Topic 1.1-transport around the body

Topic 1.1-transport around the body

1. Water in living organisms

   • Dipole
     • Separation of charge
       • Slightly positive side, slightly negative side
   • Hydrogen bond
     • Weak electrostatic attraction
     • Attraction between oxygen and hydrogen in different molecules
   • Solvent
     • Other substances dissolve it
   • Expulsions
     • Tiny droplets of one liquid suspended in another
   • Suspensions
     • Solid mixed with liquid
     • Wil separates out if not constantly stirred
   • Surface tension
     • Property that seems like surface covered in thin elastic skin
   • Anmphoteric
     • Can act as acid or a base
       • Acid: forms h+ ions and donates protons
       • Base: forms OH- ions and accepts protons

2. Blood circulation

   • Circulation systems
     • Single circulation
       • In fish (simple)
     • Double circulation
       • Involves 2 circulatory systems
       • Systemic circulation
         • Carries oxygenated blood from heart to cells
         • Carries deoxygenated blood back to heart
       • Pulmonary circulation
         • Carries oxygenated blood back to heart
         • Carries deoxygenated blood from heart to lungs
   • The blood vessels
     • Arteries
       • Carry blood away from heart
       • Carries oxygenated blood
         • Accept pulmonary artery and umbilical artery during pregnancy
       • Lumen gets smaller further away from heart
         • Furthest from heart are arterioles
       • External layer of tough tissue
       • Smooth lining around lumen
       • Middle layers contain
         • Elastic fibres
           • More nearest the heart
         • Smooth muscle
           • More further away from heart
       • Small lumen
     • Capillaries
       • Arteriolar feed into them
       • Branch between cells
       • Very thin cell wall
       • Simple
       • Carry originated blood at first
     • Veins
       • Carry blood back to heart
       • Carrie deoxygenated blood
         • Accept pulmonary vein and umbilical vein
       • Venules lead from capillaries and form 2 veins
         • Inferior vena cave
           • From lower parts of body
         • Superior vena cava
           • From upper arts of body
       • Tough outer layer
         • Mainly collagen fibres
       • Smooth inner surface
       • Thin layer of smooth muscle. Few elastic fibres
       • Relatively large lumen
       • Have semi lunar valves
         • Blood can pass towards heart but can't go back

3. The role of blood

   • Circulation
     • Passage of blood through vessels
   • Components of blood
     • Plasma
       • Main component of blood
       • Contains frininogen
       • Consists largely of water
     • Erythrocytes
       • Red blood cells
       • Contain harmoglobin
         • Red pigment that carries oxygen
       • Formed in red bone marrow
     • Leucocytes
       • White blood cells
       • Can change there shapes
       • Defend against disease
         • Make antibodies
           • Destroy pathogens
         • Make antitoxins
           • Neutralize poisons (toxins)
         • Go through phagocytosis
           • Engulf and digest pathogens
     • Platelets
       • Tiny fragments of large cells called megakaryocytes
       • Found in bone marrow
       • Involved in blood clotting
   • Pathogens
     • Disease causing bacteria/viruses

4. The blood clotting mechanism

   • Damaged tissue
     • Releases platelets
       • Releases thromboplastin
         • Catalysis prothrombin to..
           • Thrombin
             • Catalyses fibrinogen to...
               • Fibrin
                 • Mesh of fibres
                 • Traps blood cells and more platelets
                 • Forms clot
           • Ca2+ ions have to be present

5. Transport systems

   • Diffusion
     • Free movement of particles down a concentration gradient
   • Concentration gradient
     • From high concentration to low concentration
   • Hormone
     • Chemical (insulin or adrenalin)
   • Mass transport system
     • The flow of substances with a mechanism/pump
   • Osmosis
     • The movement of water along concentration gradient through a partially permeable membrane
   • Active transport
     • Energy used to move substances against a concentration gradient

6. Transporting oxygen and carbon dioxide

   • Oxygen
     • Haemoglobin picks up 4 oxygen molecules
     • Haemoglobin in red blood cells
     • Oxygen moves from lungs to red blood cells by diffusion
     • Keeps steep concentration gradient so more oxygen can diffuse
     • Diffuses into body cells
   • carbon dioxide
     • Waste CO2 diffuses into blood from cells
     • Reacts with water to form H2CO3
     • Separates to form ions H+ and HCO3-
     • HCO3- diffuse out of blood cells and Cl ions move in
     • CO2 diffuse out of blood into lungs