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Muscle Quick Facts. “Courage is very important. Like a muscle, it is strengthened by use.” -Ruth Gordon. What causes muscle cramps? . A muscle contracts with great intensity and stays contracted, refusing to stretch or lengthen again. This is a change in the nervous impulse.
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Muscle Quick Facts “Courage is very important. Like a muscle, it is strengthened by use.” -Ruth Gordon
What causes muscle cramps? • A muscle contracts with great intensity and stays contracted, refusing to stretch or lengthen again. • This is a change in the nervous impulse. • Minerals such as __________________________ _______________________________play a key role in the transmission of these signals. • Imbalances of these minerals, as well as certain hormones, fluids and chemicals can cause muscle cramps. • _____________________________________________ ______________________________________________
Muscle Spasm • A _______________________________________ _________________________contraction. • Feels like a tight knot. • Occur in muscles that are overworked or injured. • Rest and time resolve most muscle spasms.
How many muscles does it take to smile and frown? • _____ to smile • _____ to frown
What is the longest muscle in the body? • ___________________
How many muscles are involved in chewing food? • Four pairs of muscles in the face are involved in chewing (mastication). • They are some of the strongest muscles of the body.
How many muscles are in the fingers and thumbs? • _________________________________________________________________________________________________________ • The ______________ that control these_____________ are located in the hand and forearm.
Which are the fastest muscles? • _____________________________ • Allow your eyes to move.
Smallest Muscles? • ____________________________ • Found in the middle ear. • Thinner than a thread (0.05 inches) in length. • It activates the stirrup that sends vibrations from the eardrum to the inner ear.
The Muscular System “Muscles come and go; flab lasts.” -Bill Vaughan
Intro • There are more than __________muscles in the human body • Muscles are responsible for our breathing and eating • The beating of our hearts involved muscle activity
Muscle tissue • What is tissue? • _______________________________________________________________________________________ • Muscle Tissue: • Group of cells that ____________ during contraction which creates tension and results in movement. • muscle tissue can shorten by about ________ its resting length in response to nerve, nerve-like or hormonal stimulation.
Types of Muscles • There are three types of muscle in the human body:
Types of Muscles • Skeletal Muscle • _____________________________ • Attach _______________, via Ligaments. • Voluntary • We have conscious control over these muscles • The brain tells them what to do • “________________” or Striped Appearance • Series of light and dark • I bands = Light (Actin), A bands = Dark (Myosin)
Cardiac Muscles (only in the heart) • responsible for creating the action that pumps blood from the heart to the rest of the body • forms the heart’s thick wall (layers of interlacing cardiac muscle fibres) • _________________________–they are not controlled consciously • are directed to act by the autonomic nervous system –contract spontaneously in association with special impulse-conducting muscle cells _________________________________ _____________________________________________________________ • cardiac muscle is also _______________________________ • definitive junctions between cells (intercalated discs) • a centrally located nuclei
Smooth Muscles • ____________________________________________________________________________________________________________________________________________________________________________________ • centrally positioned nucleus, no cross striations • found in walls of organs with hollow cavities (viscera) and serve to propel material along the length of those cavities • Including blood vessels, hair follicles, intestines • contract more slowly than skeletal muscle tissue (sustained, rhythmic contractions –menstrual contractions and stomach cramps) • can remain contracted for longer periods of time • __________________________– their spindle-shaped fibres are usually arranged in dense sheets.
Tendons vs. Ligaments Tendon: (skeletal movement) • tough bands of connective tissue that join --________________________. • Ligament: • Attach _____________________
Properties of Muscle Fibres • Irritability • Contractibility • Elasticity • Extensibility • Conductivity