7161603
CARDIOVASCULAR SYSTEM
- FUNCTIONS OF THE BLOOD
- Transport gasses e.g. oxygen & CO2
- Distributes nutrients e.g. proteins/lipids/carbohydrates
- Transport metabolic waste
- Delivers enzymes & hormones e.g Adrenaline
- Regulate pH & Electrolytes e.g. salts
- Defends body against toxins & pathogens
- Regulate body temperature
- Restricts fluid loss through damaged vessels
- Transport gasses e.g. oxygen & CO2
- COMPOSITION OF BLOOD
- Blood cells = 45%
- Plasma = 55%
- Blood cells = 45%
- TYPES OF BLOOD CELLS
- Ethrocytes = red cells
- Thrombocytes = platelets
- Leukocytes = white cells
- Ethrocytes = red cells
- TYPES OF BLOOD VESSELS
- Arteries
- Arterioles (small artery)
- Carry blood away from heart
- Oxygenated blood
- High pressure
- Thick muscular elastic walls
- 3 layers thick
- 3 layers thick
- Expand & accommodate increase blood volume
- Arterioles (small artery)
- Veins
- Venules (small veins)
- Carry blood to heart
- Deoxygenated blood
- Valves present
- Lower pressure
- Thin elastic walls
- 2 layers thick
- 2 layers thick
- Venules (small veins)
- Capillaries
- Smallest vessel
- Extremely narrow
- 1 layer thick
- Carry blood from artery to vein
- Pressure is low
- Flow of blood slow
- Gaseous exchange & nutrients occur
- Smallest vessel
- Heart
- Arteries
- HEART WALL
- Pericardium
- Outer layer
- Blood lymph capillaries & nerve fibres
- Outer layer
- Myocardium
- Thin middle layer
- Cardiac muscle tissue
- Thin middle layer
- Endocardium
- Inner layer
- Forms part of valves in heart
- Inner layer
- Pericardium
- HEART CHAMBERS
- Left Atrium
- Left Ventricle
- Right Atrium
- Right Ventricle
- Left Atrium
- SYSTOLE
- 1. Contraction of heart muscle
- 2. Atria relax & expands
- 3. Semi lunar valve open
- 4. Tricuspid & Bicuspid valve closed
- 5. ventricles contract
- 6. Blood flows to lungs & body
- 1. Contraction of heart muscle
- DIASTOLE
- Relaxation of heart muscle
- 1. Atria contracts
- 2. Semi lunar valve closed
- 3. Tricuspid & Bicuspid valves open
- 4. Ventricles relax & expand
- 5. Blood flows from atria to ventricles
- Relaxation of heart muscle
- HEART BEAT
- Myogenic
- Inilated from within heart muscle
- Inilated from within heart muscle
- Automatic nerve system in control
- Cardiac control centre influence cerebrum & hypothalamus
- Be stimulated or inhibited by nerve impulses
- Release of adrenaline from adrenal medulla is control factor
- Myogenic
- SA NODE
- Located in wall of right atria near vena cava
- Determines heartbeat
- Initiate heartbeat
- Usually keeps heartbeat regular
- Automatic excitation pulse every 0.85 sec
- Cause artria to contract
- If SA fails, heart still beats but slower
- (Sinoatrial)
- Located in wall of right atria near vena cava
- AV NODE
- Located base of right artria near septum
- Neuromuscular tissue
- Signals ventricles to contract
- Sends impulses to bundle of His
- Then throughout ventricular walls
- Then throughout ventricular walls
- Wave of excitation conducted along purkinje fibres
- (Atrioventricular)
- Located base of right artria near septum
- ECG
- Measures electrical activity
- Consists of waves
- P
- Movement from SA to AV node
- Movement from SA to AV node
- QRS
- Movement down centre across ventricle
- Movement down centre across ventricle
- T
- ventricle repolarisation
- ventricle repolarisation
- P
- Detects abnormal heartbeats
- Arrhythmia = abnormal heart rhythm
- Fibrillation = Heart beating rapidly & contractions uncoordinated
- Measures electrical activity
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