Lymph and Immune Part 2

What is mechanical protection? (FIRST LINE OF DEFENSE)

Includes the intact epidermis layer of the skin, mucous, the lacrimal apparatus, saliva, mucus, cilia, the epiglottis, and the flow of urine. Defecation and vomiting too

Where is chemical protection localized?

In skin, in loose connective tissue, stomach, and vagina

What does the skin produce?

Produces sebum, which has a low pH due to the presence of unsaturated fatty acids and and lactic acid

What is lysozyme

An enzyme component of sweat that also has antimicrobial properties

What does gastric juice do?

Renders the stomach nearly sterile because its low pH kills many bacteria and destroys most of their toxins; vaginal secretions are slightly acidic

What does the second line of defense involve?

Involves internal antimicrobial proteins, phagocytic and natural killer cells, inflammation, and fever

What are interferons?

Proteins produced by infected lymphocyte and macrophages with viruses

• Once infected, IFNS diffuses to uninfected neighboring cells and binds to surface receptors, inducing uninfected cells to synthesize antiviral proteins that interfere with or inhibit viral replication

• BASICALLY, act as a signaling molecule to boost immune system in fighting viral infections

What comprises the complement system?

• A group of 20 protein present in blood plasma and on cell membranes

What happens when the complement system is activated?

These protein “complement” or enhance certain immune, allergic, and inflammatory reactions

What does iron-binding proteins remove?

Remove iron from the body fluids thereby inhibiting microbial growth

What are natural killer (NK) cells?

Lymphocytes that lack the membrane molecules that identify T and B cells

• Have ability to kill wide range of infectious microbes

What do NKs sometimes release?

Perforins that insert into the plasma membrane of a microbe and make the membrane leaky so that cytolysis occurs

What do phagocytes do?

Cells specialized to perform phagycytosis and includes neutrophils and macrophages

What are the three stages of phagocytosis?

1. Chemotaxis

2. Adherence

3. Ingestion

What happened after a phagocytosis completes?

A phagolysome is formed and quickly kills microbes

When does inflammation occurs?

Occurs when cells are damaged by microbes, physical agents, or chemical agents.

What are the symptoms of inflammation?

Redness, pain, heat, and swelling

• Loss of function maybe included depending on the injury

What are the three basic stages of inflammation

1) vasodilation and increased permeability of blood vessels

2) phagocyte migration

3)Tissue repair

What are substances that contribute to inflammation?

Histamines, kinins, prostaglandins, leukotrienes, and complement

What happened after phagocyte engulfs damaged tissues and microbes

They die, forming a pocket of dead phagocytes and damaged tissues and fluid called pus.

How are fevers caused?

By infection from bacteria and viruses.

• High body temp inhibits some microbial growth and speeds up body reactions