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Amazing facts of human muscular system Amazing facts of human muscular system We are born with 300 bones, but as an adult we only have 206 bones ‐ How is it possible? Do you know ‐ It takes 17 facial muscles to smile while 42 facial muscles are used up when you frown. The busiest and hardest working muscles in our body are the eye muscles, which approximately move more than 100,000 times in a day. Let′s unwind all the amazing mysteries of human muscular system.

Learning Objectives

After completing the topic, the student will be able to:

  • Analyze the organization and processes of the human muscular system.
  • Define and distinguish the terms bones, cartilage and joints.
  • Discuss and distinguish axial skeleton and appendicular skeleton and quote their functions.
  • Appreciate the importance of skull that forms the bony framework of the head and classify the bones of it.
  • Discuss and understand how rib cage acts as a protective cage around the organs in the upper body.
  • Explore the importance of vertebral column and list the five different regions of it.
  • Examine how appendicular skeleton makes locomotion possible and protects the body′s major internal organs.
  • Describe the ultra structure of skeletal muscle fiber and explore its functions in muscle contraction.
Muscle anatomy Muscle anatomy Illustration of the muscles of the human body (front view) in a standing adult male. There are more than 600 muscles in the human body, the most prominent being skeletal (voluntary) muscles which make up 40 to 45% of body weight.
Muscular System

The muscular system is a system of tissues called muscles throughout the body. It permits movement of the body. The muscular system consists of three different types of muscle tissues: skeletal, cardiac, and smooth muscles which maintains posture and provide strength, balance, movement and heat for the body to keep warm.

The muscular system in vertebrates is controlled through the nervous system. The human body contains more than 650 individual muscles served by nerves which, link each individual muscle to the brain and spinal cord. There are two types of muscles in the system and they are the involuntary muscles, and the voluntary muscles.

The muscles which are controlled by ourselves are called the voluntary muscles and the ones we can't are the involuntary muscles. The heart, or the cardiac muscle, is an example of involuntary muscle.

In the adjacent figure, muscles seen here (red) are voluntary muscles in that they are under conscious control. They are composed of bundles of specialized cells capable of contraction & relaxation to create movement. They are attached to the human skeleton by tendons (white). In this way the limbs, spine, pelvis, shoulders and head can move in relation to each other. Muscles are under the nervous control of the brain and spinal cord.

The musculature of a human male running. The musculature of a human male running. The muscles represented here are skeletal muscles. These muscles are consciously controlled by the brain. They move the body by contracting and relaxing, often in opposing pairs, which pulls tendons (white) attached to the skeleton. They account for about half the body′s weight.
Functions of Muscular system - Locomotion and Movement

Movement is one of the important characteristics of living beings. The force responsible for movement in living organisms occurs within the body itself. Movements in multicellular organisms are of two types

  1. Locomotion and
  2. Movements of body parts

Locomotion (walking running creeping flying swimming etc.) is the movement of living beings from one place to another place which enables them to go on search of food and shelter, shift from an unfavorable environment to favorable environment and to perpetuate their race.

Movements of body parts includes heart beat, peristalsis, movement of diaphragm and ribs during respiration etc. both these movements in vertebrates are enhanced by skeletal muscles (muscles attached in association with skeleton) and joints. Skeletal muscles are also called as striated muscles. The muscles that are not associated with muscles are called visceral muscles. They are responsible for the movement for example cardiac muscle of heart valve brings about heart beat without association with bones.