The Muscular System

• THE MUSCULAR SYSTEM​

  • All muscles work together by shortening or contracting. ​
  • Together with the skeletal system it forms the Musculoskeletal System, which is responsible for movement of the human body.​
  • There are over 600 muscles in the human body.​
• FUNCTIONS OF THE MUSCULAR SYSTEM:​


  • Mobility – allows human movement that contributes to gross (walking,swimming) and fine (smiling,writing) movements. ​
  • Stability – stabilizes joints and the body during certain tasks, like lifting weights ​
  • Allows development of strength, speed and endurance
• The Muscular System

  
  

  • Helps other systems do their work :​

  - Circulation – the heart is a muscle that pumps blood throughout the body  ​

  - Respiration – The diaphragm is a dome-shaped muscle located below the lungs. When it contracts and relaxes it allows oxygen to be inhaled and exhaled
• The Muscular System

  • Digestion – smooth muscles contract and relax as food passes through your body during digestion. ​
  • Urination – the bladder muscles tighten, which squeezes the urine out of the bladder then through the urethra.
•   TYPES OF MUSCLES​

  •  Striated/Striped/Skeletal Muscles​
  • They are attached to the bone and under a microscope you can see stripes across it​
  • Also called Voluntary muscles because movement takes place under your own decision
• Types of Muscles

  • Cardiac Muscles ​

  - Also Involuntary, cardiac muscles form the walls of your heart that allows the pumping action of blood​

  • Smooth/Involuntary Muscles​
  • These muscles are found in the walls of your organs eg. (digestive tract, bladder, blood vessels)​
  • Under a microscope they look smooth , without any stripes
• TYPES OF MUSCLE CONTRACTIONS ​

  When you move a part of your body, muscles must contract. Muscles shorten and bulge when contracted and return to their original length  when relaxed.​

  • There are two main types of muscles contractions ; Isotonic and Isometric
• ISOTONIC CONTRACTIONS ​

  • Occurs when any part of the body moves, that involves a change in the length of the muscle/s. ​
  • Two types of Isotonic Contractions :​
  • Concentric Contraction occurs when the muscle shortens ​

  - Eccentric Contraction occurs when the muscle lengthens (return to normal resting length)
• ISOMETRIC CONTRACTIONS ​​

  • Muscles does not change length ​
  • No movement taking place 
• MUSCLES AT WORK​

  Muscles at work are given different names according to the roles they play in movement, for example :​

  • Flexors – muscles that bend a limb at a joint​
  • Extensors – muscles that straighten a limb at a joint​
  • Adductors – muscles that move limbs towards the midline of the body​
  • Abductors – muscles that move limbs away from the midline of the body​
• HOW MUSCLES WORK

  • To allow movement, muscles work in pairs ​
  • When you bend your arm upwards, the muscles (biceps) of the upper arm contracts while other muscles (triceps) relaxes​
  • The muscles which contract to carry out the movement are called AGONISTS.​
  • The muscles which relaxes to allow this movement are ANTAGONISTS.​
• SKELETAL MUSCLES AND MOVEMENT …​ATTACHMENT TO BONES​

  • Skeletal muscles are attached to bones usually by tendons.​
  • ​
  • The attachment of the tendon of a muscle that moves the bone is called Insertion.​
  • The attachment of the tendon which acts as an anchor point is called the Origin.​
•  MUSCLE FIBRES​

  • Muscles are made up of cells called fibres. Muscles contract because the fibres do.​
  • They don’t all contract together ​
  • The number contracting at one time depends on how much force is needed. Eg lifting a book as opposed to lifting a pencil.​
  • ​
  • There are two types of muscles fibres : fast and slow twitch. ​
• SLOW TWITCH FIBRES​

  • Contracts slowly and without much force.​
  • Don’t tire easily​
  • Suited for endurance activities ​
• FAST TWITCH FIBRES​

  • Contracts much faster than slow twitch and with much more force​
  • They tire quickly ​
  • Suited for activities that require bursts of strength and power ​
• The Muscle Movement

  
• The Muscle System