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 short animation of phagocytosis in act

ion

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.

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-