BIOL 251 Chapter 17 Study points

Why is immunology important to study?

It helps understand body defenses, disease, autoimmune disorders, vaccines, and diagnostic tools.

first line of defense

• Innate

• Non-specific barriers

• skin

• mucous membranes

second line of defense

• Adaptive

• specific immune response

• develop over time with antigen exposure

How do innate and adaptive immunity differ?

Innate is non-specific and immediate; adaptive is specific and develops memory.

physical barriers

• skin

• mucous membranes

• blood-brain barrier

chemical defenses

• Lysozyme

• lactoferrin

• defensins

• cytokines

• antimicrobial peptides

mechanical defenses

• Mucocilliary escalator

• peristalsis

• urine flow

• skin shedding

the three categories of immune system cells

• Granulocytes

• mononuclear phagocytes

• lymphocytes

neutrophils

Phagocytosis and destruction of bacteria.

PAMP

Pathogen-associated molecular pattern, like LPS or peptidoglycan, recognized by immune cells.

PRR

Pattern recognition receptor on immune cells that detects PAMPs.

cytokines

Signaling proteins that regulate immune cell communication and responses.

Type I interferons

They block viral replication and promote apoptosis in infected cells.

complement activation pathways

• Alternative

• lectin

• classical

What are the outcomes of complement activation

Opsonization, inflammation, and cytolysis via membrane attack complex (MAC).

C3b

Acts as an opsonin to enhance phagocytosis.

C5a

Attracts immune cells (chemotaxis) and promotes inflammation.

C5b-C9

Lyses pathogens by forming pores in their membranes.

steps of phagocytosis

• Chemotaxis,

• recognition/attachment

• engulfment

• digestion

• exocytosis.

inflammation

Tissue damage or infection, activating immune responses for repair and pathogen removal.

signs of inflammation

• Redness

• swelling

• heat

• pain

• loss of function.

acute inflammation

short-term

chronic inflammation

long-term and may form granulomas.

fever

Inhibits pathogen growth and enhances immune functions like interferon production.