BLOOD 4. On the dark side

Hey everyone. Here is th last lesson on Blood. Enjoy!

1. Check if you understand the key words.

Immunity

innate

adaptive

leukocyte

cell

cytokines

vast

to be exposed

to originate

screening

invader

2.  What do you think are differences between innate and adaptive immune responses? Write your answer, use the picture above.

3.  Read the first two sentences. What is the difference between them? Try to guess what the text is about.

The immune system is the complex collection of cells and organs that destroys or neutralises pathogens that would otherwise cause disease or death. The immune system is a collection of barriers, cells, and soluble proteins that work together and communicate with each other in amazingly complex ways.

4.  Draw the schema of human immune system after reading the text.

The modern model of immune function is organised into three phases based on the timing of their effects and consists of the following:

• Barrier defences such as the skin and mucous membranes, which act immediately to prevent pathogenic invasion into the body tissues

• The fast but nonspecific innate immune response, which consists of a variety of specialised cells and soluble factors

• The slower but more specific and effective adaptive immune response, which involves many cell types and soluble factors, but is primarily controlled by white blood cells (leukocytes) known as lymphocytes, which help control immune responses.

The immune cells can be divided into three based on function:

• Phagocytic cells, which ingest pathogens to destroy them

• Lymphocytes, which specifically coordinate the activities of adaptive immunity

• Cells containing cytoplasmic granules, which help mediate immune responses against parasites and intracellular pathogens such as viruses.

Some lymphocytes function primarily by producing antibodies. An antibody is any of the group of proteins that binds specifically to pathogen-associated molecules known as antigens. An antigen is a chemical structure on the surface of a pathogen that binds to lymphocyte antigen receptors.

5.  Do the TEST.