B5

• Veins towards heart
• Veins - Wide Lumen and thin walls (much lower blood pressure)
• Capillaries - one cell thick, lumen is thick enough for just one blood cell
• Veins have valves to prevent backflow of blood
• Arteries have a thick, muscular wall (high blood pressure)
• Blood is a mixture with four main components:

  1. Plasma
  2. Platelets
  3. White Blood Cells
  4. Red Blood Cells
• Plasma carries liquid part (dissolved glucose, amino acids, minerals, co2 and urea)
• Platelets are small broken fragments of cells
• platelets make clots
• White blood cells are the guardians of the body
• White blood cells defend against pathogens by destroying them (lymphocytes and phagocytes)
• Red Blood cells - transport oxygen
• Oxygen bonds with haemglobin
• RBC have biconcave disc shape, no nucleus, haemoglobin
• Atrial Contraction : Systole
• Atrial + Ventricular Relaxation : Diastole
• circulatory system is a system of blood vessels with a pump and valves to ensure one-way flow of blood.
• double circulation in terms of a low pressure circulation to the lungs and a high pressure circulation to the body tissues and relate these differences to the different functions of the two circuits.
• Coronary heart disease is the blockage of coronary arteries and state the possible risk factors as diet, stress, smoking, genetic predisposition, age and gender.
• Double circulatory systems are important because they ensure that we are giving our tissues and muscles blood full of oxygen, instead of a mixture of oxygenated and deoxygenated blood.
• During exercise, your heart typically beats faster so that more blood gets out to your body. Your heart can also increase its stroke volume by pumping more forcefully
• Artery vs Vein

  A) Artery

  B) Vein

  C) Narrow Lumen

  D) Wide Lumen

  
• Heart Diagram Label

  A) Vena Cava

  B) Aorta

  C) Pulmonary Artery

  D) Pulmonary Vein

  E) Bicuspid Valve

  F) Aortic Valve

  G) Vena Cava

  H) Tricuspid Valve

  I) Pulmonary Valve

  J) Right Atrium

  K) Left Atrium

  L) Right Ventricle

  M) Left Ventricle

  
• Single Circulation: Heart -> gills -> body systems -> heart
• Double circulation: Heart -> lungs -> body systems -> heart
• left=oxygenated

  right =deoxygentated
• Blood enters the heart in the atria.  As these fill up the atrioventricular valves open and blood begins to fill the ventricles.  When these contract the bicuspid and tricuspid valves close to prevent backflow into the atria.  Blood is forced into the aorta and the pulmonary artery.  The semilunar valves then close, preventing backflow into the ventricles.
• Arteries have very thick walls to withstand pressure
• Arteries have lots of elastic fibres to expand and recoil to push blood
• Arteries have a thick muscle layer to push blood along
• Arteries are narrow and blood forces the lumen to open
• Arteries have NO valve
• Veins have thin walls, low pressure
• Veins have very few elastic fibres
• Veins have a thin muscle layer
• Veins have valves present to prevent backflow
• Veins are wide so have no resistance to blood flow
• Capillaries connect arteries and veins
• Capillaries exchange oxygen, carbon dioxide, glucose and waste products
• Capillaries are one cell thick for diffusion to occur