Muscular System

OT Dude Academy’s Free NBCOT® Exam Prep Course Medical Terminology, Anatomy, and Physiology Muscular System
Contents Hide
1 Anatomy
2 3 Types Muscle Tissues
3 Function
4 Naming of Muscles

Source 1  licensed under Creative Commons Attribution 4.0 International License.

Anatomy

  • One of the four primary tissue types of the body.
  • Made up of specialized cells called fibers.
  • 3 types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle
  • All exhibit a quality called excitability as their plasma membranes can change their electrical states (from polarized to depolarized) and send an electrical wave called an action potential along the entire length of the membrane.
  • Fascia is fibrous connective tissue that encloses muscles.

3 Types Muscle Tissues

  • Skeletal – closely associated with the skeletal system. Also known as striated muscles and are responsible for voluntary muscle movement – such as swallowing, etc.
  • Smooth – mainly associated with the walls of the internal organs. Also known as visceral muscles and are responsible for involuntary muscle movement – such as breathing, etc.
  • Cardiac – heart muscle or myocardium. Its appearance is similar to a skeletal muscle and is responsible for the pumping of blood. It gives the heart beat.

Function

  • The main function of the muscular system is to assist with movement.
  • Muscles work as antagonistic pairs. As one muscle contracts, the other muscle relaxes. This contraction pulls on the bones and assists with movement.
  • Contraction is the shortening of the muscle fibers.
  • Relaxation lengthens the fibers.
  • This sequence of relaxation and contraction is influenced by the nervous system.
  • Muscles also work to keep the posture of the body. This is done through muscle contraction where the trunk is kept straight either when sitting or standing.

Naming of Muscles

Nomenclatures for naming muscles include:

  • Divisions – biceps, triceps, quadriceps
  • Size – maximus (largest), minimus (smallest)
  • Shape – deltoid (triangular), trapezious (trapezoid)
  • Action – flexor (to flex), adductor (towards midline of body)
  1. Betts, J.G., Young, K.A., Wise, J.A., Johson, E., Poe, B., Kruse, D. H., Korol, O., Johnson, J.E., Womble, M. & DeSaix, P. (2013). Anatomy and Physiology. OpenStax. http://cnx.org/content/col11496/latest/[↩]
Previous Lesson
Back to Topic
Next Lesson