Flashcards in Exp 2: Skeletal Muscle Physiology Deck (47)
Part of sarcolemma that carries the action potential
T-tubule plus two terminal cisternae
Part of sarcoplasmic reticulum that stores calcium
Plasma membrane of muscle cell
Intracellular fluid around organelles
Endoplasmic reticulum in muscle cell
Synaptic vessicles in the motor neuron terminal end contain the neurotransmitter:
Opening of ligand-gated channels leads to ________ of the motor end plate.
Once the post-synaptic membrane depolarizes, an action potential is propagated along the _____ down into the interior of the cell via the ____.
What molecule has a binding site for myosin head?
Which molecule covers the binding site?
Which molecule has a binding site for calcium?
What molecule must bind to the myosin head in order for it to disconnect with actin?
A motor unit:
is composed of a neuron and all the muscle fibers it innervates.
Muscle tone refers to:
a state of sustained, partial contractions which is necessary to maintain posture
Muscle tone is the result of:
asynchronous firing of motor units.
The tension developed by a skeletal muscle can be increased by increasing the:
-number of motor units stimulated.
-stimulation to each motor unit.
Which of the following contract in an all or none fashion?
single muscle fiber
Match the three phase of a muscle twitch with their definitions.
A) Sarcomeres shorten
B) Sarcomeres return to resting length
C) Sarcomeres are at resting length
C) Latent period
Under normal circumstances, at the level of single skeletal muscle fibers, there are:
True or False: The muscles of the eye need to make precise small motor movements. Therefore, you would find large motor units in the eye, while you would find small motor units in postural muscle such as the thigh.
Below is a list of the four phases of temporal summation. Put them in the correct order:
Activity 1: As the stimulus voltage was increased in this activity, which of the following occurred?
The muscle force generated increased.
Activity 1: Which of the following can trigger a muscle twitch?
release of acetylcholine and electrical stimulation
Activity 1: Which of the following describes the relaxation phase?
The sarcomeres are increasing in length, and the force generated decreases.
Activity 2: As the stimulus voltage increased, the resulting muscle tension _______.
increased to a point until it reached a plateau
Interpretation-Activity 2: In the lab, if a researcher finds that the threshold stimulus to induce an action potential in a muscle fiber's sarcolemma was 3.0 volts. Which of the following would result in muscle tension?
3.0 volts and 4.0 volts
Activity 2: Increasing the applied voltage in the simulation corresponds to which in vivo event?
Motor unit recruitment
Activity 2: Which of the following is occurring during the contraction phase?
Cross-bridge cycling is taking place.