U2- Muscular System (Histology/ Contraction/ Metabolism) Flashcards
(124 cards)
1
Q
three universal chara. of muscles
A
excitability
contractility
elasticity
2
Q
functions
A
support/ posture
temp homeostasis
regulation of dig. passage
protection of soft tissue
3
Q
skeletal muscle
A
striated + voluntary
connected to bones
composed of muscular tissue + fibrous CT
4
Q
muscular tissue
A
actin and myosin
5
Q
Protective layers in muscle CT
A
endomysium
perimysium
epimysium
6
Q
endomysium
A
surr. e/ fiber
7
Q
perimysium
A
bundles fibers into fasicles
8
Q
epimysium
A
surr. entire muscle
9
Q
myofilaments
A
have actin + cross-bridging binding sites
3 types, thick, thin and elastic
10
Q
thick myofilaments
A
made of myosin (golf club head structure)
intertwined shaft tail
11
Q
thin myofilaments
A
made of fibrous + globular actin
G binds to head of mysoin
when relaxed tropomyosin blocks active site
(allows sliding)
12
Q
tropomyosin
A
binds to actin
13
Q
elastic myofilament
A
made of protein titin
stabilizes thick fila.
prevents overstretching
14
Q
striations
A
A + I bands
15
Q
A bands
A
dark
where thick and think myofil. overlap
middle = H Band
ONLY thick
16
Q
I bands
A
light
located by Z disk
anchor point
when shrink together they shorted muscle during contra.
17
Q
sarcolemma
A
plasma mem. of muscle fibers
polarized
18
Q
sarcoplasm
A
cytoplasm in btw muscle fibers
19
Q
satellite cells
A
unspecialized cells
btw muscle fibers and endomysium
20
Q
myofibril
A
arranged area of musc. fibers
section from z disk to z disk
21
Q
myoblast
A
stem cell for muscl
divide + connect
22
Q
nerve stim. and muscle contraction relationship
A
nerve stim= musc. contrac.
23
Q
motor neurons
A
located in spinal cord and brain stem
axons lead to musc.
1 neuron= 1 motor fiber
24
Q
motor unit
A
neuron and motor fiber
25
neuromuscular junction
type of synapse
| nerve fiber meets muscle cell (myocyte)
26
synapse
nerve fiber meets receptor cell
27
synaptic cleft
separates axon terminal + musc. fiber
28
axon term.
end of e/ nerve fiber
| contains synaptic vesicle
29
synaptic vesicle
filled w/ neurotrans. chem.
| excrete w/ exocytosis
30
electrical potential
"voltage"
| diff in charge btw 2 points
31
voltage
resting mem. potential
| maintained by Na- k pump
32
phases of muscle behavior
1-excitation
2- excitation-contraction coupling
3- contraction
4- relaxation
33
muscle tone
partial contraction
| prepares musc. for action
34
endpoint of contraction
contraction stops when thick filam. reach z disks
| brief and weak
35
endpoint of relaxation
stretching stops when no overlap btw thick and thin filaments.
myosin heads unable to attach to anything
36
myogram
chart for timing and strength of musc. contraction
37
threshold
min voltage necessary generate action pot. in fiber
38
latent period
delay btw threshold and twitch
39
contraction phase
musc. produces tension + moves object
| only when at max elongation (rubber band)
40
factors affecting strength of twitch
temp
intensity of stim.
frequency of stim.
41
twitch temp
if warm, enzymes wrk faster
42
twitch stim frequency
fast frequency- strong and quick
| slow frequency- weak and long
43
twitch stim intensity
higher volt- more excitability- more motor units involved
44
recruitment
chain of motor units are involved
45
temporal summation
stimulus' piggyback on e/o
causes incomplete tetanus
inc. intensity of twitch
46
complete tetanus
not normal in bio functions
| twitches fuse into single contraction
47
isometric contraction
muscle tension changes w/ same length
contraction at cellular lvl
energy absorb. by elastic
NO MVMNT
48
isotonic contraction types
eccentric and concentric
49
isotonic contraction
contraction w/ change in length w/ same tension
| object lifiting has opposite force
50
eccentric contraction
isotonic
| lengthens + maintains tension
51
concentric contraction
shortens and maintains tension
52
anaerobic fermentation
short term energy
cell produces ATP w/out O2
generates lactic acid
53
aerobic respiration
long term energy
| cell produces ATP w/ continual O2
54
fast-twitch muscles
white color
energy from anaerobic (produces ATP faster)
fast absorption and releasement of Ca
55
slow-twitch muscles
red color
energy from aerobic respir.
slow Ca absorption and releasement
56
cardiac muscle functions
contract w/ reg rhythm
involuntary
resistant to fatigue (aerboic respir.)
long contractions
57
cardiac muscle structure
striated and branched (intercalated discs)
larger T-tubules
enlarged mitochondria
no need for outside nervous stim.
58
smooth muscle function
drives food through dig. system (peristalsis)
dilate + constrict blood vessels
maintains BP
59
smooth muscle structure
no striations
ATP from aerobic respir.
latch bridge mechanism
involuntary
60
visceral muscle
"single-unit smooth muscl"
cells connected w/ gap junction
directly stim e/o and act as one unit
61
smooth musc. ways of excitation
autonomic nerve fibers
neurotransmitters
contraction / relaxation (slow!!)
62
smooth muscle contraction process
```
Ca binds to calmodulin
activates myosin light chain kinase
adds ph grp to regul. protein
hydrolases ATP
pwr/ recovery strokes occur
```
63
skeletal muscle phase 1- excitation
1-nerve signal reaches neuro-m junction,
opens Ca voltage-gated channel, Ca enters cell
2- Ca stim. release ACh into synaptic cleft
3- Ach diffuses and binds receptors on sarcolemma
4- Na flows into cell making sarcolem. less negative (depolarization) and K flows out changing sarclem. to higher negative again (repolarization)
5- change in charge of resting mem. poten. = Action. poten.
64
skeletal muscle phase 2- excitation-contraction coupling
1- Action potential charge reaches t tubules + travels down
2- action pot. opens gated channels in t tubules, which opens Ca channels
3- Ca binds to troponin of thin filam
4- tropomysoin/troponin changes shape, exposes active site on actin filam. for bonding
5- can now connet to myosin heads of thick filam.
65
skeletal muscle phase 3- Contraction
"sliding filament model"
1- ADP + Ph energize head into high energy position
2- head binds active site on thin fila.
forms cross-bridge btw myosin and actin
3- myosin releases ADP + Ph upon binding, moves into low energy position, bringing thin filam. along w/
"power stroke"
stays bound to actin until released by ATP
4- ATP binds to myosin, head releases from actin, and returns to recovery stroke in high energy position to rebind farther down thin filament
66
skeletal muscle phase 4- Relaxation
1- nerve signals stop reaching neuro-musc. junction
ACh not released
2- stimulation of fiber ceases bc ACh broken down
3- Ca dissociated from troponin not replaced
4- tropomyosin blocks active site on thin filament,
muscle loses tension
67
muscle tone
partial contraction
prepares musc. for action
consumes contin. energy
68
myogram
chart displays timing and strength of musc. contraction
69
threshold
minim. voltage necessary generate action pot. in fiber
70
maximum threshold
twitch occurs
71
contraction phase
musc. produces tension + moves object (load)
72
factors that affect strength of twitch
how stretched before stim.
temp of muscl. (if warm enzymes wrk faster)
stim frequency
together= strong and quick
apart= weak and long
intensity of stim
higher volt= mre excitability= mre motor units involved
73
recruitment
multiple motor units involved in excitation
74
temporal summation
stimulus overlap e/o before muscle can recover
causes incomplete tetanus
inc. intensity of twitch
75
incomplete tetanus
caused by temporal summation
76
complete tetanus
twitch turns into single contraction
| not normal human process
77
isometric contraction
musc. changes tenses
length is constant
maintains joint stability and acts as structure
Ex. wall sit
78
isotonic contraction
muscle tense constant
length changes
Ex. lift barbell
eccentric v. concentric
79
eccentric contraction
lengths w/ same tension
80
concentric contraction
shortens w/ same tension
81
anaerobic fermentation
```
ATP source
without O2
generates lactic acid
short term energy
used ATP + phosphate
```
82
aerobic respiration
uses O2
long term energy
produces more ATP
uses glucose + fatty acids
83
Activity level- Rest
fatty acids carboxylized
| ATP + Glycogen made
84
Activity level- Moderate
glycogen consumed
makes lots of ATP
aerobic
85
Activity level- Strenuous
lactic acid produced
demand for O2 greater than supply
makes little ATP
anaerobic
86
fatigue factors
K plus accumulation
fuel depletion
electrolyte loss
87
fuel depletion
no mol. to synthesize ATP
| energy demand> energy supply
88
K plus accumulation
lowers mem. potential
| makes less excitable
89
excess postexercise O2 consumption (EPOC)
diff. btw elevated heart rate at end of exercise and normal heart rate
O2 needed regen. ATP aerobically
convert lactic acid to glucose
90
slow twitch
```
red color
"slow oxidative"
maintain posture
fatigue resistant
aerobic resp.
```
91
slow twitch composition
blood capillaries
myoglobin
mitochondria
92
fast twitch
```
anaerobic ferm.
white color
"fast glycolytic"
fast ATP hydrolysis
fatigue quick
```
93
fast twitch composition
high con. of glycogen + phosphate
94
cardiac muscle function
invol.
contract w/ reg rhythm
resistant to fatigue (aerobic resp.)
95
cardiac muscle structure
striated, branched (intercalated discs)
not need outside nervous stim.
enlarged mitochon.
96
smooth musc. structure
no striations
not always innervated
if so- are involuntary
few T-tubules
97
smooth muscle functions
peristalsis
dilate/ contract blood vessels + airway
maintain BP
98
hypertrophy
cells divide and grow
| opposite of hypo trophy
99
latch-bridge mechanism
in smooth musc.
| maintains tonic concentration (muscle tone)
100
smooth muscle- visceral muscle
single unit smooth muscle
cells connect w/ gap junction
directly stim e/ o/ -act as one unit
101
smooth muscle-ways of excitation
autonomic nerve fibers
| neurotransmitters
102
Smooth musc- contraction and relaxation
slow process
Ca binds to calmodulin
adds ph grp to 2 proteins
hydrolysis ATP
103
the accumulation of blank ions during short exercise lowers mem. potential of the muscles and makes it less excitable
potassium
104
calcium channel pockets in the sarcolemma of smooth musc. cell pockets
caveolae
105
thickened notched ends of cardiac musc. cell w/ gap jun.
intercalated discs
106
swelling along length of nerve fiber, innervates smooth musc.
varicosities
107
regulatory protein in smooth musc. that binds to Ca and activates myosin light-chain kinase, replaces troponin in smooth musc., binds to Ca
Calmondium
108
what protein activates myosin light-chain kinase
Calmondium
109
what protein replaces troponin in smooth muscle
calmondium
110
binds to calcium in terminal cisternae
calsequestrin
111
charac. of voluntary relaxation
stop stim.
no calcitrol
Ca transported to sarcoplasmic reticulum
breaks bond w/ troponin
(tropomyosin covers active site)
112
charac. of involuntary relaxation
lack Ca
| no ATP
113
all of none principle
if at threshold, all fibers contract
114
tension
position musc. in before contraction
115
length-tension relat.
optimum overlap of myofilaments
| strength varies w/ amnt tension before contraction
116
contraction switch factors
strength and intensity
117
contraction strength
happens by motor unit recruitment
118
contraction intensity
how many motor units are involved
119
energy currency
```
ATP
Ph andGTP
required for contraction
glycogen
creatine phosphate
```
120
ATP generation
oxidative or fermentation
121
glycogen as energy
if not used turns to fat
| stores longer in aerobic resp.
122
creatine phosphate as energy
reversible rxn
ATP needs be constant
made w/ ATP and creatine
123
strength exercise
anaerobic ferm.
hypertrophy
muscl. cells build more myofilam.
124
endurance exercise
can convert intermediate fibers
inc. blood supply
aerobic resp.
