Transport in Animals

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Compare this 2 circulatory systems

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​Heart rate

​The heart rate is the number of times the heart beats in the space of a minute.

​Calculation

​1 small box = 40 ms

​From R to R = 20 small boxes

​1 beat = 20 small boxes x 40 ms

​1 beat = 800 ms = 0.8 s

​Beat per minute = 60 s : 0.8 s = 75 beat / min

​Pathogen and Immunity

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​Pathogen

• ​A pathogen​A pathogen is a disease-causing organism

• Pathogens are passed on from one host to another and therefore the diseases they cause are known as transmissible disease is a disease-causing organism

​Body Defences

​I. Mechanical barrier

​ - Skin: has thick outer layer of dead cells that is very difficult to penetrate

​Body Defences

​I. Mechanical barrier

​​ - Nostrils Hairs: to trap dust that might be carrying pathogens

​ - Cilia: trap the pathogens then sweep the mucus back to throat

​Body Defences

II. Chemical barrier

• Enzymes in tears, saliva and mucus: break down the surface of bacteria.

• Acid in sweat and in the stomach: kills cellular pathogens

​Body Defences

III. Cell

• Cells – different types of white blood cell work to prevent pathogens reaching areas of the body they can replicate in

  • By phagocytosis – engulfing and digesting pathogenic cells

​Body Defences

III. Cell

• ​By producing antibodies - which clump pathogenic cells together so they can’t move as easily (known as agglutination) and releasing chemicals that signal to other cells that they must be destroyed

Lymphocytes

Type of white blood cell (leukocyte) that is of fundamental importance in the immune system because lymphocytes are the cells that determine the specificity of the immune response to infectious microorganisms and other foreign substances.

Antibody and Antigen

• ​All cells have proteins and other substances projecting from their cell membrane. These are known as antigens and are specific to that type of cell

• Lymphocytes have the ability to ‘read’ the antigens on the surfaces of cells and recognise any that are foreign

• They then make antibodies which are a complementary shape to the antigens on the surface of the pathogenic cell

Lymphocyte - Antibody - Antigen

​Infection and Memory Cells

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Passive and Active Immunity

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