B3 2.1-2.5

B3 2.1-2.5

1. 2.1 circulatory system and the heart

   • Human beings have double circulation
   • Valves make sure blood flows in the right direction through the heart
   • Ventricles contract and force blood out of the heart
   • Pulmonary artery takes de-oxygenated blood to the lungs
   • Vena Cava brings de-oxygenated blood into the heart
   • Aorta carries de-oxygenated blood around the body
   • Double circulation ( Two transport systems)
     • 2.Carries blood around the rest of your body and back again to the heart
     • 1. Carries blood from your heart to your lungs and back

2. 2.2 Keeping the blood flowing

   • double circulation is vital in warm-blooded active animals like humans
   • Damaged heart valves can be replaced
   • The main types of blood vessels are arteries, veins and capillaries
   • Arteries carry blood away from your heart to the organs of your body
   • Your heart is made up of two pumps the beat together around 70 times each minute
   • Substances diffuse in and out of the blood in the capillaries

3. 2.3 Transport in the blood

   • Blood plasma is a yellow liquid that transports blood cells and other things
   • average person has between 4.7 and 5.0 litres of blood
   • Red blood cells pick up oxygen from our lungs and carry the oxygen to the tissues and cells where it's needed
   • Haemoglobin+oxygen(Alveolus of lungs) ---> Oxyhaemoglobin(red blood cells) ---> Oxygen+Heamoglobin(muscle)
   • Carbon dioxide which is made in in the organs in of the body is carried back to the lungs in the plasma
   • Blood Plasma transports dissolved food molecules, carbon dioxide and urea and has some blood cells suspended in it
   • White blood cells are the body's defence system against harmful bacteria and can form antibodies. They are also are much larger than red blood cells and have a nucleus
   • Red blood cells have no nucleus so more haemoglobin can fit in it.

4. 2.4 Artificial or real?

   • The simplest way to replace blood in an emergency is with donated plasma or saline (salt + water)
   • Plasma carries little dissolved oxygen whilst Saline does not carry oxygen or food
   • These just replace lost blood volume so it can buy time for your body to produce more blood or to receive a matched blood transfusion to be found
   • Perfluorocarbons (PFC's) are a more sophisticated form of artificial blood and are non reactive chemicals that can carry dissolved gases around your body
     • They do not dissolve in water so getting them into your blood is difficult
   • Artificial heart
     • advantages
       • no wait for donor
       • no need to match tissue
       • no need for immunosuppressant drugs
     • disadvantages
       • blood clotting problems
       • recently, always involved in staying in hospital

5. Transport systems in plants

   • phloem transports the sugars made by photosynthesis from the leaves to the rest of the plant, including growing stems and roots
   • sugars are also needed for making new plant cells and food is transported to the storage organs where it is needed to provide an energy store for the winter.
   • Phloem is a living tissue
   • Xylem is another transport tissue in plants and carries water and mineral ions from the soil to around the plant
   • Mature xylem cells are dead.
   • importance of transport
     • All cells need sugars for respiration as well as to provide materials for growth
     • Movement of water and mineral ions from the roots is equally important
     • It is very important to move food made by photosynthesis around the plant
     • Water is needed for photosynthesis
     • It is also needed to hold the plant upright.