Chapter 8: Muscle Physiology Flashcards
1
Q
skeletal muscle
A
- striated
- voluntary
2
Q
muscle fiber
A
- single muscle cell
- relavitly large, elongated and cylinder shape
- formed during embronic development by fusion of smaller muscles called myoblasts
3
Q
myoblasts
A
- formed during embronic developments
Features; - multiple nuclei in a single cell
- abundance of mitochondria
- specialized contractile elements
- 80% volume of muscle fibers
4
Q
myoblast are composed to
A
- thick filaments
- thin filaments
5
Q
thick filaments
A
- special assemblys of myosin
6
Q
thin filaments
A
- primary made up of actin
7
Q
Level of organization: muscles
A
- whole muscle (an organ)
- muscle fiber (cell)
- myofribril (specialized intercellular structure)
- thick and thin filaments (cytoskeleton)
- myosin and actin (protein molecules)
8
Q
muscle covering layer
A
- epimysium
- perimysium
- endomysium
9
Q
epimysum
A
covers the whole muscle
10
Q
perimysium
A
divides the muscle fibers into bundles of fascicles
11
Q
endomysium
A
innermost layer
- cover each muscle fober or cell contractile components
- transfer for to connective tissue shealths, then to the tendon, then the bone
12
Q
a band
A
Dark band
– thick and thin filaments overlap
13
Q
H zone
A
- central portions of the thick filament
14
Q
m line
A
- holds thick filaments together vertically
15
Q
i band
A
Light band
- contains only thin filaments
16
Q
z line
A
- verticle
- flat, cytoskeleton disc that connects the adjacent sacromeres
17
Q
sacromeres
A
functional unit of the skeleton muscle
18
Q
titin
A
- along with the m line and z line it help stabalize filaments
- responsible for muscle elasticity and recoil
- largest protein
19
Q
cross bridges
A
- myosin heads
- extend from thick filaments towards thin filaments
- interaction between actin and myosin bring about muscle contraction by means of the sliding filament mechanism
20
Q
myosin
A
- motor protein
- responsible for the action-baded mobility
21
Q
myosin heads
A
form cross bridges
22
Q
Actin
A
- thin filament
- spherical
- contractile protein
23
Q
tropomyosin
A
- threadlike proteins
- conversatins binding sites that bind with cross bridges
- hides actin binding sites
24
Q
troponin
A
- made up of three polypeptides
- binds to tropomyosin, actin, and calcium –. result: exposes binding sites
25
reglatory proteins
prevent / premit contraction
- tropomyosin
- troponin
26
rigor mortis
- "stiffness is dealth"
- lacking in place of skeletal muscles that begins 3-4 hours after dealth
- no ATP
- no Ca
27
Sacroplasmic reticulum
- modified endoplasmic reticulum
- Sr in lateral sacs stores calcium
28
t tubules
- action potentials spread down t-tubules trigger the release of ca
- voltage gated receptors
- dihydropridine receptors
29
features of skeletal muscles
- sacrolemma
- own nucleus
- lots of mitochondria
- lots of glycogen reserves
- SR
30
nebulin
- stabalizes
31
ryanodine receptors
"foot proteins"
- calcium release channels
32
dihydropyridine receptors
- t tubules
- causes the release of calcium --> troponin binds to ca ions --> tropomyosin is removed --> exposes binding sites --> action and myosin (crossbridges are formed)
33
power stroke
ATP bereaks down into ADP+P
34
sliding filament
- z lines come closer together
- I bands become shorter
- m-line doesnt change
- A band width doesnt change
- H band becomes shorter
35
relaxation
- Acetylcholinesterase breaks down ACh at the neuromuscular junction
- calcium returened to the neuromuscular junction
- action potential stops
- troponin and tropomyosin slips back into place
- actin and myosin can no longer bind at crossbridges
36
McArdle Disease
- absense of enzyme phophorylase ( breaks down glycogen to glucosse for ATP production)
- glycogen accumulates in the muscles
SYMPTOMS: muscle weakness, legs lacking, living rigor mortis
37
Temporal summation
- results for sustained elevation of cyostolic calcium
38
muscle tetnus
- sustained contractile activity
- flat region
- result of temporal summation
39
tetnus infection
- caused by clastridum tensi
- blacks GABA
RESULT: spasms
40
single action potental produces
a twitch
41
muscle tension factors
- frequency of stimulation
- lenght of the fiber at the onset of contraction
- extent of fatigue
- thickness of fiber
42
energy sources for contration
- creatine phosphate
- glycolysis
- fatty acids
43
Creatine phosphate break down
- breaks down into creatine kinase which breaks down into creatine and ATP
44
creatine phosphase as a supplement
- causes GI disterbances
- weight gian
- dehydration
45
creatine phosphate is used in
sphincters
46
fatty acids
enter the krebs cycle directly
47
isotonic contractions
equal stretch; creates force and movement
- concentric
- eccentric
48
concentric
towards the center of the body
EXAMPLE: shortening of the biceps
49
eccentric
- away from the center of the body
- most common cause of injury
50
51
types of contractions
- isotonic
- isometric
52
isometric
- equal movement
- force but no movement
EXAMPLE: yoga, planks, pilates
53
twitch fiber types
- fast
- slaw
54
slow twitch fibers
- slower
- uses ATP slower
- slower relase of calcium
- frequently used for daily acivities
- twitch sustained for longer
Example: posture, wlaking
55
fast twitch fibers
- 2-3x faster
- slits ATP faster
- calicum is released faster
- used occasionally
- twitch is sustained for shorter
Example: violine, piano
56
types of engergy uses
- oxidative
- glycolipid
57
oxidative
- uses oxegen, increase of myoglobin
- goes through all three cycles
- 36 ATP total
- more mitochondria
- increase bllod vessels
- rich red color
fatigues less
58
glycolipid
- does not need oxegen
- produces 2 ATP
- less mitochondria
- fewer blood vessels
- pale "white" fibers
- fatiguee more
59
muscle fatigue
occurs when muscles can no longer respond to stimulation with the same degree of muscle contraction
60
types of muscle fatigue
- central
- peripheral
61
Central muscle fatige
- psychological
- CNS
- montonomy (continous activity; like assembly line workers)
- somatic motor neuron
62
peripheral motor fatigue
contibute to the vunrability of the neuromuscular junction
- calcium release
- SR and T tubule receptors
- decreased glucose
- lack of ATP
63
solution ot muscle fatigue
E -excess
P - Post excersize
O - oxegen
C - consumption
64
control of motor movement
- spinal cord (reflexes)
- brain stem (reticular formation)
- Primary motor cortex
65
Parkiinsons Disease
- basal nuclei
- tremors, reptilian stare, difficulty walking, confusion, afffected sleep, gait walking
66
Duchennes Muscular Dystrophe
- affects more males
- genetic
- carried in x chromosone
- lack dystrophin (protein)
- affects muscles of the hip and girdle
Treatment: gene therapy
67
muscle receptors
muscle spindles
68
muscle spinals
monitor muscle stretch
69
Alpha motor neuron
forms the neurmusclular junction
70
intrafusal fibers
receptors
71
Gama mtor neuron
- flower spray ending in periphery in intrafusal fibers
- annulospiril ending in enter of intrafusal fibers
72
annulospiril ending
controls stretch
73
extrafusal fibers
ordinary muscle fibers
74
Golgi tendo organ
- monitors force/tension
- protects from injury (drop load)
- collogen
