the "head" that forms the cross bridge when the muscle cell contracts is part of what protein?
myosin
if the muscles of a weightlifter and a marathon runner were compared the weightlifter would have?
larger muscles
if the muscles of a weightlifter and a marathon runner were compared the marathon runner would have?
more mitochondria in each muscle cell
what type of muscle tissue specializes in contraction or shortening?
cardiac, smooth, and straited
strength training causes?
muscle hypertrophy
which type of contraction can be seen in an isolated muscle but plays a minimal role in normal muscle activity?
twitch
which is not a primary function of the muscular system?
protection of internal organs not protected by bones
what type of muscle tissue contains striations?
voluntary and cardiac muscles
endurance training results in?
an increase in blood vessels to the musscle
in the bending of the elbow, the?
biceps brachii is the prime mover
the difference between picking up a 5-lb weight and picking up a 20-lb weight is the number of motor units stimulating the muscle to contract
true
in isometric contraction, the muscle does not shorten so there is no tension on the muscle
false
unlike skeletal muscles, smooth muscle cells have only one nucleus.
true
both smooth muscles and cardiac muscles have striations.
false
almost all of the ATP energy used up in muscle contraction is released in the form of heat.
false
all motor neurons that stimulate a single muscle are referred to as motor units.
false
in an isotonic contraction, the origin point moves toward the insertion point
false
bursea and tendon sheaths perform the same function
true
when the elbow is bent, the biceps brachii is the prime mover
true
both cardiac muscles and skeletal muscles intercalated disks
false
voluntary muscle
another term for skeletal muscles
visceral muscle
another name for smooth muscles
intercalated disks
structures that are found only in cardiac muscle
origin
usually the non-moving attachment point of a muscle
sarcomere
functional unit of contraction of a skeletal muscle
insertion
usually the moving attachment point of a muscle
actin
protein that makes up thin myofilament
Z line
structures that spereate one sarcomere form another
bursea
a small fluid-filled sac that lies between some tendons and bones
myosin
protein that makes up thick myofilament
pain of many muscles
polymyalgia
muscle connected to internal organs
visceral
malignant tumor of smooth muscles
leiomyosarcoma
act of turning the palm upward
supination
fibrous membrane separating muscles
fascia
pertaining to heart muscle
myocardial
connection of muscle to stationary bone
origin
connection of muscle to the bone the moves
insertion
abduction
movement away from the mid line of the body
adduction
movement toward the mid line of the body
dorsiflexion
backward bending of the foot
extension
straightening of a flexed limb
fascia
fibrous membrane separating muscle
flexion
bending at a joint
insertion of a muscle
connection of a muscle to a bone that moves
origin of a muscle
connection of a muscle to a stationary bone
plantar flexion
bending the sole of the foot downward to the ground
pronation
turning the palm downward
rotation
circular movement around a central point
skeletal muscle
striated muscle connected to bones
supination
act of turning the palm upward
wasting away (no development) of muscle
atrophy
trying to lift a 500-pound weight would result in what type of muscle contraction?
isotonic
the insertion of a muscle is the?
attachment to the movable muscle
which type of muscle is characterized by the cells with tapered ends and a single nucleus?
smooth
the triceps brachii and the biceps brachii
are antagonist to each ither
muscle hypertrophy
is an increase is muscle size
which does not happen when a muscle contracts?
the muscle cells partially contract based on the amount of resistance
lifting a book off a desk is an example of what type of contraction?
isotonic
which substance is stored in the muscle's endoplasmic reticulum and then released when a nerve signal stimulates a muscle fiber?
calcium ions
chemicals are released at the neuromuscular junction that stimulates the muscle to contact
true
the main effect of endurance training is muscle hypertrophy
false
the muscle cells will contract slightly for a small stimulus and much more forcefully for a stronger stimulus
false
a muscle can be a prime mover or an antagonist depending on the movement of the joint
true
the autoimmune muscle condition that is characterized by muscle weakness, especially in the face and throat, is called
myasthenia gravis
damage to a ligament results in which type of injury?
sprain
the movement that is opposite of flexion is
extension
when a muscle contracts, its incersion bone moves towards it origin bone
true
a full family history would be most helpful in determining the risk of myasthenia gravis
false
antagonist muscles and synergist muscles act to oppose the movement of the prime mover
false
movement around a longitudinal axis
rotation
turning the hand so the palm is facing anteriorly
supination
the movement that makes the angle between two bones at their joints smaller
flexion
a strain is usually a muscle injury and a sprain is a ligament injury
true