Exam 3 Flashcards
(104 cards)
1
Q
Functions of muscle
A
-movement
-posture and body position
-stabilize joints
-generate heat
-etc
2
Q
properties (special characteristics) of muscle tissue
A
-excitability (ability to respond and receive stimulus)
-contractable (can get shorter)
-extensible (can extend)
-elasticity (recoil/ can rest after stretching)
3
Q
Where is skeletal muscle tissue located?
A
attached to bone
4
Q
what are te three types of muscle tissue
A
-skeletal
-cardiac
-smooth
5
Q
What are the characteristics of skeletal muscle
A
-striated (protein filaments overlap)
-Largest cells (long and rod shaped
-MULTINUCLEATE
-not usually mitotic when mature (protein intake )
6
Q
hyperplasia
A
increase in cell #
7
Q
hypertrophy
A
cell size becomes larger
8
Q
Does skeletal muscle have sarcomeres?
A
-yes, hence striation
9
Q
does skeletal muscle have t-tubules?
A
yes, two per sarcomere at AI junction
10
Q
does skeletal muscle have gap junctions
A
nope
11
Q
What is the skeletal muscles regulation of contraction
A
VOLUNTARY
-somatic nervous system
12
Q
what is the purpose of the skeletal muscle?
A
move the body
13
Q
location of the cardiac muscle tissue
A
heart walls
14
Q
characteristcis of the cardiac muscle tissue
A
branched, structural support =
-interdigitation helps w structural support
-striated
-cells branched. smaller
-uni or bi-nuceated
-cells meet at intercalculated discs
15
Q
speed of contraction for skeletal muscle tissue
A
rapid but tires easily
16
Q
Does cardiac muscle have sarcomeres
A
yes (striations)d
17
Q
does cardiac muscle tissue have t-tubules
A
yes, one per sarcomere at Z disc
18
Q
does cardiac muscle tissue hve gap-junctions
A
yes at intercalculated discs (allow for open doorway between cells and very rapid communication)
19
Q
regulation of contraction for cardiac muscle
A
-involuntary (autonomic nervous system)
-functional syncytium (all function at the same time)
-must be activated, but then activate each other
20
Q
purpose of cardiac muscle
A
pump blood
21
Q
where is smooth muscle tissue located?
A
located in/around tubular-shaped areas (digestive tract; blood vessels; airways)
22
Q
characteristics of smooth muscle tissue
A
non-striated
-smallest, spindle-shaped
-uninucleate
-
23
Q
does smooth muscle have sarcomeres
A
no
24
Q
does smooth muscle have t-tubules?
A
NO
25
do smooth muscle tissue have gap junctions
some
26
regulation of contraction (constriction) for smooth muscle tissue
-involuntary (instrinsic pacemaker cells -always excitatory)
-bunch up into a ball, make lumen (inside smallr
-relaxaion = dilation
27
purpose of smooth muscle tissue
control movement through tube
28
order of muscle tissues and the coverings
muscle fiber: have PM, surrounded by connective tissue
-endomysium: surrounds fibers
muscle fibers create a fascicle
-perimysium: surrounds fascicle
-epimysium: surrounds bundle of fascicles
29
sarcolemma
plasma membrane filled w sarcoplasm
30
sarcoplasm
smooth ER
-stores and sources calcium
31
transverse tubules
-sarcolemma that buldges into the cell
-signal based event
-activates all fibers at the same
32
myofibril
-individual organelle inside muscle cells
-contains contracting units (sarcomere
33
sarcomere
functional unit of skeletal muscle (smallest unit caoable of doing work)
34
myofilament
contracile proteins that make up the sarcomere (actin, myosin)
35
what are the two types of myofilamentsfilaments
-thick: thicker made of MYSOIN
-thin: thinner made of ACTIN and 2 reg proteins (troponin and tropomyosin)
36
tropomyosin
covers/hidesmyosin binding sites
37
troponin
calcium-binding protein, if calcium is free = contraction
38
What are the regions of the sarcomere
-Z-disc (outer edge)
-H-zone (thick filament)
-I bands (thin filament)
-A band (length of enture thick filament)
-M lines: in ceneter, connecting proteins
39
Whixch bands of the sarcomere change in length during contraction
Z-disc, I band, h-zone
40
Which bands do not move during contraction
A band
41
What is the mechanism of contraction
sliding filament theory
42
What are the steps of the formation of the cross-brudge
1. calcium binds troponin
2. this moves tropomyosin
3. myosin-binding site is revealed
4. activated myosin heads bind actin
5. this causes a "power stroke"
6. ADP and Pi are released from myosin
---requires : calcium, myosin binding site, activated myosin head (NEEDS ATP)`
43
Steps of breaking the cross-bridge
1. ATP binds to myosin which causes myosin to release actin
2. ATP is hydrolyzed to reposition the myosin head (activated site)
3. cross-bridge may form again
--requires ATP
44
WHAT IS THE CROSS-BRIDGE
the link between the thick and thin filaments (allows for contraction
45
steps of forming the cross-bridge
1. calcium binds troponin
2. this moves troponin
3. myosin-bidning site is revealed
4. activated myosine head binds actib
5. this interaction causes a power stroke
f. ADP and Pi ar ereleased from myosin
46
requiements for hthe formation of the cross bridge
1. intracellular calcium (needs action potential)
2. revealed myosin-head site
3. activated myosin head (needs ATP)
47
steps for breaking the cross bridge
1. ATP binds to myosin which caises myosin to release actin
2. ATP Is hydrolyzed to reposition the myosin head to "activated state"
3. cross bridge may form again
48
requirements for the breaking of the cross-bridge
ATP
49
formation of and breaking of the cross-bridge will continu eduring a conraction and will cease upon releaxation
TRUE
50
How can we achive relaxataion?
1. breaking of cross bridge
2. removal of calcium
51
How can we remove calcium from teh system in order to relax the system (muscke)
-remove teh signal/ remove the acetylcholine
-acetlycholinesterase degrades acetylcholine
-released calcium is then pumped back into the sarcoplasmic reticulum ( against the concentration gradient through active transport)
52
Calcium's role in contractioon and relaxation?
-required to reveal myosin binding-site for contraction
-must be removed for relaxation to occur (ATP is used to drive pumping back into storage
53
ATP role in contraction and relaxation?
-activates myosin
-breaks the cross bridge
-drives the calcium pump back into the sarcoplasmic reticulum for relaxation
54
definition of the nueromuscular junction?
point wher the motor nueron contacts skeletal muscle (forms synapse)
55
what are the components of the nueromuscular junction?
-somatic motor nueron axon temrinal
-snyaptic celft
-motoe end plate
-acetylcholine receptors
56
somaric motor nueron axon terminal
portion o fthe nueron that transmits the signal/ contact sthe surface of the skeletal muscle
57
snypatic cleft
small space between the nueron and the musl efiber
58
motor end plate
-area of the ed of the skeletal muscle that contacts the nueron
59
acetylcholin ereceptor
proteins on motor end plate (specific for acetylcholine attatchment)
60
What is the series of events of excitation-contraction coupling
1. signal (action potential) in alpha motorneuron travels to axon terminal
2. signals calcium to enter the axon terminal
3. calcium then send sthe release of acetylcholine (a neuroransmitter) into the snapytic celft by means of exocytosis
4. acetylcholine binds to the receptors on the motor end plate of the muscke cell
5. thiios causes sodium to enter the muscle cell
6. sodium entry depolarizes the muscle cell
7. depolarization is called an EPSP (Excitatory Post- Synaptic Potential)
8. if the ESSP is suffieciet then an action potential will occur
9. teh action potential will travel alog the sarcolemma and diwn into T-tubules
10. the action potential causes the release of calcium from the sarcoplasmic reticulum
11. the calcium binds to troponin and the contraction events begin
61
response of the skeletal muscle
1. Excitatory Post- Synaptic Potention
2. action potential
If EPSP is sufficient enough, action potential will occur
-action potential causes release of calcium from SR amd contracion will occur
62
Tension
strength of muscle contraction
63
motor unit
basic unit of skeletal muscle
64
size of motor unit increase, what will happen to tension
increase
65
small motor unit pro and con
pro: more control
con: not as much tension, few fibers working at once
66
example of a small motor unit muscle
medial rectus, oblique
67
large motor unit pros and cons
-not as much control
-more tension/strength (more fibers)
68
twitch contraction
response of a motor unit to a single stimuli
69
phases of twitch contraction
1. latent period
2. contraction period (faster than relaxation)
3. relaxation period
70
T/F all muscle twitches look the same in every muscle
FALSE
71
T/F Tension can be dependent upon the size of the motor unit
TREU
72
What are the factors that effect the strength of a contraction?
1. motor unit size
2. muscle fiber size
3. frequency of stimulation
4. recruitment
73
How does muscle fiber size effect strength of contraction?
-number does not increase, size increases
-larger diameter = more tension
74
How does frequency of stimulation effect tension?
-unfused/ incomplete tetanus: higher stimulation, frequency
-small levels of relaxation or partial relaxation
-fused/complete tetanus; signals com equickly no relaxation visible until sigal is removed
75
tetanus
based on frequency of stimulation
76
how does stimulus effect tension?
-stronger the stimulus, the more motor units recruited which are activated at a time (by increasing stimulus amplitude)
77
What happens if not enough calcium is released
stimulus is belwo threshold
78
length-tesion relastionship
how much we can move the Z-disc, not in an overshortened or overstretched position
-
79
what is the optimum length of the length-tension relastionnship
-100 % of resting length, decent amount of overlap between thick and thin filaments
80
isotonic
force is applied to shorten the muscle, overcome resistance and then we see things happen
81
isometric
tension develops, force is applied to shorten the muscle, but no change in length
82
concentric
muscle gets shorter
-isotonic
83
eccentric
lenegthen
-isotonic
84
why are eccentric and concentric both isotonic?
because their is a change in length (there is no change in length in isometric)
85
temporal summation
how contraction happen with time
-contractions with added time and no full relaxation
ex: going up the stairs
86
T/F the closer the sarcomeres are to resting length, the more contractile force they have?
TRUE
87
T/F ATP is required for both contraction and relaxation?
TRUE
88
What are the roles of ATP in contraction and relaxation?
1. breaks cross bridge (re-activates and is ready to continue contraction) (C and R)
2. gets hydrolyzed so we can activated myosin head (active state, ADP and Pi attatched to mysoin head in cocked position) (C)
3. drives the calcium pump in sarcoplasmic reticulum (R)
89
What is the net yield of anaerobic glycolysis
2 ATP/ glycolysis
90
How does anaerobic glycolysis work?
-glucose is energy source (converts to pyruvate an dlactic acid) which is cobverted to ATO and is stored as glycogen
91
How does aerobic respiration work?
-uses glucose as energy source, but can also use fat, protein, and amino acids in starvation cases
-utilizes the mitochondria and oxygen
92
What is the ATP yield of aerboc respiration?
32-28 ATP per glucose
93
How does phosphocreatine provide ATP
-direct phosphorlyation/phosphagen.
-phosphocreatine transfers a phosphate to ADP
-left with ATP and creatine
94
what is the yield of ATP for phosphocreatine
1 ATP per phosphocreatine molecule
95
sources of oxygen
-hemoglobin in bloodstream (RBCs)
-myoglobin (O storage in cell)
96
Excess Postexercise Oxygen Consumption
oxygen consumption occuring after exercise is complete (ab 11 liters extra)
97
What are the types of skeletal muscle fibers?
-slow oxidative fibers
-fast oxidative fibers
-fast glycolytic fibers
98
What effect does Mysoin ATPase have on fiber activity
-faster Mysoin ATPAse: form and break cross-bridge quickly; faster rate of contraction
99
Where are oxidative fiber's ATP from
aerobic respiration
100
Where is glycolytic fiber's ATP from
anaerobic respiration
101
slow oxidative fibers characteristics
-red appearance. slow myosin ATPase
-fatigue resistant
-endurance activity
102
fast oxidative fibers
-pink appearance
-fast ATPase
-fast twitch fiers but used in aerobic respiration
-moderately fatigue resistant
-sprinting, walking
103
fast glycolytic fibers
-white/clear appearance
-fast myosin ATPase
-fatiguable
-short-term powerful movements, hotting a baseball.
104
How doe smooth muscle differ and compare to skeletal muscle contractions?
-still has actin and myosin
-no striations, no sarcomeres
-calcium controls contraction; calcium signals contraction (binds to calmodulin – activates a kinase which phosphorylates myosin)
