Smooth muscle = intestines, urinary tract, organs, etc.
Cardiac muscle = heart tissue.
Skeletal muscle = biceps and other muscles that attach to bone.
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1. Movement
2. Posture (hold certain positions)
3. Heat production
Your bicep is a muscle on your upper arm which is attached to the humerus bone. Because it is attached to bone, it is a skeletal muscle.
An example of non-skeletal muscle is your heart. It is made up of muscle but does not touch any bone.
At rest, the average, healthy heart will beat 70 times per minute.
Muscles contract (move) by electrical impulses which are messages being sent from the brain.
Muscles work by contracting and pulling on a bone.
Muscles do not push bones.
Skeletal muscles work in pairs to pull on a bone in opposite directions. One muscle pulls in one direction while it contracts. To pull the bone back, another muscles contracts.
Most skeletal muscles are attached to 2 bones; one bone remains stationary as the muscle contracts to move another bone.
The stationary bone is called the origin. The bone that moves is called the insertion. The muscle inbetween is called the body.
Your leg muscles are so strong that if 2 muscles were pulling in opposite directions you could break your own femur.
This of course never happens because the brain will only allow one side of the muscle to work at a time. When the nerves send a message to one muscle to contract, it also sends a message to the opposite muscle to relax.
Bones that connect to another bone have a connective tissue between them called a ligament.
The muscles that attach to bones have a connective tissue between them called a tendon.
Weightlifting builds larger muscles. This is your body's way of adapting to lifting heavy objects. Weightlifters often develop callouses from lifting too. This is also an adaptation of the body.Click here for more info on athletes, muscles, and steriods
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Muscles have thousands of cells which are shaped like strings.The Strings are called sarcomeres.
Sarcomeres are made up of 2 different types of tissue: Actin and Myosin.
When muscles contract, the myosin has heads which pull on the actin while muscles contract.
This sliding action moves muscles.
Z lines are visible in striated muscle tissue. When a sarcomere contracts, the Z lines move closer together. When the sarcomere relaxes, the Z lines move away from each other.
Muscles have motor neurons attached to them. This allows the muscle to be contracted by the brain and nervous system.
When a body dies, it undergoes rigor mortis which causes the body to become as stiff as a board.
The stiffness is caused by actin and myosin freezing in whatever position the body died in. Muscles need ATP to move and if the body is no longer creating ATP, the muscles cannot move on their own.
Rigor mortis begins as soon as the body dies. It can take up to 24 hours for rigor mortis to completely set in. Then up to another 24 hours to soften up from the myosin and actin decomposing.
There are some areas of our bodies that when hit by a stimulus, it will contract automatically. This is called a reflex.The ligament attaching the patella to the tibia is one example. Doctors often check this reflex when performing physicals.
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The body has about 650 muscles. In your face, you have 50. It takes 17 muscles to smile and over 40 to frown.
