23 notecards = 6 pages (4 cards per page)
What You'll Learn
After you finish this lesson, you will be able to:
The muscular system contains over 600 muscles. About 40% of a person's body weight comes from muscles. The muscular system performs these functions:
Muscles usually act in groups to create movement, although each muscle is a distinct part. All muscles have four common traits.
Excitability or Irritability: The ability to respond to a stimulus, such as anerve orhormone. Muscles can be stimulated electrically, mechanically, or chemically.
Muscle tone refers to the ability of muscles to be slightly contracted at all times, even when not in use. It allows a person to be in a state of readiness to act.
The ability of muscles to be slightly contracted at all times to be ready to act is known as muscle _______.
Ability to be stretched and lengthened
Ability to shorten and produce movement when stimulated
Ability to respond to a stimulus, such as a nerve or hormone
Ability to return to its original shape after contracting or stretching
Types of Muscles
The three types of muscle tissue are cardiac, visceral, and skeletal.
Cardiac muscle forms the walls of the heart. When it contracts, this type of muscle causes the heart to beat to circulate blood.
Cardiac and visceral muscles are involuntary, which means that they are not controlled by a person's conscious thought, or will. Most skeletal muscles are voluntary, which means that a person can control their actions.
A person can control the actions of involuntary muscles.
Which types of muscle are generally voluntary?
Attached to the bones to help produce body movement
Forms the walls of the heart and causes the heart to beat
Found in hollow organs, in the walls of blood vessels, and in the eyes
Attachment of Skeletal Muscles
While ligaments attach bone to bone, muscles are attached to bones by bands of fibrous tissue called tendons.
The end of the muscle that is connected to the bone that does not move is called the origin.
The end connected to the bone that moves when the muscle contracts is called the insertion.
Fascia is a sheet of tough fibrous tissue that wraps around an individual muscle.
Attaches muscle to bone
End of the muscle connected to the bone that moves
Sheet of tough fibrous tissue that wraps around an individual muscle
End of the muscle connected to the bone that does NOT move
Types of Body Movements
Types of body movements made by skeletal muscles include:
Flexion: Bending a body part, which decreases the angle of thejoint.
What type of body movement occurs in the leg when a person kicks a soccer ball forward?
What type of body movement occurs in the neck when a person turns the head from side-to-side to signal "No?"
In this lesson, you learned that: