Body Systems

• 206 bones in the human body
• The four types of bone: 

1) Long bones e.g Femur

2) Short bones e.g. Phalanges

3) Flat bones e.g. Scapular 

4) Irregular bones e.g. Vertebrae

• Axial skeleton= includes vertebral column and the bones connected to it.
• Appendicular skeleton= the moving parts not connected to the vertebral column.
• Functions of the skeleton: Protection, movement, blood production and support. (PMBS)
• There are 29 indivdual vertebrae. The main ones are: Coccyx, Atlas and Axis. 
• Functions of the vertebrae: Support, movement and protection. 

• Joint categories: Fixed (immovable) e.g. the skull, Slightly moveable e.g. vertebrae and Synovial (freely moveable) e.g. at the elbow.

1) Hinge- allows movement in one direction e.g. elbow

2) Pivot- allows rotation e.g. neck

3) Ball and Socket- full range of motion e.g. hip

4) Saddle- movement in two directions e.g. base of the thumb

5) Condyloid- all movement except rotation e.g. wrist

• Ligaments= joins bone to bone
  
• Tendons= joins muscle to bone
• Flexion= when a joint closes
• Extension= when a joint opens
• Abduction= when a body part moves away from the body
• Adduction= when a body part moves towards the body
• Rotation= when a bone pivots

• Types of muscle are: cardiac, voluntary and involuntary.
• Fast twitch muscle fibres react quickly and work explosively. Good for speed events. Tire quickly.
• Slow twitch muscle fibres are strong but slow. Good for Endurance events. Last for a long time.
• Muscles work antagonistically (in pairs). One contracts while the other relaxes.
• The agonist is doing the work, the antagonist is relaxing.
• Isometric contraction= muscles working, no movement e.g. rugby scrum.
• Isotonic contraction=muscles change length and bone moves e.g. an arm curl
• Concentric contraction=an isotonic contraction when enough tension moves a body part
• Eccentric contraction=an isotonic contraction when fibres lengthen but still cause tension

• Air enters through the nasal passages, it then passes through the trachea, next it enters the lungs, below the lungs is the diaphragm.
• During inspiration: the ribs move up/forwards; the diaphragm is pulled down; the size of the thoracic cavity increases; and the size increase sucks air into the lungs.
• During expiration: the ribs are pulled down/back; the diaphragm is pulled up; the size of the thoracic cavity deacreases; and the air is squeezed out of the lungs. 
• Respiratpry tract: (1) nasal passages (nose/mouth) (2) nasal cavity (back of the nose/mouth)  (3) trachea (windpipe) (4) bronchus (the two bronchi lead into the lungs (5) bronchioles (smaller tubes branching off of the bronchus) (6) Alveolus (air sacs covered by a network of capillaries)
• Gas exchange occurs in the alveolus
• Capillaries are just one cell thick 
• Vital capacity= maximum amount of air that can be inspired/expired
• Tidal volume= the amount of air inspired/expired whilst resting
• Respiratory rate= number of breaths that can be taken in one minute
• Residual volume= the small amount of air left in the lungs after a full breath out

• Consists of the heart, blood and blood vessels
• Blood circulates in one direction in a figure eight shape
• There are two pathways: pulmonary (lungs and heart) and systematic (body and heart)
• Arteries: blood away from the heart, thick elastic walls but get thinner further away. 
• Veins: blood back to the heart, thin less elastic walls but get larger near the heart.  
• Capillaries: connect arteries and veins, thin.
• The heart--> right atrium recieves blood and pushes it into the right ventricle, right ventricle pushes blood into the lungs, the left atrium recieves blood from the lungs and pushes it into the left ventricle, the left ventricles sends the blood around the body.
• Blood pressure= the pressure in an artery as the blood leaves the heart
• Systolic pressure= when the ventricles contract
• Diastolic pressure= when the ventricles relax
• A typical reading is 120/80 for a normal resting person

• Blood components: 

plasma- the fluid part, 

platelets- cause clotting, 

white blood cells- help to fight toxins and bacteria, 

red blood cells- discs containing haemoglobin.

• Blood functions: antitoxins, antibodies, destruction of harmful organisms, clotting, repair.

• Materials transported: O2, CO2, nutrients, heat and waste products.

• Voluntary muscles: fibres become shorter and fatter, muscle girth increases, blood flow from fibres is improved, muscles increase in strenght and endurance.
• Cardiac muscles: increase in strenght and size so more efficient, increased stroke volume, increased cardiac output, lower resting heart rate, prevents coronary or arterial disease.
• Blood: number of red blood cells increases, maximum pulse rate increases, heat trasported to the skin to keep the boudy cool.
• Respiration: aerobic exercise can be carried out for longer periods of time and needs shorter recovery time; anaerobic exercise can be carried out for longer amounts of time and recovery time is also improved. Blood supply to the lungs is increased improving gas exchange at the a alveoli.