​​​Muscular System
by Gena Garza, Erica Thompson, Iliana Mata(:

Intro: The muscular system is an important and vital part of our body. Without muscles, we would not be able to sit, stand, run, blink, or smile. The muscles in our body allow our heart to beat, air to fill our lungs, and food to move through our digestive system, not to mention any type of movement. Muscles work extremely hard to make even the simplest of our actions easy and possible for us to do.


Structures and Functions​

Muscles are highly specialized tissues that enable the body and its parts to move. They are responsible for all of our body movement. They allow us to move from place to place as well as performing involuntary functions such as breathing and the beating of the heart. Muscles give our body form and shape and is responsible for producing most of our body heat.
Types of Muscles:
  • Skeletal: Attatched to the bones and causes the movements of the body. Powers movement of the skeleton as in walking and lifting. The majority of the muscular tissue in the body is skeletal muscle tissue and is voluntary-Three primary functions are movement, posture or muscle tone, and heat production.
  • Cardiac: Responsible for the rythmic contractions of the heart. Cardiac muscle is involuntary.
  • Smooth: Lines the walls of hollow organs. Smooth muscle lines the walls of blood vessels and of the digestive tract, where it serves to advance the movement of substances. Smooth muscle contraction is slow and involuntary.
-Involuntary Muscle: A muscle that contracts without conscious control and is found in walls of internal organs such as stomach, intestine, bladder, and blood vessels
-Voluntary Muscle: Muscle that is under conrol of the will and is generally attatched to the skeleton

Specific Info:

  • Muscles called flexors force your joints to bend (biceps)
  • Muscles called extensors cause your limbs to straighten(Triceps)
  • Muscles only contract or pull, not push.
  • Most muscles are set up in pairs so that one muscle can pull the bone back the other way
  • Muscle tissues consist of specialized contractile cells or muscle fibers that are grouped together in a highly organized way. Each muscle fiber is filled with two different types of very fine and threadlike structures called thick and thin myofilaments
  • Thick myofilaments are formed from the protein myosin and thin myofilaments are formed from the protein actin
  • Muscle Spasm: Sudden, involuntary muscle contraction
  • Muscle strain: Slight tear in a muscle; also called a pulled muscle
  • Tendon: Tough, white, cordlike tissue that attatches muscle to bone

Fun Facts:

  • There are over 30 facial muscles which creates facial expressions such as surprise, happiness, and sadness
  • Eye muscles are the busiest muscles. Scientists estimate they may move more that 100,000 times a day
  • The largest muscle in the body is the gluteus maximus muscle
  • Goosebumps are tiny muscles contracting to raise hair

Questions and Answers:

Q: Where are the smallest muscles located?
A: The smallest muscles are located in the ear

Q: What percent of our body weight comes from muscles?
A: Forty percent

Q: What two types of muscle fibers does skeletal muscle have?
A: Fast-twitch (anaerobic excercise) and slow-twitch (aerobic excercise)

Q: What is the longest muscle in the body?
A: The satorius muscle in your leg

Q: What exactly is a cramp?
A: A prolonged muscle spasm


The muscular system is definately important and necessary in order for a person to live. It aids in movement, body temperature, and vital bodily functions such as digestion of food and the heart's beat. Without muscles, our body would not be able to function.

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