levator labii superioris ----------- There are actually several muscles named for their actions, levator scapuli is another. Others are named for their location, brachioradialis, or their length or shape, rhomboids, etc.
Involuntary muscle action. Examples include the beating of the heart, digestion in the stomach, and reflex actions like blinking or sneezing.
The action potential is conducted into a skeletal muscle fiber by the depolarization of the motor end plate, which triggers the opening of voltage-gated sodium channels. This causes an influx of sodium ions into the muscle fiber, leading to depolarization and the initiation of muscle contraction.
The duration of action potential in skeletal muscle is typically around 2-4 milliseconds. This includes the depolarization phase (around 1-2 milliseconds) and repolarization phase (around 1-2 milliseconds).
The biceps brachii muscle is the primary muscle responsible for the down-stroke action at the elbow when hammering a nail. It is located on the front of the upper arm and is crucial for flexing the elbow.
A T-tubule is a small, tube-like invagination of the cell membrane in muscle cells, particularly in cardiac and skeletal muscle. T-tubules help to transmit action potentials quickly into the cell interior, allowing for synchronous contraction of muscle fibers.
Action of the muscle Shape of the muscle Location of the muscle's origin and or insertion Number of origins Location of muscle relative to a bone or body region Direction in which the muscle fibers run relative to some imaginary line Relative size of the muscle
antagonist muscle
THe action of the digastric muscle is to depress the mandible or evaluate the larynx
The frowning action.
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It represents contracting or shortening of a muscle.
A small muscle in the ear named Stapedius
rectus femoris
Reflex action
brachioradialis
A muscle can be named based on a variaty of things: * Its origins and insertions, eg. the sternomastoid muscle has attachments at the sternum and the mastoid process of the skull. It may also be referred to as "sternocleidomastoid" in reference to its articulation with the clavicle. * Its action, eg. the levator scapulae muscle acts to raise ("levator") the shoulder blade ("scapulae") * Qualities of the muscle itself, eg. the digastric muscle is named for its two muscle masses/bellies. "Di-" referring to "two" and "-gastric" referring to "belly" * Historical/social reasons for naming, eg. the sartorius muscle's name literally means "tailor" and was so named because this muscle was particularly defined in these workers. This was because they often sat with one leg crossed over the other as they worked.
a concentric muscle action.