Question

Explain the pathophysiology of the 3 lines of defense.

Answer 1

The three lines of defense:

1) Barriers at body surfaces:

- Skin layers chemicals in saliva, tears, mucous, etc.
bacteria we have keeps harmful ones out.

2) Innate immunity/ non-specific:

- built in automatic when 1st fails
- inflammation and swelling:

• mechanism body uses to fight infection
• increases blood flow
• brings white blood cells which squeeze through and flush out pathogens
• accompanied by fever:Full body inflammation; short time OK invading bacteria can't survive as well in heat- fights pathogens.Prevents bacteria from growing and multiplying; when low growth rate there is time for body to fight it. Dangerous for too long: good cells die, enzyme looses form and function= unable to rebuild molecule.

- compliment proteins:

• Go after bacteria and pierce wall= they leak and die
• circulate in blood and tissue fluid
• inactive till contact with pathogen.

- organs- lymph nodes, spleen, tonsils:

Lymph System

- consists of lymph nodes, lymph vessels, and other organs and tissues that collect and filter tissue fluid.
- return tissue fluid lost from capillaries to the blood, transport fats, and carry debris and foreign material to lymph nodes.
- have roles in defense: lump on head- swelling in side of neck because that's where closest lymph nodes are.

General response; inborn general defenses against infection

3) Adaptive immunity/ specific:

- high alert
- some memory some effector-

Immune system learned type of antibodies necessary

• stored information in memory T/B cells
• go back to hangout with information waiting for another call, this time knows how to control and fight it
• T cells recognize and immediately release necessary chemicals so you don't get sick again
• some memories last longer than others.

- effector T cells:

• Causes white blood cells to divide and multiply
• send out chemicals in lymph nodes to release more white blood cells= greater army
• raise alarm

- effector B cells:

• secrete antibodies
• makes antibodies of specific type to attach to bacteria, yeast, fungi, etc.
• takes time- immune system has to figure it out.