cirulatory system

Anmerkungen:

• The human body needs a transport system to move materials from one place to another. for example our blood carrys food,oxygen,wasteproducts to and from all the cells in our body

1. blood

   Anmerkungen:

   • Blood is made up of four parts or components:plasma,red blood cells,white blood cells ands platelets. Red blood cells are made in gthe jelly-like centre of bones,called bone marrow. theyt contain a red dye or pinment called haemoglobin. to make haemoglobin we need iron. Haemoglobin-and therefore red blood cells-carries oxygen
   1. plasma

      Anmerkungen:

      • Plasma is teh liquid part of blood. it is a pale yellow colour and is mostly made of water. plasma transports many dissolved chemicals around the body. Examples of these chemicals are useful materials such as food and hormones, along with wastes such as carbon dioxide , salts and urea.

      1. Anmerkungen:

         • Oxygen enters our red blood cells in the alveoli of the lungs. It attaches to haemoglobin in the red cells. when blood reaches cells in other parts of our body {such as our muscles or the brain} haemoglobin releases the oxygen into these cells.

         1. Anmerkungen:

            • The functions of blood are a combination of the functions of the parts of the blood. these functions and the parts of blood that carry them out are given in figure 6.7.

            1. Anmerkungen:

               • Artries carry blood away from the heart.{remember A is for ARTRIES and A is for AWAY. There is no danger of the blood in an artery flowing backwords

               1. Anmerkungen:

                  • VEINS  veins carry blood to the heart. the blood flow or pressure means that veins is low. to prevent blood flowing backwards in veins they have vaves at regular intervals.