Human Immune System

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Human Immune System

• How our cells work to fight disease.

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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

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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

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Organs of the system

• Spleen
• Blood is cleaned by macrophages and lymphocytes
• Lymph nodes
• Placed along lymphatic vessels
• Tonsils, adenoids
• Inguinal and AXILLARY nodes

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Diseases of the lymph nodes

• Lymphadenitis
• Lymphagitis
• Elephantiasis
• Pulmonary edema
• Lymphoma
• Hodgkins disease

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Thymus

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

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Bone Marrow

• Creates blood cells red and white
• White cells are necessary for the development of
  immunity
• Neutrophils
• Eosinophils
• Basophil
• Lymphocytes
• Monocytes

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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."

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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

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• 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 doesnt know
  what its fighting, just knows that it is not
  self

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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

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• 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

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• 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 action

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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 bodys scavengers
• They also cause the body to greatly increase
  production of leukocytes specifically
  neutrophils
• Pus is dead tissue, cells, bacteria and living wbc

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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.

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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)

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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

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• 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)

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Honors read for understanding and take notes
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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

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Go to Antibodiy-
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