Our Body Defenses Immune System Aka Lymph system

1. Skin  Skin is a solid barrier to keep things out! 2. Mucous membranes  traps pathogens; have cilia to move pathogens out 3. oil, sweat, tears and saliva  Contain enzyme LYSOZYME which breaks down bacterial cell wall and kills cell 4. Normal bacterial inhabitants  Bacteria that live on our skin and in our gut, will normally out-compete pathogens for resources 3.

Lymphatic system and circulatory system are closely related structures that are joined by a capillary system

1. return tissue fluid to blood (maintain blood volume & pressure) 2. protect body from microorganisms

 What is the “other” name for the immune system?  Name 4 barriers to invasion by foreign invaders  List 2 functions of the immune system

 1-LYMPH  2-LYMPH VESSELS  3-LYMPH NODES  4-SPLEEN  5-THYMUS

 Similar to blood plasma  Bathes all tissues of body  Exits capillaries through filtration - enters lymph vessels through movement of muscles

 Dead end capillaries in tissue spaces merge with larger lymph vessels and return fluid back to the heart  Move by surrounding skeletal muscles squeezing (no pump!)  Have one way valves to keep from moving backwards!

 Masses of lymph tissue that produce White Blood Cells  Located all around body in “groups” along lymph vessels  Acts as a filter or trap for foreign particles to be “eaten” by macrophages

LYMPH NODES:  Tonsils  protective rings of lymph nodes around nasal/oral cavities  Peyer’s patches  lymph nodes around small intestine to catch pathogens absorbed by digestive system

 Located below the diaphragm and behind the stomach  Filters/destroys bacteria & old/dead red blood cells

 Location: below the thyroid and above the heart  T cells mature here

 List 5 parts of the immune system  What does the spleen do?  Name 2 of the specialized lymph nodes in your body.  Where are your Peyer’s Patches located?  Where do your T cells mature?