chpt 8: muscular physiology Flashcards
1
Q
contract meaning
A
muscles can develop tension and shorten
2
Q
which muscle is voluntary + striated
A
skeletal
3
Q
which muscle is involuntary + striated
A
cardiac
4
Q
which muscle is involuntary + unstraited
A
smooth
5
Q
muscle covering
A
- epimysium
- perimysium
- endomysium
6
Q
epimysium covers
A
the whole muscle
7
Q
what muscle covering covers the muscle bundles/ fascicles
A
perimysium
8
Q
endomysium covers
A
individual muscle fibers/ cells
9
Q
interaction between acting and myosin that bring abt muscle contraction by means of sliding filament mechanism is known as
A
forming cross bridges
10
Q
what is extended from thick filament in 6 directions towards the thin filament
A
cross bridges / myosin heads
11
Q
when does cross bridge change shape causing the act to move inwards
A
powers stroke
12
Q
twitch summation is similar to
A
temporal summation
13
Q
why is twitch summation possible
A
- if a muscle fiber is restimulated before it has completely relaxed
- second ap comes in before rest p is achieved , summation occurs
14
Q
sustained elevation of cytosolic calcium causes
A
twitch summation
15
Q
when occurs if the muscle is stimulated so rapidly it does have a chance to relax between stimuli
A
tetanus/ muscle contraction
16
Q
how much longer is tetanus than twitch summation
A
3-4x
17
Q
excitation-contraction coupling is
A
series of events linking muscle excitation to muscle contraction
18
Q
when does muscle excitation occur
A
in the presence of ap
19
Q
sliding filament mechanism results in
A
muscle contraction
20
Q
what is dynamic contraction
A
- muscle shortens to accommodate to change of length of muscle and joint by the force exerted
21
Q
what type of contractions occurs when there is no change in body position cuz the load is too heavy and produces an increase in muscle tension
A
static contraction
22
Q
what muscle makes up the muscular sys
A
skeletal muscle
23
Q
what is skeletal muscle innervated by
A
alpha motor neurons
24
Q
muscle fiber aka myofibril =
A
muscle cell / contractile
25
what is the contractile element of muscle fiber
myofibril
26
sarcolemma is the
plasma membrane of muscle fiber
27
number of nucleus and mitochondria in muscle fiber
numerous
28
muscle fiber organelle that has lateral sacs called terminal cisternae is
SR
29
what stores Ca in muscles fibers
lateral sacs called terminal cisternae
30
t tubule structure
dips in sarcolemma at junctions of A and I bands
| surrounds SR
31
what structure causes the release of Ca
t tubule
32
contractile proteins
- myosin
| - actin
33
tropomyosin and troponin make up
- regulatory proteins
34
accessory proteins are
- titin
| - nebulin
35
what is the motor protein whose function is action-based motility
myosin
36
what do the two regions of the head of myosin bind to
actin and atp
37
what contractile protein is the component of thick filament
myosin
38
actin has
myosin binding sites
39
actin, troponin and tropomyosin make up
thin filament
40
which thread-like regulatory protein blocks myosin-binding sites on actin molecule
tropomyosin
41
what can bind to troponin
- tropomyosin
- Ca
- actin
42
function of troponin
- binds to actin
43
which molecule is found every 7 molecules
- troponin
44
function of troponin when its not binded with ca
stabilize tropomyosin
45
what protein is the largest and made of 30k aminio acids
titin
46
location of titin
run through myosin
47
which accessory protein is responsible for stabilizing myosin and muscle elasticity
titin
48
function of nebulin
stabilize actin
49
structures of muscle fiber
- sacomere
- a band
- i band
- z line
- m line
- h zone
50
sarcomere structure
b/w 2 z lines
51
sarcomere function
1 unit of contraction, function unit
52
how does one grow
adding more sarcomeres
53
m line function
myosin emerges from here/ is help in place
54
what is found at the H zone
myosin only
55
the function of a and i bands
give striated apperance
56
what zone has actin and myosin
a band
57
what band has actin only
I band
58
function of z line
cover enter length of sarcomere
- contain actin
mark ends of sarcomere
59
what happens when there is a defective protein holding the z line
muscular dystrophy
60
what causes muscles contractions
- NMJ (ACh) / execution of ap
| - Ca2+ influx
61
DHP receptors (voltage gated) belong to
T tubules
62
what causes the release of Ca from SR
spread of AP down a T tubule
63
what causes Ca2+ influx
- released when ACh binds to enter muscle and triggers ap which causes releases Ca2+
64
process of muscle contraction
- ca2+ binds to troponin
- troponin removes tropomyosin from actin
- actin = free to bind to myosin
- forms cross bridge
- pulls sarcomere towards m lines
- sarcomeres shorten
- MUSCLE CONTRACTION
65
how does the sliding filament aka contractile process start
starts w an increase in Ca2+
66
z lines during contraction
closerer together so sarcomere = short
67
h and I zone in lenght during contraction
short
68
what remains the same during filament aka contractile process
m line and a band
69
main function of filament aka contractile process
pulls sarcomere and actin inward
70
does myosin move during contraction
no
71
role of atp during contraction
- binds to myosin
| - creates a power stroke
72
when and where does atp break into adp + p1
breaks down on myosin cross bridge before actin links
73
what is released DURING power stroke
Pi
74
when is ADP released
AFTER powerstroke
75
what signals new atp and release of actin and myosin
release of ADP/ sliding filament/shortening of sarcomere
76
waht happens when all the Ca2+ leaves the cell and ACh breaks down
relaxation
77
how does rigor mortis occur
metabolism stops, no atp is produced, Ca2+ can tgp back, myosin heads are stuck `
78
what is there an increase of during rigor mortis
- adp, lactic acid and K
79
muscle/ peripheral fatigue
- prevents muscles from reaching a point where atp cant be produced
- muscle is calming down
80
what is it called when the CNS no longer adequately activates motor neurons
- central fatigue
81
what is neuromuscular fatigue
- an inability of active motor neurons to synthesize Ach fast enough to sustain ap
82
brief, weak contraction that is a single ap is called
a twitch
83
a twitch is used in
motor unit
84
what causes infectious tetanus
- bacteria called clostridium tetanus which inhibits GABA
85
what attacks NMJ and causes muscle spasm
infectious tetanus
86
what organ works before optimal length
heart
87
optimal length is the and why
the best place for a contraction to occur , has many cross bridges
88
what happens when the muscle is stretched to the max
- contraction cant occur
| - decreased tenison
89
when do we have a decrease Ca release and less tension
muscle is short
90
types of isotonic contraction
- concentric contraction
| - eccentric contraction
91
what kind of contraction is it when there is a creation of tension/ muscle movement and a load is being moved
- isotonic contraction
92
when is the force produced the same
isotonic contraction
93
concentric contraction is
dynamic produces tension during shortening
| - moving a load towards centre of body
94
what is a normal contraction
concentric contraction
95
what contraction is dynamic and produces tension while lengthening
eccentric contraction
96
which contraction is slow and can cause injury
eccentric contraction
97
what contraction is off-centered/ moving away from the body
eccentric contraction
98
isometric contraction is
- length is unchanged, no motion
| - static
99
yoga and planking / creating force that doesnt move a load in an example of
isometric contraction
100
energy sources of contraction
- glucose/ cell resp
- creatinine phosphate
- fatty acids
- oxidative phosphorylation (citric acid + etc)
- glycolytic
101
significance of creatine phosphate in energy sources of contraction
- gives phosphate to adp
| - makes people stronger
102
how do you convert fatty acids into energy
- working out
| - using O2 + fatty acids in ETC
103
which energy source produces 36 atp
oxidative
104
where is myoglobin, mitochondria, O2 and bv abundant
oxidative
105
myoglobin function
- bind to O2
| - dark aka red fibers
106
which energy source production process causes more fatigue
- glycolytic
107
location of white fibers (less bv and O2) + mitocondra
glycolytic
108
how many atp does glycolytic/ glycoysis produce
2
109
muscles fibers are based off of
energy sources
110
which type of twitch is used daily for posture and walking
slow- oxidative (type 1)
111
what neuron innverates slow- oxidative (type 1)
a2 motor neurons
112
slow- oxidative (type 1) have ___ contractile cycles
less
113
what type of twitch splits atp more and has more contractile cycles, and pump Ca2 back to SR faster
fast (tye 2)
114
when is fast (tye 2) used
- piano, violin
115
a1 motor neruons innervate
fast (tye 2)
116
which motor neurons are bigger
a1 motor neurons
117
what muscle receptor is involved in stretch reflex
muscle spindle/ intra- fusal fiber
118
larger muscle/ extra fusal fiber forms
NMJ
119
location of muscle spindle/ intra- fusal fiber
within larger muscle/ extra fusal fiber
120
what does the alpha motor neuron innervate/ trigger
larger muscle/ extra fusal fiber
121
what efferent neuron innervates the muscle spindle/ intra- fusal fiber
gamma motor neuron
122
gamma motor neuron function
make receptor work
123
name of afferent neurons that terminate on muscle spindle/ intra- fusal fiber and make up muscle spindle receptors
- primary (annulosprial) endings
| - secondary (flower-spray) endings
124
what are - primary (annulosprial) endings
- secondary (flower-spray) endings
activated by
stretch
125
secondary (flower-spray) endings form the ___ end
contractile end
126
which afferent neuron endings is noncontractile region
- primary (annulosprial) endings
127
- primary (annulosprial) endings function
detect changes in the length of fibers and speed that it occurs at
128
which ending is sensitive too ONLY changes in length
secondary (flower-spray) endings
129
what allows muscle fibers to stretch
gamma motor neuron
130
golgi tendon organ location
tendons of muscles
131
golgi tendon organ
- provides messages or force created about how much a muscle can endure
- provides relfex but doesnt intiate
- tells us when smt is heavy
- protects muscles
132
what tightens when extrafusal muscle contracts
- CT
133
what happens when the golgi tendon organ contract
- afferent neuron fires
134
what do smooth muscles lack
- z line
- sarcomeres
- troponin
- t tubules
135
do smooth muscles have poorly developed SRs
yes
136
where is Ca taken from in smooth muscles
- mostly ECf
| - and SR
137
what anchors actin filaments in smooth muscles
dense body proteins
138
the function of Ca + calmodulin in smooth muscle contraction
excite myosin light chain kinase
139
what triggers atp to bind to myosin heads and excite myopsin to bind to actin forming a cross brigde
excited myosin light chain kinase
140
what is the advantage of using smooth muscle contraction
uses less atp
141
multiunit smooth muscles are
neurogenic
142
structures located in smooth muscles
- actin
- myosin
- tropomyosin
- intermediate filament
143
neurogenic meaning
- neuron must excite each muscle
144
location of varicosity bundles
on neurons
145
varicosity function
contain neurotransmitters
146
location of multiunit smooth muscles
- ciliary muscles
- iris
- walls of large bv
147
which type of smooth muscle is activated together through gap junctions therefore syncytium
- single unit/ visceral smooth muscles
148
meaning of syncytium
functioning electrically and mechanically as a unit
149
which smooth muscle is self- excitable, slow and energy efficient
single unit/ visceral smooth muscles
150
single unit/ visceral smooth muscles location
internal organs that push things
| uterus
151
slow wave electrical activity in smooth muscles meaning
- come close to threshold then produce a bunch of aps
152
what type of electrical activity in smooth muscles creates its own pace and only when its needed
pacemaker
153
what structures do cardiac muscles have
- z lines
- myosin and actin
- troponin and tropomyosin
- large t tubles
- SR
154
what type of muscle has the most mitochondria, more energy and O2 needed
- cardiac muscles
155
what happens when theres no O2 in heart
blockage
156
Ca2+ in cardiac muscle is
- stored in SR
| and is brought in from ecf
157
loss of dopamine in basal nuclei occurs in
PD patiens
158
symtoms of PD
- resting tremors
- reptile stare
- difficult initiating natural movement
- shuffling walk
- stooped posture
159
DMD cause
missing dystrophin in sarcomere
160
how does one get DMD
genetics
161
function dystrophin
connect z lines to sacrolemma
162
gene therapy is the treatment for
DMD
163
whos the most affected with DMD
young boys (2-5)
164
what happens when one has DMD
- effected muslces in hip girdle, trunk
- wheel chair bound
- death
- muscles go through massive deformation during movement
165
RAS controls
motor input/ movement coming from the brain stem
