6.5 Post cell/muscle/nerve physio Flashcards
A bundle of muscle fiber in the skeletal muscles is called:
a. Fasciculus
b. Myofilaments
c. Myofibrils
d. Sarcomere
A
Type Ia afferents in the muscle spindle is/are also known as:
a. Annulospiral nerve endings
b. Flowerspray nerve endings
c. Alpha motor neuron
d. Gamma motor neuron
e. A beta nerve fibers
A
The following statement describes the principle of all or none law, EXCEPT:
a. Physiologic mechanism exist for fine gradation of the force of muscle contraction
b. The law applies only to individual motor units
c. All muscle fibers in a given motor unit contract or relax simultaneously
d. Activated muscle fibers contract maximally if the nerve activates the motor fibers of a motor unit sufficiently
e. In the same motor unit, it is possible for some muscle fiber to contract while others are relaxed
E
True about the myelin sheath:
a. Increases conduction velocity in large A beta and C fibers
b. Absent at the nodes of Ranvier thereby facilitating saltatory conduction
c. The Myelin sheath acts as a conductor of electricity
d. A and B
e. All of these are correct
B
Glial cell responsible for myelin production in the PNS
a. Oligodendrocytes
b. Ependydymal
c. Schwann cells
d. Microglia
e. Astrocytes
C
Generation of end plate potential in the sarcolemma of skeletal muscle is linked with
a. Voltage-gated channels
b. Ligand-gated channels
c. Mechanical-gated channels
d. Thermal-gated channels
B
The connective tissue that covers individual muscle bundle:
a. Epimysium
b. Perineurium
c. Perimysium
d. Subcutaneous fascia
e. Endomysium
C
The portion between two Z-discs is called:
a. H zone d. Y band
b. I band e. Sarcomere
c. A band
E
The plasma membrane of a skeletal muscle fiber is called:
a. Sarcoplasm
b. Sarcolemma
c. Sarcomere
d. Sarcoplasmic Reticulum
e. Neurolemma
B
Type of nerve fiber that has the fastest conduction:
a. Large myelinated axons
b. small myelinated axons
c. Small unmyelinated axon
d. large unmyelinated axon
A
The main neurotransmitter of the neuromuscular junction:
a. Calcium
b. Acetylcholine
c. Serotonin
d. Norepinephrine
e. Epinephrine
B
This thin filament has a high affinity for calcium:
a. Troponin I
b. Troponin C
c. Troponin T
d. Actin
e. Tropomyosin
B
Which among the following is the correct sequence for muscle contraction?
I. Action potentials arrive at the presynaptic terminal
II. Troponin C of the actin filament binds with Calcium
III. Acetylcholine is released in the synaptic cleft
IV. Power stroke occurs
V. ATP attaches to the myosin head
a. I II III IV V
b. I III II V IV
c. I II IV III V
d. I III II IV V
D
Location of the “triad” in skeletal muscles i
a. At A-H junction
b. Along the Z line
c. At A-I junction
d. Along the M line
C
Which of the following does NOT properly describe a sarcomere?
a. The M line divides the A band
b. I band contains thin filaments
c. The H zone contains thin and thick filaments
d. Width of I band changes during contraction, A band does not
e. Actin filaments slide toward each other during contraction
C
True of thin filaments:
a. Actin is the only thin filament
b. Consists of two heads: one is a binding site for ATP, the other is for the formation of cross bridges
c. Its backbone is a double stranded filamentous G actin, made of individual globular molecules called F actin
d. Tropomyosin spiral around the binding sites and attached intermittently are troponin molecules altogether forming a troponin- tropomyosin complex
e. None of these
D
In comparing electron micrographs of a relaxed skeletal muscle fiber and a fully contracted muscle fiber which would be seen only in the relaxed fiber?
a. Z lines d. A bands
b. Triads e. H zones
c. Myosin
E
Which of the following generates the lowest tension?
a. Fast concentric
b. Slow concentric
c. Fast eccentric
d. Slow eccentric
e. Isometric
A
Skeletal muscle contraction stops when:
a. ATP is released from myosin
b. Decreased concentration of intracellular calcium ions
c. Ionization of cell
d. Sodium pump reversal
e. Depolarization of the cell
B
Which of the following muscle is involuntary non- striated?
a. Cardiac and smooth muscles
b. Cardiac muscles
c. Skeletal and cardiac muscles
d. Smooth muscles
D