Immune/Lymphatic System

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Immune/Lymphatic System
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I. Brief history of disease

• A. Disease any change, other than injury, that
  disrupts the normal functions of the body.
• 1. Inherited
• 2. Environmental
• 3. Infectious agents (pathogens- sickness maker)

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B. Spread the Fight Against

• 1. Fight a disease by avoiding it?
• 2. Understand disease so you are better able to
  prevent it.
• 3. Remove vectors organisms that carry disease
  causing agents.
• a. Ex mosquito spray insecticides
• 4. New Drug Treatments Antibiotics-work by
  killing bacteria BUT not the host cells.

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• C. For thousands of years people did not know
  what caused illness
• 1. Curses, evil spirits, etc
• 2. Mid 19th century Louis Pasteur Robert Koch
  concluded that disease was caused by
  microorganisms or germs called Germ Theory of
  Disease

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II. Body Defenses

• A. The body is constantly in contact with
  bacteria, fungi, and viruses
• B. Because of our two defense systems
• 1. Nonspecific defense system
• 2. Specific defense system

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C. Nonspecific Body Defenses

• 1. 1st line of defense
• a. Intact skin production of sweat, body oils
  Mucous
• b. Chemicals produced by the body (very low pH in
  the stomach, slightly lower pH in urine and
  female reproductive tract.)

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• 2. 2nd line of defense
• a. Defensive Cells- cells that roam the body
  engulfing (phagocytosis) intruder cells
• Neutrophils
• Phagocytes-gt macrophages
• b. Natural Killer Cells
• i. can recognize invader cells based on chemicals
  on cell membrane (cancer and viral cells) before
  specific defense kicks in.
• Use perforin, not phagocytosis

Figure 12.7a
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• c. Inflammatory Response
• i. Triggered when body tissues are injured
• ii. Produces 4 cardinal signs
• Redness
• Heat
• Swelling
• Pain
• iii. chain of events which lead to protection and
  healing

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Steps in the Inflammatory Response

• histamine
• Allow Blood vessels to dilate, become more
  permeable allow more Defense cells to the wound
  area
• 3 parts of the inflammation responses?
• 1. Blood Vessels dilate
• heat
• 2. leaky capillaries
• Pain Swelling (aka edema)
• 3. NEUTROPHILS ENTER BLOOD FROM BONE MARROW AND
  GO TOWARDS CHEMICAL SCENT
• SQUEEZE THROUGH THE CAPILLARY WALL (DIAPEDESIS)
• NEUTROPHILS GATHER AT SPOT OF TISSUE INJURY. EAT
  FOREIGN MATERIALS
• PHAGOCYTES COME LATER- turn into MACROPHAGES
  (eating machines)
• Pus indicates a possible problem.

Figure 12.8
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Complement proteins

• ENHANCE THE INNATE DEFENSES EITHER BY
• ATTACKING MICROORGANISMS
• OR HINDER THEIR ABILITY TO REPRODUCE.
• COMPLEMENT FLOAT AROUND INNATE UNTIL ACTIVATED BY
  FOREIGN MATERIAL THROUGH COMPLEMENT FIXATION
  (THEY ATTACH TO MATERIAL).
• ALSO ACTIVATE INFLAMMATION.
• Interferon. CHEMICAL RELEASED BY INFECTED CELLS
  TO TELL HEALTHY CELLS INCREASE DEFENSE
  PROTEINS.

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Fever

• Caused by pyrogens activating the hypothalamus.
• ? Allows the liver and spleen to pull in iron
  zinc, taking it away form invaders use.
• ? Increases metabolism.
• ? if too high it can be detrimentaldenatures
  proteins and can kill you if too high.

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Understanding Specific Immune

• 1800s scientists determined
• Antigen specific- acts against particular
  pathogens/foreign substances
• Systemic- full body not just sight of initial
  infection
• Memory- amounts a stronger attack upon 2nd
  exposure

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Specific defense system

• Humoral-makes the antibodies (memory)
• Cellular immunity- lymphocytes (white blood
  cells) defend directly with lysing or indirect
  with chemicals
• a. A.K.A. immune system

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Types of Immunity

• 1. Antibody-mediated immunity (HUMMORAL)
• a. Cells (lymphocytes) produce chemicals
  (anti-bodies) to mark antigens for disposal.
• 2. Cell-mediated immunity
• a. Cells target virus infected cells directly

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Antigens (Nonself)

• 1. Any substance capable of activating the immune
  system and provoking an immune response
• 2. Examples of common antigens
• a. Foreign proteins
• b. Pollen grains
• c. Microorganisms

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Self-Antigens

• 1. Our cells have many surface proteins thus our
  system can recognize itself
• 2. Our immune cells typically do not attack our
  own cells (If it did that would be a homeostatic
  imbalance!)
• 3. BUT each persons surface proteins are unique
  so, our cells in another persons body can
  trigger an immune response because they are
  foreign
• a. Restricts donors for transplants
• b. Can cause miscarriage

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Cells of the Immune System

• 1. Lymphocytes
• a. from stem cells in the red bone marrow
• b. B lymphocytes create antibodies memory cells
  (hummoral)
• c. T lymphocytes specialized in the thymus gland
  (cell Mediated)
• 2. Macrophages (cell mediated)
• a. Large cells that eat other invader cells
• b. Become widely distributed in lymphoid organs

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Immunocompetance

• All of your immune cells need to mature before
  they can do their job. Being immunocompetant
  means that the immune cell is able to bind to its
  specific antigen.
• B cells in bone marrow
• T cells in thymus
• 1 receptor for 1 antigen so each immune cell is
  immunocompetent is for 1 specific antigen!

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Self-Tolerance

• The immune system need to be trained to go after
  antigens and avoid self cells.
• T cells go through this in the thymus.
• The T cells with the best ability to identify
  antigens survive.
• T cells that strongly identify with SELF antigens
  are destroyed!
• B cells go through this in the bone marrow but
  little is known about that
• Autoimmune diseases are an issue with this
  process

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• Your GENES determine what specific foreign
  substances our immune system will be able to
  recognize and resist.
• Ebola is new to our immune system so it does
  not have a receptor for it in our bodies.

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antigen-presenting cells

• Engulf antigens and present fragments of them on
  the outside of their cell. So they can activate T
  cells.
• A big part of activating the immune system
• Dendritic cells
• Macrophages- stay in the lymph nodes
• B lymphocytes

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Antibody-Mediated Immune Response (HUMMORAL)

• 1. B lymphocytes with specific receptors bind to
  a specific antigen
• 2. activates the lymphocyte to clone itself
• A large number of clones are produced with same
  receptor.
• 3. most clones become plasma cells
• Make antibodies at 2000 per minute!!!

Other B cells become Memory cells
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Secondary Response to an invader

• 1. Memory cells are long-lived
• 2. A second exposure causes a rapid response
• 3. The secondary response is stronger (w/i hours)
  and longer lasting (weeks to months)
• Gives you life-long immunity

Figure 12.13
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Immunity

• 1. Active
• a. Your B cells actively encountered antigens and
  produce antibodies
• b. usually life-long immunity
• 2. Passive
• a. Antibodies are obtained from other source.
• b. B cell memory does not occur because your body
  did not create the antibodies

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Antibodies (Immunoglobulins)

• 1. proteins secreted by cloned plasma cells
• 2. Carried in blood
• 3. Bind to specific antigens to inactivate them

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Cell-Mediated Immune Response

• 1. Antigen presenting cells directly attack
  invaders.
• 2. eat invaders displayed bits of antigen on
  surface.
• APC Essential in activating T cells!
• 3. Helper T ( the managers)cells bind to these
  macrophages antigens and release cytokines
  (attract more lymphocytes)

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T cell activation and interactions with other
cells of the immune response.
Antigen
Presented antigen
Cell-mediated immunity (attack on infected cells)
Cytotoxic (killer) T cell
T cell antigen receptor
Helper T cell
Dendritic cell
Cytokines
Humoral immunity (secretion of antibodies
by plasma cells)
Self- protein
Antigen processing
B cell
Cytokines
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• 4. Cytokines attract Killer T, B cells other
  phagocytic WBC.
• A. B cells are activated by Helper T cells.
• B. Killer T Cells (cytotoxic T) are very
  effective in killing. Because they actively seek
  out the specific invader.
• a. Killer T makes organ transplant difficult?

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Other T Cells

• 1. Regulatory T cells
• a. Once the invader has been removed chemicals
  are released to suppress the activity of T and B
  cells
• b. Stop the immune response to prevent
  uncontrolled activity ?
• 2. Memory T
• Again, respond quickly to later invasions.

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Figure 12.19 A summary of the adaptive immune
responses.
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• Immune game log onto a desktop and go to the HW
  website for the link. Play the game reading all
  of the information as you go? Take notes on any
  NEW information
• http//biomanbio.com/GamesandLabs/Physiogames/conf
  lictimmunity.html
• If there is time well watch the flu video.
• HW wp 4 review worksheets

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Transplant

• 4 types of grafts
• Auto- self to self, like a skin graft for a burn.
• Iso- twin to self grafts, this would be bestbut
  if doesnt exist
• Allo- other person to self, family member
  possible or donor list. This is the most common
  transplant from a donor who has recently died.
• Xeno- animal to self, mostly pig heart valves

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Allograft Success

• Check ABO, other blood group antigens and
  membrane antigens.
• minimal 75 match of above
• Difficult to find
• Immunosuppressive therapy
• Reduce rejection
• Drugs and therapy kill rapidly dividing cells
  like WBC
• All have severe side effects
• Biggest issue is body not protected from
  infection as well
• 50 rejection of organ by 10 years?
• New look at teaching the body tolerance vs
  current drugs.

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Disorders of Immunity

• Autoimmune Diseases T cells attack its own
  tissues
• Example Juvenile diabetes destroys pancreatic
  beta cells that produce insulin
• Self-Tolerance Breakdown?
• New self antigens appear
• hidden in sperm, eye lens, thyroid
• New mutations that change the structure of
  self-proteins
• Bacterial or viral damage
• Foreign antigens look like self
• Antibodies produced during rheumatic fever
  cross-react with heart antigens causing damage to
  the heart muscle, valves, joints and kidneys.

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Allergies (Hypersensitivity) a. Abnormal,
vigorous immune responses
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hypersensitivity

• Immediate/Acute
• Triggered by histamine from mast cells (a type of
  WBC)
• Anaphylactic shock
• Rare!
• Allergen directly enters the blood and circulates
  rapidly or some foods (peanuts)
• Same as regular allergy attack but whole body
  involved.
• Delayed
• Takes 1-3 days
• Cytokines cause
• Ex poison ivy, heavy metals, cosmetics,
  deodorants

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Immunodeficencies

• Severe combined immunodificiencie disease (SCID)
  have all or some of their immune system missing

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AIDS

• Acquired Immune Deficiency Syndrome
• Caused by HIV (Human Immuno Deficiency Virus)
• Virus attacks helper T.
• People die of other infections.
• NEWS 2015 HIV has been reclassified as a chronic
  life long illness vs. a death sentence.

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Unique

• Incurable but treatable.
• Before the development of anti-virals it had
• high mortality
• quickly spread
• no vaccine.
• This combination was RARE in this technological
  age.
• Spread through intimate contact w/ an infected
  person
• THIS is a limiting factor!
• UNFORTUNATLY a person can carry and transmit HIV
  for years before symptoms arise

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How its contracted

• Unprotected sex (of any kind) is the most common.
  You can also be exposed
• Sharing needles
• Blood transfusion (rare if blood is tested)
• Mother/baby
• Breastfeeding

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Not transmitted through

• Sweat, saliva, tears
• Insects
• Environment HIV is fragile and dies quickly
  outside of the body.
• Same toilet use
• Touching, hugging, hand shaking
• Sitting next to or where someone has been sitting

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Life Cycle

• HIV attacks the helper T cell which reduces the
  number of helper T (hT) cells until the person
  has AIDS
• Usual amount 1million hT cells in 1 ml pf blood
• AIDS gt 200,000 hT cells per 1 ml blood
• Takes 2-15 years
• HIV is really good at mutating
• No one dies from HIV/AIDS
• They die from infections that their body can no
  longer fight off. Can be the common cold to a
  minor infection.

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Lymphatic System Anatomy

• Consists of two semi-independent parts
• Lymphatic vessels
• Lymphoid tissues and organs
• Lymphatic system functions
• Transport fluids back to the blood
• Play essential roles in body defense and
  resistance to disease

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Organs of the Immune System

• outside
• Skin-
• Mucose Membranes-

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Inside

• Lymph System
• When the Dr. checks your neck they are feeling
  for swollen lymph nodes.
• Lymph system follows the pattern of the
  circulatory system BUT it is not pressurized, it
  is passive.
• Fluid diffuses into the lymph system and is
  pushed by normal body and muscle motion to the
  nodes.

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Lymph Fluid?

• Clear fluid that bathes the cells in nutrients.
• interstitial fluid blood plasma are similar
• Also carries away waste and proteins and random
  bacteria through the lymph vessels to the lymph
  Nodes.

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Lymphatic Vessels
Figure 12.2
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Lymph Nodes

• Filter lymph before it is returned to the blood
• Defense cells within lymph nodes
• Macrophages present to B T cells here
• These nodes swell during some infections due to
  filtration (full of dead invaders and defense
  cells)

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Lymph Node Structure
Most are kidney-shaped, less than 1 inch long
Figure 12.4
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Other Lymphoid Organs

• Several other organs contribute to lymphatic
  function
• Spleen
• Thymus
• Tonsils
• Peyers patches

Figure 12.5
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The Spleen

• Filters blood Destroys worn out blood cells
• Forms blood cells in the fetus
• An adult can live w/o the spleen, but youll be
  sick more often

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The Thymus

• Located low in the throat, overlying the heart
• Functions at peak levels only during childhood to
  produce/mature t-cells.

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Tonsils

• Small masses of lymphoid tissue around the back
  of the throat
• Trap/remove bacteria and other foreign materials
  give immune system a heads up.
• Tonsillitis is caused by congestion with bacteria
• They are no longer removed because we now
  understand their purpose is to become infected
  (rather than the whole person)

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Peyers Patches

• Found in the wall of the small intestine
• Resemble tonsils in structure
• Capture and destroy bacteria in the intestine
  (same idea as tonsils)
• Appendix?