Transport and Immunity

• Phagocytosis


  Engulf and absorb the pathogen the release an enzyme to destroy the pathogen
• Lymphocytes


  Produce antibodies to attach to the antigens on the pathogens
• Your body ___ makes antibodies for ___ antigens

  Only

  Foreign
• Antigens


  Proteins on the cell membrane of a pathogen
• Antibodies


  Proteins produced by lymphocytes that attach to the antigens (they have a complimentary shape)
• What do antibodies do?


  - Destroy/damage pathogens

  - Clump together to help the phagocyte

  - Release chemical signals to attract phagocytes
• How do bacteria make you ill?

  Bacteria make you ill by producing toxins
• How do viruses make you ill?

  Viruses make you ill by destroying your cells by injecting DNA into them
• Why do we have vaccines?


  - Some diseases could kill you or leave you with serious side effects before your body could produce antibodies for them, for diseases we have vaccines
• Memory cells


  Enable the body to produce antibodies more quickly and in greater numbers if that pathogen enters the body again, this is said to make you immune to the disease
• What are vaccines made of?


  - Vaccines are made of weakened or dead antigens

  - The body responds to them by making antibodies but you don't become unwell

  - Your memory cells will then produce more antibodies more quickly if the actual pathogens enter your body
• What are the 3 types of blood vessels?


  - Arteries

  - Veins

  - Capilleries
• Arteries


  - The heart pumps the blood out at high pressure so the artery walls are strong and elastic

  - The elastic fibres allow the arteries to expand

  - The walls are thick compared to the size of the hole down the middle (the lumen), they contain thick layers of muscle to make them strong

  - The largest artery in the body is the aorta
• Capillaries


  - Arteries branch into capillaries

  - Capillaries are really tiny

  - They carry the blood really close to every cell in the body to exchange substances with them

  - They have permeable walls, so substances can diffuse in and out

  - They supply food and oxygen, and take away waste like CO2

  - Their walls are usually only 1 cell thick, this increases the rate of diffusion by decreasing the distance over which it happens
• Veins


  - Capillaries eventually join up to form veins

  - The blood is at a low pressure in the veins so the walls don't need to be as thick as artery walls

  - They have bigger lumen than arteries to help blood flow despite the low blood pressure

  - They also have valves to help keep the blood flowing in the right direction

  - The largest vein in the body is the vena cava
• What are the 4 different parts of blood?


  - Red blood cells

  - White blood cells

  - Platelets

  - Plasma
• Plasma


  Plasma is a pale yellow liquid which carries just about everything that needs transporting around your body:

  - Red/white blood cells and platelets

  - Digested food products (like glucose and amino acids) from the gut to all the body cells

  - Carbon Dioxide from the body cells to lungs

  - Urea from the liver and kidney's

  - Hormones, which act as a chemical messenger

  - Heat energy
• Platelets


  - When you damage a blood vessel, platelets clump together to 'plug' the damaged area

  - This is known as blood clotting, blood clots stop you losing too much blood and prevents microorganisms from entering the wound

  - In a clot, platelets are held together by a mash of proteins called fibrin (though this process also needs other proteins called clotting factors to work properly)
• Red blood cells


  - They carry oxygen from the lungs to all the cells in the body

  - A red blood cell is well adapted to its functions:

  . Red blood cells are small and have a biconcave shape to give a large surface area for absorbing and releasing oxygen

  . They contain haemoglobin, which is what gives blood it's colour (it contains a lot of iron), in the lungs haemoglobin reacts with oxygen to become oxyhemoglobin, in the body tissues the reverse reaction happens to release oxygen to the cells

  . Red blood cells don't have a nucleus (this frees up space for more haemoglobin so they can carry more oxygen)
• Vena cava


  Carries deoxygenated blood from the body to the heart
• Aorta


  Carries oxygenated blood from the heart to the body
• Pulmonary artery


  Carries deoxygentated blood from the heart to the lungs
• Pulmonary vein


  Carries oxygenated blood from the lungs to the heart
• Right atrium


  Pumps deoxygenated blood to the right ventricle
• Right ventricle


  Pumps deoxygenated blood to the lungs via the pulmonary artery
• Left atrium


  Pumps oxygenated blood to the left ventricle
• Left ventricle


  Pumps oxygenated blood into the aorta
• Which ventricle has a thicker wall?

  Left
• Why does the left ventricle wall need more muscle?


  Because it has to pump blood around the whole body, where as the right ventricle only has to pump blood to the lungs
• Which ventricle has a higher blood pressure and why?

  The left ventricle as it needed to pump blood all the way around the body
• Why does your heart have valves?


  To prevent back flow of blood
• How does exercise increase heart rate?


  When you exercise, your muscles need more energy, so you respire more. You need to get more oxygen into cells and remove more carbon dioxide for this to happen the blood has to flow faster, so your heart increases.

  - Exercise increase the amount of carbon dioxide in the blood

  - High levels of CO2 are detected by receptors in the aorta and carotid artery (an artery in the neck)

  - These receptors sand signals to the brain

  - The brain send signals to the heart, causing it to contract more frequently and with more force
• How does the hormone system help to control heart rate?


  - When an organism is threatened the adrenal glands release adrenaline

  - Adrenaline binds to specific receptors in the heart, this causes the cardiac muscles to contract more frequently and with more force, so heart rate increases and heart pumps more blood

  - This increases oxygen supply to the tissues, getting ready for action
• What type of blood do arteries carry?

  Oxygenated blood
• What type of blood do veins carry?

  Deoxygenated blood
• Which blood vessel are except from the vein and artery rule?


  - Pulmonary artery

  - Pulmonary vein
• What does type of blood does the pulmonary vein carry?

  Oxygenated
• What types of blood does the pulmonary artery carry?


  Deoxygenated
• Pulmonary means to the ___


  Lungs
• Hepatic means to the ___


  Liver