Chp. 7- Muscle Twitch, Summation, Tetanus, and Skeletal Muscle Anatomy

Muscle twitch
A single contrsction that lasts only a fraction of a second

Three phases of a muscle twitch
Latent phase, contraction phase, & relaxation phase

Contraction period
The duration of a muscle twitch when the muscle contracts or shortens in length

Latent period
The duration of a muscle twitch between stimulation and the initiation of the contraction

Relaxation period
The duration of a muscle twitch when the muscle returns to its resting length

Two ways the force of a muscle contraction can be increased
Summation and recruitment

Summation
Increases the force of contraction by increasing the frequency of the stimulus of the muscle fibers

Recruitment
Increases the force of contraction by increasing the number of motor units stimulated.

Tetanic contraction (tetanus)
The sustained contraction that occurs when the frequency of stimulation is so rapid that there’s no relaxation

The cause for muscle fatigue
ATP is used during a muscle contraction faster than it can be produced and lactic acid builds up faster than it can be removed

Motor unit
A motor neuron and all the muscle fibers that it innervates

Two classifications of muscle contractions
Isometric and isotonic

Muscle tone
When some muscle fibers are always contracting and under tension over long periods of time

Isometric contraction
Muscle contracts but does not shorten

Isotonic
Muscle contracts and muscle size changes

Two types of isotonic contractions
Concentric contraction & eccentric contraction

Concentric contraction
Muscle shortens

Eccentric contraction
Muscle lengthens

Origin
The muscle attachment location on the stationary bone

Insertion
The muscle attachment location on the bone that moves

Agonist
Muscles that accomplish or perform certain movements

Prime mover
The agonist that is the main muscle that performs the movement

Synergist
Groups of agonists that work together to perform a movement and assist the prime mover

Antagonist
Muscles acting in opposition to the agonist

Fixations
Muscles that hold a bone in place while another bone is moved

M

1) Muscle twitch a brief, contractile response of a skeletal muscle elicited by a single maximal volley of impulses in the neurons supplying it. 2) Lag phase Latent Period: duration of a muscle twitch between stimulation and the initiation of …

muscle twitch a single momentary muscle contraction, and is the response to a single stimulus. lag phase Phase where muscle fiber is preparing for contraction. Muscle tension is beginning to increase at this time, but no response is seen on …

Muscle twitch A small, local, involuntary muscle contraction and relaxation which may be visible under the skin. Lag phase The period when the bacteria are adjusting to the environment. WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY …

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characteristics of skeletal muscle -move body by pulling on bones -each cell is a single muscle fiber -each muscle tissue is a complex organs that contain skeletal muscle fibers (contraction), connective tissues (harness contractile forces), blood vessels (nourish muscle fibers), …

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