Human Immune System How our cells work to fight disease.

Lymphatic System  Excretes excessive fluid from tissue to blood stream  Absorbs fats in the intestine and puts it n the blood system  Defends the body against disease What we are most interested in

Lymph  Excessive fluid found in blood  Carried by lymphatic vessels A one way system to drain the body  The fluid enters the blood stream at the subclavian vein

Organs of the system  Spleen Blood is cleaned by macrophages and lymphocytes  Lymph nodes Placed along lymphatic vessels Tonsils, adenoids Inguinal and AXILLARY nodes

Diseases of the lymph nodes  Lymphadenitis  Lymphagitis  Elephantiasis  Pulmonary edema  Lymphoma  Hodgkin’s disease

Thymus  Just under the sternum  Thymus lymphocytes (T cells) mature in these lobules  Secretes thymosin Causes pre-T cells to become

Bone Marrow  Creates blood cells – red and white  White cells are necessary for the development of immunity Neutrophils Eosinophils Basophil Lymphocytes Monocytes

Immunity  The immune response is the ability to distinguish between "self" and "non- self."  Every cell in your body carries the same set of distinctive surface proteins that distinguish you as "self."

Non-Specific Defenses  Barriers to entry Mechanical barriers stop pathogens from entering the body  Skin secretes oil containing a chemical that weakens or kills bacteria  Respiratory track lined with cells with cilia that sweep mucus and trapped particles into throat to be expelled  Stomach with high pH that inhibits growth of bacteria  Other organs with good bacteria that prevent pathogens from lodging

 Stomach with high pH that inhibits growth of bacteria  Other organs with good bacteria that prevent pathogens from lodging there  Non-specific means that the body doesn’t know what it’s fighting, just knows that it is not “self”

Inflammatory reaction  When skin is broken there is reddening and swelling at the site of the injury The capillaries rupture and release histamine Histamine causes capillaries to dilate and become more permeable Bradykinin increases the effects of histamine and begins nerve impulses that result in pain

 Larger capillaries are the redness  Increased permeability allows fluid and cells from the blood stream to escape and that results in the swelling surrounding an injury

 A break in the skin allows pathogens to enter  Neutrophils and monocytes enter tissue with the fluids and carryon phagocytosis  Steps of phagocytosis Steps of phagocytosis  short animation of phagocytosis in action short animation of phagocytosis in action

Macrophages  Monocytes turn into macrophages These are large phagocyte cells that can kill many invaders and survive Some organs have resident macrophages that act as the body’s scavengers They also cause the body to greatly increase production of leukocytes – specifically neutrophils Pus is dead tissue, cells, bacteria and living wbc

Protective Proteins  Complement has plasma proteins named letter C and a number or letter.  Once activated it increases other proteins in a set series of reactions  Creates a cascade response  Wiki – complement Honors students must read and take notes. Wiki – complement

How they work  The complement forms holes in cell walls and it allows fluids to enter  The cell then lyses (bursts like a water balloon)

Specific Defense  The immune system must identify self v. non-self.  The proteins on the out side of human cells, foreign cells or cancerous cells are not like the ones on the body cells  The part of the protein that is recognized is called an antigen

 The body fights these antigens with a molecule called an antibodies  These molecules are made by cells called B lymphocytes – B stands for bone marrow  Antibodies can combine with and stop antigens from harming the body  They work like a key/lock system; a specific type of antibody disables a specific antigen (marker molecule)

Honors read for understanding and take notes

T Lymphocytes  T stands for thymus where these lympocytes mature in the thymus grand.  Called T cells; they do not produce antibodies but directly attach cells that have antigen marker proteins they recognize  Will be important when we discuss HIV

Go to Antibodiy-