Most skeletal muscles cross one or more joints to bring about movements in those joints. Which attach of a muscle usually remains stationary when a muscle contracts?
Most skeletal muscles cross one or more joints to bring about movements in those joints. Which attach of a muscle usually moves when a muscle contracts?
What portion of a whole muscle produces the force?
What is a muscle producing a particular movement called?
What is a muscle that assists the prime mover in its action?
Synergist (examples: Triceps & anconeus)
What is a muscle whose actions oppose those of the prime mover?
Because of the tissue composition of an individual skeletal muscle what level of organization is a muscle such as the biceps brachii or pectoralis major classified within?
What is the study of muscle?
List the four characteristics of muscle tissue.
In some situations, as when you lay an object on a table, a muscle is actually getting longer while doing what you want. One of the characteristics of muscle that most authors list is contractility. Yet a muscle allowing you to extend your elbow in a controlled fashion is not getting shorter. What is it
What is another term for skeletal muscle cell?
What are five functions of muscle tissue. Be aware of how smooth and cardiac muscle as well as skeletal muscle might be involved in these functions.
maintenance of posture
storage and movement of materials
What are cordlike structures that attach muscle to bone, skin, or other structures?
What are sheets of tissue that connect muscle to bone, skin, or other structures?
What is another term for the plasma membrane of a muscle fiber?
What histological term refers to the stripes seen in cardiac and skeletal muscle fibers?
What is histological term for the functional connection between a muscle fiber and a motor neuron?
the neuromuscular junction
What is the specialized region of the sarcolemma at the neuromuscular junction?
motor end plate
What are all of the muscle fibers innervated by a single motor neuron?
a motor unit
What is the functional unit of a whole skeletal muscle?
the motor unit
How are contractions of varying strengths produced within a skeletal muscle?
by recruiting varying numbers of motor units
What is the number of muscle fibers innervated by a single motor neuron?
the innervation ratio
What is the relative innervation ratio for muscles involved in fine skeletal movements?
low (1:10 is the low end)
What is the relative innervation ratio for muscles involved in gross skeletal movements?
high (1:2000 is the high end)
What is the process of activating motor units?
What are the longitudinal, parallel subunits within a muscle cell?
What are the long, thin strands of contractile proteins within a muscle fiber?
What are the two types of myofilaments within a muscle fiber?
thick and thin filaments
What protein makes up the thick filaments of a muscle fiber?
What protein makes up the thin filaments of a muscle fiber?
What is the functional unit of a muscle fiber?
What structure are thin filaments attached to proximally and distally within a sarcomere?
What structure makes up the proximal and distal borders of a sarcomere?
What structure attaches a thick filament to the Z-line?
a titin filament
Shortening of a sarcomere occurs due to what action?
sliding of the myofilaments over one another
What part of myosin changes configuration to bring about contraction?
the cross bridge (myosin head)
What part of a sarcomere functions to split ATP to ADP and Pi and thus release energy for contractions? What is a second name for this part?
the myosin head acts as myosin ATPase
What term describes the change in configuration of a cross bridge that is attached to actin?
What two chemicals are attached to a cross bridge that is cocked but not attached to actin?
ADP + Pi
What chemical must be released from a cross bridge in order for the power stroke to occur?
What chemical is released from the cross bridge after the power stroke?
What chemical must attach to the cross bridge in order for it to release from actin after the power stroke?
What is the immediate source of energy for muscle contractions?
What is the result of the hydrolysis of ATP to ADP and Pi after the power stroke?
the energy is used to cock the cross bridge
What molecule covers the active sites on actin when a muscle is relaxed?
What molecule is attached to tropomyosin to allow its regulation?
What ion binds to troponin to change it configuration?
What organelle stores calcium within a muscle fiber?
the sarcoplasmic reticulum
What neurotransmitter occurs at the neuromuscular junction?
What structures open to the extracellular environment outside of a muscle fiber and conduct action potentials through the cell?
Action potentials within a muscle fiber are not graded. What is this effect called?
the all-or-none law
What type of structure opens within the t-tubules in response to depolarization?
voltage-gated Ca2+ channels
What type of mechanism regulates the release of Ca2+ from the sarcoplasmic reticulum?
Ca2+-induced Ca2+ release mechanism
What structures remove Ca2+ from the sarcoplasm once a muscle fiber is no longer depolarizing?
What type of contraction occurs as a muscle actually gets shorter when producing force?
isotonic or concentric
What type of contraction occurs when a muscle does not change its length as it produces force?
What type of contraction occurs when a muscle is elongated as it produces force?
eccentric or lengthening
What is the general relationship between the length of a muscle and the tension it is able to produce?
There is an ideal length (2-2.25 m) at which the fiber produces maximum force. Any increase or decrease in this length lessens the force produced.
Skeletal muscles at rest obtain most of their energy from what?
aerobic respiration of fatty acids
What is the main source of energy for skeletal muscle during heavy exercise?
Exercise increases the what carrier molecule in the plasma membranes of muscle fibers?
GLUT 4 (the carrier protein for glucose)
What source of energy usually makes up the largest percentage of that used by a muscle?
free fatty acids from the plasma
What is the maximum rate of oxygen consumption by the body?
VO2max (maximal oxygen uptake or aerobic capacity)
What units is V-O-2 max measured in?
ml of oxygen per minute per kilogram of body weight
What is the general range of V-O-2 max overall?
12 ml/min/kg in older, sedentary people to 84 ml/min/kg in young, elite, male athletes
What is the percentage of the maximal oxygen uptake at which a significant rise in blood lactate
Why does a person continue to breathe heavily after exercise?
to repay the oxygen debt
What is the cause of oxygen debt?
the use of oxygen stored in hemoglobin and myoglobin
What substance is used to make ATP when ATP is used faster than it can be produced through
What are the two categories of skeletal muscle fibers based on contraction time?
slow-titch (type I) and fast-twitch (type II)
Within muscles, what is the red pigment, similar to hemoglobin, that stores oxygen?
Based on metabolism, what other term may be used for slow-titch muscle fibers?
Based on the amount of myoglobin, what is another term for slow-twitch muscle fibers?
Based on the amount of myoglobin, what is another term for fast-twitch fibers?
Based on metabolism, what are the two types of fast-twitch fibers?
fast oxidative (type IIA) and fast glycolytic (type IIX)
What is exercised-induced reduction in the ability of a muscle to generate force?
What appears to be the cause of muscle fatigue during maximal contractions?
an accumulation of K+ outside of the cells
What are the two major components of muscle fatigue?
peripheral (within muscles) and central (in the CNS)
What is the general adaptation shown in muscles trained for endurance?
an increase in aerobic capacity through such changes as more mitochondria and capillaries
What is the general adaptation of muscles trained with high-intensity exercise?
hypertrophy from an increase in cross-sectional area of fibers and an increase in the number of fibers
How can damaged muscle fibers be replaced?
through the conversion of satellite cells into muscle fibers
What sensor responds to the tension put on tendons?
Golgi tendon organ
What sensor responds to changes in muscle length?
muscle spindle apparatus
What is a response to sensory input that does not depend on the activation of upper motor neurons?
What is the neural pathway of a reflex?
a reflex arc
What type of reflex arc involves a single synapse within the CNS?
a monosynaptic reflex
What reflex occurs in all muscles in response to a rapid change in their length?
the stretch reflex
What type of reflex has two synapses within the CNS?
a disynaptic reflex
What is the effect of feedback from the Golgi tendon organs?
inhibition resulting in relaxation
Stretch reflexes involve dual innervation. The agonist is excited. The antagonist is inhibited. What is this dual innervation called?
What is reciprocal innervation of both the side of the body sensing a reflex stimulus and the contralateral side?
double reciprocal innervation
What type of double reciprocal innervation occurs when a painful stimulus occurs on the sole of one