Transcript immune - varmeckygahs

Defending Against Infection
• Immune Surveillance - cells monitor the
body for infection
*These “surveillance cells” ID body cells by
their surface protein markers
Pathogens - disease carriers - have different
protein markers
Pathogens are opposed by 3 lines of
defense
3 lines of defense
1. Epithelial layers
• Skin
*secretes chemicals
*surface is acidic
*lysozyme attacks and digests pathogens
*host to symbiotic bacteria
3 lines of defense
1.epithelial layers, con’t
• Mucus membranes of digestive system,
nasal passages, lungs, reproductive tract
*mucus traps pathogens
*cilia sweeps away mucus(+pathogens)
*smoking destroys cilia
If first line is penetrated . . . . .
3 lines of defense
2. Counterattacks
• Killer cells: macrophages, neutrophils,
natural killer cells
• Killer proteins: create holes in pathogen’s
cell membrane
• Inflammatory response: a blockade that
isolates the damaged area
• Temperature response: fever - inhibits
microbial growth
3 lines of defense
3. Immune System involves 4 kinds of white
blood cells
• killer T cells attack and kill infected cells
• B cells label invaders for destruction
• Helper T activate killer T +B cells
• macrophages consume pathogens and
infected cells
Lymphatic and Immune System
• Consists of cells, vessels, structures,
organs, and a fluid called lymph
• Circulates body fluids and defends
against pathogens
Lymphatic and Immune System
• Interstitial fluid
*fluid between cells and blood vessels,
draining waste
*as this fluid moves into lymphatic vessels
its name changes to lymph
Lymphatic and Immune System
• Lymph
*interstitial fluid that has moved into the
lymphatic vessels where it meets
lymphocytes and travels through nodes
*you produce 3L of lymph per day
Lymphatic and Immune System
• Lymphocytes
*white blood/immune cells
• Vessels
*where lymph travels, similar to veins
*from capillary size to aorta
• Ducts very large vessels to drain very
metabolically active areas, ex. Brain
Lymphatic and Immune System
• 600 Nodes
*little ‘bulbs’ that lymph passes through
*contain many lymphocytes to kill
pathogens and ‘eat up’ worn out cells
*swollen glands are nodes enlarged with
lymphocytes and pathogens during an
infection
Lymphatic and Immune System
nodes con’t
• Tonsils are modified nodes of the throat,
this position allows quick attack on
inhaled or ingested pathogens
Lymphatic and Immune System
Additional parts of the immune system:
• Red marrow produces precurser (baby) blood
cells
• Spleen
*largest mass of lymphatic cells in the body
*maturation, storage, and fighting of pathogens
in blood
• Thymus site of T-cell maturation
Lymphatic and Immune System
• Antigens: foreign invaders that cause an
immune system response
*you have millions of different B cells and
million of different T cells to respond to all the
millions of antigen types you will encounter
*antibodies respond to each antigen as a lock
fits a specific key
Lymphatic and Immune System
Your immune system must recognize the
rest of your body cells as belonging to
you and must be able to distinguish
between dangerous invaders and nondangerous invaders
*dysfunction leads to . . . .
Lymphatic and Immune System
dysfunction
• Allergies: the immune system over-reacts to
non-dangerous invaders
*varies in severity from bothersome to deadly
• Autoimmune diseases: immune system sees
your own cells as dangerous invaders and
destroys them
*Ex. Rheumatoid arthritis, lupus
Attack on the
Lymphatic and Immune System
• HIV virus attacks and destroys the
immune system resulting in AIDS
• AIDS is a collection of diseases that
your immune system, if still intact, would
have fought off
treasure your
immune system