79 terms

Anatomy chapter 10

which type of muscle tissue has the greatest effect on the body's heat production?
sacromere is best defined as
a repeating unit of striated muscle
when a muscle contraction develops tension but doesn't shorten the muscle, the contraction is called
skeletal muscle does each of these except
pump blood
muscle fatigue occurs due to a buildup of _______ and _____ in pH
lactic acid; decrease
which thick filament binds to actin once its active binding sites are exposed
all of the following are found in both skeletal and cardiac muscle fibers except
intercalated disks
the biochemical reaction that consumes the majority of a muscle's ATP is the
actin myosin cross-bridge cycle
muscles are attached to bones by tendons or
a thin layer of connective tissue that surrounds a muscle fascicle is called the
the dense layer of connective tissue that surrounds the entire skeletal muscle is the
in a sacromere, thick filaments are linked laterally by proteins of the
M line
the advantage of having many nuclei in a skeletal muscle fiber is
the ability to produce large amounts of the muscle proteins needed for growth and repair
skeletal muscle fibers are formed from embryonic cells called
the plasma membrane of a skeletal muscle fiber is called the
muscle fibers differ from "typical cells" in that muscle fibers
have many nuclei
at rest, the tropomyosin muscle is held in place by
troponin molecules
at rest, active sites on the actin are blocked by
tropomyosin molecules
the series of membranous channels that surround each myofibril is the
sacroplasmic reticulum
when a skeletal muscle fiber contracts
the zones of overlap get lager, the h bands and i bands get smaller, zline gets closer together, width of a band remains constant
since each myofibril is attached at either end of the muscle fiber, when sacromeres shorten, the muscle fibers
the neuromuscular junction is a connection between a neuron and a
muscle fiber
the end of a neuron, where acetylcholine-filled vesicles are located is called the
synaptic terminal
what is the synaptic cleft
space between the synaptic terminal and the motor end plate
inside a neuron, acetylcholine is contained within
what causes the vesicle inside a neuron to fuse with the plasma membrane
an action potential in the neuron
acetylcholine receptors are primarily located
on motor end plate
an action potential in the muscle fiber causes
the muscle fibers to contract
the role of acetylcholinesterase in the neuromuscular junction is to
remove acetylcholine from the synaptic cleft
inside a muscle, bundles of single muscle fibers from
the muscle action potentials that initiate contraction are transmitted from the interior of the muscle fiber by
t tubules
t tubules and the terminal cistern are clustered into structures called
the sacroplasmic reticulum contains
which organelle completely surrounds each myofibril inside a muscle fiber
sacroplasmic reticulum
to what regulatory protein does calcium bind during the initiation of the contraction cycle in skeletal muscle fibers
which causes the active site of actin to be exposed or uncovered
which most correctly describes excitation in the context of excitation-contraction coupling in skeletal muscle
the generation of an action potential in the sacrolemma
which of the following phrases best decries how excitation is couples to contraction in skeletal muscle fibers
through calcium release from the sacroplasmic reticulum
MH is a rare genetic disease. which of the following best describes how anesthesia would affect the skeletal muscles of a patient with MH
the muscles would contract because of calcium binging to troponin
during neuromuscular transmission, the axon terminals release
the muscle action potential penetrates into a fiber along the
transverse tubules
in response to an action potential along the transverse tubules, the ____ release(s) calcium ions into the sacroplasm
sacroplasmic reticulum
the narrow space between the synaptic terminal and the muscle fibers is the
synaptic cleft
each skeletal muscle fiber is controlled by a motor neuron at a single
neuromuscular junction
active sites on the actin become available for binding after
calcium binds to troponin
receptors for acetylcholine are located on the
motor end plate
the action potential is conducted into a skeletal muscle fiber by
transverse tubules
the most important factor in decreasing the intracellular concentration of calcium ion after contraction is
active transport of calcium into the sacroplasmic reticulum
the calcium ion binds to troponin
tropomyosin moves into the groove between the helical actin strands
after death, muscle fibers run out of ATP and calcium begins to leak from the sacroplasmic reticulum into the sacroplasm resulting in a condition known as
rigor mortis
in sacromere, cross-bridge attachment occurs specifically in the
zone of overlap
triggering of the muscle action potential occurs after
acetylcholine binds to chemically-gated channels in the end plate membrane
how would the loss of acetylcholinesterase from the motor end plate affect skeletal muscle
it would cause spastic paralysis- muscles contract and unable to relax
when acetylcholine binds to receptors at the motor end plate, the end plate membrane becomes
more permeable to sodium ions
the cytoplasm of the neuromuscular terminal contain vesicles filed with molecules of the neurotransmitters
synaptic vesicles contain neurotransmitters that are released by ____ when the action potential arrives
the muscle weakness of myasthenia gravis results from
loss of acetylcholine receptors in the end-plate membrane
a patient takes a medication that clocks ACh receptors of skeletal muscle fibers. What is this drug's effect on skeletal muscle contraction
reduced the muscle's ability for contraction
to increase muscle tension, the nervous system can
increase stimulation frequency, recruit large motor units, increase the number of active motor units
the rapid rise and fall in force produced by a muscle fiber after a single action potential is
a twitch
a single motor neuron together with all the muscle fibers it innervates is called
a motor unit
in an isotonic contraction
muscle tension exceeds the load and the muscle lifts the load
anaerobic glycolysis provides energy for muscle contraction when the supply of __ is limited
during the core cycle, in the liver
glucose is produced from lactic acid
during the recovery period the body's need for oxygen is increased because
additional oxygen is required to restore energy reserves consumed during exercise
a resting muscle generates most of its ATP by
aerobic metabolism of fatty acids
creatine phosphate
acts as an energy reserve in muscle tissue
during anaerobic glycolysis
oxygen is not consumed, pyretic acid and ATP produced, carbohydrate is metabolized
after heavy exercise, if energy reserves in a muscle are depleted, ___ occurs
an oxygen debt
which would lead to increased oxygen comsuption
all of the above
the ___ type of muscle fiber has relatively few mitochondria
type of muscle fiber that is most resistant to fatigue is the ___ fiber
fast fibers
have low resistance to fatigue and have quick twitches
fast muscle fibers can adapt to aerobic metabolism by generating more mitochondria in response to
repeated, exhaustive stimulation
slow muscle fibers compared to fast muscle fibers
generate less tension, rich in red protein myoglobin, take 3x as long to reach peak tension, have smaller fiber diameters
which is true about cardiac muscle fibers
single nucleus, have long twitch duration compared to skeletal fibers, fibers branch
ability of smooth muscle to function over a wide range of lengths is called
what is not a characteristic of smooth muscle
s. muscle connective tissue forms tendons and aponeuroses
which is not a function of smooth muscle tissue
forcing blood from heart into major arteries