Motor Neuron
What is the function of motor neuron?
Signal muscles to contract.
Allows for voluntary control.
The striated appearance of skeletal muscle fiber is mainly due to:
a. Variations in the thickness of the sarcolemma
b. The arrangement of the actin and myosin
c. The t-tubules
d. The intracellular myoglobin
b. The arrangement of the actin and myosin
What is the plasma membrane that encloses the muscle fiber?
Sarcolemma
Which of the following occurs first in the sliding filament theory?
a. Ca2+ is released from the SR
b. Myosin binds to actin
c. AP travels through the T-tubules
d. Depolarization of the sarcolemma
D. Depolarization of the sarcolemma
Which of the following fiber types would be expected to have the fastest maximum shortening velocity?
a. T1
b. T2X
c. T2A
a. T1
When a nerve impulse is initiated, the action potential will travel the entire length of the axon without a decrease in voltage. What is this known as?
a. An Action Potential Law
b. All or None Law
c. Sliding Filament Theory
d. Henneman Size Principle
b. All or None Law
Skeletal muscle is important for what function?
a. Force generation for locomotion and breathing
b. Force generation for postural support
c. Heat production periods of cold stress
d. A & B
E. All of the above
e. all of the above
What triggers depolarization in the T-tubules?
a. ATP
b. AP
c. Calcium
d. Actin
c. calcium
True or false. During the power stroke, the myosin head pivots moving the z-lines closer to the M-line.
true
True or False. Force and velocity are positively related.
false
What site receives AP? Stores?
Dendrites. Cell body.
This muscle has over 600 in the body.
A. Skeletal
B. Cardiac
C. Smooth
Skeletal
Stores calcium in the muscle fiber
Sarcoplasmic reticulum (SR)
Once Ca2+ is bound to the thin filament, what part of the thin filament changes its shape and position?
a. Troponin
b. Tropomyosin
c. Actin
d. Myosin
b. Tropomyosin
What are the three items needed for a muscle contraction?
AP
CALCIUM
ATP
Comprised of a motor neuron and all of the muscle fibers it connects to
Motor unit
Which of the following is not associated with Type 1 fibers?
a. High oxidative capacity
c. small CSA
b. Low force production
d. high contractile speed
d. high contractile speed
Which structure within the skeletal muscle spreads the AP impulses rapidly within individual myofibrils?
a. T-tubules
b. Sarcoplasmic Reticulum
c. Mitochondria
a. T-Tubules
Once the binding site is revealed, a crossbridge is formed. This is a connection between:
Actin and Myosin
In relation to the size principle of motor unit recruitment, the mechanism of recruitment order is directly related to
a. The size (CSA) of muscle fibers
b. Size (diameter) of the motor axon
c. Size of the motor neuron (cell body and dendrites)
d. None of the above
a. The size (CSA) of muscle fibers
Axons with larger myelin sheaths conduct impulses ___________ small, or non-myelinated fibers.
faster than
Somewhat fatigue resistant, high anaerobic capacity and a large CSA all explain
A. Type 1
B. Type 2a
C. Type 2x
B. Type 2a
The ______ neurotransmitter is released from the synaptic bulb, crosses the synaptic cleft and binds to the _________.
ACH, Muscle
After contraction, when Na+ moves back out of the muscle cell and k+ in, this is known as:
a. Depolarization
b. Repolarization
c. Hyperpolarization
b. Repolarization
At what percent does peak power occur at?
a. 10%
b. 20%
c. 30%
d. 40%
c. 30%