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Exercise Physiology > EXAM 3 > Flashcards

EXAM 3 Flashcards

1
Q

skeletal muscle is responsible for _
- 400+ in body
- ~40-45% of body weight

A

all movement and support

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2
Q

skeletal muscle is mostly made up of _
- 20% protein
- 5% other: fats, CHO, high energy phosphates, urea, lactic acid, enzymes, Na+, K+, Cl-, and minerals - Ca2+, Mg, and phosphorous

A

water (75%)

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3
Q

skeletal muscle is _ in appearance
- structure is fascia and connective tissue sheaths which separate individual muscles and hold muscles in place
- under fascia: epimysium
- under epimysium: fascicles
- there are ~ 150 fibers/fasciculus

A

striated

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4
Q

connective tissue surrounding muscle

A

epimysium

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5
Q
  • bundle of muscle cells (fibers) surrounded by perimysium
  • each fiber in _ is surrounded by endomysium
  • under endomysium is _, cell membrane
  • connective tissue surrounds muscle and forms a network that extends throughout the muscle
A
  • fasciulus
  • sarcolemma
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6
Q

bundles of muscle fibers enclosed by perimysium

A

fascicles

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7
Q
  • cytoplasm of muscle cell
  • under sarcolemma
  • contains contractile proteins, enzymes, fat, and glycogen particles, nuclei, and specialized cellular organelles
A

sarcoplasm

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8
Q

greatest amounts:
- myosin
- actin
- tropomyosin
- also, large amounts of myoglobin

A

proteins in skeletal muscle

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9
Q

muscles cells are: _ and _

A
  • multi-nucleated
  • striated appearance
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10
Q
  • embedded in sarcoplasm
  • network of channels and vesicles
  • lies parallel to the myofibrils
  • lateral end: sac-like cisternae which stores Ca2+
A

sarcoplasmic reticulum (SR)

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11
Q
  • perpendicular to myofibril
  • _ and two terminal cisternae are the region of the Z line
  • called a triad
  • two triads/sacromere
  • one sacromere: Z line to Z line
  • Tubules open to the outside of each muscle fiber
  • functioning as a network, spreading the AP from outer to inner portions of muscle fiber
A

Transverse Tubules (T-Tubules)

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12
Q
  • composed of 6 polypeptide chains
  • 2 heavy
  • 4 light
  • one myosin filament is made up of 200 or more myosin molecules
  • exactly 1.6 micrometers in length
A

myosin molecule

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13
Q

Myosin molecule:
- _ are in center
- _ coming out from center (0.2 micrometers)
- hinges at two points
- arm separates from the filament
- where the head attaches to the arm
- filament is twisted, cross-bridges are displaced from previous set by 120 degrees
- ensures that cross-bridge extend in _ from the filament

A
  • tails
  • heads
  • all directions
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14
Q
  • primary protein
  • forms backbone of filament
  • approx. 3,000 actin/myofibril
  • Troponin and Tropomyosin
  • two other proteins in filament
A

actin

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15
Q

Two shapes of actin:

A
  1. globular (G-actin)
  2. Fibrous (F-actin)
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16
Q

Type of shape of actin:
- polymerizes and unfolds

A

globular (G-actin)

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17
Q

Type of shape of actin:
- double stranded in helix, complete revolution every 70 nanometers

A

fibrous (F-actin)

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18
Q
  • 13 _ molecules in each revolution of the helical strand
  • Each G-actin has an _ molecule attached to it
    • ADP are purported to be the active sites on the actin for _ interaction
    • active sites are staggered, one site on total filament every 2.7 nanometers
  • each actin is 1mm long
A
  • G-actin
  • ADP
  • cross-bridge
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19
Q
  • inserted into Z discs, other end protrudes into sacromere
  • in spaces between myosin molecules
A

filament bases

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20
Q
  • actin filaments extending from either side
  • into neighboring sacromeres
  • passes from myofibril to myofibril
  • attaching the myofilaments to each other across the muscle fiber
A

Z line

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21
Q

Basic contractile unit, Z line to Z line

A

sacromere

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22
Q
  • associated with the actin filament
  • loosely connected to the F-actin strands
  • wrap themselves spirally around the sides of the F-actin helix
  • at rest, _ molecules lie on top of the actin sites, inhibiting interaction between actin and myosin
  • each _ covers about 7 active sites
A

tropomyosin

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23
Q
  • protein attached near one end of each tropomyosin molecule
  • complex of 3 protein subunits
  • _ complex may attach the tropomyosin to the actin
  • each subunit plays a role in the contractile process
A

troponin

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24
Q

Troponin complex:
- strong affinity for actin

A

Troponin I (TnI)

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25
Q

Troponin complex:
- strong affinity for tropomyosin

A

Troponin T (TnT)

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26
Q

Troponin complex:
- strong affinity for calcium

A

Troponin C (TnC)

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27
Q

Troponin complex includes 3 subunits:

A
  • TnI
  • TnT
  • TnC
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28
Q
  • alternating light and dark bands along the length of the muscle fiber gives its characteristic striated appearance
  • lighter area: I band
  • darker area: A band
A

sacromere ultrastructure

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29
Q

sacromere ultrastructre:
- when light passes through this band, its velocity is the same

A

I band (isotropic)

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30
Q

sacromere ultrastructure:
- light does not scatter equally

A

A band (anisotropic)

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31
Q

sacromere ultrastructure:
- Z line bisects the _ and adheres to the sarcolemma, adding stability to the sacromere

A

I band

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32
Q

sacromere ultrastructure:
- Z line has _ (maintains spacing of actin) and _ (connects Z lines of different myofibrils together)
- position of the actin and myosin redults in an overlap of the filaments in the sacromere

A
  • alpha actin
  • desmin
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33
Q

sacromere ultrastructure:
- center of the _ is the H band
- lighter area due to the absence of the actin filaments in the region

A

A band

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34
Q

sacromere ultrastructure:
- central part of _ is bisected by the M line

A

H band

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35
Q

sacromere ultrastructure:
- _ is protein structures that support the arrangement of the myosin filaments
- also has myomesin which provides an anchor for titin (elastic filament)
- helps maintain centering between _ and _
- CK, provides ATP from CP

A
  • M line
  • Z line, M line
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36
Q
  • Tropomyosin and troponin regulate the interaction between actin and myosin proteins of thick and thin filaments
  • During contraction, cross-bridges attach between actin and myosin
  • Two filaments slide over each other when energy is provided by the hydrolysis of ATP
A

Sliding Filament Theory (AF Huxley & Neidergerke, 1954)

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37
Q
  • skeletal muscle contracts only after stimulation from a motor neuron
  • normally, each motor neuron branches several times and stimulates a few to several hundred muscle fibers
A

neuromuscular bases of contraction

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38
Q
  • motor neuron (cell, etc.)
  • muscle fibers it innervates
  • at muscle site: neuromuscular junction, motor and end plate, myoneural junction
A

motor unit

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39
Q
  • initiation of the action potential by the motor neuron
  • transmission of the AP across the motor end plate to the muscle fiber
A

contraction begins

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40
Q

~ 200-300 vesicles of acetylcholine (ACH, neurotransmitter) are released into the gap between the motor neuron and the motor end plate (cleft)

A

Action potential reaches NMJ

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41
Q
  • reaction causes an increases in permeability to sodium ions, resulting in depolarization of the sarcolemma or end-plate potential
  • if end-plate potential is large enough to exceed a threshold (depending on skeletal muscle type), the nerve impulse will be successfully transformed into a muscle impulse
  • the impulse travels in all directions over the muscle membrane when being transmitted
  • deep into the fiber through the transverse tubules (T-tubules)
A

ACH diffused across the gap and reacts with receptor molecules in the sarcolemma

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42
Q
  • as the AP is transmitted throughout the fiber
    • the membranes of the cisterane in the SR becomes more permeable to Ca++
    • Ca2+ diffuses into the sarcoplasm of the fiber
  • once the Ca 2+ concentration is high enough, (100x increase), the Ca2+ binds with the TnC molecule
  • Binding of Ca2+ to the TnC causes a propositional change of the Tn, which also effects the positioning of the tropomyosin, moving it deeper into the groove between the two actin strands
A

wave of depolarization reaches T tubule

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43
Q
  • two different iso forms
    • fast muscle
    • slow muscle
A

TnC

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44
Q
  • fast contain low binding sites for Ca2+
    • site I & site II
  • slow have only one binding site
  • both sites must be filled to trigger contraction
A

TnC

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45
Q
  • there is a _ with binding that exposes a hydrophobic cavity (the TnI binding site)
  • alters the interaction between TnI and TnC
  • instead of TnI binding to actin, it perferentially switches to binding domain on TnC, allowing actin and myosin to interact
A

conformational change

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46
Q
  • _ skeletal muscle has no site I
  • _ and _ are activated by one, not two calcium ions by the TnC isoforms subunit
  • therefore,
    • contraction frequency
    • power output
    • strength are typically down regulated
A
  • slow
  • slow and cardiac muscle
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47
Q
  • ubiquitous in eukaryotes
  • responsible for a wide range of functions requiring directed movement of molecules, subcellular components, cells, tissues, and whole organisms
  • utilize the energy of hydrolysis of ATP
A

motor proteins

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48
Q
  • ATP utilizing motor protein
  • generates movement by interaction with actin filaments
  • all members of the myosin family share the same basic structure
  • a single polypeptide chain: the heavy chain is folded to form the head and tail domain
  • light chain monomers bind to heavy chain just below the head domain to form the neck domain
  • the basic myosin structure is modified to generate the _
A

myosin
- myosin family of motor proteins

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49
Q
  • actin composed of long polymers of the actin monomer subunits
  • ubiquitous in animal and plant cells
  • major component of the cytoskeleton
  • from the ‘ thin filaments ; in skeletal and cardiac muscle
A

myosin generates movement by interaction with actin filaments

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50
Q
  • muscle is comprised of interdigititating filaments of actin and myosin polymers
  • during muscle contraction, myosin heads move over and bind to an adjacent actin filament (swinging cross-bridge hypothesis)
  • hydrolysis of ATP in myosin head results in a conformational change in the myosin which cause the neck to wing, pulling on the actin filament
  • the net result of many actin=myosin interactions is that the filaments slide, relative to one another, causing the muscle fiber to shorten (sliding filament hypothesis)
A

skeletal muscle myosin II

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51
Q
  • light microscopy
  • electron microscopy
  • X-ray diffraction
A

muscle ultrastructure

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52
Q
  • resolution is limited by the wavelength of the illuminating light
  • for visible light microscopy this limits resolution to approx. o.2 nm
A

light microscopy

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53
Q
  • to improve resolution, we need to use shorter wavelengths
  • the de Brogile wavelength is given by: wavelength=h/mv
  • to achieve a wavelength of 1 nm, we need to accelerate the electrons to about 100,00 ms-1
  • a high voltage is required (100,00v)
  • circular magnetic lenses focus electrons onto the sample
  • advantages:
    • much high resolution (to 1 nm)
  • disadvantages:
    • samples are dead ( drying, heavy metal staining, vacuum)
    • artifacts due to staining procedures are common
A

electron microscopy

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54
Q
  • can achieve resolution below 0.1 nm
  • much greater resolution than light or electron microscopy
  • fiber diffraction methods can detect changes in the structure of living muscle fibers but:
    • can only be used on relatively large arrays of molecules (fiber or protein crystal)
    • crystals of large proteins (like myosin) can be extremely difficult to grow
    • x-ray crystallography of proteins provides a static picture of a single, possible confirmation of a protein
A

x- ray diffraction

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55
Q
  • optical tweezers
  • in-vito motility
  • pre-steady state kinetics
A

myosin dynamics

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56
Q

Myosin dynamics:
- individual myosin heads are attached to surface
- the motion of flourecently-labeled actin filaments, propelled by the myosin heads, can be monitored

A

in-vito motility

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57
Q

fluorescence techniques:
- _: tryptophan residue fluorescence is sensitive to changes in polarity of its environment

A

intrinsic fluorescence

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58
Q
  • intrinsic fluorescence
  • fluorescent substrate (Ex: mant-ATP)
  • fluorophore labeling on cysteine residues (Ex: pyrene labeled actin)
  • FRET (fluorescence resonance energy transfer) techniques: distance measurements between two fluorophores
  • quantum dot: large, intense fluorophore, enables detection of single molecule fluorescence
  • chimeric constructs with GFP, YFP
A

fluorescence techniques

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59
Q

a detailed reaction mechanism for the actin: nucleotide interaction can be determined using _

A

pre- steady state kinetic techniques

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60
Q

structural studies using _ and _ techniques have been used to study the conformational changes in actin and myosin during muscle contraction

A

EM and X-ray diffraction

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61
Q

_ techniques measure force generation and step size in myosin heads

A

single molecule (optical tweezers, in-vito motility)

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62
Q
  • contraction cycle of myosin cross-bridges of a muscle shortens a muscle by 1% of its resting length
  • consequently, the contraction cycle must be repeated over and over to significantly shorten the whole muscle
A

single contraction cycle

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63
Q
  • when a new ATP attaches to a myosin head, the cross-bridge can detach from the actin
  • greater amount of work performed by the muscle
  • greater amount of ATP which is cleaved
A

Fenn Effect

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64
Q
  • at the same time contraction is occurring, ACH that stimulated the contraction is being _ by the action of _ (enzyme present at the myoneural junction within the membranes of the motor end plate)
  • rapid removal of ACH insures that a single nerve impulse will not cause a continued stimulation of the muscle
A
  • rapidly decomposed
  • cholinesterase
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65
Q
  • usual duration of an impulse to skeletal muscle is about 20 milliseconds
  • in order for contraction to continue:
    • continual stimulation of the muscle fiber
A

impulse duration

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66
Q

the signal to stop contraction is the absence of a nerve impulse at the junction (see notes for diagram)

A

tetanus

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67
Q

Action Potential stops:
- continually _ located in the walls of the SR pumps the calcium ions out of the _

A
  • active calcium pump
  • sarcoplasm
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68
Q

Action Potential stops:
- back into the SR via the _ , and then the calcium diffuses back into the _

A
  • fenestrated collar
  • cisternae
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69
Q

Action Potential stops:
- calcium diffuses back into cisternae
- this lowers the concentration of calcium, removing it from the conformation and the _
- fiber returns to its relaxed position

A

active sites are covered

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70
Q
  • actin and myosin uncoupled
  • calcium stored in SR
A

rest

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71
Q
  • nerve impulse generated
  • ACH released from the vesicles
  • sarcolemma depolarized
  • muscle impulse transmitted through the fiber
  • calcium released from cisternae
  • calcium binds to troponin
  • actin binding sites activated
  • myosin ATPase activated
A

excitation

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72
Q
  • myosin cross-bridges swivel
  • release Pi + ADP
  • Actin slides over myosin
A

contraction

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73
Q
  • ATP attaches to myosin
  • actin and myosin dissociate
  • ATP – ADP + Pi
  • contraction process repeats
A

regeneration

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74
Q
  • ACH decomposed by cholinesterase (ACHase)
  • nerve impulse stops
  • calcium removed by calcium pump
  • actin binding sites inhibited (Tn/tropomyosin complex returns to original position)
  • muscle returns to resting state
A

relaxation

75
Q
  • process by which myofibrils translate nerve impulses into muscle contraction
  • depolarization of t-tubule membrane (a change in the membrane potential) results in the calcium release from the terminal cisternae of the SR
  • this results in muscle contraction
A

excitation contraction coupling

76
Q
  • calcium is sequestered in the SR via active calcium-ATPase pumps
  • not clear how the change in membrane potential of the t-tubule system is communicated into the SR to cause calcium release
A

ECC

77
Q

structure and function of triad:
- t-tubules and SR communicate at the _
- a _, a large protein complex which is the release channel of the sarcoplasmic calcium, located at the t-tubule SR junction
- the receptor has two parts: channel region and a large cycoplasmic region

A
  • triad junction
  • ryanodine receptor (RyR)
78
Q
  • within t-tubule protein complex, the voltage sensor controls the opening and closing of the RyR and DHP (dihydropyridine receptor complex)
  • RyR and the DHP receptor interact with each other to cause the action potential to induce calcium release from the SR
A

Plunger hypothesis

79
Q

Correct order from beginning of a contraction to the end:
1.

A

calcium is sequestered in SR

80
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2.

A

AP is propagated down motor nerve

81
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3.

A

AP reaches neuromuscular junction

82
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4.

A

ACH releases across the junction

83
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5.

A

ACH binds with receptors on sarcolemma

84
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6.

A

AP is propagated across sarcolemma, down t-tubules

85
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6. AP is propagated across sarcolemma, down t-tubules
7.

A

SR releases calcium

86
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6. AP is propagated across sarcolemma, down t-tubules
7. SR releases calcium
8.

A

calcium binds with TnC

87
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6. AP is propagated across sarcolemma, down t-tubules
7. SR releases calcium
8. calcium binds with TnC
9.

A

Tn undergoes a conformational change

88
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6. AP is propagated across sarcolemma, down t-tubules
7. SR releases calcium
8. calcium binds with TnC
9. Tn undergoes a conformational change
10.

A

Tropomyosin is pulled off of the actin binding sites

89
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6. AP is propagated across sarcolemma, down t-tubules
7. SR releases calcium
8. calcium binds with TnC
9. Tn undergoes a conformational change
10. tropomyosin is pulled off the actin binding sites
11.

A

myosin attaches to actin

90
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6. AP is propagated across sarcolemma, down t-tubules
7. SR releases calcium
8. calcium binds with TnC
9. Tn undergoes a conformational change
10. tropomyosin is pulled off the actin binding sites
11. myosin attaches to actin
12.

A

ADP + Pi released

91
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6. AP is propagated across sarcolemma, down t-tubules
7. SR releases calcium
8. calcium binds with TnC
9. Tn undergoes a conformational change
10. tropomyosin is pulled off the actin binding sites
11. myosin attaches to actin
12. ADP + Pi released
13.

A

myosin heads pull or power stroke

92
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6. AP is propagated across sarcolemma, down t-tubules
7. SR releases calcium
8. calcium binds with TnC
9. Tn undergoes a conformational change
10. tropomyosin is pulled off the actin binding sites
11. myosin attaches to actin
12. ADP + Pi released
13. myosin heads pull or power stroke
14.

A

new ATP molecules attach to myosin

93
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6. AP is propagated across sarcolemma, down t-tubules
7. SR releases calcium
8. calcium binds with TnC
9. Tn undergoes a conformational change
10. tropomyosin is pulled off the actin binding sites
11. myosin attaches to actin
12. ADP + Pi released
13. myosin heads pull or power stroke
14. new ATP molecules attach to myosin
15.

A

myosin head detaches from actin

94
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6. AP is propagated across sarcolemma, down t-tubules
7. SR releases calcium
8. calcium binds with TnC
9. Tn undergoes a conformational change
10. tropomyosin is pulled off the actin binding sites
11. myosin attaches to actin
12. ADP + Pi released
13. myosin heads pull or power stroke
14. new ATP molecules attach to myosin
15. myosin head detaches from actin
16.

A

ATP is cleaved into ADP and Pi

95
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6. AP is propagated across sarcolemma, down t-tubules
7. SR releases calcium
8. calcium binds with TnC
9. Tn undergoes a conformational change
10. tropomyosin is pulled off the actin binding sites
11. myosin attaches to actin
12. ADP + Pi released
13. myosin heads pull or power stroke
14. new ATP molecules attach to myosin
15. myosin head detaches from actin
16. ATP is cleaved into ADP and Pi
17.

A

ACHase decomposes all the ACH

96
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6. AP is propagated across sarcolemma, down t-tubules
7. SR releases calcium
8. calcium binds with TnC
9. Tn undergoes a conformational change
10. tropomyosin is pulled off the actin binding sites
11. myosin attaches to actin
12. ADP + Pi released
13. myosin heads pull or power stroke
14. new ATP molecules attach to myosin
15. myosin head detaches from actin
16. ATP is cleaved into ADP and Pi
17. ACHase decomposes all the ACH
18.

A

tropomyosin covers binding sites

97
Q

Correct order from beginning of a contraction to the end:
1. calcium is sequestered in SR
2. AP is propagated down motor nerve
3. AP reaches neuromuscular junction
4. ACH releases across the junction
5. ACH binds with receptors on sarcolemma
6. AP is propagated across sarcolemma, down t-tubules
7. SR releases calcium
8. calcium binds with TnC
9. Tn undergoes a conformational change
10. tropomyosin is pulled off the actin binding sites
11. myosin attaches to actin
12. ADP + Pi released
13. myosin heads pull or power stroke
14. new ATP molecules attach to myosin
15. myosin head detaches from actin
16. ATP is cleaved into ADP and Pi
17. ACHase decomposes all the ACH
18. tropomyosin covers binding sites
19.

A

muscle returns to resting length

98
Q

motor units have an _ response
- all of the fibers innervated by the motor neuron contract or none of them do

A

“all-or-none”

99
Q
  • smaller motor units are recruited first
  • the frequency of motor unit recruitment (use/firing) is directly related to the size and ease of triggering an action potential in the soma (neuron cell body)
  • smaller cell bodies (slow motor units) will be recruited first and overall, most frequently
A

Hennennman’s size principle (1974)

100
Q

control of movement:
- _: brain and spinal cord
- _: all the nerves extending from the brain and spinal cord

A
  • CNS
  • PNS
101
Q

control of movement:
- _: direction of AP is toward the spinal cord, usually involves sensory information
- _: direction of AP is away from the spinal cord, usually involves motor information
- reflexes are “all-or-none” contractions, monosynaptic
- resting membrane potential: ~70 Mv

A
  • afferent nerves
  • efferent nerves
102
Q

Activity in neuron within CNS
- depends on the sum total of _ and _, in a narrow range of time and space

A

EPSPs, IPSPs

103
Q

Activity in neuron within CNS
- _: excitatory post-synaptic potential; release of ACH increases post synaptic permeability to Na+, potential rises but may not reach depolarizing threshold level
- _: inhibitory post-synaptic potential; another neurotransmitter is released which decreases Na+, permeability, reducing the chance for potential reaching the threshold

A
  • ESPS
  • ISPS
104
Q
  • connective tissue capsules in the shape of footballs that are filled with lymph and specialized fibers, implanted between muscle fibers
  • afferent and efferent innervations
  • provide information about absolute length of muscle and rate of change in length of the fiber
  • when muscle is contracted, activation of the Y motor neurons occurs, these efferent Y-neurons cause contraction of the muscle fibers within these
  • this “takes up the slack” within the fibers of the capsule, allowing it to respond to further stretch
A

muscle spindles

105
Q
  • exert inhibitory effects on the agonist and facilitate the effects on the antagonist muscles
  • is possible to disinhibit with training (minimizing the effectiveness of the _)
A

Golgi tendon organs (GTOs): respond to tension
- GTOs

106
Q
  • allows athlete to push the limits of the tissue
  • wrist wresting: fractures and ruptures muscles and tendons occur
A

GTO

107
Q
  • capacity of skeletal muscle for adaptive change
  • due to training, nutrition, endocrine millieu
A

myoplasticity

108
Q

increase in fiber size

A

hypertrophy

109
Q

increase in fiber number

A

hyperplasia

110
Q

Gender differences:
- men typically have _ area than women
- men are able to generate _ than women
- NOT true when strength is expressed Str/BW or Str/FFW, gender differences disappear
- when examined for the ability to generate force and power (normalized for cross-sectional area) there are _

A
  • greater mass cross-sectional
  • more absolute strength
  • no differences
111
Q
  • shortening of muscle
  • force is generated
  • train: increase strength
A

concentric or myometric contraction

112
Q
  • no change in length
  • force is generated
  • train: specific to joint angle
A

isometric contraction

113
Q
  • lengthening of muscle
  • force is generated
  • ability to generate most force
  • utilizes less O2 than concentric
  • more hypertrophy and strength gains
  • more muscle damage
A

eccentric contractions

114
Q
  • blood flow plays an important role
  • build up of lactic acid stimulates pain receptors
  • disappears when activity stops
A

acute muscle soreness

115
Q
  • eccentric work (pain peaks after 48hrs)
  • isometric work (pain peaks after 12hrs)
  • LA disappears in one hour
A

Delayed Onset Muscle Soreness (DOMS)

116
Q

_ cause most damage
- could be due to:
- strains in the MU
- popping of sarcomeres
- stretching produces over-extended sarcomeres
- may be that myosin heads are “loosely” bound during contractions and heads are “popped off” the chain, causing damage

A

eccentric contractions

117
Q

Lactic Acid Theory:
- myth: “the burn” is caused by lactic acid build up
- when ATP is broken down, _ are released, plus acidity equals that _

A
  • hydrogen
  • burning sensation
118
Q

Lactic Acid Theory:
- myth: lactic acid is waste
- 75% of lactate is _
- lactate – glucose — fuel

A

recycled

119
Q

Lactic Acid Theory:
- myth: lactic acid builds up and causes muscle soreness
- 30-60 min most lactate is _
- DOMS actually caused by _

A
  • flushed from muscles
  • micro trauma
120
Q
  • spasm due to ischemia
  • release of P substrate that causes pain stimulus
  • pain reflex: muscle continues to contract
  • break spasm by: massage, ice, and stretching
  • P substrate is unknown
A

spasm theory

121
Q
  • 4 substances: LDH, 3mH (increases in urine), hyroxyproline (Hp) and CPK
  • CPK and LDH leak into blood when muscle breaks down
  • HP increases in blood and urine when break down connective tissue
  • all 4 are markers of muscle damage
A

connective tissue theory

122
Q

DOMS: 5 components
- structural components of _ and _ are distributed
- structural damage causes a change in permeability in muscle cell, allowing high levels of _ into the cells (kills cells)
- high calcium causes a release of _
- fragments of broken proteins leak into serum/blood and lead to immune response; WBC flood the area
- histamine response: fluid flows to area, swelling and heat production, stimulates pain receptors

A
  • skeletal muscle, CT
  • calcium
  • proteolytic enzymes
123
Q
  • MRI
  • swelling
  • muscle protein in blood
  • impaired substrate utilization
  • decrease in strength and ROM
  • decreased in motor control
A

analyze damage via

124
Q

If entire muscle is not damaged, small areas can recover
- in resting state, z lines are zig-zagged
- connection between titin and myomesin is broken, distorting the _ arrangement
- _ (connects z lines of different myofibrils) is gone 3 days post exercise
- _ (connects membrane to matrix inside fiber) is also disrupted

A
  • myofibril
  • desmin
  • fibronectin
125
Q

most damage is repaired after _
- soreness decreases with repeated bouts
- adaptation

A

10 days

126
Q

NSAIDs on repair:
- Cox-2 and prostaglandins are important to adaptation of _ to mechanical stimuli
- prolonged NSAID use may reduce rate of matrix production following injury
- mouse models have shown IB decreases endurance running adaptations in IIa myofibrils and capillary-to-fibre ratios
- studies investigating changes in modeling on muscles and tendons in humans mixed
- _ may also have effects on tendons

A
  • connective tissues
  • acetaminophen
127
Q

NSAID Recommendations:
- Don’t use NSAIDs _ exercise
- be very, very,very careful about NSAID use _, especially endurance events
- think about why you are using them after exercise

A
  • before
  • during exercise
128
Q

skeletal muscle fiber types:
- not all skeletal muscle has the same _ or _
- are generally classified according to their _ on different metabolic pathways for the production of ATP

A
  • biochemical or functional characteristics
  • primary dependence
129
Q

_ based on:
- myosin ATPase pH lability: histochemical staining
- glycotic staining
- oxidative staining

A

nomenclature

130
Q

Fiber sub-types:
- Type I, _, red fibers
- Type IIa, _, intermediate fibers
- Type IIb, _ white, rare, under differentiated fiber; perhaps found during re-innervation of motor unit transformation, between I and IIa on the continuum of metabolic potential
- Type IIx, not classified

A
  • SO (slow oxidative)
  • FOG (fast oxidative glycolytic)
  • FG (fast glycolytic)
131
Q

Slow twitch fibers:
- _ resistant, good for prolonged exercise
- primary synthesized ATP via _
- recruited for aerobic activities such as prolonged moderate exercise
- have smaller resting membrane potential, -50-70 Mv vs 80-90 Mv in fast muscle
- _ period due to less extensive SR

A
  • fatigue
  • aerobic energy transfer
  • longer latency
132
Q

Slow twitch fibers:
- _ activity of myosin ATPase
- _ speed of contraction
- low _
- increased size and number of mitochondria
- higher levels of _
- higher concentrations of mitochondrial enzymes
- increased blood flow – increased _

A
  • low
  • slow
  • glycolytic capacity
  • myoglobin
  • capillarization
133
Q

Fast twitch fibers:
- activated in _ activities, and forceful contractions which rely primarily on anaerobic metabolism energy
- important in stop and go and change of pace activities
- more extensive SR
- greater capability for _ (due to increased SR)

A

short-term, sprint
- electrochemical AP transmission

134
Q

Fast twitch fibers:
- high activity level of _
- rapid SR _ release and uptake
- high rate of cross-bridge turnover and development
- intrinsic speed of _ and _ is 2-3 times that of slow twitch fibers
- primarily use the _ system for energy transfer

A
  • myosin ATPase
  • calcium
  • contraction, tension
  • glycolytic
135
Q

one complete movement of an exercise (concentric/eccentric)

A

repetition

136
Q

group of repetitions

A

sets

137
Q

maximum number of repetitions that can be performed at a resistance with proper technique; 1 RM

A

repetition maximum (RM)

138
Q

rate of performing work, weight lifted times the vertical distance it is lifted, 50-80%

A

power

139
Q

the ability of a muscle group to perform repeated contractions against a submaximal load for an extended period of time (NSCA 15 reps)

A

muscular endurance

140
Q

the force that a muscle or muscle group can exert in single maximal effort (NSCA 1-5 reps)

A

muscular strength

141
Q

a fraction of a 1 RM for training prescription (Ex: intensity)

A

% 1-RM

142
Q

speed or velocity of repetitions (Ex: 2/4 tempo)

A

rep tempo

143
Q

total work performed during a specific time period
- load x reps x sets

A

volume

144
Q

maximal amount of force a muscle or muscle group can generate in a specified movement pattern at a specified velocity of movement
- HR is not appropriate measure of exercise intensity with resistance training
- minimal intensity to generate strength gains is 60-65% 1 RM

A

strength

145
Q

1 RM testing is done to determine the _ appropriate for each lift; key to developing an appropriate exercise program prescription
- Two methods:
1. _ RM
2. _ RM

A
  • loads
  • 1
  • 10
146
Q

Determining loads method:
- warm up with light exercise
- estimate load that will allow you to complete 3 to 5 reps
- upper body 10-20lbs, lower body 30-40lbs
- rest 2 mins
- increase load that will allow you to finish 2-3 reps
- rest 2 mins
- increase load to one that will allow you to finish 1 rep

A

1 RM

147
Q

Determining loads method:
- warm up with light loads allowing 10-15 reps
- rest 1 min
- increase load so it is moderately difficult to compare 10 reps
- rest 1 min
- increase load so it is difficult to complete 10 reps
- upper body 5-10lbs, lower body 15-20lbs
- use chart to estimate 1 RM

A

10 RM

148
Q

basic principles:
- _ differences - will respond differently to strengthen training
- _ principle - effects of training are transient and reversible
- _ - organizes training into cycles of training objectives, tasks and content
- usually in macro/micro cycles
- rest intervals - interval between sets are critical to success of training goal
- rest periods for achieving strength are longest

A
  • individual
  • reversibility
  • periodization
149
Q
  • the less fit the person being trained the longer the recovery period
  • shorter as fitness improves
  • near maximum training sessions take more time to recover
  • multi joint lifts in a session require more recovery time when training sessions utilizing single joint lifts
A

frequency

150
Q
  • increase the amount of weight lifted use of RM
  • increase the training volume (number of sets or reps)
  • easy to overtrain
    • especially with increase in training volume
A

progressive overload

151
Q
  • if goal is to improve performance and power for short, intense activities, rest period should be short (<1 min)
  • one day of recovery is usually recommended for a specific body part
A

rest periods

152
Q
  • isometric
  • isotonic
  • variable resistance
  • eccentric
  • plyometric
A

types of strength training

153
Q
  • single angle specific
  • must avoid valsalva maneuver
  • dynamic constant external resistance (DCER)
A

isometric

154
Q
  • muscular contraction in which the muscle exerts a constant tension
  • not the type of contraction with free-weights
    • free-weight, force varies throughout the ROM
A

isotonic

155
Q
  • equipment operates through a lever arm or cam
    • attempts to match resistance with changes in strength throughout a ROM
  • no perfect machine out there yet, cannor match ROM demands with individual differences
A

variable resistance

156
Q
  • muscular action performed at a constant angular velocity
  • resistance is not controlled, only the velocity (speed)
  • theoretically, it is possible for the muscles to exert a continual, maximal force throughout the full ROM
  • optimal number of sets is not clear
  • training velocity should be between 180-240/sec
A

isokinetic

157
Q
  • training can lead to significant strength gains, not clear what appropriate volume should be for strength gains and DOMS
  • can do training on isokinetic devices
  • can do training on machines by lifting weight greater than 1 RM with both legs/arms and then lowering with one
A

eccentric

158
Q
  • 20-30% of the difference between countermovement and a noncounter movement may be explained by elastic energy
  • elastic energy can be stored in tendons and other connective tissue
  • things to consider:
    • number of jumps
    • height of frop
    • weighted exercises
    • concurrent strength training
    • injury potential
A

plyometrics or stretch-shortening cycle exercises

159
Q
  • dynamic warmup, focus on mobility
  • skill work/check
  • WOD
  • recovery/flexibility
  • eat within 30 minutes
A

basic framework for all exercise bouts

160
Q

_ phase:
- 50-70% 1 RM (or estimated)
- one exercise/group
- 1-3 sets
- 8-15 reps
- rest varies for type of training

A

novice or preparatory phase (NSCA)

161
Q
  • increase MU recruitment
  • increase synchronization
  • increase firing frequency
A

neurologic adaptations

162
Q

development of _:
- 90-100% of 1 RM
- 3-4 exercise/group
- 1-5 sets
- 1-5 reps
- 3-5 min rest between sets

A

muscular strength

163
Q

development of _:
- 50-70% 1 RM
- 2-3 exercise/group
- 1-3 sets
- no more than 15 reps (advanced 25+)
- 30 sec-1 min rest between sets
- 2-6x/week

A

muscular endurance

164
Q

development of _:
- 80-90% 1 RM
- 3-4 exercise/group
- 1-4 sets
- 6-12 reps
- 1 min rest between sets

A

muscular strength/endurance

165
Q

development of _:
- 80-90% 1 RM
- 4-6 sets
- 12-15 reps
- 30 sec-1 min rest between sets

A

muscle size (hypertrophy)

166
Q

variation in the volume and intensity needed for optimal gains in power and strength

A

periodization

167
Q

periodization:
- _: high volume, low resistance exercise (50-80% 1 RM)
- _: increase strength, moderate volume and intensity
- _: peak, selective strength training, low volume, high intensity with intervals and sport specific exercises
- _: or active recovery, recreational activities and low intensity resistance training, different exercise modes

A
  • preparatory
  • first transition (specific)
  • competition
  • second transition
168
Q
  • basic beginners
    • high skill movements
    • lower skill strength movements
    • after several months, determine 1 RM
  • periodization
    • prep/hypertrophy 5+ reps
    • strength conversion 3 reps
    • power/competition 1-2 reps
A

USA weightlifting

169
Q
  • week 1: introduction of stimulus
    • 4 sets with 3 at top % or weight
  • week 2: high volume week
    • 5 sets with 3 at top % or weight
  • week 3: unloading week
    • 3 sets with 1 at top % or weight (wk 1)
  • week 4: max week
    • 4 sets with 1 at top new % or weight
A

USA weightlifting guidelines

170
Q

muscle _:
- strength training: in search of optimal strategies to maximize neuromuscular performance

A

hypertrophy

171
Q
  • 2x/week 48hr rest
  • 3/7: 5 sets- 1:3 reps, 2:4 reps, 3:5 reps, 4:6 reps, 7:7 reps
  • 70% 1 RM, 15 sec rest
  • 4x6 and 4x8 at 70%
  • 2.5 min rest
  • effective and efficient
A

3/7 method

172
Q

determine 1 RM for:
- bench
- press
- deadlift
- back squat
- 90% of 1 RM is training intensity
- deload week 3

A

JIm Wendler’s 5-3-1

173
Q

resistance training for _:
- be active for 60 mins/day
- resistance training
- recommendations for health is 1-3 sets

A

special populations

174
Q

strength training for kids:
- it is safe for children to begin strength training at _ if the following guildelines are observed:
- proper program design
- competent supervision
- correct teaching of exercise technique
- benefits:
- increased muscle strength and endurance
- increased bone development
- decreased injuries

A

8 years old

175
Q
  • no more than 20-60 minutes
  • maximum lifts are never attempted
  • determine 1 RM from a 10 RM
  • do not exceed 3 sets per exercise
  • do not perform fewer than 10 reps/set
A

training session for kids

176
Q

age and training progression for kids:
- any child that starts a training program with no experience
- should start at a _
- advance as they _

A
  • previous age group level
  • master the required techniques
177
Q
  • 2 days/week
  • these types of activities will help keep you from sarcopenia
  • 8-12 reps/activity that count as 1 set
  • at least 1 set of muscle-strengthening activities, but no gain even benefits, do 2-3 sets
A

seniors

178
Q

substance of technique used to improve performance; many are placebos
- categories:
- nutritional
- pharmacological
- physiological
- mechanical or biomechanical

A

ergogenic aid

179
Q
  • alcohol
  • anabolic phytosterols (plant sterols)
  • anabolic/androgenic steroids (AAS)
  • creatine
  • carbohydrate loading
  • ephedrine
  • caffeine (trimethylxanthine)
  • nitric oxide
  • Blood doping
  • EPO (erythropoetin)
  • sodium bicarbonate
  • tart cherry juice
A

examples of ergogenic aids

180
Q

Ephedrine, ergogenic aid:
- Classification and usage: _ sports ergogenic, _ drug, mimics the effects of natural epi and norepi
- Rx: asthmatic and cold/cough medications, herbal teas, and dietary supplements marketed for weight loss
- sports performance: mental strength and physical power, sport that uses any of the energy systems
- Theory: by activating the sympathetic response, enhance contractility, increase _ and _ ; enhance all performance especially aerobic activity
- Effectiveness: limited research, _ as an ergogenic aid

A
  • pharmacological, sympathomimetic
  • Q (cardiac output), blood glucose levels
  • no support for use
181
Q

Ephedrine, ergogenic aid:
- Safety: side effects include _, _, _, _, _
- Legal and Ethical: _ by IOC, many organizations do not check for use, can be difficult for those with asthma
- Recommendations: _ because there is no research to support their effectiveness and may be associated with severe health risks

A
  • headache, nervousness, GI distress, seizures, psychoses (death as well)
  • prohibited
  • not recommended
182
Q

prohibited by:
- NFL
- World Anti-Doping Code
- NCAA
- Olympic Comitte

A

blood doping and EPO bans

183
Q

Tart Cherry Juice (Montmoreney Cherry concentrate)
- Classification: _ ergogenic aid
- Theory: improves _ – anti oxidant & inflammation
- Effectiveness: early most research is promising, upregulation of antioxidant gene and protein expression
- Safety: _, can interact with some medications
- Legal and Ethical: considered _
- Recommendations: _

A
  • nutritional
  • recovery
  • stomach upset/diarrhea
  • legal and ethical
  • may be recommended

Exercise Physiology (9 decks)

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