ANATOMY AND PHYSIOLOGY LECTURE NOTES

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ANATOMY AND PHYSIOLOGY LECTURE NOTES
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IMMUNITY
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MECHANISMS OF NON SPECIFIC IMMUNITY

• SPECIES RESISTANCE
• species specific antigens found on the surface of
  all cells
• strongest reaction
• the greater the evolutionary distance between the
  greater the rejection mechanism are

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MECHANICAL AND CHEMICAL BARRIERS

• FIRST LINE OF DEFENSE
• healthy and intake skin epidermis
• healthy and intake mucous membranes
• mucous cilia-traps microorganisms

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Lines of Defense
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CHEMICAL BARRIERS

• enzymes --lysozyme found in tears and saliva
• sebum contains chemicals which are toxic to
  bacteria

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NON SPECIFIC IMMUNITY, cont.

• acid- base balance
• skin pH3-pH 5 kills many pathogens
• HCl acid in the stomach kills some pathogens
• vagina is very acidic

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Macrophages
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Phagocytosis
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Second line of defense- INFLAMMATION

• Cardinal signs of Inflammation
• heat - local vasodilation of arterioles
• redness- local vasodilation of arterioles
• swelling- increased permeability of capillaries
• pain- free nerve endings pressed due to
  swelling

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INFLAMMATION RESPONSE

• tissue injury
• vasodilation of arterioles
• increased capillary permeability
• chemotaxis - WBC are attracted to area
• migration of phagocytic cells to the area
• phagocytosis occurs -pus may form
• healing occurs

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NON SPECIFIC IMMUNITY

• Inflammation mediators
• histamine
• kinins (bradykinin)
• prostaglandins
• complement
• lymphokines

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NON SPECIFIC IMMUNITY

• PHAGOCYTES
• Neutrophils
• macrophages
• Kupffer cells in liver
• alveolar macrophages - lungs
• Mast cells

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NON SPECIFIC IMMUNITY

• PHAGOCYTOSIS
• phagosome
• fusion with lysosome to form phagolysosome

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NATURAL KILLER CELLS

• NK cells are lymphocytes
• nonspecific
• release cytolytic chemicals
• antimicrobial proteins
• interferon
• antiviral
• not virus specific

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antimicrobial proteins

• interferon (glycoprotein)
• antiviral
• not virus specific
• complement (group of plasma proteins)
• lysis microorganism
• enhances phagocytosis

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fever- systemic response to pathogens

• pyrogens- endogenous
• pyrogens- exogenous

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SPECIFIC IMMUNITY

• SPECIFIC IMMUNITY
• is antigen specific
• is systemic
• it has memory
• implies protection from normal levels of
  pathogens

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origin of B and T lymphocytes

• stems cells originate in bone marrow
• pre T lymphocytes migrate to the thymus where
  they mature into T cells
• pre B lymphocytes migrate to gut associated
  lymphatic tissue (G.A.L.T.) where they mature
  into B cells

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definitions

• Antigens - are large (10,000 daltons) substances
  
• which induces the immune response.
• Antigens - surfaces of pathogens
• Antigens are non-self.
• MHC proteins

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definitions

• Antibodies
• gamma globulin's made in response to antigens
• many antibodies can be made against a single
  pathogen
• antibodies kill specific pathogens

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cells of the immune system

• lymphocytes-T cells B cells
• macrophages- antigen internalization
• antigen adheres to macrophage
• engulfment of antigen occurs
• phagolysosome forms
• processed antigen presented through cell surface
  membrane
• indigestible and toxic material exocytosis

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cell mediated immunity

• T cells
• sensitized (activated) T cells
• T killer cells (Cytotoxic T cells)
• release lymphokines
• helper T cell
• present antigen to B cells

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T cells
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T cells
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cell mediated immunity, cont.

• suppressor T cell
• turn off B cell response
• memory cell
• maintains immunity

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Cell mediated immunity

• sensitized T cells are specific
• for example T cells sensitized to TB antigens
  cause skin reaction in the TB skin test

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lymphokines (cytokines)

• produced by sensitized T cells
• chemotactic factor (CF)
• Macrophage activating Factor (MAF)
• Migration inhibition Factor (MIF)
• lymphotoxin (LT)
• lymphotoxins can kill cancer cells

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Lymphokines
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antibody mediated immunity

• types of B cells
• stem cells give rise to inactive B cells
• inactive B cells have membrane receptors
  (antibodies)
• inactive B cells migrated to lymph nodes, liver
  and spleen

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B cells
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antibody mediated immunity

• activation of B cells
• antigen is presented to B cells either by B
  helper cells or macrophages
• activation involves the binding of antigens to
  membrane receptors
• activated B cells transform into plasma cells
• plasma cell- produces specific antibody

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antibody mediated immunity

• B memory cells
• stored in lymph nodes
• upon subsequent exposure rapid response produces
  specific antibodies
• provides long term protection
• immunization must result in the production of B
  memory cells

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INTERACTION OF T AND B CELLS

• role of macrophages
• processes and presents antigen
• T helper cell presents antigen to B cells

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Immunoglobulins

• five classes of immunoglobins
• IgM found in membranes ( receptors)
• IgG found in the plasma
• IgA secreted by mucous membranes
• IgE is involved in allergic reactions
• IgD - membrane receptors found in B cells

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Actions of antibodies

• agglutination of bacteria
• precipitation of viruses
• neutralization of viruses ( killing)
• lysis activation of complement

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Role of complement
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TYPES OF IMMUNITY

• naturally acquired active immunity - had
  disease
• naturally acquired passive immunity- from
  mother
• artificial acquired active immunity-
  immunization
• artificial acquired passive immunity- received
  shot of immune IgG

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ALLERGIC RESPONSES

• immediate reaction -
• abnormal amounts of IgE (Hay fever, asthma)
• delayed hypersensitivity
• contact dermatitis
• poison ivy

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TB skin test

• T cell reaction-
• prior exposure activates T cells
• swelling is due to T cells

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Disease of the Immune system

• AIDS is a immunodeficiency disease.
• Infected cells are the T-4 helper cells.

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HIV infection
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Opportunistic infections

• Pneumocystis carinii (protozoan) infections
• fungal
• viruses (cytomeglovirus, herpes, hepatitis)
• Kaposi's sarcoma (virus)
• tuberculosis (bacteria)

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mechanism of the immunosuppresion

• T helper cells decrease
• T suppressor cells have a relative increase
• increase production of suppressor factors

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auto- immune diseases

• Grave's disease - thyroid
• Rheumatoid arthritis
• Myasthenia gravis
• Lupus
• multiple sclerosis

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Delayed Hypersensitivity disorders

• T cell mediated
• Bee stings, poison ivy, allergies
• involve degranulation of mast cells or other
  histamine containing cells
• membrane receptors- IgE combine with allergens
  (antigens which trigger allergic responses)

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Cytotoxic (killer) T cell and cancer
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