EXPH 386 Exam 3
coordination and integration of the muscles of the body together with the nerves
that supply them - CORRECT ANSWER-Neuromuscular system
Cell body (soma) action - CORRECT ANSWER-dictates the critical firing rate of
the action potential
Cell body (soma) contains what - CORRECT ANSWER-structures involved in
replication and transmission of the genetic code
Are larger cell bodies (somas) associated with higher or lower critical firing rates?
- CORRECT ANSWER-higher
short neural branches that receive impulses through numerous connections and
conduct them toward the cell body - CORRECT ANSWER-Dendrites
extends from the cell body to deliver action potentials toward the muscle to the
motor endplate - CORRECT ANSWER-Axon
Are larger axons associated with slower or faster conduction velocities? -
CORRECT ANSWER-faster
a lipoprotein membrane that wraps around the axon over most of its length -
CORRECT ANSWER-Myelin sheath
What does the myelin sheath act as? - CORRECT ANSWER-an electrical
insulator that envelops the axon similar to the plastic coating around an electrical
wire
specialized cells that create or deposit myelin sheath around the axon -
CORRECT ANSWER-schwann cells
structures that interrupt the myelin sheath every 1 to 2 mm along the length of
the axon - CORRECT ANSWER-nodes of ranvier
,what do the nodes of ranvier allow? - CORRECT ANSWER-they allow the action
potential to jump from node to node covering a larger distance, increasing the
speed of the action potential
when the action potential jumps from node to node because of the uninsulated
gaps - CORRECT ANSWER-saltory conduction
What would happen if no myelin were present? - CORRECT
ANSWER-conduction velocities would be a lot slower since the action potential
would have to be conducted along the entire length of the axon
multiple extensions of the axon that innervate individual muscle fibers -
CORRECT ANSWER-nerve terminal branches
True or False. any one muscle fiber is only going to receive innervation from one
nerve terminal branch - CORRECT ANSWER-true
represents the interface between the end of the axon at the terminal branch and
the muscle fiber - CORRECT ANSWER-Motor endplate or neuromuscular
junction
Break down of skeletal muscle from biggest to smallest (6) - CORRECT
ANSWER-1. whole muscle
2. bundle of fibers
3. single fiber
4. myofibrils
5. sarcomere
6. contractile proteins
what are the skeletal muscles of the body composed of? - CORRECT
ANSWER-multi-nucleated cylindrical cells called fibers which run parallel to
eachother
Force is directed along what? - CORRECT ANSWER-the fiber's long axis
fiber length variation - CORRECT ANSWER-few millimeters (eye) to approx. 30
cm (leg)
,what are the connective tissue layers associated with skeletal muscle? -
CORRECT ANSWER-Endomysium
Perimysium
Fasiculus
Epimysium
Tendons
Periosteum
a fine layer of connective tissue that wraps each muscle fiber and separates it
from the neighboring fibers - CORRECT ANSWER-Endomysium
surrounds a bundle of up to 150 fibers - CORRECT ANSWER-Perimysium
a large bundle of fibers - CORRECT ANSWER-fasiculus
a fascia of fibrous connective tissue that surrounds the entire muscle -
CORRECT ANSWER-epimysium
dense connective tissue, the extension of the epimysium at the ends of the
muscle - CORRECT ANSWER-tendons
bone's outermost covering; tendons connect the muscle to this covering of the
bone - CORRECT ANSWER-periosteum
the muscle fiber membrane; a thin elastic membrane that encloses the fiber's
cellular contents - CORRECT ANSWER-Sarcolemma
What is the true fiber boundary? - CORRECT ANSWER-the sarcolemma
a loose collection of glycoproteins and collagen; outside the muscle fiber -
CORRECT ANSWER-Basement membrane
, contains the nuclei, substrates, and enzymes required for metabolism, the nuclei,
mitochondria, and other specialized organelles - CORRECT
ANSWER-Sarcoplasm
highly specialized network of tubular channels - CORRECT
ANSWER-sarcoplasmic reticulum
What does the sarcoplasmic reticulum allow for? - CORRECT ANSWER-a wave
of depolarization to spread rapidly from the sarcolemma to the inner environment
through the T-Tubules to initiate muscle contraction
What does the sarcoplasmic reticulum store? - CORRECT ANSWER-a large
concentration of calcium in the muscle fiber
Where do myonuclei reside? - CORRECT ANSWER-directly under the
sarcolemma at the periphery of the fiber
Myonuclei represent how much of the total nuclear pool? - CORRECT
ANSWER-85 to 95%
Explain the myonuclear domain hypothesis - CORRECT ANSWER-
normally dormant myoblasts that lie between the basement membrane and the
sarcolemma - CORRECT ANSWER-satellite cells
upon activation, this cell's functions include muscle regeneration, muscle growth,
exercise-induced adaptations, and recovery from injury - CORRECT
ANSWER-satellite cells
the location where the tendon joins a relatively stable skeletal part, generally the
proximal end of the muscle - CORRECT ANSWER-muscle origin
the location where the tendon joins a movable skeletal part, generally the distal
end of the muscle - CORRECT ANSWER-muscle insertion
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