biology

• label the diagram

  label:

  A) trachea/ windpipe

  B) right bronchus

  C) bronchiole

  D) alveoli

  E) nose

  F) mouth

  G) ribs

  H) left lung

  I) diaphragm

  J) thorax

  
• Function of the breathing system:


  It moves air in and out of the lungs.
• Function of the lungs:

  To exchange the gases oxygen and carbon dioxide between the air in the lungs and the blood.
• Thorax-abdomen-diaphragm:

  The lungs are situated in the upper part of the body called the thorax. The lungs are protected by the ribcage. The thorax is separated from the lower part of the body, the abdomen, by a sheet of muscle called the diaphragm
• Trachea:

  Air enters the body through the nose and mouth. It travels past the back of the throat into the trachea. The trachea splits into two tubes called the right and left bronchi.
• Function of bronchi (singular: bronchus):

  Each bronchus carries air into one of the two lungs.
• Bronchioles:

  The bronchi divide into smaller and smaller tubes called the bronchioles.
• Alveoli:


  At the ends of the bronchioles are bunches of tiny air sacs called alveoli. It is across the walls of the alveoli that gas exchange occurs.
• The trachea


  If you gently rub the front of you throat you can feel hard ridges.

  These ridges are C-shaped rings of cartilage that make sure the trachea always stays open (even when you bend your neck).

  The gap in the C runs at the back of the trachea.

  The gap is there so that cartilage does not rub against the oesophagus (the tube that carries food to the stomach).
• Goblet cells

  These are specialised cells which line the trachea.

  Function: They secrete a thick, sticky liquid called mucus that traps dirt and microorganisms.
• Cilia

  the cells lining the tráchea have many tiny hair-like structures; called cilia, on their surface

  Function: The cilia constantly move to sweep the mucus up and out of the trachea and the lungs. This helps to keep the lungs clear.
• How the alveoli are adapted for gas exchange

  • Alveoli are tiny air sacs found at the ends of the bronchioles in the Figure 6 The position and structure of alveoli lungs
• How the alveoli are adapted for gas exchange

  Alveoli are tiny air sacs found at the ends of the bronchioles in the Figure 6 The position and structure of alveoli lungs
• Gas Exchange

  It is the movement of oxygen from the air into the blood AND the movement of carbon dioxide in the opposite direction.

  Diffusion

  The gases move by the process of diffusion.

  Diffusion is the movement of particles from an area where they are in high concentration to an area where they are less concentrated.
• Examples of diffusion in the body:Blood returning to the lungs from the body contains a high concentration of carbon dioxide and a low concentration of oxygen.

  Air in the alveoli contains a higher concentration of oxygen than the blood and a lower concentration of carbon dioxide.
• Examples of diffusion in the body:

  Blood returning to the lungs from the body contains a high concentration of carbon dioxide and a low concentration of oxygen.

  Air in the alveoli contains a higher concentration of oxygen than the blood and a lower concentration of carbon dioxide.
• How the alveoli are adapted for gas exchange

  Alveoli are tiny air sacs found at the ends of the bronchioles in the Figure 6 The position and structure of alveoli lungs. Alveoli provide a large surface area for gas exchange.

  a tennis court.

  The walls of the alveoli and capillaries are only one cell thick, so the gases do not have far to diffuse.

  Each alveolus is well ventilated by breathing. This maintains a steep concentration gradient for the diffusion of oxygen into the blood and carbon dioxide out of the blood.
• How the alveoli are adapted for gas exchange

  The walls of the alveoli and capillaries are only one cell thick, so the gases do not have far to diffuse.

  The lining of each alveolus is moist. Oxygen dissolves in this layer, which speeds up diffusion into the blood.

  Each alveolus has a good blood supply to transport gases and to maintain a steep concentration gradient.
• Gas exchange surfaces in other organisms

  Insects have tiny holes along their abdomen called spiracles. Gases move in and out of these holes, which are connected to a network of tubes called tracheae. The trachea carry oxygen to respiring cells, and carbon dioxide away from the cells
• The mechanism of breathing

  Breathing is the movement of muscles to alter the volume of the chest cavity. This results in the movement of air into and out of the lungs.

  The muscles involved in breathing are the diaphragm and the muscles between the ribs. These muscles contract when you breathe in and relax when you breathe out.
• The circulatory system is made up of:

  -The heart

  -Blood vessels

  -Blood Function of circulatory system: To transport substances around the body.

  Function of heart: To pump blood around the lungs and body.
• The Heart

  The heart is a double pump. The right side of the heart pumps deoxygenated blood, which is high in carbon dioxide and low in oxygen, to the lungs. Here carbon dioxide diffuses out of the blood and oxygen is collected from the air in the alveoli.

  Blood leaving the lungs is therefore rich in oxygen and low in carbon dioxide. It is returned to the left side of the heart, which pumps this oxygenated blood around the body.
• The structure of the heart

  Blood is pumped out of the left side of the heart to go to the body.

  Blood is pumped from the right side of the heart to the lungs to pick up oxygen and release carbon dioxide.

  Blood returns from the lungs into the left side of the heart, to be pumped around the body.

  Blood returns to the right side of the heart from the body.

  The heart is a muscular pump.