Muscular Tissue Review

Review and Supplemental Information for Unit 1 HPER 259

Muscle Fiber Types

The human body is composed of 3 different types of muscular tissue; cardiac, smooth, and skeletal.

Cardiac tissue is so name for its location. This type of muscle tissue is found in the heart. A muscular contraction of cardiac muscle results in a heart beat. Cardiac muscle is striated, involuntary, and branched.

Smooth muscle is also called visceral muscle. The Merriam-Webster defines visceral as "in the internal organs of the body" (n.d.). Both terms are very descriptive as the term visceral references a primary location where we find this muscle tissue and the term smooth describes its appearance. Smooth muscle fiber is found in arteries, the bladder, respiratory tract, and gastrointestinal tract, to name a few. This fiber type is without striations and is involuntary.

Skeletal muscle is attached to bones by tendons and is responsible for voluntary bodily movements. Skeletal muscle is striated and voluntary, but unlike cardiac muscle tissue it is not branched.

Note the images and descriptions below.

Skeletal Muscle Tissue Microanatomy

The key player in this unit is the skeletal muscle tissue. Students will need to develop a keen understanding of its anatomical structure as they move forward in subsequent units. In the image below, you should be able to identify the following structures:

  1. nucleus
  2. Sacromere: how can you identify an individual sarcomere
  3. I Bands
  4. A Bands
  5. The banding pattern: notice the I and A Bands organization within the muscle cell

Image Credit: Open.Michigan/

Big picture

Interesting Facts! by Marley, contributing editor

Here are some of the interesting and important facts about skeletal muscle fiber. Please note, these bits of information could appear on your final test over muscle fiber.

  1. There are over 600 skeletal muscles in the human body.
  2. Muscles can only contract. They cannot lengthen unless an opposing (antagonist) muscle contracts and causes that muscle to lengthen.
  3. Muscle have a high metabolic rate. This means that they burn a lot of calories. Therefore, increasing your muscle mass can in fact help you burn fat.
  4. The largest muscle of the human body is the Gluteus Maximus.
  5. The strongest muscles of the human body are evaluated on their weight and/or force that they can generate. The massester muscle group are the muscle that work together to create movement in the jaw. When all of the muscles of the jaw work together they can generate a force of 200 pounds on the molars! The soleus muscle is the muscle that can pull with the greatest force. Remember that this muscle has to pull against the force of gravity with every step you take!
  6. Did you know that the tongue is made up of a of eight different muscles? Four intrinsic and four extrinsic muscles. This is one of our hardest workers that never sleeps. The tongue even works at night pushing saliva down your throat!

(Alexandrou, P., Alexandrou, M. Infolific, 2011-2016).