MUSCULOSKELETAL SYSTEM [CSEC HSB & BIOLOGY]

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SYLLABUS REFERENCE 

CSEC HSB 

  • [B4.1] identify the major bones of the skeleton; 
  • [B4.2] relate the structure of the skeleton to its functions; 
  • [B4.7] identify a hinge joint, fixed joint, and ball-and-socket joint; 
  • [B4.9] identify the biceps and triceps of the upper arm; 
  • [B4.10] explain how skeletal muscles function in the movement of a limb; 
  • [B4.11] explain the importance of locomotion to man. 

CSEC Biology 

  • [B6.2] relate the structure of the skeleton to its function in humans;
  • [B6.3] discuss the importance of locomotion in animals; 
  • [B6.4] describe the mechanism of movement in a human forelimb.  

IMPORTANCE OF LOCOMOTION TO HUMANS 

Locomotion is the ability to more the entire individual from one place to another independently. 

This ability is very important to our independence and identity. 

Generally, locomotion is required:

  • for defence 
  • to search for food and shelter 
  • to care for young ones 
  • to work 
It is also a major aspect of our socialisation and community building. 

COMPONENTS OF THE MUSCULOSKELETAL SYSTEM 

The Skeleton 

The skeleton has a basic framework that consists of the following:

  • Axial Skeleton 
  • Appendicular Skeleton 


Types of Joints




At CSEC level, the focus is on the following types of joints... 

Hinge 

Fixed 

Ball-and-Socket 

Both hinge and ball-and-socket joints are SYNOVIAL JOINTS. 




Functions of the Skeleton 

Movement

Bones act as points of attachment for the skeletal muscles. The skeleton acts as a system of levers, powered by muscular contraction. 



Protection

  • The cranium protects the brain, eyes, and ear canal.
  • The rib cage protects the lungs and heart. 
  • The vertebral column protects the spinal cord. 
  • The pelvis protects the uterus (womb). 

Support

The skeleton acts as a framework (or scaffolding) for the rest of the organ systems of the body. 

The backbone supports the limbs and head. The jawbones support the teeth. 

Breathing

The intercostal muscles move the rib cage up and down, in and out, in order to facilitate breathing. 

This movement increases and decreases the volume of the thoracic cavity, causing air to move in and out of the lungs. 



Production of Red Blood Cells

Red bone marrow, found on the inside of short bones and at the ends of long bones such as the humerus, have stem cells. 


These special cells divide by mitosis to produce red blood cells, thus continuously replacing the older cells. 


Important Comparisons






MECHANICS OF MOVEMENT 

Using Biceps and Triceps as an Example:
  • Muscles can only contract. 
  • The bones act as levers and points of attachment. 
  • Each arrangement consists of two or more bones, plus muscles are arranged to pull the bone in opposite directions. These are called antagonistic muscles. 








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