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FUNCTIONS OF THE BLOOD
1. Transport gasses e.g. oxygen & CO2
2. Distributes nutrients e.g. proteins/lipids/carbohydrates
3. Transport metabolic waste
4. Delivers enzymes & hormones e.g Adrenaline
5. Regulate pH & Electrolytes e.g. salts
6. Defends body against toxins & pathogens
7. Regulate body temperature
8. Restricts fluid loss through damaged vessels
COMPOSITION OF BLOOD
1. Blood cells = 45%
2. Plasma = 55%
TYPES OF BLOOD CELLS
1. Ethrocytes = red cells
2. Thrombocytes = platelets
3. Leukocytes = white cells
TYPES OF BLOOD VESSELS
1. Arteries
  1. Arterioles (small artery)
  2. Carry blood away from heart
  3. Oxygenated blood
  4. High pressure
  5. Thick muscular elastic walls
    1. 3 layers thick
  6. Expand & accommodate increase blood volume
2. Veins
  1. Venules (small veins)
  2. Carry blood to heart
  3. Deoxygenated blood
  4. Valves present
  5. Lower pressure
  6. Thin elastic walls
    1. 2 layers thick
3. Capillaries
  1. Smallest vessel
  2. Extremely narrow
  3. 1 layer thick
  4. Carry blood from artery to vein
  5. Pressure is low
  6. Flow of blood slow
  7. Gaseous exchange & nutrients occur
4. Heart
HEART WALL
1. Pericardium
  1. Outer layer
  2. Blood lymph capillaries & nerve fibres
2. Myocardium
  1. Thin middle layer
  2. Cardiac muscle tissue
3. Endocardium
  1. Inner layer
  2. Forms part of valves in heart
HEART CHAMBERS
1. Left Atrium
2. Left Ventricle
3. Right Atrium
4. Right Ventricle
SYSTOLE
1. 1. Contraction of heart muscle
2. 2. Atria relax & expands
3. 3. Semi lunar valve open
4. 4. Tricuspid & Bicuspid valve closed
5. 5. ventricles contract
6. 6. Blood flows to lungs & body
DIASTOLE
1. Relaxation of heart muscle
2. 1. Atria contracts
3. 2. Semi lunar valve closed
4. 3. Tricuspid & Bicuspid valves open
5. 4. Ventricles relax & expand
6. 5. Blood flows from atria to ventricles
HEART BEAT
1. Myogenic
  1. Inilated from within heart muscle
2. Automatic nerve system in control
3. Cardiac control centre influence cerebrum & hypothalamus
4. Be stimulated or inhibited by nerve impulses
5. Release of adrenaline from adrenal medulla is control factor
SA NODE
1. Located in wall of right atria near vena cava
2. Determines heartbeat
3. Initiate heartbeat
4. Usually keeps heartbeat regular
5. Automatic excitation pulse every 0.85 sec
6. Cause artria to contract
7. If SA fails, heart still beats but slower
8. (Sinoatrial)
AV NODE
1. Located base of right artria near septum
2. Neuromuscular tissue
3. Signals ventricles to contract
4. Sends impulses to bundle of His
  1. Then throughout ventricular walls
5. Wave of excitation conducted along purkinje fibres
6. (Atrioventricular)
ECG
1. Measures electrical activity
2. Consists of waves
  1. P
    1. Movement from SA to AV node
  2. QRS
    1. Movement down centre across ventricle
  3. T
    1. ventricle repolarisation
3. Detects abnormal heartbeats
4. Arrhythmia = abnormal heart rhythm
5. Fibrillation = Heart beating rapidly & contractions uncoordinated

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CARDIOVASCULAR SYSTEM

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	Created by offintowonderland about 10 years ago

	Copied by Max Hobbs almost 8 years ago