Muscle Physio Flashcards
•Striated- a striped or banded pattern due to the arrangement of contractile proteins (actin and myosin) within the cells.
•Voluntary-This means that the contraction of skeletal muscles is under conscious control, meaning you can decide when to move them.
Skeletal muscle tissue
•Striated
•Involuntary
•Autorhythmicity-This is the unique ability of cardiac muscle to generate its own rhythmic electrical impulses, independent of external nerve stimulation
Cardiac muscle tissue
Involuntary
Smooth muscle tissue
ability to respond to certain stimuli by producing electrical signals/action potentials
Electrical excitability
ability of muscular tissue to contract forcefully when stimulated.
Contractility
ability of muscular tissue to stretch within limits, without being damaged.
Extensibility
ability of muscular tissue to return to its original length and shape after contraction or extension.
Elasticity
main component of thin filaments
Actin
main component of thick filaments
Myosin
compenent of thin filament
Tropomyosin
component of thin filament
Troponin
has strong affinity to actin
Troponin I
has strong affinity to tropomyosin
Troponin T
has strong affinity to calcium
Troponin C
connects & aise to M mne of sarcomere
Titin
Helps stabilize thick filament
Titin
Accounts for the elasticity and extensibility of myofibrils
Accounts for the elasticity and extensibility of myofibrils
Titin
Prevents overstretching of the sarcomere
Titin
attaches to actin molecules of thin filaments and to titin molecules
A-actinin
forms M line of sarcomere
Myomesin
Binds to titin molecules and connects thick filaments to one another
Myomesin
wraps around entire length of each thin filament
Nebulin
Helps anchor thin filaments of Z discs and regulate length of thin filaments
Nebulin
links thin filaments of sarcomere to integral membrane proteins in sarcolemma
Dystrophin
Help reinforce sarcolemma and transmit tension generated by sarcomere to tendons
Dystrophin
separates one sarcomere from the next.
Z disc
dark, middle part of sarcomere that extends entire length of thick filaments; and those parts of thin filaments that overlap the thick
A band
lighter, less dense area of sarcomere that contains the remainder of thin filaments but no thick filaments
I band
narrow region in center of each A band
H zone
region in center of H zone that contains proteins that hold thick filaments together
M line
contain only actin filaments
Light bands/I bands
WIDTH OF THE A BAND IS
Constant
Z lines move _____
Closer together
Lies between two successive Z discs
Sarcomere
actin filaments completely overlap the
Myosin filaments
The side-by-side relationship between the myosin and actin filaments is
Difficult to maintain
This is achieved by a large number of filamentous molecules of a protein called
Titin
is the repeating sequence of events that causes sliding of the filaments:
CONTRACTION CYCL
the cross-bridge generates force as it swivels or rotates toward the center of the sarcomere
Power stroke
myosin ATPase splits ATP and becomes energized
Splitting ATP
the myosin head attaches to actin, forming a cross-bridge
Forming cross-bridges
Nerve Resting Membrane Potential=
-70mV
Threshold potential=
-55 mV
Overshoot=
+30mV
•Overshoot= +30mV
•Skeletal Muscle Resting Membrane Potential=
-90 mV
Cardiac Muscle Resting Membrane Potential=
-80 mV
When the muscle fiber contracts _______, the tension developed is proportional to the number of cross-bridges between the actin and the myosin molecules
Isometrically
When muscle is _______, the overlap between actin and myosin is ______ and the number of cross-linkages is therefore reduced.
Stretched, reduced
Conversely, when the muscle is _______ than resting length, the distance the thin filaments can move is _______.
Shorter,reduced
The velocity of muscle contraction varies _______, with the load on the muscle
Inversely
At a given load, the velocity is _______ at the resting length and declines if the muscle is shorter or longer than this length
Maximal
Carries high-energy phosphate bond similar to the bonds of ATP
Phosphocreatine/ Anaerobic lactic system
Release of ________ causes bonding of a new phosphate ion to ADP to reconstitute the ATP
Phospocreatine
Doesn’t require oxygen to function and lactic because it doesn’t produce lactic acid.
Phospocreatine
Used to reconstitute ATP and phosphocreatine
Glycolysis of glycogen
Rapid enzymatic breakdown of the glycogen to ________ and l liberates energy that is used to convert ADP to ATP
Pyruvic, lactic acids
The _____can then be used directly to energize additional muscle contraction and also to re-form the stores of phosphocreatine
ATP, glycolysis
The contribution of the fast glycolytic system to energy production _______ rapidly after the initial ten seconds of intense exercise. This coincides with a drop in power output as the immediately available phosphagens, ATP and PC begin to _____
Increases, run out
of sustained activity the majority of energy comes from the anaerobic glycolytic system
30 seconds
Combining oxygen with the end products of glycolysis and with various other cellular foodstuffs to liberate ATP.
Oxidative metabolism
More than 95 percent of all energy used by the muscles for sustained, long-term contraction is derived from this source.
Oxidative metabolism
If the energy demands of exercise cannot be met by oxidative phosphorylation, an ______ is incurred.
Oxygen debt
After completion of exercise, respiration remains above the resting level in order to ______this oxygen debt. The extra oxygen consumption during this recovery phase is used to restore metabolite levels (such as creatine phosphate and ATP) and to metabolize the lactate generated by ______.
Repay,glycolysis
The increased ________ work during recovery also contributes to the increased oxygen consumption seen at this time and explains why more oxygen has to be “repaid” than was “borrowed.”
Cardio,respiratory,
•Some ________occurs even with low levels of exercise because ______ motor units consume considerable ATP, derived from creatine phosphate or glycolysis, before oxidative metabolism can increase ATP production to meet steady-state requirements.
Oxygen debt,slow oxidative
•Some ________occurs even with low levels of exercise because ______ motor units consume considerable ATP, derived from creatine phosphate or glycolysis, before oxidative metabolism can increase ATP production to meet steady-state requirements.
Oxygen debt,slow oxidative
is much greater with strenuous exercise, when fast glycolytic motor units are used
Oxygen debt
is approximately equal to the energy consumed during exercise minus that supplied by oxidative metabolism
Oxygen debt
