Muscular System Flashcards
Protozoans and primitive algae use ___ or __ by means of a __ __ and ___ __. Amoeba extend their ____ in which the advancing cell membrane extends forward
cilia, flagella, power stroke, recovery stroke, pseudopodia
Flatworms contain longitudinal and ___ ___ muscles that contract ___ the hydrostatic skeleton. This causes the skeleton to flow ____, lengthening the animal
circular, bi-layered, against, longitudinally
Annelids or segmented worms advance by the action of ____ on the hydrostatic skeletons, The bristles in the lower part of each segment known as ___, __ the worms in the earth while the muscles push ahead. They also use ___ of longitudinal and circular muscles to worm
muscles, setae, anchor, peristalsis
The muscular system consists of __ ___ held together by ___ __ and muscles covered by a loose connective tissue known as ___.
contractile fibers, connective tissue, fascia
skeletal or ___ muscles are involved in ___ movement and contain fibers with ____ cells.
striated, voluntary, multinucleate
___ of striated muscle contain microfilaments and are divided into ___, which are individual contractile units separated by the border or _____. ___ are present in large amounts in myofibrils
myofibrils, sarcomeres, z-line, mitochondria
the sarcoplasm reticulum stores ___ and surrounds the myofibrils. The ___ is the same as the cytoplasm but in striated muscles. The ____ are the plasma membrane of muscles cells that can propagate ___ __. They are invaginated by ___ which are channels for ion flow. The plasma membrane wraps several myofibrils together to form a muscle ___/___
Ca2_. sarcoplasm, sacrolemma, action potentials, t-tubules, cell/fiber
The sarcomere is a structural unit of a myofibril in striated muscle and is composed of thin _____ made of ___ __ and thick filaments made of _____ ____.
filaments, actin polymers, protein myosin
The boundary of a single sarcomere and anchors thin filaments
z-line
the center of a sarcomere
m-line
the region containing thin filaments only
i band
the region containing thick filaments only
h band
the area where actin and myosin overlap
a band
the __ and ___ bands reduce during contraction but the ___ band does not
H, I, A
The contraction of skeletal muscles can squeeze ___ and ___ vessels, aiding in circulation. The process occurs via the __ ___ model, which occurs via an _____ ___ ___ response.
blood, lymph, sliding filament, all or nothing
In the all or nothing response, the action potential of a neuron releases _____ when it meets a ___ __. The action potential is then generated on the ___ and throughout the ____. The sarcoplasmic reticulum releases ____ and __ __ ___ form, resulting in the binding of the former to ____ on an __ ___. At the end of each contraction cycle, Ca2_ is actively pumped back to the __ ___
ACh, neuromuscular junction, sarcolemma, t-tubules, Ca2_, myosin cross bridges, toponin, actin helix, sarcoplasmic reticulum
Initially, the myosin head is bound to the __ __ from the previous contraction. When ___ binds to the myosin head, myosin and actin ___. When ATP is converted to ____ and ___, the myosin head is cocked back. After death, ATP production ceases, and the __ ___ remain locked in place.
actin filament, ATP, unbind, ADP, Pi, cross bridges
After myosin and actin unbind, Ca2+ binds to ___, pulls back the ____ and exposes the ___ ___ on actin. Then ___ __ between the myosin heads and actin filaments form. The sliding motion of actin brings the ____ together and ___ and ___ are released. Then the cycle starts again when new ___ attaches to the myosin head
troponin, tropomyosin, attachment sites , cross bridges, z-lines, ADP, Pi, ATP
The strength of contraction of a ____ muscle fiber cannot be increased but the strength of the __ ___ can be increased by recruiting more muscle fibers.
single, overall contraction
A neuron and the muscle fibers it innervates
motor unit
Each muscle fiber forms synapses with ____ motor neuron, but each motor neuron typically synapses with ___ muscle fibers. The force of contraction depends on the __ and __ of active motor units and the ___ of action potentials
one, many, number, size, frequency
___ motor units tend to be activated first, and ____ ones are recruited as needed. There is a smooth increase in force generated, from ___ ___ to ___ ___. This occurs when one muscle fiber contracts in response to a stimulus
small, larger, slow twitch, fast twitch
Recruitment occurs when a greater ____ of muscle fibers are activated by the brain rather than an increase in the ___ of action potentials that stimulate muscle fiber contraction. ____ ____ tend to use smaller motor units, whereas muscles like the ___ requiring greater force, have larger motor units
quantity, frequency, intricate movements, back
response of a single muscle fiber to a brief stimulus
simple twitch
In a simple twitch the __ __ is the time between the stimulation and the onset of contraction, or the ___. This is when an __ __ spreads on the sarcolemma and ____ ions are released. The muscle then contracts following the ___ __ model. Then the muscle returns to a ______ position and undergoes a ___ ___ period.
latent period, lag, action potential, Ca2+, sliding filament, relaxed, absolute refractory
when contractions combine and become stronger and more prolonged
summation
continuous sustained contraction where a muscle cannot relax
tetanus
A state of partial contraction where the muscle is never completely relaxed
tonus
____ stimuli is where no motor units respond, whereas ____ is where one motor unit responds. ___ is when an increasing number of motor units respond
sub-threshold, threshold, sub-maximal
In type I skeletal muscle, there is ___ twitch, lots of __ and ___, and ____ ____, meaning they split ATP at a slow rate causing the fibers to be flow to ____ but have slow ___ __. They appear __ and have a ___ diameter
slow, myoglobin, mitochondria, aerobic endurance, fatigue, contraction velocity, red, small
In type IIA skeletal muscle there is ___ twitch, lots of ___ and less ___ than type one. They can use both ____ and ___ unequally, and split ATP at a higher rate and contract ___. This also means they are faster to ___. They appear ___ __ and are ___ in diameter
fast, myoglobin, endurance, aerobic, anaerobic, faster, fatigue, reddish pink, intermediate
In type IIB skeletal muscle there is ____ twitch, and ___ myoglobin, as it primarily uses ____ _____. There is lots of ____ to generate power and ATP is split at a ___ rate, making it the fastest to fatigue. They appear __ and have a ___ diameter.
fast, low, anaerobic glycolysis, glycogen, faster, white, large
Adult human skeletal muscle generally doesn’t undergo ___ to create new muscle cells, but will increase in ____ (____) which results in an increase in the ___ of muscle fibers, the number of ____ and ___ and the ___ ___
mitosis, size, hypertrophy, diameter, sarcomeres, mitochondria, sarcomere length
The smooth muscle is mainly ______ contains one central ___, lacks ___, is stimulated by the ___ ___ ____, and are ___ to contract.
involuntary, nucleus, striation, autonomic nervous system, slow
Smooth muscle does not rely on ___ ___. Instead ___ ___ are attached to __ __ spread throughout the cell
sarcomere organization, intermediate filaments, dense bodies
For smooth muscles to contract, the __ and __ filaments are attached to ___ ___ which contract. The Intermediate filaments pull __ __ together and the smooth muscle length shrinks
thick, thin, intermediate filaments, dense bodies
single-unit smooth muscles are ___ and connected by __ ___. They are found in the ___, ___ and ___. Multi-unit smooth muscles have each fiber directly attached to the ___ and can contract ___. They are found in the __ and ____.
visceral, gap junctions, stomach, uterus, bladder, neuron, independently, iris, bronchioles
In addition to the neuronal response, smooth muscles can respond to __, changes in ___, ___, ___ levels, ___ and ion concentration
hormones, pH, O2, CO2, temperature
Smooth muscles do not have ____, striations, troponin or tropomyosin. It instead uses ___ __ ___ ___ to overcome the lack to troponin
t-tubules, myosin light change kinase
Cardiac muscle has a ___ appearance due to sarcomeres and has one or two central ___. The cells are separated by _____ ___ that have gap junctions to allow action potentials to ___ __via __ ___. They contract ___ and have lots of ___. Cardiac muscle is not connected to ___ rather it forms a __ that contracts upon itself and grows via ___.
striated, nuclei, intercalated discs, chain flow, electrical synapse, involuntarily, mitochondria, bone, net, hypertrophy
___ and __ muscles are ___ or capable of contracting without stimuli from nerve cells
smooth, cardiac, myogenic
