CH. 16 Flashcards
Resistance
Ability of the immune system to ward off disease.
Susceptibility
Lack of resistance
Nonspecific Defenses
defense that protects against any pathogen, are the first line of defense.
Specific Defenses
based on the actions of specialized cells in the body and the production of antibodies.
- Skin
A. external layers are made of stratified squamous which serve as a physical barrier when not compromised.
B. langerhans cells in the epidermis assist T cells in the identification of foreign antigens.
- Mucous Membrane
A. Line of the GI, respiratory and urogenital tracts.
B. produce mucous which may trap foreign particles.
C. May be lined with cilia that facilitate filtration.
- Lacrimal Apparatus
A. Produce tears that cleanse and rinse the eye
B. tears dilute irritants in the eye.
- Saliva
wash the surface of the teeth and gums to prevent colonization of microbes.
- Urine
cleans the urethra.
- Vaginal Secretions
discharge organisms from the female reproductive tract.
- Sebum
contains fatty acids that maintain the pH of the skin at a range of 3-5 which helps to inhibit microbial growth.
- Perspiration
rinses microbes from the surface of the skin.
- Lysozyme
A. enzyme found in tears, saliva, nasal secretions and tissue fluids.
B. breaks down the cell walls of G+ and a few G- bacteria.
- Gastric Juice
A. HCI which maintains a pH range of 1.2-3 in the stomach
B. Heliobacter pylori neutralizes the acid and will colonize in the stomach causing ulcers.
- Transferrin
A. Used by the body to transport Fe from broken down RBCs
B. Because Fe is bound to this enzyme in the body, it is unavailable to use by bacteria
- Phagocytosis
A. performed by cell called phagocytosis which develop from WBCs
B. Macrophages - one type of phagocyte
1. Fixed - located in the liver, spleen, bone marrow, lungs, lymph nodes
2. wandering - travel to the site of infection, stimulated by chemotaxis
- Inflammation
A. Characterized by 4 signs - Redness, Pain, Heat, and Swelling.
B. Functions are to destroy the infecting agent, confining the organism to an area, to repair damaged areas.
- Fever
A. abnormally high body temp as a result of an infection
B. Stimulated by the hypothalamus after detecting Interleukin 1 from phagocytes.
- Complement
A. a series of 20 proteins in the blood
B. Each of the 20 has a specific function which helps to increase the response time o the body’s defense.
C. may stimulate cytolysis, inflammation or opsonization (coating a pathogen to allow phagocytes to adhere easier.
- Interferon (IFN)
produced by viral infected body cells, when released it stimulates neighboring body cells to create anti-viral proteins which will prevent viral replication.
