Quiz Info Exam 2 Prep Flashcards
Role of sacroplasmic reticulum ca2+ ATPase (SERCA)
As soon as calcium flows into sarcoplasm from SR, SERCA begins pumping calcium back into SR against gradient
What leads to stop in muscle contraction and muscle relaxation
SERCA
A bundle of muscle fascicles
Whole muscle
Intracellular storehouse of calcium ions
SR
Contracting subunits that make up each myofibril
Sacromeres
A bundle of muscle fibers
Muscle fascicle
Contractile assembly of proteins in a muscle cell
Myofibirl
In the presynaptic terminal of a neuromuscular junction there’s what…
Somatic motor neuron, clusters of synaptic end bulbs, contains ach
Which property was of slow twitch muscles exceeds the performance of fast twitch muscles
Endurance
Slow myosin ATPase is better for
Endurance exercise, for long periods of time
Slow twitch muscles have what diameter
Small
Do slow twitch or fast twitch muscles stores more glycogen
Fast twitch
Structural feature of sacromere that serves as an anchor to actin thin filament or edges of sacromere
Z line or disc
Which factor determines the amount of tension generated by a single motor unit
Number of muscle fibers that have synapses with the motor neuron
Each motor unit has how many motor neurons
1
To counter the perceived length change reported by muscle spindles, the quad…
Activated to contract
Reflex actions don’t require
Higher centers of motor control
What membrane protein facilitates muscle relaxation by returning calcium into SR
Ca ATPase
Calcium release channel
RyR
Open flow occurs down calcium concentration gradient, calcium flowing out of SR through which membrane protein
RyR
Facilitates muscle activation by opening the calcium release channel
DHP membrane protein
is the DHPR involved in muscle relaxation
No
What causes the detachment of myosin from actin at the end of the cross-bridge power stroke
Binding atp
Without conformational change that atp binding causes myosin would
Remain tightly associated with actin (rigor mortis)
If myosin has atp in its nucleotide binding site it
Hydrolysis it
If an attached myosin bound, then released ATP its affinity’s from actin would be
Strong and reattach firmly
What description best describes the isotonic twitches measured during the muscle lab by stimulating the subjects motor point
The time to reach the peak of the twitch was shorter than time to return to rest position (activation faster than relaxation)
What event is triggered by the binding of ach to its receptor on a skeletal muscle cell at the neuromuscular junction
EPP
Binding of acetylcholine to its receptor opens the
Ligand gated channel to cause an EPP
Ach binding is or is not a direct cause of calcium release
Is not
Action potentials require
VG Na channels
Network of connecting passages that conduct action potential through a muscle cell
T tubules
Extension of the plasma membrane
T tubules
Network of passages but doesn’t run from the sarcolemma through entire cell
SR
Gap junctions only found in
Cardiac muscles
What factor determines the duration of the latent period for an isotonic contraction
The load the muscle is working to move
Heavier load=
Longer it takes to generate force
Additional time when generating enough force to move a heavy load is the
Latent period
Muscle action potentials __ in amplitude
Don’t vary
Skeletal muscle doesn’t use what during its contractions
EC calcium
In a contractile myocyte, the lengthening of the cardiac sarcomere corresponds to which ONE of the following?
Ventricular diastole
Consider the direction of DE-polarization versus the direction of RE-polarization of the left ventricular muscle. What does this mean for the cells of the endocardium (inside heart muscle) compared to the epicardium (outside heart muscle)?
Cells in the endocardium are first to depolarize and last to re polarize
Autorhythmic activity of pacemaker cells can be modulated by:
Atrial DE-polarization
Rapid RE-polarization by voltage-gated K+ channels
The unstable resting potential due to the F-type channel by the autonomic nervous system
The unstable resting potential due to the F-type channel by the autonomic nervous system
The “funny” current or channel has an unstable resting membran potential and can be modulated by the
ANS
Which ONE of the following is TRUE regarding calcium-induced calcium release (CICR)?
A. The Na+/Ca2+ exchanger (NCX) returns Ca2+ to the sarcoplasmic reticulum
B. Ca2+ from the sarcoplasmic reticulum is released into the cytoplasm by the ryanodine receptor
C. DE-polarization of the sarcolemma activates voltage-gated dihydropyridine receptors to prevent Ca2+ release
B
Consider electrical conduction in the heart. Which ONE of the following is TRUE?
A. There are fewer pacemaker cells in the SA node compared to the AV node
B. Conduction slows down in the intermodal pathways of the atria
C. The AV node is the slowest to conduct because it has the fewest gap junctions
C