Download Chapter 11 Immune

Ch 11: Immune System
Notes
Immune System - network of cells, tissues, and organs that work together to protect the
body against foreign “invaders”
*In order to do this, the body must be able to recognize foreign substances.
ANTIGENS AND IMMUNITY
*Define the term antigen and explain it’s significance in immunity
Antigens - any foreign molecule capable of stimulating an immune response
- Large complex molecules (small ones won’t elicit an immune response)
- not naturally occurring within the body (keeps the immune system from attacking itself)
Collections of lymph tissue distributed throughout the body detect antigens.
Lymphatic vessels (similar to blood vessels) carry lymph fluid back to the bloodstream.
Lymph - fluid that is created from interstitial cell fluid to nourish cells; is not reabsorbed
into the bloodstream
- travels passively; activity by the animal helps keep it moving
- stocking up - build up of fluid in the legs (horses) due to lack of activity
ORGANS & SYSTEMS OF IMMUNE SYSTEM
1. Lymph system
a. Tonsils - located at back of pharynx to trap invading organisms
b. Lacteals in intestinal villi - absorb lipids from intestinal tract
c. lymph nodes - collections of lymph tissue spread throughout body (figure 11-3)
i. mandibular - under lower jaw
ii. cervical - near clavicle
iii. axillary - behind elbow
iv. inguinal - groin area
v. popliteal - caudal to stifle
2. Spleen - large organ located within the abdomen;
a. filters blood;
b. contains immune cells to scan for antigens;
c. produce antibodies
d. removes aged red blood cells from circulation
e. reserve for red blood cells
3. Bone marrow - produces white blood cells (functional cells of immune system)
a. wbc’s phagocytize (eat) antigens
i. neutrophils & macrophages
Response of immune system to infection/illness:
• Elevated body temperature (fever) - hinders replication of infectious organisms or kills
them
• Inflammation - serves to deliver more white blood cells and antibodies to the area
• Edema (swelling) - increased blood flow to area causes more fluid to enter tissues
Antibody - large proteins made by the immune system designed to recognize antigens
- production occurs primarily in lymph nodes; also in spleen and bone marrow
Humoral Immunity - production of antibodies in response to an antigen
IMMUNITY AND IMMUNE RESPONSE
Distinguish between passive/active immunity, humoral/cellular immunity.
Explain primary and secondary immune response.
How does the immune response happen?
1. Animal is exposed to antigen.
2. Primary response triggers the recognition of antibody by lymphocytes.
3. 3-14 days are required to generate enough antibody.
4. Memory cells are produced; don’t produce as much antibody, but respond more
quickly to the same antigen.
5. Secondary response is triggered.
6. This prevents an animal from developing the infectious disease a second time.
Can come from natural infection or vaccination.
Vaccine - small amount of pathogenic organism designed to elicit an immune response
• Modified Live Vaccines - weak strains that are able to divide
• Killed Vaccines - pathogen is dead and unable to divide; booster is required
Immunity - having defenses against pathogens
• Active Immunity - results from vaccines or exposure to natural infections; long term
• Passive Immunity - antibodies are transferred from one animal to another; short term
• Colostrum - antibody-rich milk that is produced during pregnancy
• Humoral immunity (see above)
• Cell mediated immunity - T-cells produced in bone marrow and mature in thymus;
once mature are released into lymph tissues. T-cells are specific to antigens.
Humoral and cell mediate immunity work together.
CLINICAL PRACTICE
1. Vaccines come in injectable and intranasal form.
a. Kennel Cough = IN vaccine (respiratory)
2. Pruritis - severe itchiness
a. Often an immune reaction (spring pollens)
3. Anaphylaxis - severe and life threatening allergic reaction
a. Bronchoconstriction to the point of suffocation
b. Treated with epinephrine
4. Titer - measure of antibody levels in the bloodstream
a. Preferred to vaccinations.
5. ELISA test - (enzme-linked immunosorbent assay) - measures either antigens or
antibodies in the blood
a. Heartworm tests are examples of ELISA tests; measures antibodies present if
heartworm is detected