The Healthy Performer (4) (Skeletal and Muscular systems)

SKELETAL SYSTEM:

• The five major functions of the skeletal system are as follows: support, protection, movement, production of blood cells and storage of ions.
• The skeleton is split into two main sections: axial (skull, ribs, spine) and appendicular (shoulder girdles, arms, legs, pelvic girdle)
• We have 206 bones in our bodies.
• Bone are connected together by ligaments, and muscles are connected to bones by tendons.
• There are four types of bone: long (femur), short (carpals of the wrist), flat (sternum) and irregular (sacrum).
• There are four types of bone cells: osteogenic (bone growth), osteoblasts (build bones), osteoclasts (destroy bones) and osteocytes (holds bones together).
• Joints: bony (bones merge together as you get older), synovial (joints surrounded by liquid), fibrous (fibres join the bones) and cartilaginous (cartilage joins the bones). Hinge joints (e.g. elbows) move in one direction, saddle joints (thumb) can move in two directions, and ball and socket joints can move in all directions (hips and shoulders). 

MUSCULAR SYSTEM:

•  The purposes of the muscular system are movement, and to maintain posture and body position. Voluntary muscles are muscles that we can control to perform tasks like walking, whilst involuntary muscles are for the beating of your heart and for digestion. All muscles work in groups to undergo the tasks that you set them.
• There are five types of muscles: fusiform (thicker in the middle and thinner at the ends - biceps), parallel (thighs), convergent (fan shaped - pectorals), pennate (feather shaped - quadriceps) and circular (orbicularis oris).
• Antagonist and agonist muscles often work in pairs. As one muscle relaxes the other one contracts (e.g. the triceps relax so the biceps can contract, so you can lift your arm).