Lungs & blood

• Blood Clotting


  A process that reduces bleeding when we are injured.
• oxygen


  used for survival - to help organisms grow, reproduce and turn food into energy.
• Blood is a tissue and it's carried around the body in blood vessels.

  • It's made up of 45% of cells and 55% of plasma.
• Blood's functions includes:


  Transporting substances

  Defence against pathogens

  Control of body temperature

  Maintaining pH of fluids.
• Structure of Lungs

  A) trachea

  B) bronchioles

  C) alveoli

  D) bronchi

  E) capillary network

  F) alveoli

  
• In order to get energy, cells must carry out cellular respiration and for that, they need oxygen.
• The respiratory system


  takes up oxygen from the air we breathe into our bloodstream to be transported to the rest of the body and expels the unwanted carbon dioxide.

  The organs are:

  • lungs
  • trachea
  • bronchi
  • bronchioles
  • diaphragm
  • nose / mouth
  • throat

  
• Structure of the Lungs

  1. Air enters the lungs through the TRACHEA
  2. The TRACHEA divides into two BRONCHI, one for each lung.
  3. The BRONCHI branch further divides into smaller tubes called BRONCHIOLES
  4. The BRONCHIOLES end in tiny air sacs known as ALVEOLI (The site of gas exchange).

  A) trachea

  B) bronchi

  C) bronchioles

  D) alveoli

  
• Gas Exchange Process


  1. ALVEOLI are the sites of gas exchange, and are surrounded by a CAPILLARY NETWORK.
  2. Oxygen diffuses through the wall of the alveoli into the blood.
  3. Carbon dioxide diffuses from the blood in the capillaries into the air in the alveoli to be exhaled.
  4. This exchange ensures oxygenation of blood and removal of carbon dioxide, a by-product of respiration.

  
• Carbon dioxide is transported around the body dissolved in the blood plasma, it doesn't binds to the haemoglobin inside red blood cells, like oxygen.

  
• Breathing rate (Breaths/Min) = No. of Breaths taken / No of minutes
• Components of blood

  • Red blood cells
  • White blood cells
  • Platelets
  • Plasma

  
• Red blood cells:

  • Produced in the bone marrow.
  • makes up half our blood by volume
  • Its role is to carry oxygen from the lungs to the body tissues, so our cells can use it in cellular respiration.
  • Contain a protein called haemoglobin, which binds to oxygen in the lungs and releases it in body tissues.
  • No nucleus to increase space for haemoglobin and oxygen.
  • Shaped like a Biconcave disc to increase surface area for absorbing oxygen.

  
• Haemoglobin


  A large protein in the red blood cells.

  • The haemoglobin gives the RBC its red colour.
  • It binds to oxygen in the lungs to become oxyhaemoglobin
  • once the red blood cells have travelled around the body to the tissues, the oxyhaemoglobin can split back to the haemoglobin and oxygen.
  • so that the oxygen is released to diffuse into our tissues

  
• White blood cells

  • Makes up < 1% of out blood.
  • Does has a nucleus, to divide by mitosis.
  • produced in bone marrow.

  • It fights infection and are part of the immune system.
  • Phagocytosis
  • SOME Produce antibodies and antitoxins.

  
• Phagocytosis 


  The process by which a white blood cell binds to, and then engulfs a pathogen, in order to destroy it.

  
• antibodies 


  Produced by some white blood cells (like B-cells) where it binds to pathogens and help immune cells to destroy them.

  
• antitoxins


  Produced my SOME white blood cells to neutralise any toxins any other pathogens produce.

  
• Types of white blood cells:

  • T-cells = Kills diseases
  • B-cells = Produces antibodies
• Platelets


  • broken off from large cells in the bone marrow.
  • Cell fragments important for blood clotting.
  • Has no nucleus
  • Floats about in the blood, waiting until we get a cut to clot blood, which then dries out and form a scab.
  • It prevents excessive bleeding
  • Stops microorganisms from getting in.
  • A lack of platelets can lead to EXCESSIVE BLEEDING and INFECTION.

  
• Plasma


  A pale yellow coloured liquid that makes the blood watery and makes up 55% of the bloods volume.

  • It carries substances and cells around the body like:
  • red blood cells
  • white blood cells
  • platelets
  • oxygen

  Chemical substances that the plasma carries around:

  • nutrients: glucose, amino acids, proteins, glycerol, fatty acids, vitamins, water, ions, minerals
  • carbon dioxide
  • cholesterol
  • enzymes
  • urea
  • anti-bodies
  • anti-toxins
  • hormones

  
• If there's not enough blood flowing through the circulatory system, then there might not be enough blood to deliver the required oxygen to their tissues.
• Doctors can give patients new blood by:

  • Artificial blood:
  • consists of salt water
  • it adds volume to the circulatory system to keep vessels full and allows the heart to keep on pumping.
  • Doesn't contain any red blood cells to transport any more oxygen.
  • can only replace 1/3 of our blood with it.
  • Blood transfusion:
  • Real blood, donated by blood donors, that comes with its own red blood cells - the key to surviving blood loss.

  
• Alveoli is adapted for efficient gas exchange by:

  • walls are one cell thick for short diffusion path to increase the rate of gas exchange.
  • lots of alveoli for a large surface area, so more molecules can diffuse at the same time.
  • It's moist to allow gases to dissolve, it increases the rate of diffusion.
  • Good blood & air supply, for a strong concentration gradient:
  • as blood is constantly replaced.
  • as the air in the alveoli is constantly replaced with new oxygen rich air from the atmosphere.
  • Its Surfaces are permeable, so Oxygen and carbon dioxide are able to diffuse across.

  
• Function of Ribs:

  • Gives protection of lungs / heart.
  • It helps you breathe, by inflating the lungs.

  
• Describe how pathogens cause infections and describe how the immune system defends the body against these pathogens.

  Bacteria and viruses are pathogens, they reproduce rapidly inside the body:

  • Bacteria may produce poisons / toxins
  • viruses live and reproduce inside cells, causing damage.

  Platelets clot the blood to stop the entry of pathogens.

  white blood cells help to defend against pathogens by:

  • phagocytosis to engulf pathogen
  • producing antibodies to destroy specific pathogens
  • producing antitoxins to counteract toxins released by pathogens
  • This leads to immunity from that pathogen.
• Red blood cells has no nucleus because:

  • to increase SA:V
  • increase more space for haemoglobin and oxygen, so more oxygen is able to be given to the body tissues
  • They are only carriers, so it don't need proteins to synthesis
  • For its biconcave shape
• Doctors can give patients new blood by:


  • Artificial blood
  • Blood transfusion
• Artificial blood:


  • consists of a salt solution as a blood substitute
  • it adds volume to the circulatory system to:
  • keep vessels full
  • Allows the heart to keep on pumping
  • Keep people alive, even if red blood cells lose is at ⅔
  • Buy time for natural production of red blood cells.
• Artificial blood disadvantages:


  • Doesn't contain any red blood cells to transport any more oxygen.
  • can only replace 1/3 of our blood with it.
• Blood transfusion:


  Real blood, donated by blood donors, that comes with its own red blood cells - the key to surviving blood loss.