules; voltage sensitive proteins; calcium; sarcoplasm
41
Tropomyosin and Troponin in excitation contraction coupling:
calcium will bind to ______ which is also bound to _______. Intracellular calcium is _______. _________ changes shape and pulls _________ away from myosin binding sites.
troponin; tropomyosin
higher
Troponin; tropomyosin
42
repetitive cyclical process of cross bridge formation, myosin propelling thin filaments toward M line and cross bridge detachment; requires ATP and calcium
contraction
43
What provides energy for contraction?
hydrolysis of ATP
44
What is responsible for hydrolysis of ATP?
myosin ATPase
45
Which step of contraction?
| ATP changed to ADP; myosin binds to actin; myosin head in energized state
step 1
46
Which step of contraction?
myosin is pulling thin filaments to the center of the sarcomere; the power working stroke; myosin heads in a low energy state because they have given away their energy
step 2
47
Which step of contraction?
cross bridge detachment; ATP attaches to myosin; the link between myosin and actin weakens; the myosin head detaches and the cross bridge breaks down
step 3
48
Which step of contraction?
myosin ATPase is changing ATP to ADP; myosin head is cocked (high energy state); this cycle will continue as long as ATP is available and Ca is bound to troponin
step 4
49
Relaxation- When the stimulus (AP from neuron) ceases:
______ regulated channels on axon close; _______ is no longer released into synaptic cleft; _____________ break down ACh in synaptic cleft; _______ is pumped back into the sarcoplasmic reticulum via active transport (actively transported into cisternae and sarcoplasm); calcium unbinds from _______; myosin binding sites on actin molecules are covered by _________ (actin and myosin no longer bind)
voltage; acetylcholine; acetylcholinesterase; calcium; troponin; tropomyosin
50
Calcium:
Causes release of _________ from axon terminal; released from _______; causes ________ to expose binding sites on actin; involved in _________ (pumped back into ________); necessary for _______ and _______
```
Ach
sarcoplasmic reticulum
troponin
relaxation
relaxation and contraction
```
51
muscles stiffen after death due to change in calcium permeability and lack of ATP synthesis after death
rigor mortis
52
autoimmune disease resulting in fewer ACh receptors; symptoms include drooping eyelids, difficulty swallowing and talking, general muscle weakness
myasthenia gravis
53
a motor neuron and all the muscle fibers it innervates; change force and tension of muscle; stimulus strength and frequency
motor unit
54
type of muscle contraction in which the muscle length changes (includes concentric and eccentric contractions)
isotonic
55
type of muscle contraction in which the muscle shortens when it contracts; ex. biceps curl - flexing
concentric
56
type of muscle contraction in which the muscle lengthens when it contracts (moving up a hill); usually setting up for a concentric contraction; ex. biceps curl - extending
eccentric
57
type of muscle contraction in which the muscle length doesn't change because the load is heavier than the amount of tension the muscle can generate
isometric
58
a motor unit's response to a single stimulus from the motor neuron
muscle twitch
59
graph showing the contractile activity of a muscle
myogram
60
What are the 3 phases of a muscle twitch?
1. latent period (latency)
2. contraction
3. relaxation
61
phase of muscle twitch:
| all the processes that occur from a stimulus to the binding of actin and myosin
latent period (latency)
62
phase of muscle twitch:
| myosin heads pull thin filaments toward the center; tension-power stroke
contraction
63
phase of muscle twitch:
| actylcholinesterase, calcium pumped into sarcoplasmic reticulum
relaxation
64
includes changes in frequency of stimulation and changes in strength
graded muscle responses
65
a change in force of contraction depending on the frequency of the stimulus
wave or temporal summation
66
wave or temporal summation:
| decreased relaxation time between consecutive twitches; some of the calcium is being pumped back
incomplete (unfused) tetanus
67
wave or temporal summation:
| no relaxation; maximum tension
complete (fused) tetanus
68
force of contraction will be greater as stimulus strength increases because more motor units are recruited
multiple motor unit summation
69
multiple motor unit summation:
| produce no observable contractions
subthreshold stimuli
70
multiple motor unit summation:
| stimulus required for observable contraction
threshold stimulus
71
multiple motor unit summation:
| the strongest stimulus that can increase contractile force
maximal stimulus
72
Which threshold is recruited first?
lowest
73
bacterium (clostridium tetani); causes sustained muscle contraction; starts in jaw and progresses to other muscles
tetanus "lockjaw"
74
Each cross bridge in muscle contraction uses _____ ATP/sec. An active muscle fiber needs _______ trillion ATP/sec.
100
| 600
75
What are the 3 places that energy can be stored?
1. ATP stores
2. Creatine phosphate
3. Glycogen stores (in glycosomes)
76
creatine phosphate + ADP = ?
creatine + ATP
77
anaerobic/aerobic metabolic pathways are a part of _____ stores
glycogen
78
What are the 2 steps of anaerobic pathways?
1. glycolosis (glucose converted to pyretic acid = 2 ATP)
| 2. pyruvic acid converted to lactic acid
79
What are the pros of anaerobic pathways?
fast process; can occur without oxygen
80
What are the cons of anaerobic pathways?
lactic acid buildup (lowers body's pH if used for long periods of time); lots of glucose needed for a small amount of ATP
81
accounts for 98% of energy when exercising
aerobic respiration
82
What are the 3 steps of aerobic respiration?
1. glycolysis
2. kreb's cycle
3. oxidative phosphorylation
83
occurs in mitochondria; pyretic acid converted to acetyl coA; produces ATP; produces coenzymes NADH and FADH2; 1 glucose = 2 ATP
kreb's cycle
84
coenzymes give up electrons; electrons combine with water; energy from electrons attaches phosphorus group to ATP
oxidative phosphorylation
85
What are the pros of aerobic respiration?
yields lots of ATP for each glucose; provides energy fro hours of activity; other acids can enter the cycle and yield energy
86
What are the cons of aerobic respiration?
slow process; needs oxygen
87
In short duration exercise, _______ stored in muscles is used first. ATP is formed from _______ and ______. Glycogen stored in muscles is broken down to glucose which is _______ to generate _______ (anaerobic pathway). Uses both pathways at the same time (________ process). Relies on the same process for ________ exercise.
ATP; creatine phosphate and ADP; oxidized; ATP; continual; long duration
88
What are the 2 types of muscle fibers classified according to speed of contraction?
fast and slow muscle fibers
89
What are the 2 types of muscle fibers classified according to the pathway for ATP formation?
oxidative and glycolitic
90
What are the 3 types of muscle fibers classified according to a combination of speed and pathway?
slow oxidative fibers
fast oxidative fibers
fast glycolytic fibers
91
How many of the muscle fiber types will a motor unit have?
one
92
What would happen if a stimulus intensity exceeds the maximum?
force of contraction would stay the same
93
What are the 4 ways that marathon runners get their energy?
1. ATP stored
2. Creatine phosphate
3. Glycolysis
4. ATP via ETC
94
What are the effects of excessive muscle contraction?
muscle fatigue; blood shunted from peripheral systems (puke, lose bowels); recovery
95
Muscle fatigue:
What results in an ionic imbalance?
What causes lactic acid buildup?
What is the least likely cause of muscle fatigue and why?
1. RMP isn't established soon enough
2. lower pH
3. ATP depletion; muscles never run out of ATP
96
What happens during the recovery stage of excessive muscle contraction?
Lactic acid yields _______ and ________. ______ and _______ stores are replenished.
pyruvic acid; glucose
| Glycogen; ATP
97
Smooth muscle is innervated by _____ nerve fibers, while skeletal muscle is innervated by ______.
autonomic; motor neurons
98
swelling in nerve fibers; release transmitters into synaptic cleft (narrow synaptic cleft for skeletal)
varicosities
99
In smooth muscle, actin and myosin are arranged in a _______ pattern (no sarcomere); when smooth muscle contracts, it causes the fiber to _______
diagonal; bunch up
100
Smooth muscle can contract without _____ from the nervous system
stimulus
101
In smooth muscle there is no presence of ______ and site of ______
t-tubules; invagination
102
infoldings of plasma membrane with calcium channels
calveolae
103
Smooth muscle is the site of calcium ________; _________ in the cytosol; when intracellular calcium levels rise ________ will bind to an enzyme and activate ________
regulation; calmodulin; calmodulin; myosin
104
What are the 3 main differences of smooth muscle contraction from skeletal muscle contraction?
1. Ca influx initiale action potential (can come from extracellular fluid or sarcoplasmic reticulum)
2. action potential spread between cells via gap junctions
3. Ca binds to calmodulin
105
What are 4 similarities of smooth muscle and skeletal muscle contraction?
1. actin/myosin interact via sliding filament mechanism
2. need rise in intracellular Ca for contraction
3. ATP needed for sliding of thin filament along thick filament
4. relaxation when Ca pumped out of cell
106
Skeletal muscle has the presence of _____ and site of ______. It is a site of calcium regulation in which ______ attaches to actin containing thin filaments
T-tubules
invagination
troponin
107
What are the 3 functions of the nervous system?
1. sensory
2. integration
3. motor output
108
```
function of nervous system:
sensory input (changes in internal and external environment)
```
sensory
109
```
function of nervous system:
process/interpret
```
integration
110
```
function of nervous system:
activate effectors (muscles or glands); sent to effectors to elicit a response
```
motor output
111
What are the 2 divisions of the nervous system?
1. central NS
| 2. peripheral NS
112
contains the brain and spinal cord
CNS
113
contains the cranial and spinal nerves
PNS
114
What are the 2 divisions of the PNS and what do they do?
sensory (affarent) division - impulses to CNS
| motor (efferent) division - impulses from CNS
115
What are the 3 impulse types classified under the sensory afferent division of the PNS?
1. special senses
2. somatic sensory fibers
3. visceral sensory fibers
116
impulses from eyes, ears, nose, and tongue (typically cranial nerves)
special senses
117
impulses from skin, skeletal muscles, joints (mainly spinal nerves); transmit pain, changes in temperature, and pressure
somatic sensory fibers
118
impulses from organs; transmit impulses from organs in ventral cavity (mainly spinal nerves); detect pain, pressure, changes in temperature
visceral sensory fibers
119
What are the 2 divisions of the motor (efferent) division of the PNS?
1. somatic NS
| 2. autonomic NS
120
somatic motor neurons; voluntary nervous system; sleep paralysis
somatic nervous system
121
interruption to REM sleep but somatic NS is asleep
sleep paralysis
122
visceral motor neurons; involuntary; from CNS to cardiac cells, smooth muscle, and glands
autonomic NS
123
What are the 2 divisions of the autonomic NS?
1. sympathetic NS
| 2. parasympathetic NS
124
speeds up heart rate, breathing, sweating; dilation of airways to increase oxygen to tissues; fight or flight
sympathetic NS
125
directs vital activities; rest and digest
parasympathetic NS
126
What are the 2 types of nervous cells?
1. neurons
| 2. neuroglia (surrounding)
127
nervous cells require a constant supply of ______
oxygen (can only last 5 minutes without)
128
clusters of cell bodies in the CNS
nuclei
129
clusters of nerve cell bodies in the PNS
ganglia
130
receptive region of the neuron (branched)
dendrites
131
slender process of the neuron that generates and conducts and action potential and can branch and have many axon terminals
axon
132
cone shaped region where the axon ends (where action potentials are generated because there are lots of Na channels)
axon hillock
133
branches of the axons
axon collaterals
134
branches at the end of an axon
terminal branches
135
knob endings of axon (also called synaptic knobs or buttons)
axon terminal
136
cell membrane surrounding an axon
axolemma
137
protects, insulates neurons, and aids in the speed of conduction
myelin sheath
138
The myelin sheath is formed by _____ in the PNS and _____ in the CNS
schwann cells
| oligodendrocytes
139
gaps in the myelin sheath
nodes of ranvier
140
neurons are myelinated; lots of layers of phospholipid bilayers
white matter
141
cell bodies or axons are unmyelinated
gray matter
142
What does the structural classification of neurons refer to and what are the 3 structural classifications?
number of processes; unipolar, bipolar, multipolar
143
What does the functional classification of neurons refer to?
direction of nerve impulse relative to CNS
144
single short processes; mostly sensory neurons; found mainly in PNS; distal (peripheral) process associated with sensory receptors
unipolar neurons
145
two processes - axon and dendrite; mostly sensory neurons; found in some special sense organs (retina of eye); rare in the body
bipolar neurons
146
3 or more processes - axon and dendrites; most are interneurons; some are motor neurons; most common type in CNS
multipolar neurons
147
What are the 3 functional classifications of neurons?
1. sensory (afferent) neurons
2. motor (efferent) neurons
3. interneurons
148
impulses from sensory receptor to CNS; most unipolar; some bipolar
sensory (afferent) neurons
149
impulses from CNS to effectors (muscles and glands); all multipolar
motor (efferent) neurons
150
between sensory and motor neurons (can transmit both ways); most multipolar; 99% of neurons in body within CNS
interneurons
151
support/protect neuron; speed up nerve impulse conduction
neuroglia (glial cells)
152
What are the 4 types of neuroglia in the CNS?
1. oligodendrocytes
2. astrocytes
3. microglia
4. ependymal cells
153
functional equivalent of schwann cells; wrap around multiple neurons; purpose is for rapid impulse transmission
oligodendrocytes
154
star cell; control chemical environment; wrap around capillaries; neuron is in constant contact with its nutrient supply; control exchange of substances between neurons and blood (around capillaries and neurons); can sop up extra potassium ions and neurotransmitters; blood/brain barrier
astrocytes
155
barrier between capillaries feeding the brain and extracellular fluid of brain (tight junctions regulate substances that enter the brain)
blood/brain barrier
156
phagocytize microorganisms/dead neurons; immune cells cannot enter CNS
microglia
157
form permeable barrier between brain/spinal cord and cerebrospinal fluid (CSF); cilia help circulate CSF
ependymal cells
158
What are the 2 types of neuroglia in the PNS?
1. satellite cells
| 2. schwann cells
159
function like astrocytes in CNS; surrounds cell body; also surrounds capillaries
satellite cells
160
wrap around axon and form myelin sheath; nerves are white in color due to myelin
schwann cells
161
Myelination speeds __________ due to insulating property of myelin sheath and nodes of ranvier; salutatory conduction (action potential and depolarization)
impulse conduction
162
myelinated long processes
PNS - nerves
CNS - tracts
white matter
163
unmyelinated and cell bodies
PNS - ganglia (cluster of cell bodies)
CNS - nuclei
gray matter
164
DCT covering peripheral nerves
epineurium
165
DCT at fascicles (bundles of nerve fibers aka axons)
perineurium
166
DCT at neuron processes (around individual axons - all DCT)
endometrium
167
autoimmune disease attacks myelin sheath; conversion of myelin sheath into sclerosis (hardened lesions - scar tissue); reduces rate of nerve transmission; symptoms (blindness, weakness/paralysis, speech disturbances); can slow progression but not cure; can go into remission (when body produces more sodium channels; increase nerve impulse transmission)
multiple sclerosis
168
junction between 2 neurons or neuron and effector
synapse
169
conducts impulses towards synapse
presynaptic neuron
170
conducts impulse away from synapse
postsynaptic neuron
171
ion channel with no gate, always open
leakage channels
172
ion channel where part of the protein functions as a gate
gated channels
173
ion channel that opens when appropriate chemical attaches to the protein
chemically (ligand) gate
174
ion channel that opens and closes in response to changes in membrane potential
voltage gated channels
175
ion channel that opens in response to physical deformation of membrane
mechanically gated channels
176
Na+/K+ pumps (active transport) maintains the _________. __ Na+ out for ever ____ K+ in
RMP
| 3 for 2
177
short lived, localized changes in membrane potential; can be depolarizations or hyperpolarizations; decrease in magnitude with distance; vary with stimulus strength
graded potentials
178
local graded depolarization events; NT bind to receptors on dendrites or cell body of postsynaptic neuron; opens Na+ and K+ channels ---> net depolarizations; if current strong enough to spread through cell body to axon hillock; may trigger action potential
excitatory post-synaptic potentials (EPSPs)
179
local graded hyper polarization events; NT bind to recepters on dendrites or cell body of postsynaptic neuron; opens Cl- or K+ channels ----> hyperpolarization; if current is strong enough to spread through the cell body to the axon hillock, it reduces the chance of an axon generating an action potential
inhibitory post-synaptic potentials (IPSPs)
180
post synaptic neuron stimulated (or inhibited) simultaneously by large number of presynaptic axon terminals; resulting EPSPs and IPSPs add together
spatial summation
181
postsynaptic neuron stimulated (or inhibited) in quick succession by one or more; resulting EPSPs or IPSPs ad together
temporal summation
182
Voltage-gated channels located at ________. Graded potentials spreading to axon hillock cause channels to _____. If ion movement causes depolarization to threshold, it triggers _______
axon hillock
open
action potential
183
membrane potential becomes less negative than resting potential
depolarization
184
negative membrane potential is reestablished
repolarized
185
membrane potential becomes more negative than resting potential
hyperpolarized
186
closed when cell is in resting state; open when plasma membrane depolarizes
voltage sensitive activation gate; K+ activation gate
187
open when cell is in resting state; slowly close soon after activation gate opens
inactivation gate
188
where axon joins cell body; enough Na+ ions have to reach AH to initiate an AP
axon hillock
189
responsible for generation and propagation
VR Na+/VR K+
190
neuron cannot respond to another stimulus; period between opening of Na+ channels until Na+ channels reset to resting state
absolute refractory period
191
only strong stimulus can stimulate another action potential; during depolarization Na+ channels in resting state, some K+ channels still open
relative refractory period
